this post was submitted on 09 Apr 2024
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I get the sentiment in here, but the poster is missing an important point: there is a reason some group of lunatics (called the TSO or Transport System Operator or in some cases other power producers) are willing to pay for people to consume electricity when there is too much of it; They are not doing it for the sake of being lunatics, the electrical system cannot handle over or underproduction. Perfectly balanced (as all things should be) is the only way the grid can exist.
The production capacity in the grid needs to be as big as peak demand. The challenge we face with most renewables is that their production is fickly. For a true solarpunk future, the demand side needs to be flexible and there need to be energy storages to balance the production (and still, in cold and dark environments other solutions are needed).
In off-grid, local usages we usually see this happen naturally. We conserve power on cloudy low-wind days to make sure we have enough to run during the night (demand side flexibility) and almost everyone has a suitably sized battery to last the night. The price variability is one (flawed) mechanism to make this happen on a grid or bidding zone level.
This has me thinking
The resurgance of sand batteries has been interesting. While not great for converting back into electricity, it's great for heating and cooling which is a massive portion of our energy consumption. They can also store quite a ton of energy with crazy efficiency, especially when paired with heat pumps. And from what I've been able to deduce, they aren't dependent on beach sand and can use rougher or man-made sand reliably.
First if we could get enough large buildings and neighborhood/home installation sand battery heating & cooling infrastructure operating with heat pumps. Then when during high times of energy production we can dump the energy into the sand battery infra and help keep the grid stablizied and keeping our heat & cooling overall percentage of use down.
In the end, we're going to need tons of solutions and strategies for storing excess production during low demand times. I'm hopeful to see where we go here, the crazy things were seeing in energy storage is extremely interesting. I'm super excited to see the advances were seeing in calcium and sulfur based batteries expand in adoption and the production lines can scale with demand.
I've been really curious about the possibility of a small DIY sand battery type system. I currently store my "negative value" midday solar power by dumping it into a water tank and using it to feed my hydronic heating system.
However as we know that results in a tank containing useless low-grade heat on a cloudy day, where a sand battery would result in a small amount of usable high-grade heat.
The cooling equivalent could actually be implemented fairly easily at home with common consumer ice machines (which are effectively heat pumps). Make ice when there's surplus, dump it in an insulated hopper with a heat exchanger for night-time cooling, recycle the near-freezing melt water to make ice the next day. Water is a lot easier to handle because it can be pumped instead of conveyed, and you get the advantage of phase change storage.
That's really interesting you're storing power. Was it diy??
Entire system is home built and programmed except the inverter which was a surplus rack-mount.
The dump load in the water tank tracks the battery bank voltage, drawing more power as the voltage rises into the float range. This is used to sense available surplus power, which is used to turn on other dump loads, i.e. air conditioning in summer.
I have a couple window units that are cranked to max cooling and come on in sequence as the surplus power rises, on an early summer day with clear skies it can get to the point of needing a sweater in the house :D I'm migrating to a homebuilt multi-stage heat pump this year after the prototype worked quite well last year.
Also seriously considering the ice storage concept for hot nights, though I might need to make an actual ton of ice!
Just made a deal on 8 massive surplus AGM batteries too to refresh my bank
Fucking amazing😮😮 Write a blog if you document things.. Might come handy to beginners