In order to balance out varied frequencies on the grid caused by changing power supply, grid operators often ramp up natural gas plants for short periods of time. But one company believes this “spinning reserve” doesn’t need to be fossil based – maybe it could be truly spinning.
Beacon Power, a Massachusetts manufacturer and installer of flywheels – levitating, spinning wheels that turn electrical energy into kinetic energy and then turn it back into electrical energy on demand – is about to finish the largest storage plant in the world using the technology:
The company said today it plans to host a ceremony for the 20-megawatt energy storage system in Stephentown, N.Y., where the flywheels supply short bursts of power to maintain a steady frequency over the grid.
The expected completion of the plant is a milestone for flywheel-based storage, which has been used for tests and smaller, 1-megawatt systems. Beacon Power’s spinning flywheels, which are made of carbon fiber and levitated in a vacuum by magnets, absorb energy from the grid and discharge 1 megawatt for as much as 15 minutes.
Frequency regulation will is becoming more important as more intermittent renewables are added to the grid.
People often think of lithium ion batteries or chemical “flow” batteries when talking about grid-scale storage (The east-coast utility AES is currently building a 32-MW lithium ion battery for frequency regulation services as well). But if all goes well with the project, Beacon will put flywheels, which have only been used for smaller-scale applications, on the utility-scale map (see paper here)
The question for all these storage technologies on the east coast, however, is how they’ll get compensated:
Frequency regulation is traditionally done by various power-generating units, which get paid per-kilowatt rates set by utility regulators. However, generators take longer to get up to speed than flywheel units and can’t absorb excess power.
“We respond in four seconds, and a generator responds in five minutes, yet we’re paid the same amount. Wouldn’t it be fair if we were paid more?” said Hunt.
The Federal Energy Regulatory Commission has published a notice that it plans to institute a new “pay for performance” rule for energy storage for frequency regulation, which would compensate operators not just for the amount of power they put on the grid on command, as has long been the case, but also for the speed at which they do it. Hunt says this could double or triple Beacon Power’s compensation for running the new plant, giving the still-growing company a boost.
Regulators are preparing for more of these technologies with incentives that match their performance characteristics. To do so would encourage more such projects, which would also allow for a greater penetration of renewables while keeping the grid stable.