Adding energy storage to sites with rooftop solar power generation offers a range of potential benefits. A battery can help smooth out solar’s inherently variable supply of power to the local grid, and even keep buildings powered during blackouts. Consequently, power-conversion innovators are developing a host of new products designed to reduce the cost and improve the efficiency of integrated solar-storage systems.
According to Vic Shao, CEO for the Santa Clara, California-based energy storage startup Green Charge Networks, tightly integrating storage with photovoltaics in some key states—including Hawaii and California—runs afoul of the “net metering” rules by which PV owners earn lucrative retail rates for the surplus power they feed to the grid. Adding storage can disqualify solar systems for net metering, in which utilities can pay their owners wholesale power rates that are several times lower than retail. “That is obviously a pretty big problem for anybody considering solar. That could kill a lot of projects,” says Shao. Continue reading →
Renewable energy is often intermittent, and that variability presents a variety of challenges to power grids. The nature and magnitude of the challenges depends on the time frame — from fractions of a second to seasonal or even multiyear variations — as well as the nature of the grid itself. The latter is evident in two of my articles from last week looking at how seconds-to-minutes fluctuations in solar power complicate grid controllers’ efforts to maintain alternating current at the 60 hertz frequency and the roughly 110 volt power levels required by North American devices.
Flywheel energy storage developer Beacon Power filed for bankruptcy last weekend, prompting immediate comparisons to infamously failed solar manufacturer Solyndra. But while both firms used millions of dollars in federal loan guarantees to expand their businesses, Beacon Power — which Spectrumprofiled this summer — has working assets and a good shot at restructuring and carrying on. Continue reading →