green hacks

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The Coolest Batteries You’ve Never Heard Of

March 9, 2025 by 55 Comments

Imagine cooling your building with the same principle that kept Victorian-era icehouses stocked with lake-frozen blocks, but in modern form. That’s the idea behind ice batteries, a clever energy storage hack that’s been quietly slashing cooling costs across commercial buildings. The invention works by freezing water when energy is cheap, and using that stored cold later, they turn major power hogs (air conditioning, we’re looking at you) into more efficient, cost-effective systems.

Pioneers like Nostromo Energy and Ice Energy are refining the tech. Nostromo’s IceBrick modules pack 25 kWh of cooling capacity each, install on rooftops, and cost around $250 per kWh—about half the price of lithium-ion storage. Ice Energy’s Ice Bear 40 integrates with HVAC systems, shifting up to 95% of peak cooling demand to off-peak hours. And for homes, the Ice Bear 20 replaces traditional AC units while doubling as a thermal battery.

Unlike lithium-ion, ice batteries don’t degrade chemically – their water is endlessly reusable. Combining the technology with this hack, it’s even possible in environments where water is scarce. But the trade-off? They only store cooling energy. No frozen kilowatts for your lightbulbs, just an efficient way to handle the biggest energy drain in most buildings.

Could ice batteries help decentralize energy storage? They’re already proving their worth in high-demand areas like California and Texas. Read the full report here and let us know your thoughts in the comments.

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A balding man in a blue suit and tie sits behind rows of plants on tables. A bright yellow watering can is close to the camera and out of focus.

Phytoremediation To Clean The Environment And Mine Critical Materials

February 28, 2025 by 10 Comments

Nickel contamination can render soils infertile at levels that are currently impractical to treat. Researchers at UMass Amherst are looking at how plants can help these soils and source nickel for the growing EV market.

Phytoremediation is the use of plants that preferentially hyperaccumulate certain contaminants to clean the soil. When those contaminants are also critical materials, you get phytomining. Starting with Camelina sativa, the researchers are looking to enhance its preference for nickel accumulation with genes from the even more adept hyperaccumulator Odontarrhena to have a quick-growing plant that can be a nickel feedstock as well as produce seeds containing oil for biofuels.

Despite being able to be up to 3% Ni by weight, Odontarrhena was ruled out as a candidate itself due to its slow-growing nature and that it is invasive to the United States. The researchers are also looking into what soil amendments can best help this super Camelina sativa best achieve its goals. It’s no panacea for expected nickel demand, but they do project that phytomining could provide 20-30% of our nickel needs for 50 years, at which point the land could be turned back over to other uses.

Recycling things already in technical cycles will be important to a circular economy, but being able to remove contaminants from the environment’s biological cycles and place them into a safer technical cycle instead of just burying them will be a big benefit as well. If you want learn about a more notorious heavy metal, checkout our piece on the blessings and destruction wrought by lead.

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An overhead shot of a parking lot. A road with cars parked along it is on the right hand side of the image. The top center shows a drilling rig on tracks drilling at a slight angle into the ground. Many different semi trailers dot the parking along with several different pallets of construction supplies. An excavator and skylift/forklift are also at work in the lot.

District Heat Pump Systems Save Money And Gas Utilities

February 26, 2025 by 50 Comments

Ground-source heat pump systems are one of the most efficient ways to do climate control, but digging the wells can be prohibitively expensive for the individual citizen. What if you could do it at a larger scale?

Starting with a pilot to serve 37 commercial and residential buildings in Framingham, MA, Eversource is using its experience with natural gas drilling and pipe to serve up a lower carbon way to heat and cool this neighborhood. While district heating via geothermal has precedents elsewhere in the country, Boise is a notable example, it has remained a somewhat niche technology. Once networked, excess heat from one location can be used elsewhere in the system, like data centers or industrial facilities being used to heat homes in the winter.

As gas utilities look to transition away from fossil fuels, their existing knowledge base is a perfect fit for geothermal, but there are some regulatory hurdles. Six states have passed laws allowing natural gas utilities to expand beyond just gas, and bills have been filed in six more. This will likely accelerate with the formation of the Utility Networked Geothermal Collaborative which includes many utilities including giants like Dominion Energy who are looking to expand their energy portfolios.

If you want to dig more into district heating systems or geothermal energy, we’ve covered cogeneration from power plants to serve up the heat instead, doing it with wind, or even using old coal mines for geothermal heat.

NEMA Releases Standard For Vehicle-to-Grid Applications

February 22, 2025 by 70 Comments

Vehicle-to-grid (V2G) has been hailed as one of the greatest advantages of electrifying transportation, but has so far remained mostly in the lab. Hoping to move things forward, the National Electrical Manufacturers Association (NEMA) has released the Electric Vehicle Supply Equipment (EVSE) Power Export Permitting Standard.

The new standards will allow vehicle manufacturers and charger (EVSE) suppliers to have a unified blueprint for sending power back and forth to the grid or the home, which has been a bit of a stumbling block so far toward adoption of a seemingly simple, but not easy, technology. As renewables make up a larger percentage of the grid, using the increasing number of EVs on the road as battery backup is a convenient solution.

While the standard will simplify the technology side of bidirectional charging, getting vehicle owners to opt into backing up the grid will depend on utilities and regulators developing attractive remuneration plans. Unfortunately, the standard itself is paywalled, but NEMA says the standard “could put money back in electric vehicle owners’ pockets by making it easier for cars to store energy at night or when turned off and then sell power back to grids at a profit during peak hours.”

We’ve covered some of the challenges and opportunities of V2G systems in the past and if you want something a little smaller scale, how about using a battery that was once in a vehicle to backup your own home?

An Electric Converted Tractor CAN Farm!

January 23, 2025 by 12 Comments

Last October we showed you a video from [LiamTronix], in which he applied an electric conversion to a 1960s Massey-Ferguson 65 which had seen better days. It certainly seemed ready for light work around the farm, but it’s only now that we get his video showing the machine at work. This thing really can farm!

An MF 65 wasn’t the smallest of 1960s tractors, but by today’s standards it’s not a machine you would expect to see working a thousand acres of wheat. Instead it’s a typical size for a smaller operation, perhaps a mixed farm, a small livestock farm, or in this case a horticulture operation growing pumpkins. In these farms the tractor doesn’t often trail up and down a field for hours, instead it’s used for individual smaller tasks where its carrying or lifting capacity is needed, or for smaller implements. It’s in these applications that we see the electric 65 being tested, as well as some harder work such as hauling a trailer load of bales, or even harrowing a field.

In one sense the video isn’t a hack in itself, for that you need to look at the original build. But it’s important to see how a hack turned out in practice, and this relatively straightforward conversion with a DC motor has we think proven itself to be more than capable of small farm tasks. Its only flaw in the video is a 30 minute running time, something he says he’ll be working on by giving it a larger battery pack. We’d use it on the Hackaday ancestral acres, any time!

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Electric Vehicle Charging Heats Up

January 22, 2025 by 64 Comments

As the electric vehicle takeover slowly lumbers along, marginally increasing efficiencies for certain applications while entrenching car-centric urban design even further, there are some knock-on effects that are benefiting people and infrastructure beyond simple transportation. Vehicle-to-grid technology has applications for providing energy from the car back to the grid for things like power outages or grid leveling. But [Technology Connections] is taking this logic one step further. Since a large number of EV owners have charging stations built into their garages, he wondered if these charging stations could be used for other tasks and built an electric heater which can use one for power.

This project uses a level 2 charger, capable of delivering many kilowatts of power to an EV over fairly standard 240V home wiring with a smart controller in between that and the car. Compared to a level 1 charger which can only trickle charge a car on a standard 120V outlet (in the US) or a DC fast charger which can provide a truly tremendous amount of energy in a very short time, these are a happy middle ground. So, while it’s true a homeowner could simply wire up another 240V outlet for this type of space heater or other similar application, this project uses the existing infrastructure of the home to avoid redundancies like that.

Of course this isn’t exactly plug-and-play. Car chargers communicate with vehicles to negotiate power capabilities with each other, so any appliance wanting to use one as a bulk electric supply needs to be able to perform this negotiation. To get the full power available in this case all that’s needed is a resistor connected to one of the signal wires, but this won’t work for all cases and could overload smaller charging stations. For that a more complex signalling method is needed, but since this was more of a proof-of-concept we’ll still call it a success. For those wanting to DIY the charger itself, building one from the ground up is fairly straightforward as well.

Thanks to [Billy] for the tip!

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Hydroelectric Generator Gets Power From Siphoning

January 21, 2025 by 43 Comments

Siphons are one of those physics phenomena that, like gyroscopes, non-Newtonian fluids, and electricity, seem almost magical. Thanks to atmospheric pressure, simply filling a tube with liquid and placing the end of the tube below the liquid level of a container allows it to flow against gravity, over a barrier, and down into another container without any extra energy inputs once the siphon is started. They’re not just tricks, though; siphons have practical applications as well, such as in siphon-powered hydroelectric turbine.

This is an iteration of [Beyond the Print]’s efforts to draw useful energy from a local dam with an uneconomic amount of water pressure and/or volume for a typical hydroelectric power station. One of his earlier attempts involved a water wheel but this siphon-based device uses a more efficient impeller design instead, and it also keeps the generator dry as well. Using 3″ PVC piping to channel the siphon, as well as a short length of thinner pipe to attach a shop vac for priming the siphon, water is drawn from the reservoir, up the pipe, and then down through the impeller which spins a small DC generator.

This design is generating about 9 V open-circuit, and we’d assume there’s enough power available to charge a phone or power a small microcontroller device. However, there’s a ton of room for improvement here. The major problem [Beyond the Print] is currently experiencing is getting air into the system and having the siphon broken, which he’s solved temporarily by adding a bucket at the outflow. This slows down the water though, so perhaps with any air leaks mitigated the power generation capabilities will be greatly increased.

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