Sitting here staring out at my green front lawn, which only yesterday was covered with a blanket of the pre-Christmas snowfall we received last weekend. The temperature is well into the 50s (Fahrenheit), which seems bizarre given the sub-teens readings that made my car tire-pressure system go haywire last Monday. This, my friends, is the reason why it's so difficult to rely on renewable energy sources such as the sun or the wind or the ocean waves: the natural world is highly unpredictable, along with the weather.
That's why, in tandem with cost-efficiency advances that will make some of these options cheaper throughout 2009, one big investment bet will be on battery technologies that can help us store up all the energy that the world creates around us. One example is investments being made by Xcel Energy, which is the subject of this article published a few days ago by Scientific American.
Xcel has installed a system of 20 sodium-sulfur batteries from NGK Insulators that can store up to seven megawatt-hours of electricity, which translates into enough power to run 500 average American homes for up to seven hours. The problem is, this stuff is really expensive right now: about $3 million per megawatt for starters.
Here are more details on the project, which was first announced last February.
Here are some other links with information about battery technology meant to extend the impact of renewable energy.
Some frequently cited companies in the game: VRB Power Systems