I’ve long believed that in our quest to match electricity supply and demand, especially when both are varying, that it’s easy to overlook physical storage. We keep looking for the sexy solution, like gigantic lithium batteries, when a more economical solution could be vastly simpler. Probably my favorite example of this approach is pumped storage, in which water is pumped from a low to a higher reservoir and then allowed to flow back and drive a hydroelectric generator.[1]
A close second is flywheels: An array of big honkin’, heavy wheels on high-tech bearings that store energy by spinning it high speeds. When you need to tap the energy they contain, you let them drive generators. Again, see the Wiki machine for some details.
I bring this up because there’s at least a little movement on the flywheel front, as described in: Storing energy for when needed:
The state [NY] is ready to invest $2 million to build a flywheel-based electricity storage system designed to help reduce greenhouse gases, which cause global warming.
The plant will house an array of massive flywheels spinning at up to 16,000 revolutions per minute. They’re designed to store excess power from the electrical grid, releasing it as needed to match the ebb and flow of statewide demand for electricity to avoid brownouts and blackouts.
Smoothing the electric supply is now done by ramping up fossil-fuel-powered electric plants, which burn coal, oil and natural gas. Emissions from those plants produce carbon dioxide, identified by an international scientific consensus as the cause of global warming.
… Instead, 200 flywheels — each a rotating disk 7 feet tall and 3 feet wide — will spin, using motors that draw excess energy from the power grid when it is not needed.
…
Because of an almost total lack of friction, the flywheels can spin out power for about a hour, meaning power plants won’t have to increase capacity to meet demand.
A 20-megawatt flywheel plant, like the one planned for the seven-acre facility, should prevent the release of up to 12,000 tons of carbon dioxide each year. That’s equal to saving 20,000 barrels of oil or taking about 2,000 cars off the road.
In the longer run, the ideal solution would be to link things like wind and solar PV across large geographic areas via a supergrid. The rationale for such an approach is is simple: Wind might not blow all the time in any given place, but it’s always blowing somewhere. Build a lot of wind farms and link them, and you can relatively efficiently funnel electricity from where it’s generated to where it’s needed.
But building that level of supergrid is anything but a cheap, easy, or quick proposition. Just getting the right-of-way access for the transmission lines across state, county, and local jurisdictions in the US would be a nightmare, even before you addressed the “real” issues of funding and implementation. With that preferable solution delayed (possibly indefinitely), I expect to see more use of localized and on-site electricity storage.
In other words: Flywheels, baby!
[1] See the Wikipedia entry on pumped storage for a fascinating overview of how it works and how widely it’s used (hint: a lot more than most people think).
