Can Flywheels Make Wind Energy Reliable?

Big wind energy suffers from a host of problems. Wind power is not baseload power -- it is too intermittent to rely on for routine daily loads. Wind power is not dispatchable -- it is unable to rise and fall at will in order to meet unanticipated loads and overages. Wind power is expensive -- without subsidies it would die outright. Wind turbines and gearboxes break down and must be replaced far more often than time-proven power sources -- at enormous cost.

Can flywheels help?

One of the big challenges for solar or wind power is that they are intermittent, not constant. The sun only shines half the hours at best (not even counting clouds or rain), and similarly, the wind does not blow continuously. To make these energy sources more practical, efficient power storage is necessary; you need to be able to top up the “battery” when the power is on and then use it to provide electricity at night, on overcast days, or when the air is still.

As reported by the New York Times Monday, a Massachusetts company thinks it has a solution to the problem of energy storage: flywheels.

A flywheel is a nothing more than a heavy wheel that rotates or spins freely. If you connect it the right kind of dual-purpose electric motor—some electric motors, like the ones in hybrid and electric cars, can function as both motors and generators—you can use the motor to spin the flywheel up to speed when there’s a surplus of power. Then, when you need energy, you slow down the wheel and convert its momentum back to electricity. If the wheel is heavy enough and spinning fast enough—the ones that Beacon Power is installing near Albany, New York, weigh a ton each and spin up to 16,000 times a minute (267 times a second)—you can store an enormous amount of energy in them. _Source

Flywheels themselves are untested at the scales that they would be needed for large-scale wind farms and solar facilities. They are mechanical, and more prone to breakdown than a solid state form of storage would be. They are expensive. Flywheels may help with dispatchability -- load leveling -- but they cannot correct for extended periods without wind.

Small and medium scale wind power can be quite useful for particular niche applications and for off grid. Large scale wind and solar are markedly inferior to nuclear and clean coal in virtually every way -- but particularly in terms of reliability.

Al Fin power engineers like the concept of the flow cell battery for utility scale load leveling, once the bugs are ironed out. Such an approach would have to be paired with gas turbines, and would be extremely useful as long as the baseload power was provided by nuclear, enhanced geo, or clean coal / biomass.