South Australia Vs. Too Much Home Solar

Once upon a time, the consensus was that renewable energy was too expensive and in too sparse supply to be a viable power source to run our proud, electrified societies on. Since then, prices of solar panels have tanked, becoming more efficient along the way, and homeowners have been installing them on their rooftops in droves.

Where once it was thought we’d never have enough solar energy, in some cities, it’s becoming all too much. In South Australia, where solar output can be huge on a sunny day, electricity authorities are facing problems with grid stability, and are taking measures to limit solar output to the grid.

Isn’t More Usually Better?

The problem faced by South Australian utilities is one of how to properly control an electrical grid with many thousands of distributed power sources. Typically, in conventional modern power grids, voltage and frequency is controlled within set limits by carefully matching the supply from major power plants with the demand from users. Fast-response plants can be brought online to meet shortfalls, and switched off when demand drops, and everything hums along nicely.

Unfortunately, solar power isn’t so easy to throttle, and even less so when it’s coming from thousands of separate households each with their own rooftop install and an inverter to feed back into the grid. This has led to authorities contemplating measures such as charging homeowners to export energy to the grid in peak periods in an effort to slow the huge uptake of home solar systems. Export limits have also been proposed for suburbs with the highest concentration of home solar, as substations in certain residential areas struggle to cope under the huge inflows of energy.

Wayne National Forest Solar Panel Construction by Wayne National Forest, CC BY 2.0

With 280,000 homes in South Australia equipped with rooftop solar, or 35% of the state’s housing stock, it essentially creates a huge power plant that authorities have little to no control over. In some situations, South Australia’s energy needs have been 100% met by solar power alone, with gas, wind and other generation resources then exporting their energy to interstate markets. Things can quickly become dangerous in situations where there is nowhere to export the excess energy, however. In a recent incident, interstate links were down for routine maintenance on a day of particularly high solar delivery. The electricity regulator made the decision to shut down 12,000 home solar systems via a newly-granted power in order to keep grid demand above 400 MW, a level high enough that major gas plants could stay online.

This was achieved through relatively crude means, but if left unchecked, voltages would have risen high enough that home solar inverters would suddenly flick off en masse, leading to a sudden drop in supply and widespread blackouts. The same can happen in the case of short-term voltage dips. If a major generator goes offline and the grid voltage drops below set levels, thousands of home inverters can trip off suddenly in response, exacerbating the problem and causing blackouts.

Major blackout where large chunks of the grid goes offline at once are hard to come back from; black starts are stressful and expensive and avoided at all costs. Authorities are therefore taking measures to limit the chance of these problems in future. New installations are mandated to have inverters that come with voltage ride-through protection, allowing them to keep operating through voltage perturbations to avoid sudden shocks to the grid. Additionally, inverters that can be remotely commanded by the electrical authority are required, controlled over the Internet or via 4G data links. Substations are also being upgraded with improved voltage management hardware, to allow suburbs with high penetration of rooftop solar to better export their energy to the wider grid.

Other measures can help, too. Grid storage batteries like the Hornsdale Power Reserve can help, by storing excess energy when available for later use when the solar demand is lower. Home batteries could become an excellent solution in these cases as well, allowing homeowners to make the most of their solar panel output even when the grid has had enough. These measures aren’t cheap at the moment, and home battery penetration is a fraction of that of solar, but government subsidies are in place to boost uptake.

Home storage is best implemented in concert with grid control measures however, rather than alone, else thousands of home battery systems going offline at the same time could present the same risk as home solar currently does. Additionally, it’s not a panacea on its own – a long, bright week in summer could saturate home battery resources.

Such measures weren’t necessary when home solar first hit the market. The small number of homeowners with the hardware didn’t have enough generation capacity to sway the grid one way or the other. However, since the number of home generators has taken off, it’s become necessary to implement a way to command this huge resource. By implementing controls on home solar generators, it allows the electrical authority to make the most of the generation capacity, without placing the grid at risk of blackouts due to over- or undervoltage events. Having huge amounts of solar power is a great victory for renewable energy in the fight against climate change. However, investment will be required for the electrical grid to keep up if this new technology is going to be exploited to the fullest. If home solar generators are going to provide Australia with electricity, they’re going to have to work together.

205 thoughts on “South Australia Vs. Too Much Home Solar

        1. Who say’s ithas to be fresh water? On the SA coast, near to current wind farms, we have lots of cliffs. Create a salt water pond at the top of these are there’s your pumped hydro solution.

          1. Not so much. The salt will corrode the pumps and other equipment. It will also leach into the ground water, killing everything it touches.

        2. Whereas USA has something like 150 times as many potential pumped hydro sites as needed for all its electricity network storage needs, Australia has something closer to ten times. We just need to build HV power lines to them, build the pumps/generators … and fill ’em with water. ;-)

          “Snowy 2.0” is a multi billion dollar project to retrofit the Snowy River Hydroelectric Scheme with pumped hydro capability, so a start has been made. It’s just that long tunnels through mountains take longer than saying “I can burrow through an elephant”.

          There is talk here of charging domestic PV generators a fee for grid feed-in, ostensibly to pay for network upgrades to manage overvoltage and modified energy flow. That’s great for network operators – they don’t have to invest in making their outdated networks fit for purpose. Our government does all it can to delay the demise of coal, despite renewables being cheaper as well as more survivable. Our prime minister “Slow-Mo Morrison” once held up a lump of coal in parliament to sing its praises.

          Mind you, with the millions of homes with solar, the electricity providers do at some point become fed up with increasing numbers of them having negative electricity bills, i.e. the electricity company has to pay them. Thus the fees, I guess.

      1. This is an actual good solution. Easily scalable, sets a nice cut off curve which is individualised.

        I.e. people will switch from solar to mining Bitcoin at different thresholds.

        1. We’ll need the hydrogen for steel production at the least, it’s pretty much all from natural gas right now. Also will need it for making ammonia for fertilizer, which is also petrochemical sourced. Even if we don’t use any of it for fuel, it would still get used.

        1. Australia copper or alumina refining can use all the “extra” energy anyone could ever generate. As a bonus, the lack of conversion losses could cut conventional fossil fuel use, and reduce the long-term CO2 cycle emissions.

          Desalination costs were a major issue in Singapore at one time too, but the waste refinery energy eventually turned it into an exporter of fresh water. As other posters noted, even the highest quality reverse osmosis water purification plants use a surprisingly large amount of energy.

          I wish we had Australia’s temporary over supply problem domestically… ;-)
          Like most problems in the world it is likely _not_ a technical engineering problem, but rather a political, fiscal, and or social one. If a power company thinks they can stop Jevons paradox, than they are fooling themselves:
          https://en.wikipedia.org/wiki/Jevons_paradox

          Cheers,
          J

          1. You make a great point about aluminum production being able to absorb excess solar output. But it’s even better than that: use aluminum production to modulate ALL sources of electrical power as needed. Yes, have the big smelters — all of which are in South Australia or Tasmania, by the way — absorb excess power whether it’s solar OR keeping utility power plant output above a certain minimum. It’s doubtful that this would even require extra infrastructure since the smelters are already addicted to operation during cheap power times. Just change their tariffs to reward proper behavior. If that doesn’t do the job on its own the smelters can install battery capacity because they’ll make more profit by doing so.

          2. Though these refineries require a steady supply of power. Aluminum refining operates in a molten state, and if it only gets power for a couple hours mid-day, it’s going to be terribly inefficient if it can operate at all.

          3. @Dude
            Waste heat and power recovery systems can often still be viable with terrible efficiency as the source cost is essentially zero.
            The carbon offset credits however, could be lucrative for the company running the industrial processes.
            ;-)

          4. @Robert

            Except for Portland (VIC), which uses so much power that it appears on the AEMO generation map as a power station with negative output.

          5. Besides, aluminum smelting does not only run on electricity but it requires carbon as well, which results in net CO2 output regardless as the cheapest carbon is source from fossil deposits (coke).

          6. > it is likely _not_ a technical engineering problem, but rather a political, fiscal, and or social one

            Political!

            Our federal grubmint are hell bent of preserving fossil fuels come what may. So they have paid at best lip service to the clear need to transform the power grid. The individual states are basically going it alone with renewables. South Australia was the first place in the world to have a Tesla Big Battery, which paid for itself in its first few months of operation.

          7. There is talk of laying a billion dollar cable to Singapore from the Northern Territory to supply Asia with excess solar power. Mind you, the plan also involves covering many square kilometers with yet more panels.

            “Twiggy” Forest is in the planning stages of converting iron refining from coal to hydrogen. If he doesn’t build all the solar arrays he’ll need, then we can sell him a few GWh here and there.

            Hydrogen doesn’t export well, so the plan is to convert it to Ammonia (NH3), but that’s all in the early dreaming/experimenting stage. A Danish company is trialling running a marine engine on ammonia, so even the transport is fossil fuel free.

            My brother exports up to 70 kWh to the grid per day, as he’s only able to use 20 kWh in the home.
            That’s with 19 kW of panels on the roof. I’m going off-grid, so there’ll be a bunch of batteries.

            State governments and a wide swathe of corporations are bulldozing the troglodyte “feral gummint” efforts to keep the coal rump alive, but coal power stations keep closing down as they can’t compete – just as the horse and cart did.

            Incidentally, the excess of solar power is permanent. As it’s variable, there will be days every week where there’s a surplus. WInd, and storage such as pumped hydro an grid-scale batteries are beginning to fill in the holes and provide frequency regulation better and cheaper than coal.

        2. That makes no sense. Why would it require a different payment model? When you sell something legal, it doesn’t matter who buys it or what legal uses they use it for. You’re going to need some proof for that claim.

      1. Unless the big weight is something that can be pumped into a reservoir, this is totally impractical. There’s an “I majored in industrial design” startup currently scamming people with the idea of using electric cranes to build big towers, but it will fail as an energy storage system for many, many reasons.

        1. A friend and I have been thinking about doing something like that, more for fun than anything else, but I would be interested to know the name of the startup and all the reasons you can think of why it wouldn’t work :-)

          1. When it comes to mechanical energy accumulators, a flywheel stores _much_ more energy in much less mass, especially if the material is strong enough for higher speeds; above 10,000 RPM is a good start. Is it Caterpillar which makes/made a UPS with flywheel accumulator? The Dutch have some small grid-scale flywheels, half buried in the ground for safety. Mind you, I can’t see them being much chop unless they have magnetic non-contact bearings, not just for reduced self-discharge, but for longevity.

            Jaap, if focussed on cranes, choose how much energy you want to store, then calculate the mass x height product needed. A calculation appears elsewhere in this discussion. Then figure out what you’d hoist it with, reliably, repeatedly, and with affordable maintenance. There’s a difference between thinking and just dreaming, as I’m sure you’re aware.

          2. @Erik thanks for this! Flywheels are very cool, but they do kind of scare me :-) Picking up weights in an automated way, with accuracy and reliability is indeed the hard part.

    1. Or have some system to crank every dedicated freezer to max cold during peak production and return to previous setpoint afterwards. Same goes for cranking water heaters to maximum safe temperatures during that time.

    2. All of these solutions are great but it ignores the fact that the excess power is created in localised areas (rather than across the whole grid). Reducing the localised supply is easier/cheaper than solving the problems with the lack of grid sophistication or building lots of distributed demand.

    3. This is already happening in Hawaii. Now, in some parts of Hawaii new residential solar installs are not allowed back feed the grid, period. Enphase makes a special firmware for their micro inverters to achieve this. Excess power produced by residential panels is essentially curtailed at the residence, which is a huge waste but won’t mess up the grid until something like pumped hydro, mges or something like that can be implemented.

      1. Yep, the “nessie curve” which is like California’s “duck curve” but worse. No net demand at noon and afternoon, then the sun goes down and suddenly everyone wants to buy power and everybody’s scrambling to boot up gas turbines.

      2. I seriously doubt we’ll ever get pumped hydro in the ‘aina. If a telescope is too big a deal, I can’t imagine cutting out a couple huge holes to fill with water would go over well.

      1. sort of. We do need those big old school power plants to run during poor solar days. But it is a problem that should solve itself with a bit of upgrading local substations. Plus more electric cars that can charge during the day would probably solve the issue too; local generation Vs Local use. The main problem is the unbalancing of it all. A bathtub with warm water is nice. A bathtub with tepid water in most parts and 100C up one end…not so much.

        1. Australia’s NEM (National Electricity Market), while only covering the eastern and southeastern coasts, runs for four or five thousand kilometers at least. During daytime, it’s going to be impossible to cover all of that with cloud, so once the outdated networks can better feed power upstream, there’s zero need for coal in the long run. Wind can still generate at night, and hydroelectric generation can be conserved for night use – to the point of taking power during the day for pumped hydro. The success of Elon Musk’s grid-scale battery for South Australia has other states wanting them too.

          What is the progress with CST in North Africa? Energy storage in molten salt (NaNO3?) has for a couple of years been used to power a city at night, first stage for 4 hrs, then 8 hrs, AFAIR. There are so many available technologies and so much scope for ramping them up in a highly profitable job-creating bonanza.

          Melbourne is a city of ten thousand square kilometers (OK, only 9,992) and a lot of electric trams.
          They’re all powered by electricity bought from big solar farms. Dunno about the trains – that’d be a bigger chunk.

          Pertinent Note: Australia has more employed today then when we went into this Covid crunch, and there’s talk of bringing in more skilled workers from overseas. Getting off coke/coal is hard work, but the health benefits for a nation’s economy are stimulating in the extreme.

          1. “it’s going to be impossible to cover all of that with cloud”

            That sounds remarkably like a challenge…

            Hey, New Zealand! Got any active volcanoes?

      1. In Denmark, Aarhus university, in collaboration with the University of Queensland, is running a pilot plant which utilises excess renewable energy (usually wind energy there) to generate hydrogen, then injects that into a biogas generator. Why? Because biogas is usually 55% methane and the rest CO2, but when hydrogen is added, the microorganisms convert more CO2 to methane. As approximately 21% of the gas in the gas net in Denmark is biogas, the process has significant climate implications once fully developed and rolled out nation wide.

        Especially with our prime minister Slo-Mo Morrison’s pathological go-slow on energy reform, Australia will be last to adopt and adapt, if he has his way. But households, corporations, and state governments struggle on despite his Luddite laggardly intransigence.

    1. Or the grid needs a better supply demand model. Big planrs just can’t spool up or down all that fast and nobody is crazy enough to just rely on solar and peaker plants

      1. The supply side of solar is disconnected from the market by feed-in-tariffs, so they don’t have to care what’s happening on the grid. Just push everything you got out through the wires, and it’s somebody else’s problem – you get paid anyways.

        1. Here in California, and many other states, you don’t get paid for more than your total consumption (annually). So if you make excess, the electric company keeps it for free, but you still paid for the equipment that’s generating the power you’re giving away for free, increasing the time until you hit break-even.

          1. But then again, you can pile up subsidies up to 95-97% of the cost by combining various federal, state, and county level tax credits, including some infrastructure costs such as building a new garage or a roof underneath your panels. Some of these may not be available anymore since I last checked, but the point is – if you’re rich enough you can get your solar panels essentially for free, and then you get to offset your electric bill as well.

            So who cares about the duck curve?

          2. Hm.. okay, the solar tax credit will drop quite dramatically to 10% in 2022 and phase out in 2023. Businesses will still get 10% with an extra stipulation that the generated energy cannot be used to heat a swimming pool.

          3. And, you can roll your excess generation towards your next bill. If you do not state your wish to do so, THEN the utility takes your power for free.

            https://programs.dsireusa.org/system/program/detail/276

            “Net Excess Generation: Credited to customer’s next bill at retail rate. After 12-month cycle, customer may opt to roll over credit indefinitely or to receive payment for credit at a rate equal to the 12-month average spot market price for the hours of 7 am to 5 pm for the year in which the surplus power was generated. (If customer makes no affirmative decision, credit is granted to utility with no compensation for customer.)”

          4. “At the end of a customer’s 12-month billing period, any balance of surplus electricity is trued-up at a separate fair market value, known as net surplus compensation (NSC). The NSC rate is based on a 12-month rolling average of the market rate for energy. That rate is currently approximately $0.02 to $0.03 per kWh”

            Of course this incentivizes you to roll your credits over and use more electricity, since the retail rate is much higher than the NSC – so you can ride free in your subsidized EV, and turn the AC up without paying extra.

  1. I find the sketched cause of mass high voltage switchoffs incredible. Assuming 240V with a “10%” range, the inverters will not all work at 263.99V and switch off at seeing 264.00V. Also, due to transmission line resistance, they won’t even see the same voltage at the same time. This creates a slow dropout of small generating capacity, essentially keeping the voltage at around the switchoff voltage.

    The undervoltage is a different problem though, even a minor sag in voltage can shutdown generatimg capacity which drops the voltage amd spirals into a gridwide brown- and eventually blackoit.

    1. Operating so close to the limits risks a transient event.

      A sudden disturbance, such as shedding a large load or cutting a transmission branch will send a large number of generators over the limit and shutting down, which changes the overall situation from an oversupply to an under-supply, and the rest will follow to protect themselves.

    2. Why not implement some sort of random delay before switch-off in each inverter? Then some would drop off sooner than others and things would self-stabilize.

      1. That’s what “voltage ride-through protection” basically means. They slow the inverters’ safety function so it rides through transient disturbances in the grid without shutting down instantly. Of course that also means it does not react to real faults in a hurry and this may then continue to feed the fault and destroy more equipment because you can’t get the inverters to shut down.

        1. Well, it seems like they could / should be designed to turn off immediately in case of a gross over/under voltage, but have randomly delayed response to smaller variations. Or maybe they already do, I’m not an inverter expert, by any means…

          1. Well, It’s just kicking the can down the road. The problem is that there’s not enough flexible supply and demand on the grid with solar power producing way more than anyone CAN use at peak output, so even as you relax the fault boundaries, this will not solve the problem. It merely ignores the symptoms for a while, until they add yet more solar power, and then it’s banging against the new limits.

  2. Install window shades over the cells. As the grid starts to reach it’s limits, closing the vanes a little, or a lot, limits the amount of energy the cells are able to generate.

    Sure, there may be issues to be overcome with the mechanical aspect of it, moving parts that get dusty may start to fail or get stuck, but nothing that can’t be dealt with.

    Another solution would be to switch off the output of cells as needed to accomplish the same. Although I do not know if that would have negative effects on solar cells being hit by light and not being able to move those electrons along.

    1. That leads me to wonder how one could build a home system with an ‘alternative load’ (?) so when the grid isn’t buying, any excess can be put to use. Maybe set it up to increase the output of the home AC, raise the temp of the water heater by a small amount, automate certain appliance cycles like the laundry or dishwasher, or only charge the electric car when there’s a surplus of solar?

      It’s not like kinetic storage or water desalination makes sense at homeowner scale.

      1. Hot/cold storage is pretty much what you can do at home, but there’s no incentive to do so because you lose the subsidies for power you don’t sell out, and for heat you’re competing in price with gas which is much cheaper than electricity anyways.

        I see people in California buying solar panels to sell to the grid, and then install gas power furnaces, showers, fridges…

        1. Do you have a reference for that? In my experience (and with current legislation and power company attitudes), that’s just not possible.

          As I pointed out earlier, in California power companies will only buy the same amount of electricity that is consumed. If you produce more than you consume, power companies keep it for free. Produce less than you consume and you get a big bill at the end of your annual billing cycle. There is also the “All Electric” home initiative which is stopping/reducing gas powered appliances in homes.

          Why are so negative about home solar?

          1. The California energy model is Zero Net Energy (ZNE), and all new residential construction must now be compliant. But like many things out of California, the politics are subjective/emotional or don’t deal with technical (objective) realities. They sue their own utility for causing a fire due to poor line maintenance, and then reap rolling blackouts as a result. Energy reliability is not their first priority. They write feed good “visionary” policy in hopes that engineers will make it workable eventually. Just saying that California is not the best model to follow.

          2. Well, granted, I’ve seen ONE person do it and then brag about the money they saved by going gas for the house and solar for the free electricity.

            Home solar is a negative, because it’s a tax break for the upper middle class and rides on taxpayer money – a sort of reverse robin-hood scheme. It doesn’t really solve anything, it’s not upwards scalable, and it wreaks a havoc on the grid.

            And the net metering rules in California so allow you to cash in your excess production at the average market rate or roll the credit over to next year. See my reply to your comment above.

          3. @Dude

            So your friend owned a house, spend a year running up a really large electric bill (setting their base consumption and base NEM limit very high), then installed a solar PV system, then installed lots of gas appliances to reduce the electric consumption. After a year get some portion of the base NEM purchased back. While this sound possible, it seems a lot of effort/money for what will be a small gain, and that gain is unlikely to last more than a year of few.

            Say average home consumption is 20kWh per day. And some how your friend manages to reduce their electric consumption to zero after installing a solar system that generates 20kWh per day. This means that all generated power is surplus, so the IOU pays $0.03 * 20 * 365 at the end of the billing year: $219. Will that pay for the additional gas consumed?

            But next year (or after a couple of years) the IOU adjusts the base NEM to match the previous years consumption, which was zero. The IOU will now buy back zero of the surplus, although it’s really happy to take anything above the base NEM limit (now zero) without paying for it.

            I don’t think they are going to benefit a lot, and very likely to loose money over all. Maybe it was just for bragging rights (or prepping).

            You seem bent on making home solar out to be evil, but home solar has a lot of unnecessary draw backs put in place by IOUs that quickly mutes the benefits.

            Also, what about all the subsidies going to the IOUs… PG&E alone has had something like $200M in the last 10 years, record profits in that time, and still dodging doing proper maintenance and upgrades…..

            @RF Dude
            “California is not the best model to follow”
            Yes, agreed. The vision is nice, but politics, corporate greed, and monopolistic power leaves the IOUs doing pretty much what they want.

          4. >some how your friend manages to reduce their electric consumption to zero

            That’s not what happened. You still need electricity for lighting and the TV etc. What did happen was, the guy had gas water heaters, gas stove, heating, etc. and then started bragging about how they’re running their house on solar, how environmental they’re being, and how cheap it is because they get free electricity.

            Well, in reality they were running their house on gas, and offset what little electricity they used with solar, which is extremely irresponsible because their electric demands (mornings and evenings) was perfectly off-beat with their solar production, so they’re not actually using any of it themselves.

            In other words, they made the economic case that solar power works for you IF you don’t actually use it. Having a system that would capture the daytime energy in hot water would have cost more than having an instant-on gas heater and a gas furnace. Extrapolate to other homeowners and you start to get the big picture – this is why in California they’re banning the installation of gas lines to new apartments.

          5. Point being, of course you don’t make much money by building more than your net metering limits. Yet everybody who can does this: everybody wants to sell solar power to offset their net use, but nobody actually wants to use the power they’re generating, so you get the duck curve. The average producer rates are dipping to low $15/MWh in the middle of the day, and up to $60/MWh in the evenings, and the transition between the price regimes gets sharper and sharper every year with ramping requirements of a dozen gigawatts in just couple hours.

          6. @Dude,

            You appear to be operating under the assumption that all of California runs on the same provider under the same rules. While I haven’t researched what folks under Edison pay, up North under PG&E, your experience doesn’t match my own experience.

            I’m looking to put solar on my roof as my rates are roughly $0.28KwH right now. Most of that is for the fixed cost elements of transmission like wires; very little of that is actual power. I’ve been quoted a number of systems in the last few months and discovered some limitations I wasn’t expecting. Because, until a few months ago, I assumed the same scheme you describe here was the way “California” worked.

            1) I can only install enough solar capacity to cover my average monthly consumption. This is a potential issue because I’ve been wanting to ditch my gas stove and go electric (they cook better.) However, I’ve been advised to buy the stove first because adding capacity later is difficult to permit. (easy enough as a technical solution but not as a bureaucratic one.)

            2) Solar power households must switch to a time-of-use billing system. (And in my city, all citizens are being moved to time-of-use.) Peak power costs are 5-9pm M-F. Cheap power is all other times. During the Winter, the sun sets too early to offset peak with solar unless you have batteries. And most families with two working adults consume most of their power M-F from 5-9.

            3) With batteries, I’m quoted a breakeven point at roughly 5 years. The best and biggest battery I can get is the Tesla (or, at least, *could* get when I was quoted.) This sets a limit on an effective solar system to no more than I can pump into my battery each day because the price I get for selling power is not worth it. The battery I was quoted was rated at 13.5KwH. And, by no coincidence, my roof system was set to supply almost exactly that amount.

            4) I’ve been considering getting a hot tub on a heat pump and using any excess power to generate heat for that. My new washing machine has a feature that lets it start on a timer, bluetooth command, or via app. Some solar equipment can now initiate appliances to consume power on demand. Selling power back to the grid at one or two cents per KwH and buying it back at 28 cents later in the day isn’t economically viable.

            The problem with the time-of-use scheme they’re moving us to is that it will encourage more gas appliance use for those, like myself, that already have a gas connection–it’s cheaper to run and there is no variability in the price. But this is no surprise since the utility is “Pacific *gas* & electric.”

          7. As far as I can tell, all the utilities have similar rules and schemes. Net metering comes from the federal level, and so do about half the tax credits and other incentives.

            >The problem with the time-of-use scheme they’re moving us to is that it will encourage more gas appliance use for those, like myself, that already have a gas connection–it’s cheaper to run and there is no variability in the price.

            That’s exactly my point.

            Net metering works on a net basis over a year, not time-of-use – hence the name – so you get to write off expensive peak power with worthless waste power pushed onto the grid at non-peak times. To save money, you would have gas appliances and then just slightly more solar to cover the remainder – no storage, no batteries because that costs extra. This is a problem, so the state then subsidizes the batteries and bans the installation of gas lines to new premises.

          8. HaD has eaten two long replies on this, so I’m not going to wasting much more finger tip skin on this…

            If you want to NEM, you need to switch to TOU first, they are not mutually exclusive. I get a very complex energy statement every month (not a bill) detailing what power I used when and what power I generated when.

            At the end of the (billing) year my IOU will balance out what was used and generated (based on TOU) and send me a bill for any consumption costs over my generation. If I’ve generated more, then they just keep that (barring the unlikely event of a small % delta between the previous and current years consumption coming out in my favor).

            That seems to work the way you are complaining it should work…. but less fair to home solar owners since the amount of energy the IOU will pay for is only 100% of past consumption[1], then they keep the rest for free and sell it at profit[1].

            Your rants sound of IOU FUD-y-ness…. There is no free money, there is no nearly 100% subsidized home solar installation everybody is getting, and the villains are not home solar owners. Please consider the IOUs should be accountable, PG&E has had over $200M in subsidies in the last 10 years, it’s made record profits in that time, and continuously failed to maintain grid infrastructure to the point we now turn it off or burn to death is it’s just a little windy….
            IOUs are also just as responsible (if not more so) for the duck curve problem as home solar folks.

            Reality: Solar is just barely worth it, most folks are going to find it takes longer to pay off than expected and doesn’t provide any advantage in a power outage (thanks to IOUs’ anti-islanding policies)…

            [1] Unless you are in DC, then you might be able to sell up to 200% of your past consumption.
            https://pv-magazine-usa.com/2020/08/12/dc-citizen-wins-increase-in-net-metering-limit-to-200-of-past-usage/

          9. — Trying shorter posts since HaD moderation is eating my posts —

            If you want to use NEM, you need to switch to TOU first, they are not mutually exclusive. I get a very complex energy statement every month (not a bill) detailing what power I used when and what power I generated when.

            At the end of the (billing) year my IOU will balance out what was used and generated (based on TOU) and send me a bill for any consumption costs over my generation. If I’ve generated more, then they just keep that (barring the unlikely event of a small % delta between the previous and current years consumption coming out in my favor).

          10. >That seems to work the way you are complaining it should work

            Not quite. NEM works on a net kWh basis, so it doesn’t care about the time of generation when offsetting your bill. TOU simply makes you pay more for the power you have to buy.

            What I’m after is a buy-all-sell-all scheme, which pays you according to the actual market value of the power you generate. This is net $ not net kWh. This means, if people want to make any money out of their solar power they can’t just shovel it down the grid like everyone else – they have to put it in batteries or storage boilers etc. to save from buying power later.

            NEM/TOU still means you get to trade low value power (off peak) for high value power (on peak), and the only difference from the past fixed rate contracts is that the utility gets to charge you more money on the months when you don’t output enough solar power.

            If you’re already on a net value based contract instead of net kWh, then that’s not NEM – that’s not how the federal regulations define it.

          11. It seems a true/pure buy-all-sell-all scheme would eliminate any solar value and strengthen IOUs’ monopolies. IOUs would pay $0.02-$0.03 per kWh for any power generated, and charge $0.23 (and up) per kWh for any power consumed. Even if the home is consuming power generated by the home, they will still pay full price $0.23, although they get $0.03 back…

            This creates near zero insensitive to have any solar at all. This also doesn’t really address the duck curve from renewable energy. But it does protect the profits of IOUs, and helps ensure we will see future record profits now that they can monetize power they didn’t generate. Also heavily re-enforcing IOU monopolies, which will help ensure that future renewable energy programs won’t happen if they hurt IOUs’ profits. As is, this is basically an effort to eliminate any behind-the-meter generation that IOUs can’t bill for.

            There is a need for a fair system, but buy-all-sell-all is not it. Neither is NEM-TOU.

            Also, why should IOUs pay just $0.03 per kWh for my off peak generation and sell it to my neighbor next door for $0.22 per kWh (off peak TOU consumption price this month)? I also generate a fair amount of power during peak prices, this is also purchased at bulk rates, but sold to my neighbors at $0.56 per kWh! But wait, that’s only if I have any surplus above my annual consumption, otherwise the IOU get’s it for free. Shouldn’t I get the bulk of the money and the IOU just gets $0.03?

            IOUs are not incentivized to do anything (like address the duck curve, or fix their transmission lines) other than optimize profits. Blaming the home-solar isn’t going to fix that (or an accurate placement of blame).

        1. Irox, just above, claims that domestic PV is charged a net 20c/kWh for self consumption. That rampant misinformation is indistinguishable from coal-funded FUD, but let’s be generous and ascribe it to ignorance.

          Self consumption occurs behind the meter here in Australia. The electricity provider doesn’t see it, can’t measure it, and has zero legal basis for any related charge.That is the case in any jurisdiction where the citizens have the most minimal democratic freedom imaginable. If you let a rogue make you pay for self consumption of self generation, then you’re unimaginative as well as a slave. If such a gulag exists on tnis planet, just don’t connect the PV generation and its loads to the network – keep them off-grid – simple.

          Here in Australia, Tasmania’s electricity supply is 99.2% renewable _now_. South Australia is 59.7%, though here in Victoria it’s only 27.7%, so we have a lot of wind and solar to install well before 2050, when coal generation will have been extinct for a decade or more, and net carbon emissions must be zero. Annual installation of small scale (typically domestic) solar generation was 3.2 GW in 2020, and the installation rate is still accelerating. Coal is dead, rolling on only by momentum.

          1. Sorry Erik, I did NOT make that claim, I claimed there is *proposed* legislation in the USA that is aimed at ending tariff free behind the meter consumption.

            Here’s some details of the “rampant misinformation” you are claiming:

            Some random news articles:
            https://www.blackhillsfox.com/2021/04/23/black-hills-energy-looks-to-amend-tariff-on-renewable-energy-to-ensure-electric-rates-are-fair-and-reasonable/

            https://www.keloland.com/news/capitol-news-bureau/s-d-regulators-allow-late-interveners-as-black-hills-energy-seeks-changes-for-co-generation/

            And the actual proposal:
            https://puc.sd.gov/commission/dockets/electric/2021/el21-011/StaffMemo.pdf

            See here:
            “BHE is requesting to switch to a “buy all/sell all” method. This means that a QF customer would buy all of the electricity they use from BHE and would sell all of the electricity that they generate to BHE. So, if a customer consumes 500 kWh of electricity and produces 100 kWh of electricity in a given month, they would buy all 500 kWh from BHE at the tariff rate and BHE would purchase from the QF customer all 100kWh that they produced at the avoided cost rate.”

            Possibly you can explain why it’s my “ignorance”, or why this is “misinformation”? Your little ramble after the accusations doesn’t seem relevant, perhaps you can better tie it in after you’ve read up a bit.

            If you like your behind-the-meter consumption, you should pay attention to these things, even in not in your backyard/country, because once the IOUs get a sniff of money from selling our own power back to us, we’re screwed…. And the IOUs thank you for helping them out by labeling this as FUD/misinformation.

            As somebody from the UK, perhaps I should be lowering my expectations of Australians…. (?)

          2. Shorter version as HaD moderation seems to be 50/50 chance of happening.

            I didn’t claim that, I called out plans to do that.

            And the actual proposal/plans:
            https://puc.sd.gov/commission/dockets/electric/2021/el21-011/StaffMemo.pdf

            See here:
            “BHE is requesting to switch to a “buy all/sell all” method. This means that a QF customer would buy all of the electricity they use from BHE and would sell all of the electricity that they generate to BHE. So, if a customer consumes 500 kWh of electricity and produces 100 kWh of electricity in a given month, they would buy all 500 kWh from BHE at the tariff rate and BHE would purchase from the QF customer all 100kWh that they produced at the avoided cost rate.”

            Misinformation/FUD/ignorance? I’ll leave that to you.

      1. Now Irox tells us “I claimed there is *proposed* legislation in the USA that is aimed at ending tariff free behind the meter consumption.” I.e. It’s not here yet, but coming, so basically the same story. There does seem to be a default assumption in America that corporate threats become reality. Here in Australia they are recognised for the (often vacuuous) bluster that they are – just running a flag up the mast to see how much fire it draws, followed by a rapid retreat if the citizenry is awake and places any value on their own property.

        The proposal has neither legal merit nor practical chance to be put into practice. Firstly, the wiring behind the meter is your property; paid for, installed by your contractor, and maintained at your cost. The utility company’s property rights end at the meter. What they can do is determine what sort of equipment you are allowed to connect, and could forbid PV or other generation being connected while you are on grid.

        Even forbidding connection of domestic generation to the grid could not prevent running a second set of circuits, not grid connected, off a second main switchboard, so dishwasher, aircon, pool pump, and other heavy consumption loads really only needed during the day, can still be powered by domestic PV. Add batteries, and move lighting over as well.

        Given your new president’s vocal commitment to renewable energy, it would be inordinately defeatist to encourage the bluster by meekly surrendering to it. Organise protest, hit the media, embarrass the president if he doesn’t come to the party quickly. A comparison: McDonalds wanted to build a store in our suburb. We raised $45,000, sent a team to USA to protest outside their headquarters, complete with large inflatable kangaroo, took out advertising on a prominent billboard, took out a full page advert in one of your major newspapers, had flash mobs striking with lightning protests, circulated the clips on youtube, and held several large rallies here in Melbourne. The price of democracy is eternal vigilance, they say. Try a web search on: burgeroff tecoma
        Coverage was international: https://www.bbc.com/news/business-24364204
        And yes, they threatened us with court action for protesting, but that fizzled in the end, as we stuck to our guns.
        While they did finally build it, with police guards to hold us at bay, it is an inconspicuous stone-faced conservative building with negligible signage, so could be any other business by appearances. Add in that case it was their use of _their_ property we wanted rights over. So may I recommend manning up in the face of threat.

    2. You don’t even need to go that far. You can throttle panels electronically by moving them to a less efficient part of the IV curve.

      But really the best solution is supply storage – throwing away free energy is just a bad thing.

      1. Well, it isn’t really free – you already paid for it, you’re just not using it, which is dumb.

        However, storing the energy means paying even more for it. Significantly more at today’s battery prices.

        1. I mean at the grid level: from the grid’s point of view (if you think of the grid as “the aggregate consumer”) if supply’s so high it can buy energy for free… it should find a way to store it. All it does is just lower market price later.

          In my mind a lot of the problem is that there’s nowhere near enough incentive to push for grid-scale energy storage. At scale, they should be *extremely* cheap – easily enough to put peaker plants out of business. There are *plenty* of grid-scale energy storage mechanisms (molten salt, flow batteries, compressed-air) which can be either competitive with peaker plants if there were either subsidies/taxes pushing for it, or even outperform them at scale. And of course grid-scale battery isn’t terrible either.

          But, of course, the problem with any subsidy is that once it’s in place, it’s very hard to make it go away unless you built in a natural mechanism to do so. (Which is why the pushback against tax/dividend systems is so effing annoying).

          1. True, but that’s still missing the forest for the trees. There’s no free lunch here: one person pays for the panels and puts out “free” electricity, a different person pays for the batteries and buys the “free” electricity, but the consumers will eventually foot the bill for both because the taxpayer pays the first guy subsidies to sell electricity at a loss, and also the second guy to offset the cost of the batteries.

            There isn’t any technology presently available that would make grid scale batteries “extremely cheap”. Even at the cheapest, it’s still going to at least double the cost of energy you put through it, and that’s no good if you want to push for renewable energy all-day-round.

          2. Uh, yes there is, and I listed several of them. Compressed air and hydro are already within spitting distance of gas peaker plants (less than an order of magnitude), enough that there are plenty of systems already built. Other systems (molten salt, flow batteries) are close enough that there are projects in planning.

            A moderate tax/dividend system would be enough to tip the balance, and I mean, levelized electricity prices have been dropping for forever, so it’s not like they can’t support a subsidy.

          3. The main issue for CAES (and molten salts for that matter) is the low efficiency of it. It’s throwing away roughly half the energy you put in, which obviously doubles the cost of energy coming out even if the technology itself was free.

          4. I said *peaker*. Of course energy storage can’t compete with baseload. Peaker plants have a way higher cost and they’re pretty terrible carbon wise. You’re not trying to smooth *everything* out yet.

          5. The problem I keep having is people pushing for half-solutions like “Oh we’ll just replace the peaker plants”, but this isn’t doing what we’re supposed to be doing. It’s not really solving any problems – it’s just masking them.

            Grid-scale energy storage is not “extremely cheap”. It’s expensive enough that it can presently replace some of the most expensive ways we generate power, and if we lean on this system – massive over-production and then peakers for the rest of the day – then the power system prices will keep climbing.

          1. Plain thermal energy such as from burning gas, is much cheaper than solar electricity plus storage.

            One may argue for heat pumps, but that’s also just higher investment cost, and adsorption heat pumps exist for gas burners (and coolers) as well. You have cheap gas, you have cheap HVAC. Only thing you need the electricity for is running the fans.

  3. This seems like a problem with how these commercial measures were implemented. If used in just a handful of cases, this little ‘hack’ would have had little to no ill effects. But when lots of people did it, the problems made themselves known.

    So it seems like the long-term solution would be to have something to store energy for non-peak (dark) times, or to reduce our widespread energy usage to only when the solar panels are on. Eventually, after we address all of the stability concerns, we may be able to shut off those power plants for good, but unfortunately I may no longer be alive then.

  4. This is an opportunity to examine issues that will be likely to generalized in the rest of the world as solar spreads. How the existing grid and the existing electricity producing assets (and workers) are allocated is just beginning to be examined and imagined. Throw in home storage, huge solar and wind and storage farms, EVs at scale, and politics and you have a major human challenge. The driver is climate change and for large facilities lower cost for cheap solar and wind; and the resistance will be changing the infrastructure and manpower that currently exists. Thank you, Australia, for being the tip of the iceberg.

  5. We need incentives for folks to point some or all of their solar in different directions. 10% E, 20%NE, 20%N, 20%NW, 30%W would be really nice to draw out production during the day.

    Either add incentives for installing panels facing those directions, or change the price paid per kWh to favor morning and evening production.

    1. See below: pay market rate instead of subsidy – oversupply results in negative prices and people HAVE to re-orient their panels and install batteries, or they’ll simply make no money.

      The best solution is to stop coming up with elaborate bureaucratic schemes and regulations, and let the problem solve itself.

      1. California is already moving to this model with Time-of-Use pricing and limits on installed capacity.
        Since ToU pricing leads to peak hours being the “home from work” timeframe, people will orient panels towards afternoon sun to maximize value. And people with batteries and electric cars will charge late at night.

        1. Net metering doesn’t care about time of use because it offsets your bill on a net kWh basis. The “NEM 2.0” still retains this.

          You simply pay more time-of-use power in the winter when you can’t produce so much solar power, and switching your panels towards west would diminish your returns even further by reducing the overall output. This does not incentivize anyone to help the supply-demand mismatch – it merely gives the utilities the opportunity to charge more money out of people.

          The utilities are pushing for more fixed charges and a “buy-all-sell-all” scheme for NEM 3.0 but good luck with that.

  6. Here’s a though: stop paying subsidies (feed-in-tariffs) and instead pay the market rate: when the price goes negative, people will automatically stop selling power to the grid. Then they have to buy batteries or find some other use for the power, or it won’t be economically sensible to install any more. Problem averted.

    All these coping mechanisms and bodges on the grid to deal with this issue ARE the cost of renewable energy that people kept complaining about. This was simply swept under the rug by political means, and now somebody else has to pay the cost while the people who install solar panels get guaranteed profits.

    1. Hear hear.

      Seems like the same people I know that are mad with the government ‘propping up’ this industry or that industry are A-OK with the ‘green’ subsidies… Keep the government out of it!

      1. Government has a legit role in creating new markets. Subsidies helped move solar and electric cars into more mature markets faster which improves economies of scope and scale and reduces prices to consumers. These subsidies are rightly diminishing over time as the market matures. Keep in mind that fossil fuels have a lot of external costs borne by residents that aren’t captured in fuel pricing or taxes including medical costs and the impacts of climate change. Subsidies to create improved technologies and markets that offset those external costs are a legitimate activity.

        If the government left the market alone, we wouldn’t have electric cars right now. Tesla wouldn’t exist. The solar industry would still be too expensive and inefficient to make much of a difference. Capital only shifts to profitable markets; when was the last time a new industry was born without direct government involvement bearing the high costs of basic research and market development?

        1. They “helped”, but most of it was just spent on people peddling the old stuff that couldn’t hack it on the market without the subsidies. It’s a terribly inefficient way to fund research and development, when you could just do a proper government funded research program that directly addresses the issue.

          1. If anything, paying subsidies retards development because the usual suspects move in onto the market to grab those subsidies. The companies that don’t do any R&D of their own are cheaper and out-compete those companies that do spend some of the money gained on R&D – this is why China was able to capture 80% of the solar power market by selling old technology, while the western companies that tried to develop new technology like thin film solar went bust.

            In other words, the subsidies have been wasted on imports from a country which made solar panels cheap by disregarding environmental issues and simply pushing for volume, stalling or delaying any actual development.

        2. >If the government left the market alone, we wouldn’t have electric cars right now.

          We don’t -really- have electric cars right now either. It’s just too expensive – and Tesla would still not be making any profit if it weren’t for government subsidies in the form of clean vehicle credits that other car companies have to pay them.

    2. I mean, boosting the green side via, say, something like a carbon tax/dividend is pretty reasonable. It doesn’t make sense for a fossil plant to provide peaking capability if solar capability’s so high that you can do energy storage/recovery and balancing that way. In that sense taxing the fossil-generated stuff and splitting that revenue between the renewables makes sense. Once you’ve got significant solar capacity, you’d really like to be encouraging development of energy storage, too, and this would do that.

      “Then they have to buy batteries or find some other use for the power”

      To be clear, a lot of the problem here is that with distributed energy generation you *really* want more smarts in the grid-tie inverter and the solar setups in general. Throttling a PV panel is easy. Managing oversupply from panels should be a joke, but the grid doesn’t have any control over them.

      1. Going the opposite way, installing carbon taxes creates a perverse incentive for the government to keep having carbon/fossil fuels around because it makes them a lot of money. Taxing is a poor way to control the market because the money doesn’t go away – the government uses it for something, and then gets caught up in those commitments, and then has to keep the taxes coming in to keep paying whatever.

        1. It’s basic crony capitalism after all. As long as the alternatives to fossil fuels and carbon energy don’t actually work well, tax away – the consumers don’t really have a choice and both the corporations and the government profit from it. The renewable power industry as well, because they get to run a legal cartel with fixed prices to prop the whole business up as it would not work otherwise. Everybody’s just dragging their feet and pretending.

          Now why do you think we aren’t building any nuclear? Why is fusion research chronically underfunded?

          1. “Why is fusion research chronically underfunded?”

            Yeaahh… fusion research really, really isn’t chronically underfunded. It’s practically like cancer research, in the sense that yeah, you can throw buckets of money at the problem, but it isn’t going to make the hard problems suddenly have a breakthrough.

            It’s a fundamentally challenging issue, and we really don’t know where the right points are in terms of size/scale/design. Especially right now fusion research is *exploding*.

          2. The theme of the game is that large budget projects like ITER suck up the public funding with project timelines stretching to multiple decades, while small budget projects like the Wendelstein 7-X post results and progress but they’re slowed down by the lack of interest and funds.

          3. The fact that ITER was funded *at all* given the state of knowledge at the time pretty much counters your entire argument of “chronically underfunded.”

            “like the Wendelstein 7-X post results and progress”

            I mean… the W7-X is neat and all, but you’re talking about an experiment with a fusion triple product ~2-3 orders of magnitude away from a viable power plant, as opposed to tokamaks which are only about an order of magnitude or less. So I don’t get your point. The jump from W7-X to, say, HELIAS (about a factor of 5-ish in scale) is *much* larger than the jump from JET to DEMO, for instance.

            You’re welcome to have your own horses in the race for preferred fusion design, but it’s hard to fault the community for coalescing on a JET-style design. So maybe in the end it’s “misfunded” but certainly not because of any nefariousness.

          4. Yes, except the triple product is a product of temperature, density, and confinement time, and the W7-X is the only one that has shown the potential for steady state operation with no theoretical or technical showstoppers, and has a roadmap for actually achieving it. Meanwhile, the conventional tokamaks like ITER are limited because they’re unstable and nobody’s figured out the trick to get around that, and even as such they’re still a decade out for completion at any rate because it’s a government-industry boondoggle.

            You need a triple product of around 10^28 while the 7-X has achieved 10^26 and it’s limited by the lack of cooling for the reactor walls, so it can’t run for longer, but they’re completing the cooling system and diverter upgrades this year, and should resume plasma tests in 2022 with real steady state operation. If it works as planned, and I don’t see why not, they will have leapfrogged ITER by 20 years in proving that you can build a real fusion reactor. The next question is, will they get funded for building another that can actually be fueled up and ignited?

            My guess is: no. It would not serve the interests of the governments or the other industries because it would disrupt the whole pork-barrel scheme going on around renewable energy.

          5. W7-X is a *concept* experiment to understand stellarator operation – it’s much more akin to, say, JET than ITER (and the timescales of both explain *why* ITER is a tokamak). The scaleup from W7-X to an actual reactor (equivalent to reaching a DEMO stage) is covered well by, say, Warmer et al., and *includes* many of the materials issues that ITER is also researching.

            There’s no “leapfrogging” here. It’s not like the “stellarator people” walk over to the “tokamak people” and say “haha you suck” and walk away with the money. A *lot* of the ITER studies/work are directly applicable to stellarator design.

            Even if after the ITER stage they evaluate the W7-X data and ITER data and say “yeah, OK, commercial plants should be stellarator-based” the ITER research wasn’t “wasted.” Materials research, superconductor studies, diagnostics – all of those things still stay directly applicable. You’re confusing “ITER the machine” with “ITER the program.”

            “My guess is: no. It would not serve the interests of the governments ”

            OK, now you’re well into tinfoil hat range. W7-X is a billion-dollar experiment. You’re not talking about some piddly little thing. It’s not like you just go “hey, here’s some tritium, give us some energy!” Again – the scaleup to an actual fusion reactor needs *a ton* of materials engineering, much of which is currently done under the ITER umbrella.

            In other words: W7-X completes, hits steady-state, shows scaleability, but a reactor-scale device doesn’t get funded immediately. Why? Because it doesn’t make sense. You still need to wait for the materials engineering from ITER, so it *does not matter*.

            It’s clear that you think a stellarator would’ve been a better design choice in the beginning. You’re welcome to that opinion, but I *highly* disagree that that was forseeable 20 years ago. And the idea that governments somehow sent them down the wrong path on purpose (which… is the only conclusion you can reach if you think $50B was invested in a program that they knew was a dead end) is just insane.

          6. We aren’t building nuclear because it costs too much and has a massive waste problem. Plus, no one wants them nearby, especially after the Japanese disaster. Besides, the levelized cost of energy of solar plus storage has already reached the cost of nuclear power. Why build a massive plant that creates radioactive waste when you can build a solar array and plop some batteries down? Notice that even when Trump was trying to “save coal,” the industry itself was shutting down because the cost of new plants was too high. Not only that, but the cost of solar plus storage had even cut into some existing plants where replacing it was cheaper than keeping the existing plant.

            Government may like the tax income but corporations don’t. Corporate lobbying is very effective at eliminating taxes.

          7. >W7-X is a billion-dollar experiment. You’re not talking about some piddly little thing.

            That IS still peanuts, and it’s spread over 20 year, because the funding is pitiful. Meanwhile, renewable energy how many billions per year in subsidies just to BUY the ELECTRICITY off of the suppliers?

        2. That’s why I said tax/dividend. As in, government nets nothing.

          It’s like, suppose you tax the fossil providers 2.5 c/kWh. If the market price of electricity is, say, 10 c/kWh, and 50% of it comes from renewable (and 50% from fossil), you pay the renewables, say, 12.5 c/kWh and the fossils 7.5 c/kWh. As the renewable fraction goes up, the boost goes down, as the renewable fraction goes down, the boost goes up. Naturally diminishing subsidy.

          1. It’s the same thing though. The people who get the dividend then depend on it. The more subsidies you pay to say renewable power producers, the more they’ll drag their feet on actually improving the economics of production – in order to argue for the continued flow of subsidies.

            One can always waste money.

          2. If you’re paying market-based rates, no one will actually depend on the dividend, because you can’t do market prediction. The issues with the current subsidy-types are that the solar types based things on a constant income. Move away from that and it won’t be nearly as bad.

          3. Besides, the government does get something: they get to decide who gets the dividend and how much, for how long, for what reasons… any way you try to dress it up, it’s just the same tax and spend, which is traditionally used to buy votes from the public and pay kickbacks to your business buddies.

          4. >because you can’t do market prediction

            You can predict a macroeconomic balance: the system will not eliminate fossil fuel production because the REE production depends on fixed prices. Shifting money from one to the other allows the renewable generators to exist as they do, but as they gain in fraction they will lose the additional fixed transfers and new investments will stop.

      2. >but the grid doesn’t have any control over them.

        Because the politics doesn’t allow you to. The owners must be able to sell and collect the feed-in tariffs to recoup investment and make a profit. In many countries, such as in Germany, this is accomplished by writing explicit laws that say solar power has a right of way on the grid. Net metering also assumes that the utility will accept all power at any time. There’s also some politicians pushing for similar right-of-way laws as in Germany.

        I couldn’t find information about Australia, but the general theme is that you can’t curtail, and if you do curtail then you have to pay the owners a compensation for it, which is stupid because you pay the solar owners to produce AND not to produce energy.

        1. “Because the politics doesn’t allow you to.”

          Uh, no, I’m pretty damn sure the reason is because last time I checked, grid-tie inverters have a grand total of 3 connections and none of them are “please reduce the power you’re supplying.”

          There’s both a political *and* technological problem here.

          1. True, but here’s the main issue: solar power competes with itself. It has the unfortunate property that all the producers are on at the same time, so the more you have on the market the lower the price will be. That’s why they can’t make ends meet without fixing the prices through the subsidies – the tax credits, net metering, and feed-in-tariffs. If they can’t all sell as much as they can put out, then they can’t exist.

            That is the main reason why there’s no utility side control options.

          2. Yeah, I get the societal/economic problem, but without solving the technological issue none of that matters. You don’t want to revamp the economic infrastructure and then have someone go “uh… now how do we do all that?”

          3. There is no technological issue. The technology to control generators with signals through the power lines themselves have existed since the 50’s if not earlier. They used to have those signal generators to switch between day/night metering in customer premises up until smart meters working over radio/internet came along.

          4. Yeah, but they own the meters, not the grid ties. I’m not saying you *couldn’t* do it, but because they didn’t require it before they became everywhere, *now* there’s a technology problem.

          5. We have a different understanding on the meaning of “technological”. In Germany they’re having mandatory retrofits for inverters in systems above 10 kWp for the same reason. Again, it’s a socio-economic problem, not a question of technology.

    1. one problem though – during normal times, said car is likely to NOT be at home when solar is at peak production. Furthermore – the car will likely require charging at night…

  7. Cry me a fucking river, the planet’s dying. Fix the grid so we can actually take advantage of all this rooftop solar instead of coming up with convoluted ways to cut off solar producers and keep fossil fuel plants online.

      1. Try to find more than 5 sites that were actually successfully reclaimed after a reactor was decommissioned. The dirty secret is the cooling ponds contain a 1000 to 15000 year depleted fuel problem no one wants to pay for, have in their back yard, or even partially recycle in many places.. it will still be your great great grand kids problem.

        Traditional Nuclear fuels should be reserved for space travel projects… where the waste can be dumped where no one will ever live.

        I am sticking with my vision of a future filled with wifi enabled goat-carts prediction for now, as it is far more probable than viable fusion power in our lifetimes.

        1. Many/Most of the existing nuclear power stations were built primarily to produce fuel for nuclear weapons and only produce power as a side effect/excuse. If we build modern power stations for just energy production then we could have much cleaner nuclear power than we currently experience.

          1. Not really, the terrible CANDU reactors we have domestically use many types of fuel, and no one here would ever tolerate nuclear weapons. In fact, we burn most decommissioned Pu for countries like the USA trying to lower global tensions as a general policy (arguably with mixed results).

            Thorium reactors are still not a real option yet, but who knows,,, did you know that goat carts get 0 mpg fuel economy. ;-)

          2. no. That applies for the RBMK series reactors (Chernobyl…), which were pretty much a scaled up plutonium breeder connected to a turbine.
            A normal PWR or BWR reactor is very unsuitable for plutonium breeding

          3. Sorry, dude, I’m not letting you get away with this one. I’m tired of people spreading personal-opinion information such this, and expecting it to be believed simply because you say so, AND because it makes a good ‘sound bite”.

            There’s one simple, easy path to credibility:

            GIVE UNASSAILABLE, HIGH-QUALITY ATTRIBUTIONS FOR YOUR CLAIMS.

            For your information: no one would be more excited than I to see proof of this. Absolutely true.

          1. Do you really need people to run down the list of contaminated/leaking sites (even the ones hidden on google maps)? I am sure those giant tanks of Uranium hexafluoride are even safer now than decades ago. ;-)

            Also, moving the problem around in rail-cars doesn’t really solve anything. Thus, we will have to agree to disagree on this technology,.

            If your scientific hubris is still stronger than your sense of survival, one could always dig for clams near the Hanford sites drainage run off. Building something to remain waterproof for even 30 years has proven difficult, and no one has ever really solved the problem economically.

            Goat cart for the win again… did you know most goats are still safe to eat, but I will concede the cart is less edible. ;-)

          2. That’s a bit of a red herring though, since you’re lumping together wastes produce by the Manhattan project and other military nuclear stuff (Hanford etc.) with commercial nuclear power production which isn’t responsible for those “giant tanks of Uranium hexafluoride” because it never made them.

            At least 2/3rds of the nuclear waste in the US is because of military weapons programs, and it’s that stuff which was neglected and dumped around the place while the commercial nuclear waste is entirely contained.

          3. >Building something to remain waterproof for even 30 years has proven difficult, and no one has ever really solved the problem economically.

            Yes they have: deep borehole disposal. The main issue with that is political, not economical or rational, because the existence of an effective waste disposal method means losing the waste argument against nuclear power.

            The last time they tried to drill an empty test hole in Nevada, the whole project was shut down by protesters and politicians pandering to them – even though they didn’t intend to put any nuclear waste down the hole at all. Merely RESEARCHING and PLANNING nuclear waste disposal meets stiff resistance from the public for irrational reasons, so how do you expect anyone to solve it?

    1. Exactly. The free market HAS spoken, and it’s wishes are solar. The utilities must adapt or be allowed to fail. THAT is what the market wants, and the market wants to make sure they’re not screwed over in the process. There’s no need to prop up dying systems at the expense of our planet.

      1. How has the free market spoken anything, when the existence of solar is due to the existence of feed-in-tariffs that pay a fixed price for any power sold? The problem was caused by politics, and it goes away by the same: remove FiT and all the power that does not fit the grid goes away.

  8. Not to put too fine a point on this, but this is a problem which should have been (and, more likely than not, WAS) anticipated, AND SOLVED, by the manufacturers and vendors of the solar power industry. It only takes someone of slightly higher than simian-level IQ to anticipate this as a real consequence of feeding power back into the existing power grid. The manufactures had to have known this would be a problem, and instead of investing in a solution, abdicated, up front, their responsibility and decided to pass it on to the consumer, who now will be forced–through governmental regulations and solutions imposed on the power companies–to pay.

    Perhaps it’s time to devote as much energy to all possible consequences of a problem’s solution as it is to the solution itself, BEFORE an industry is allowed to offer for sale a product or solution which has far-reaching consequences.
    Good luck on getting the marketeers–and management–to sign on for this approach. This strategy does NOT generate any revenue.

    Of course, this is precisely why flow charts and commentsare very–extremely–unknown and unusedin the world of writing computer programs–it’s just not the sexy thing to do; and it’s very hard to convince the end user to pay for such frivolity.

    There is a sign posted on my desk:

    “Why is there never enough time to do it right the first time, but always time to do it over?”

  9. Power is mooved by advancing phase not increasing voltage. There must always be a refrence and stable phase source to work against so a generator is a must. Phase control capability shoud be installed in every solar inverter and controlled by the power company via power line signals. Thus the grid stability can be balanced against the generator’s ability to retain phase control without changing frequency.

    1. South Australia uses its big grid-scale battery, installed by Elon Musk, for network Frequency Control Ancilliary Services. It puts out the power of a medium sized generator, and reacts faster than the old fashioned methods. The network boffins are apparently quite pleased with the 21st century way of doing things, and other jurisdictions want ’em too now.

  10. Seems to me (from my lofty perch here in N.A.) this is probably the best problem they could have. I’m curious how many of these systems have battery storage and how many are exclusively grid tie? If grid tie install battery’s and forgo connection to the utility. Of course your mileage may vary, depending on local, federal policy’s and laws. My system is not now, nor will it ever be grid tied. Screw them…. I prefer to be as self reliant as possible.

  11. As far as I’m concerned, this story just underlines what I’ve been saying for more than a decade – that ‘the grid’ as currently implemented is largely an anachronism. Sure, it may be needed for heavy industry, and possibly a few other corner cases. But by and large, we should be redesigning infrastructure around local power self-sufficiency. Segments of grid infrastructure would still be useful for allowing areas experiencing temporary power problems to get power from surrounding areas; but on the whole, neighbourhood-sized areas should be self sufficient when it comes to power. Yes, there are challenges around keeping things in phase in case one power area needs to be bridged to another – but these days that should be an easily solvable problem.

    And wouldn’t it be great to have major winter weather events NOT knock out power in a large portion of a continent, or in most of a state the size of Texas? ‘Cascade failure’ would no longer be a term commonly applied to power generation and distribution.

    1. > on the whole, neighbourhood-sized areas should be self sufficient when it comes to power.

      They should, but that is only practically attainable if you have a gas turbine or a diesel generator in every neighborhood. It doesn’t work with intermittent and non-dispatchable renewable sources. Wind power has to be far removed from habitation by necessity, and solar is only available through parts of the day, parts of the year, weather permitting.

      1. The Levelized Cost of Energy numbers for grid scale solar plus battery (4 hour storage) are competitive with all forms of fossil fuels. The issue isn’t intermittency any more but a grid sophisticated enough to handle a more complex mix of sources and consumers.

        1. I’d like to see those sources, because for what I can calculate just the battery will cost the same as the produced prices for baseload power from gas turbines.

          If you’re comparing LCOE+storage for RETAIL prices, then you’re doing apples to oranges.

          1. Point being, the bulk cost of natural gas off of the pipeline is just around 1 cents per kWh and the cost of electricity through a turbine makes this around 3-4 cents. Most of the 28 cents you’re paying is fixed system costs, taxes and company profit.

            The cheapest plausible lithium battery, let’s say $75/kWh and 2,000 cycles to death at 90% efficiency, costs you 4.16 cents a kWh just for the battery, not including the price of electricity. I cannot see any way in which solar LCOE+battery would be cheaper than fossil fuels on the same basis of comparison.

    2. The grid is still very useful, not just for heavy industry, but also for integrating other sustainable energy sources such as wind. Even distant PV generation then reduces the size of local battery needed, and they’re not cheap. But I see the major benefit of a grid being that it will link widely distributed pumped hydro to cities and their night-time energy needs.
      A grid-scale battery may last 10 years, but hydro generators will last at least 50 years or more.

      What we don’t need is fusion reactors on Earth. We already have all the fusion reactors we need, for free, and it also distributes that power, for the cost of some PV panels. The problem has been solved, in a much safer manner, so let’s move on.

    3. Here in the the Netherlands, there is a phenomenon called “stadsverwarming” Probably best translated as “district heating”. The Idea is to use “waste heat” from power plants for domestic heating. I think most of the installations were built in the ’80-ies, and I’m not sure about the overall efficiency of the system. One of the problems is heat loss from the 10km or longer pipes.

      A few years back this system was extended in my neighborhood. The local waste water treatment plant (It’s smelly so a few km away from populated areas) pumps methane gas to a small generator smack in the center of the neighborhood where it is converted to both electricity and heat.

      One of the nice things of such small-scale systems is that they can be added when and where they make economic sense, while still having the regular grid as a “backup”.

      Methane can also be stored for some time (A round tank of 10m or so was added) and the system may also help with easing peak-loads.

      1. Likewise. Our district heating plant burns wood trimmings and other industrial waste wood like sawdust. Their main issue is that the system is even older and was originally built as an open loop running on coal, so the tail end of the pipe runs into the sea. Since the water has to be hot up to the last building that uses it, what goes past that house is wasted energy.

  12. Is no one else looking at the security of this. Controlling large amounts of power via 4g. What happens when the network goes down. Are they updating firmware when vulnerabilities are identified.

  13. I see a lot of comments here about addressing or what is thought to be addressing the issue, but it comes down to this in a nut shell. The power grid is no where near close to being maxed out 90% of the time. WHAT it truly comes down to is this. The utility company has to pay for the power which is not generated by them but by a producer, such as a gas fired, coal fired or nuclear plant or from a hydro plant on a river which has been dammed. The utility companies do invest in wind, solar and sometimes they do invest in some of the others, but for the most part, utility companies are service, billing agencies. They purchase the power and distribute it to the regional, local consumers and maintain the local grid which is a subsidy of the national grid which has been funded by the Government ! Production plants have also been funded by the Government and contracted by firms that maintain them. Take Hoover Dam for instance, that was such a massive project the only way it could have been undertaken was through Gov. backing. Same goes for most other high capacity plants like nuclear and the only way those could be completed is through Gov. inspection and regulation. The problem with the renewable grid system is that when people are producing the required power they need and or production exceeds demand on the system the renewable is connected to, the utility company sees a reduction in revenue and this to them is almost unacceptable as they cannot cut back on wages and operating expenses. Therefore they suffer a lose of profit. Here’s how it works, AC current flows bidirectional, solar production works on a gradual cycle, little power in the morning and evening no power in the night! Cloudy days make fluctuations an issue for sure. Grid tie inverter systems are unstable in such a case however and granted utility companies can run into fits when everyone is producing and then no one is producing. For this reason a smarter system is absolutely needed. Since grid tie systems must monitor utility line conditions from the start, they have to in order to connect or they would simply NOT work and or cause unsafe circumstances with the power system. Next point as is mentioned in one post causing an issue with the frequency, NO WAY, solar has NOTHING to do with FREQUENCY, or voltage for that matter, grid tie inverters run in sync with line frequency or they could not be grid tie period. Line voltage is controlled by the inverters with set perameters in the sycronous inverter, which is what they are, they sync with the line voltage and frequency before they connect the solar output to the utility line and when that happens the meter either runs in reverse or stops metering power fed to the load circuit, the consumers appliances. I haven’t been involved in this for a while lately however I do know that when I was involved, the utility required a contract with the owner of the backfeed system and the meter monitored output from the renewable, 2 meters, the utility companies meter and the owners meter, the utility company would read both and adjust for the difference in what consumer used and produced. Truly the best constructed system would be set up with a multiple system, which would store excess current for later use and limit what is fed back into the system, this is not hard to do either. All it would take would be system utilizing a limited inverter output and another inverter/charger to make use of the stored power in time of higher demand. It would necessitate a switching system in the fed line, which would really not do anything more to the grid load than as when a heavy load for a particular facility does when suddenly switched on and there are devices to condition this also. As I said earlier, when everyone has a solar system installed and the power sales goes down, the utility firms are going to, have done implementation of policy to limit the public from cutting into their revenue. It’s the only way they will be able to stay in business, like any other business, they must produce and sell or they go out of business.

    1. Let’s put them out of business. If they can’t or refuse to adapt, they must cease operations. A company’s profits, public or private, should not be our reason for maintaining a failing and outdated system.

      1. Who will benefit from the solution by the subsequent lowering of prices during peak and off-peak hours as the batteries feed into the grid at steady rates. Who can ALSO buy solar and batteries, further benefiting from the same system.

        1. The only reason the prices come down is because they’re offset by subsidies, but in reality the cost goes up and you pay more for the same energy indirectly through taxes.

  14. Nothing South Australia does matters much, they have a population of less than 2 million people. They have very high insolation levels too so they are as irrelevant an example as you can find if you are looking for case studies that apply to the rest of humanity.

    1. Europe is planning to use the high insolation in North Africa to support their power requirements, so those who actually understand the issues will in fact be looking for the very relevant learning opportunities. The Mediterranean undersea power cables won’t even be as long as those being planned for North Australia to Singapore.

      Australia is not up with world leaders in the rapidly accelerating solar revolution, but Sundrop Farms in South Australia grows tomatoes in 20 hectares of greenhouses. All the water is desalinated seawater, about 2.8 ML per day, as SA is pretty dry, even by aussie standards. All the power comes from 23,000 mirrors focused onto a 127m high boiler tower.
      The steam generates all electricity needs, condensation warms the 20 Ha of greenhouses, then irrigates the tomatoes.
      They produce $100 million worth of tomatoes annually, sold on a 10 year contract. The greenhouse heating alone saves 14,000 litres of diesel per week. It’s financed by American private equity, and uses European technology. The operators are a German family It’s as international as can be, and only irrelevant to the part of humanity which does not eat.

      May I respectfully suggest that it is COAL which is irrelevant to the future of humanity.

      1. Australia has 300 years worth of carbon based energy reserves and a very large percentage of the world’s uranium and thorium reserves too. They will not even get to exploit a fraction of that before commercial fusion reactors make all other energy systems irrelevant for large scale grids. Nothing that South Australia does is relevant to most of humanity. Well except for all of the uranium sourced there, some of which sits in French reactors and powers the grid in Germany when there renewables prove to be inadequate, on a regular basis. ROFL

  15. The trouble is simply that batteries aren’t yet cost competitive – over their life cycle. It costs more to put the energy in, and get it out again (divided by how often you can do it and the battery cost) than what buying electricity from the grid is – last time I did the numbers in Aus.

    What most of my friends do (in the sunny parts of australia) is put the solar up, use it to run the central air con, pool pump, do the washing etc during the day – and export a small amount to the grid. Then use the grid at night (when the air con isn’t working as hard etc etc) as their battery. They normally end up with about a zero usage bill – but still the fixed cost service fee (which is quite high in Aus).

    The other option – which I’ll do when I retire to my holiday house in the tropics – is put a relatively small battery on, and either disconnect the grid entirely (a few of my friends have done that) or have the grid as a separate backup – ie you have to go out and throw the switch to connect it if your battery is flat because the wet season rain has come for three days.. I mean, there are plenty of places in Aus with more than 300 days sunshine a year, it’s not that hard..

    1. Here in Australia, where there is still a lot of coal fired power generation, it would be no more environmentally irresponsible to add a backup generator to your system, and chuck the grid connection entirely. A modest 3 KVA alternator does not cost the earth, and a few litres of petrol per year is insignificant. (Biofuel would be better.)

      I have no choice but to do that, with no grid connection available, as a week’s worth of good batteries costs another mortgage.

  16. Serious questions.
    I pay for off peak electricity (mainly for hot water) at night, in Victoria, not too far from South Australia.
    With solar, shouldn’t off peak be during the day?
    Also, isnt stored hot water a cheap form of battery\?
    Could fridges incorporate a big ice block to also store energy for daytime?
    These changes are not huge but hot water can be up to a third of household electricity and fridges about 20%?

    We were sold the incredibly annoying on-sellers of electricity as being market driven and therefore innovative and flexible. Financial losses are supposed to stimulate innovation. Seems like BS. Market loss stimulates political intervention so that they can keep making a profit they way they always have.

    1. Thermal energy storage is already at play in medium and large scale in certain areas, usually either district heating and cooling or hydronic systems with ice banks. We certainly could move to more grid balancing solutions in the home, but that’s a choice by the consumers.

      There are of course some hurdles, you can’t start and stop heat pump compressors whenever there is a spike in production, you’ll short cycle and ruin them, so would still need some other solution for buffering.

      Just as there are community solar installations, because of the shared cost, economies of scale, and plain inability for some communities to have rooftop solar, perhaps there should be community storage. It could be mini district heating and cooling with thermal storage buffers, or peak shaving with batteries, flywheels, or whatever works best.

      The initial cost born is always lower per unit as the scale increases, but the economies change from a community or individual saving money to a business making money as you move to larger grid scale installations, like Hornsdale. And thus it moves to politics, where it all gets bungled.

      We must bear the cost of this energy transition, in some form or another, as the global community. It’s already proving to be quite the messy affair, and what comes out on top will only be seen once the dust settles.

  17. I live in South Australia, if the idiots running the state and country try to charge me for export it will just be an incentive to go off grid.

    There’s a lot of hype around the negatives of solar at the moment as the federal government is firmly behind their mates in the fossil fuel industry.

    I’m currently running a 1st gen Tesla Power wall and 3Kw solar which is enough to cover 90% of my power usage.
    2017 4.82MWh, 2018 4.77MWh, 2019 4.89MWh, 2020 4.74MWh

    In summer I utilise the excess power by remotely turning on my pool pumps and solar pool heating when the battery is fully charged. In winter I just run the pumps for a reduced duration once the battery is full.
    I pay more to be connected to the grid than for the power i draw from it.

    If everyone went for solar and battery setup the power companies would go broke, this is the real reason for the negative hype around solar in South Australia.

  18. If the grid and large generators keep screwing around trying to pass their failing off onto the consumers, they’re going to see people buy storage systems and abandon the grid entirely. Then they’ll realize they should have done something else when they’re all facing bankruptcy. I say let dinosaurs die. If they don’t want to pay for power they’re using, cut them off. Again we have the masses subsidizing massive corporations who ignore the failing environment. Time for them to close up shop.

  19. When they say they want to use things like 4G to signal back-feeding on or off, I always scratch my head. Can’t they just modulate a signal into the power line itself? I’m sure there are complexities I’m missing, but I don’t see how it would be any worse than a 4G modem

    1. > modulate a signal into the power line itself

      That’s called ripple control, and used to be used to control off-peak water heaters, especially IFAIK in NSW. I’m not sure if it’s still used. There was one moment of madness a few years ago when someone had the bright idea of using the power grid for Internet. Thank goodness nobody told the grubmint about that! Within properties power line signalling is used for things like WiFi extenders – I have a pair in my house.

      These days the cellular infrastructure is so established it makes more sense to use it.

  20. Sure, the success of solar has presented some near term challenges, but also tremendous opportunity. With differential pricing based on demand, homeowners (or businesses) with batteries can make money buying and selling power. Then there are the businesses that can regulate their usage to take advantage of the low cost “excess” power. It’s not a problem of too much solar, it’s too little imagination.

  21. I question whether it’s still prudent to have every structure’s entire electricity supply relying on external power lines that are susceptible to being crippled by unforeseen events, including storms of unprecedented magnitude, especially considering our very vulnerable overreliance on electricity. (There also are coronal mass ejections to consider, albeit their damaging effects are rare, in which power grids are vulnerable to potentially extensive damage and long-lasting power outages.) Personally, I would really appreciate the liberating effect of having my own independently accessed solar-cell power supply (clear skies permitting, of course)

    To me, each building having its own solar-cell-panel power storage system — at least as an emergency/backup source of power — seems to make sense; albeit it likely would not to the various big energy corporation CEOs whose concern is dollars-and-cents profit margin. If solar-panel universality would come at the profit-margin expense of the traditional energy production companies, one can expect obstacles, including the political and regulatory sort. If it notably conflicts with corporate big-profit interests, even very progressive motions are greatly resisted, often enough successfully.

    Of course there will be those, usually Internet trolls, who will mock the idea for ‘not being realistic’. One based his rebuttal solely on the erroneous notion that if it were possible to have such independent solar-power generation and storage, it would have been done by now and made a few people very wealthy. Unfortunately, when such illogic is widely believed, it’s much easier for some entity to maintain an outdatedly problematic but still very profitable status-quo energy system.

    1. Off-grid solar power is not uncommon in Australia. There are enough takers that most major installers offer a completely self-sufficient off-grid solar installation. Not every inverter is suited to that, so inverter choice is somewhat reduced. Compatibility with the chosen batteries (first consideration) further reduces the choice.

      Some installers are still coming up to speed on the intricacies. My brother’s installation sometimes throws the battery circuit breakers when the back-up generator is started. (For deep winter with several consecutive days of dark skies.)
      Resetting them is annoying, but the installer is trying to find the cause.

      As I’d have to pay for several km of SWER line and a stepdown transformer, I’m going from domestic generator to off-grid solar before moving permanently to the new build. WInter water heating is primarily from an in-flue water jacket on the wood heater. (With an oven in the bottom for baking bread.)

  22. This sounds FAR MORE like an end run around to get out from under having to compensate small producers for their contributions. You could just as easily PENALIZE LARGE PRODUCERS for their inefficient / ineffective ability to connect to the small producers. The net effect would be the same, a solution would be found, but the little guy wouldn’t be getting SCREWED in the process.

  23. Putting shades across PV to control output is not really a suitable solution.

    Your other idea -that’s how lead-acid battery charge controllers work – constant current up to 30V (for a 24V system), then switch to constant voltage – approx 28V – for an hour or two, then “float” voltage at 27.4 until the sun starts to go down and output drops naturally. The output can be controlled electronically – no need for a mechanical solution.

  24. My charge controller can be programmed to switch excess current to a different load once the batteries reach float voltage – water pump, or a second, backup battery bank.

    1. There is a ready to use solar energy accumulator in many homes – the Hot Water Service. OK, hot water is not nearly as low entropy as electrical energy, but it is needed daily, and we don’t want to burn coal to heat it. Rather than put a water heating panel (with a potential to leak) on my roof, it’s wired for diverting excess power to the heating element.
      Rather than spend money on a heat pump whose mechanicals will pack it in after a time, it is more reliable to spend the money on more PV panels. That shades more roof, saving on aircon, especially good on a 43 deg. C (109 F) day.

      It’s not hard to store just as much energy as a 10 kWh battery:
      250 L of water heated 34.4°C = 10 kWh (250 kg * 4.1813 kJ/(kg·K) * 34.4 / 3600 = 9.99 kWh)

      Here in Australia, you’re considered a bit slow if you still have the HWS time switch set for night rate electricity, if you’ve put enough solar on the roof. Even with a 12c feed-in tariff, self consumption is far superior at 24c or so.
      And that’s something electricity distributors can implement with remote control switching. After all, we have remote meter reading, and that’s an order of magnitude more complex.)

    1. It might be necessary to equip the kids with parachutes as well as school lunchboxes. If the house weighs 100 tonnes, then to equal one 10 kWh battery, it’d have to be lifted:

      10000*3600/(9.8*1000*100) = 36.73m (or 120 feet, in the old money.) And that’s before losses.

      Not good for tiny homes, then. You’d get nosebleed.

  25. The comments are TLDR, but solar today is centered around a “grid” when it’s main benefit is providing 90% self sufficiency. Instead of solar being designed to be part of a complicated grid-tie system, it is better to design solar as a self-sufficient commodity. People for 100 yrs have purchased cars for personal consumption. It is only in the past 5 yrs that Uber sharing and peer to peer car rental services have been explored, but I don’t think it’s very practical. Is it possible to make a little money car-sharing a car that I own? Yes. Do I want to stress over the possibility that some weird ticks are in the backseat along with some unreported vomit? No.

    The same goes for solar. I don’t want to deal with the demands of other peak usage, especially if the usage is completely inconsiderate- (i.e user s of solar that have no idea how much power they are using or where it’s coming from- i.e distributed solar).

  26. Hugh amount of fake news going on with this , corporations are seeing less profit from the fossil fuel investments and trying to keep their monopoly intact…. we should start offering tax breaks for homes that install panels to collect early morning and late afternoon sun and bring to the grid outside of the mid-day peak. other ideas posted here make sense , pump water up hill to spin out at night … solar is the path forward ,
    the grid must flex to accept this new tec going forward or the grid will become obsolete .
    full discloser I have a 7kw solar home and ran for office as a board member of the local electric utility…
    fighting from the inside for the public.
    FYI keep your solar system clean from dust and RFI EMI , here is how.
    http://valleymedia.org/satchat/k1kp-416-34-35.JPG

  27. At least in Australia, there is a financial incentive to orienting domestic arrays to both east and west. A north facing (southern hemisphere) array peaks from 10 till 2, when many households are at work and school, and self consumption is minimal. At least in the sunnier half year, panels on an eastern roof can power breakfast cooking and morning heating or aircon, and a western array powers the evening meal, dishwashing, etc. As we don’t have steep roofs here (don’t know what snow is), the two arrays will still produce handsomely in the middle of the day in summer, so can cool the home all day. Not having to buy electricity for peak consumption – at peak prices, is already a strong incentive to plan the solar installation around domestic consumption patterns.

    The second incentive is that network operators now require the ability to throttle your grid-tied inverter at times of peak solar generation, for network stability. Thus a north facing array will not earn feed-in credits in the sunniest weather, or at least much less than it can produce, because the vast majority of installations face that way. An E-W installation on the other hand produces well in peak times when the network is hungry for power, so little chance of throttling.

    The third incentive is that coal burners already have to pay to feed into the grid when solar has flooded the grid with power, i.e. the middle of the day. By edging toward the same situation on the shoulders of that period, you steal their lunch for longer, sending them bankrupt sooner. They’re closing down one by one here, as they burn money to keep operating. Yes, we have negative electricity prices here when the power is not wanted. (Clearly not enough bitcoin mining. ;-)

  28. Two grossly ignorant observations: 1) Limit the number of solar panels for home use. 2) I think that solar power is far more a money-grab appeal than, in reality, an environmental one, like a gigantic white sale. Around here, an inordinate amount of “free” government monies, including those specifically meant to address pandemic problems, are diverted, by municipal/county government, to the installation of solar arrays that will serve either no one within the state, or are only being installed so that the local government can make money – not using it to run facilities, mind you – that they claim will offset utility and other expenses. This is an abuse, but no one “in charge” cares.

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