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Non-Tech : Alternative energy -- Ignore unavailable to you. Want to Upgrade?

To: Eric who wrote (4442)	3/18/2008 2:15:29 PM
From: gg cox	Read Replies (1) \| Respond to of 16955

I have problems with the article on energy storage. Page 2 half way down.. <<Compressed-air energy storage has emerged as a successful alternative. Electricity from photovoltaic plants compresses air and pumps it into vacant underground caverns, abandoned mines, aquifers and depleted natural gas wells>> Lets call the energy used to compress the underground caverns.. X Now we have this.. <<The pressurized air is released on demand to turn a turbine that generates electricity, aided by burning small amounts of natural gas. Compressed-air energy storage plants have been operating reliably in Huntorf, Germany, since 1978 and in McIntosh, Ala., since 1991. The turbines burn only 40 percent of the natural gas they would if they were fueled by natural gas alone, and better heat recovery technology would lower that figure to 30 percent.>> So now the amount of energy used to compress the air for storage is X (compressing air is without doubt an energy hog) PLUS 40 percent of normal natural gas used to make equivalent amount of electricity, says to me this would be far more expensive and inefficient than storing it in massive VRB ESS at 80 percent efficiency DC current round trip. See #9 vrbpower.com Hot Salt storage is a stretch.... <<The molten salt does slowly cool, however, so the energy stored must be tapped within a day.>> Once VRB electrolyte is charged it can remain charged indefinitely. And, of course more losses for compressed air natural gas storage ... <<Typically, a natural gas-fired combustion turbine-generator operating in a "simple cycle" converts between 25 and 35 percent of the natural gas heating value to useable electricity>> fossil.energy.gov VRB is proven technology and has been working for years.<g>