A new report “US-German Clean Energy Leadership Series” highlights best practices for integrating renewable energy into the grid in both Germany and the United States. Compiled by Ecofys and the Center for Climate and Energy Solutions, the study says energy storage is an ideal technology for intermittent renewables since it can simply store electricity during peak generation and release it during peak demand. However, new electricity storage projects are often prohibitively expensive, though costs are trending downward.
Possible technologies include hydroelectric pumped storage, power-to-gas, power-to-heat, batteries, flywheels, and compressed air.
In terms of highlighted best practices in the US, a proposed Bethel Energy Center in Texas will use a combined compressor/generator to pump air into a salt dome cavern when there is a surplus of wind energy available on the grid. The built-up air pressure can then be used to bring the generator to its maximum output of 317 MW to meet demand. The combined wind and storage project should be able to deliver electricity at costs that are competitive with other forms of generation.
Also in Texas, the Center for the Commercialization of Electric Technologies (CCET) is installing a 1 MW/1 MWh lithium ion-based battery energy storage system (BESS) at the Reese Technology Center in Lubbock, as part of a $27 million smart grid demonstration combined wind/storage project.
A best practice energy storage example in Germany it a virtual power plant in the Harz region. A central control room at the renewable energy combined-cycle power plant receives real-time information on the energy situation in the region. This control room combines and coordinates renewable energy producers, controllable appliances and energy storage (pumped storage and batteries in electric vehicles) and integrates them into one system. This creates a “virtual power plant” that integrates the different power sources and matches supply and demand.