Quote:
Originally Posted by ZeroID
It basically is a lossy process ie only ~80% of the energy used to pump the water up is recovered in the regeneration of power. It only works financially by saving during cheap power periods and generating when the spot price goes up. Unless it uses power that would otherwise be lost, ie wind or solar excess, it seems to be a rather ineffective way to support the system.
|
Yes, pumped-storage hydro is a "lossy" system - but so is ANY energy storage system - the First Law of Thermodynamics tells us that!
However, the "round-trip" efficiencies are comparable to any other large-scale energy storage system that has been demonstrated to date, and it scales MUCH bigger than any other currently available technology (such as Li-Ion batteries etc.)
As to the economics - there have been some notable "market failures" where pumped-storage systems have been owned and operated by traditional "carbon-based" energy companies, and the pumped-storage plant has been run to generate maximum revenue for the energy company, rather than to provide maximum benefit to the community as a whole.
"Maximum revenue" means that you run all your plant to provide as much power as possible at times of high demand / high spot price - but not TOO much, because that lowers the spot energy price. (Energy companies actually do best when there is a slight shortfall of supply, so the spot price stays high.) For energy companies who are reliant upon fossil fuels, pumped-storage hydro reduces the amount of base-load plant they need to build, but it doesn't help with reducing our net CO2 output.
"Maximum benefit to the community" would mean you "farm" as much renewable energy as possible and store it for release when demand exceeds supply, minimising our reliance upon fossil fuels, or even eliminating it altogether. If you are a carbon-based energy supplier, this isn't possible, because every mega-watt-hour you generate ultimately comes from burning fossil fuels. If you are a renewables-based energy company, then pumped-storage hydro (and other "battery" schemes) are a natural adjunct to help us move to a zero-emissions energy future.
I for one can't really see a MORE effective and sustainable way to supply our energy needs.