A Californian company proposes using weighted electrically-driven rail vehicles on inclines to store energy. At times when the capacity of electricity supply exceeds demand the vehicles would be driven up inclined tracks, and when demand exceeds generation they are allowed to run down, generating electricity as they fall.
This link includes a video that shows a prototype vehicle (which appears to be built on a conventional locomotive chassis), an interview with a promoter, and an animation of a "farm" of these devices. There is a shortage of hard data, such as how much energy could be stored, for how long, and how steep the tracks are, etc., but a quick calculation shows that some thousands of these vehicles would be required for them to be useful. The control panel for this prototype has a power dial that appears to go up to only 20 kW. The promoter in the interview focuses instead on how the construction material can be recycled at end of life.
(Score: 2) by captain normal on Tuesday July 03 2018, @05:16PM (3 children)
Why bother with water storage and pipes? How about a big pressure vessel? Just use the excess (solar, hydro etc.) production to pump air into pressure container, then release it through a turbine to generate power. Truckers have long stored compressed air to start their diesel engines. Companies are already building large pressure tanks to transport compressed natural gas. Pressure pumps, turbine engines, and generators are off the shelf stuff.
There ya go...the first billion dollar idea is free, the next ones will cost you.
When life isn't going right, go left.
(Score: 2) by requerdanos on Tuesday July 03 2018, @05:26PM
Sometimes [thelocal.es], it's because the storage is provided by nature itself, in the form of natural bodies of water separated in elevation, which, when combined with pipes, pumps, and turbines, is arguably simpler (and more failsafe) than using trains or pressure vessels.
(Score: 4, Insightful) by c0lo on Tuesday July 03 2018, @05:42PM (1 child)
You know what happens when you compress a gas? Yes, it heats up.
And if you maintain the pressure constant, that heat dissipates. Like, it's lost, man, gone.
And when you decompress the gas, you'l be missing that energy.
True, you can use the idea, but for high volume and small delta-pressure - this way, the amount of energy gone by thermal transfer is less a fraction of the total stored energy. Or invent a perfect thermal insulator - with the today's technology, you get around a 700% efficiency.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by c0lo on Tuesday July 03 2018, @08:34PM
Make that efficiency to 70%.
When taking the conversions electricity->pressure->electricity, you get about half what you've put in.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford