Analysts see a strong, upcoming demand for energy storage as part of the grid. This will likely be a combination of some kind of central storage (for example, a 20MW flywheel installation near a power generation station) and distributed storage (for example, batteries or supercapacitors next to the familiar green transformers in people's yards).
These types of energy storage are primarily driven by a need on the part of utilities for load balancing, since it's expensive for them to constantly adjust the output of traditional power generation systems as the load varies. Energy storage may even allow them to offset or delay the requirement of additional power plants, such as a gas-fired "peaker" plants.
To a lesser extent, the need for energy storage will also be driven by the inherently intermittent nature of many renewable energy sources, such as solar power and wind. As more of this kind of power generation comes online, it makes sense to store the energy for times when the wind isn't blowing or the sun isn't shining.
Proponents of solar power, however, like to point out that although PV is intermittent (due to clouds and of course darkness), it's actually highly predictable. Clouds don't cause that much variability if the PV is spread out over a wide enough area. And because clouds are visible, it's relatively straightforward to predict the impact on power generation on a short-term basis and even easier to predict the amount of power that will be generated the next day based on weather reports.
Also, depending on location, peak demand is often in near-perfect sync with PV-generated power, since it's the heat of the sun that creates the need for air conditioners, which are the primary source of demand.
In five to 10 years when PV and other renewables have come to represent a significant percentage of the overall power generated for the grid, energy storage could play an increasingly important role. "As you go from a scenario where 2 percent of the peak load is generated by PV to 20 to 30 to 40 percent, you start to get into a situation where you need storage," Shugar said. But he also said that many other ways exist to control demand with a smart grid in place.
