AGES Of Renewable Energy Storage

As society transitions toward renewable energy sources, energy storage inevitably comes to mind. Researchers at the University of Illinois at Urbana-Champaign have found one way to store renewable energy that re-purposes existing fossil fuel infrastructure.

While geothermal electricity generation shows a lot of promise, it’s currently limited to a select few areas where hot rock is close to the Earth’s surface. Advanced Geothermal Energy Storage (AGES) stores energy underground as heat and recovers it later, even in places without high subsurface temperatures. For this study, the researchers located an old oil well and instrumented it with “flow meters, fiber optic
distributed temperature sensing (DTS) cable, surface pressure and temperature gauges, and downhole pressure and temperature gauges to monitor the thermal and hydraulic changes during the injection test.”

This field study found that AGES system efficiency could be as high as 82% and yield an “economically viable” levelized cost of electricity (LCOE) of $0.138/kWh. Using existing deep hole infrastructure speeds up site selection and deployment of AGES when compared to developing on an undisturbed location, making this a very interesting way to deploy grid-scale storage rapidly.

We’ve covered reusing fossil fuel infrastructure before as well as challenges and unusual solutions to the energy transition if you’re looking for more about what might be on a future smart grid.

26 thoughts on “AGES Of Renewable Energy Storage

  1. They state they can recover 82% of the stored heat. OK. Not implausible.
    The storage temperature is 250C.
    They then state “and a[sic] electricity generation efficiency of 73% can be achieved.” OK. Not plausible. Monsieur Carnot would like to have a word.

    1. Yeah, this smells a lot like “73% theoretical efficiency”, which comes in at 32% absolute in my book (with an exemplary 20°C 250°C meaning 44% Carnot efficiency).

      Would love to hear what wonderful minerals they are leaching with 250°C hot water that will cake up the heat exchangers :)

      1. There’s always something that mucks up the works, isn’t there? Geothermal’s got minerals. Hydropower has silting. Coal burners have coking and the ash issue. Gas turbines it’s sulfur and ptting. Wind turbines it’s unrecyclable worn blades. Solar it’s toxic production waste. And nuclear’s got the NIMBYs. Some can be mitigated by engineering. Others, not so much.

        1. But some of those are a bigger problem than others – turbine blades are fairly inert and easily handled compared to nuclear waste, for example.

          Plus people are already pressing ahead rapidly with improving a lot of those issues, and I’m not seeing anything compelling to suggest production of renewables like solar panels is anywhere near as awful as the traditional alternatives like coal-fired power stations.

        2. No. Nuclear doesn’t have “NIMBYS” in the same way as wind turbines, for example.

          Nuclear (fission) has Chernobyl, Sizewell B, Three Mile Island and Fukushima. And you only even needed just one of those to demonstrate why it’s so crazy. Just one can go disastrously wrong, really rapidly, and cause centuries of severe damage – and that’s not even taking into account the nuclear waste from all of the other fission plants that haven’t (yet) gone wrong…

    1. Theoretical is well worth knowing – as it provides the upper limit of what you might be able to get, in the real world the first prototype might only get 1%, may get 20%, maybe even 50% but it is never going to be all that close to 100% of that theoretical, add in years of refinement and 80% of that theoretical maximum is you hope now possible, with some expectation you can still get some gains in the future.

      You have to start somewhere – if you judged every idea only by the first tests efficiency nobody would ever have successfully advanced any technology…

      All that said I am not sure if this tech actually makes sense, the theoretical maximum return to me doesn’t seem high and it is not cheap to the point of being practically free to create (plus we don’t yet have enough renewable energy sources that we are so desperate for anywhere to put the excess where we can get some of it back). It is interesting though.

      1. A little different take. First pass measured, not theoretical, efficiency (or any other metric) matters a lot. When I worked in petrochemical chemistry, the problem with new stuff is you not only have to be economically viable out of the chute but do not forget that you are competing with existing tech and that existing tech is going to continue to mature as well. If I remember right the rough and dirty approximation is you have to be 20% better, off the bat, to overcome that hurdle and even have a shot at commercialization. Practical real world experience. No one is gonna invest in theoretical efficiency, they want hard numbers and they better be good. My company folded after 6-8 years BTW, just like 95% of all the other startups and I’m sure tech startups too.

  2. Meanwhile over at TAE Technologies they have been working with Japanese researchers and have achieved magnetically-confined hydrogen-boron fusion. With the exception of remote and niche applications pretty much all “renewable” technology is not going to be commercially competitive in the near future, if it ever was.

      1. Actually Phil even now the world’s energy production is still dominated by coal. That will be replaced with fusion or fission reactors, not solar panels etc. There will not be any point in using solar power in Earth’s mega cities where most humans will live. So yeah it most definitely will become a niche option. But thanks for you _opinion_ anyway.

  3. This makes much more sense as a municipal hot water/heating system, where heat can be stored from solar collectors in summer, and used throughout the year. But I think oil wells are not usually colocated people.

    1. There was a guy in the UK with a website which I can’t find any more who was doing this on his own property.
      Solar thermal being pumped into the ground during summer and a GSHP system pulling the heat back out during the winter.
      “Charging the earth” he called it.
      Over a few years he supposedly bought the ground temperature up higher and got better efficiency.
      But a lot of people claimed it was faked and would never work…

      Now lots of people are talking about it.

      An interesting paper:

      1. London Underground has been doing it for 100 years unintentionally – the older tunnels are unbearably hot in summer now and weren’t designed with AC in mind. They used to advertise the underground as being a cooler way to travel in summer.

  4. Just build nukes. They refuse to build nukes not because of safety (do you really think they care about safety after all that’s happened?) but because it’s not as profitable as this “innovation.” Renewable energy is just a scheme for tax dollars. They aren’t trying to fix the problem, they’re manufacturing sinecures.
    We already have the solution to clean energy. We’ve had it for nearly a century.

  5. There is two years of energy storage in the core of every reactor. It’s called “fuel.”

    We need to transition to carbon-free fuel, not fuel-free systems.

    1. Or at least carbon-neutral fuels. It’s pretty tough to beat the energy density of hydrocarbons for motive power applications, and synthetic liquid fuels made from recovered CO2 can be the way to do it.

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