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How do we store solar and wind energy?Asked by Signe Klange
Why invent anything else?
Quote from: thedoc on 23/02/2016 17:28:50How do we store solar and wind energy?Asked by Signe KlangeQuote from: alancalverd on 23/02/2016 22:53:46Why invent anything else?My favorite has always been to use gravitational potential as a storage system. This is more of a local storage system and is not necessarily connected to and distributed by the grid, although there is no reason why it couldn't be. And it is not a new invention. The system consists of two water tanks separated by enough height to allow an on demand hydro generator enough head to supply all the requirement that a household can demand. Obviously the water capacity of the system has to be enough to maintain that output for a minimum of 24 hours. It uses solar energy and any other energy input you want to couple to it, to pump water from the bottom to the top. It then uses this gravity battery to run the hydro generator. It can be a stand alone Off-Grid system, or hooked into the Grid to sell power back once the top storage tank is at capacity. In Off-Grid mode such a situation would just overflow the top tank back in to the bottom tank. In a Grid-connect system this overflow is run through the hydro unit into the Grid. $$$$$ The normal problem with local storage of excess power is the batteries. They are expensive and need regular replacing. Done properly this Gravitational potential battery, has minimum maintenance and no replacement costs.
Imagine every household having a 100 m high tower with a 10m3 capacity, plus the pumps and dynamos required for conversion: $$$$ indeed!
Alan's idea sounds fine but it would require new technology. New metering and a pressure system to override the supply pressure so gas can be stored that way. There would also major safety concerns with such a generation and pumping system in a private home. Research, development, installation and maintenance costs are at this stage unknown as I have not heard of a feasibility study on such a thing.
If anyone wants to use small-scale storage from off-grid electricity, I'd advocate generating Brown's Gas by simply electrolysing water with alternating current, inside an ordinary steel gas bottle fitted with an ordinary gas regulator. This will give you all the delivery pressure you could possibly want, without pumping. The stoichiometric mix of hydrogen and oxygen can be burned in an unventilated space, unlike methane or pure hydrogen, which should make for a very efficient miniature central heating boiler. And you can condense the exhaust for drinking or recycling.
Then, if you can't store it, and just convert it to heat as it's produced, why not just drive an electric heater with the excess energy and avoid conversions altogether?
Quote from: chiralSPO on 27/02/2016 02:24:06Then, if you can't store it, and just convert it to heat as it's produced, why not just drive an electric heater with the excess energy and avoid conversions altogether?The problem, particularly for the UK, is that the hottest and coldest days are those with no wind, so we absolutely need to store energy from windmills if they are going to replace more than 10% of our electricity supply.