While nanotech batteries, fuel cells and black boxes receive most of the attention, the most cost-effective methods for storing large amounts of energy are relatively down-to earth: pumped water and compressed air.
A compressed air storage firm, General Compression, announced today that it raised a $17 million round of venture capital. The basic technology is far from new. Essentially, it uses motors to compress air into tanks or caverns when electricity is plentiful (and cheap), which is then released when energy is needed (and expensive). The result is remarkably cost-effective, at least when compared to the other options. From a post today by earth2tech on the subject:
In general, big (100-300 megawatt) underground gas-fired CAES storage costs about $600-$750 per kilowatt of storage capacity built, according to the Electric Power Research Institute. Smaller scale (10-20 megawatt) above-ground CAES costs about $1,000-$1,800 per kilowatt and $250 to $450 per kilowatt-hour, EPRI reported, cheaper in kilowatt-hour terms than the battery technologies EPRI surveyed in its 2008 cost comparison.
What further efficiencies General Compression has brought to the technology remain to be seen, but it’s an important reminder that a technology’s “sexiness” does not necessarily correlate with its efficiency.
