Beacon Power, dropped 18% today on over $10 m of sales to finance ongoing operations, including the expected completion of Beacon's Smart Energy 25 flywheel development and the design of the first 20-megawatt frequency regulation power plant.

My general view is that flywheels are much closer to widespread commercial application than fuel cells, but that's not saying much. I was particularly intrigued to read earlier this year that research at Lawrence Berkeley National Laboratories indicates that 10 MW of fast-responding flywheel energy could provide the grid with the equivalent energy of 20 MW or more of traditional slow-responding power plant energy.

I'd like to know what kind of slow-responding power plant they are referring to. A semi warmed-up combined cycle gas turbine can start up in 3 minutes, a coal station perhaps 12 hours. 20 MW though is a really decent amount of power - the highest quantity so far for high-tech energy storage.