Old-time tech could power new age

The rocky road to reducing greenhouse gasses is focused on improving reliability of renewables by storing energy for use in downtimes, and also to extend the life of expensive batteries for electric cars and trucks.

In the mix of ways to improve all this, researchers are turning to something used by ancient potters to smooth momentum of a rotating, round stone to fashion fine jugs.

It's the flywheel, commonly used today to make engines run smoothly.

Some will recall the big round flywheel on the side of legacy John Deere tractors that smoothed energy between the uneven, distinctive power pops of their two-cylinder engines.

But Deere drivers of yesteryear wouldn't recognize what's being done today with the simple flywheel. Today's versions feature special-alloy wheels magnetically levitated in vacuum tubes so they may spin ungodly fast.

There's urgency to store energy from renewables, key to reducing greenhouse emissions that promote climate change. Batteries, the storage technology of choice, are expensive with limited life spans, and there's growing concern over production of their main components, lithium and cobalt.

Then there's the matter of aligning public subsidies with policy priorities. While the U.S. is committed to halving greenhouse emissions by 2030, some $20 billion in annual subsidies remain in place for coal, oil and gas — not counting indirect support. The energy lobby remains stronger than clean-energy advocates.

Here's how flywheels work:

A heavy wheel is constructed of carbon and steel alloys — blended for optimum weight and super strength, so wheels can spin incredibly fast (to optimize energy storage) without disintegrating. Car engines cruise at around 3,000 revolutions per minute (rpm); modern flywheels now do up to 50,000 rpm, on their way to 200,000 rpm.

To attain such speeds, flywheels operate in a vacuum tube and are magnetically levitated to overcome resistance from air and ball bearings. Eliminating rubbing parts means minimal maintenance and impressive longevity (15 years or more).

In transportation, flywheels can store and release enough energy to extend the life of lithium batteries up to five times, cutting high replacement costs. Most electrics already have "regenerative braking" that captures energy from spinning drive shafts to recharge batteries as the vehicle decelerates.

Longer battery life also would ease demand for lithium and cobalt, whose mining operations are risky (hard rock lithium is precipitated out with sulfuric acid), and even morally appalling as some African cobalt mines use small children to work long hours in the deep dark.

Circling above, meantime, NASA's orbiters already use flywheels to store solar energy during times of light for use when it's dark. Call it another small step for humankind.