This is how it should be done

Source: RENEWABLES: On Kodiak Island, flywheels are in and diesel is 99.8% out -- Friday, June 10, 2016 -- www.eenews.net

KODIAK, Alaska -- Darron Scott, CEO of the Kodiak Electric Association, unlocked the door to a small building on a gravel road along Chiniak Bay and pointed to two innocuous metal boxes tucked into a corner beyond a bank of computers.


"Those are the flywheels," Scott said, turning on a computer screen to follow the ebb and flow of the system's electrical output.


More than a mile down the coast, a 340-foot-tall electric crane operated by Matson Inc. shipping company lifted a series of heavy metal cargo containers from the shore and transferred them onto the deck of a waiting ship.


Each time the regenerative crane raised a container into the air, it pulled electricity from the flywheel energy storage system. As it lowered its load, electricity flowed back to the flywheels.


"It's sort of like a Toyota Prius," Scott explained. "When you hit the brake [on the car], you actually make power, which goes back into the battery.


"Well, the crane does the same thing," he said. "When the crane drops the load, it will actually inject power back into the flywheels, which helps speed them back up again. The flywheel has just enough time to get recharged as the crane gets ready to pick up the next box for the next lift."


KEA's two flywheels can each store up to 1 megawatt of electricity. That's enough power to lift a heavy cargo container from the dock and move it to the ship.
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KEA estimates that power from the company's Terror Lake station costs 6.8 cents per kilowatt-hour. Wind energy is a little more expensive at 11 cents per kWh. But the two renewable sources are significantly cheaper than diesel generation, which costs 28.9 cents per kWh, given an average cost of diesel fuel at $3.50 per gallon.


Scott said the company still maintains four diesel generators on "hot standby." But thus far, those units have been turned on only during maintenance work on the hydropower facility and every few months to make sure they're still functioning.
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"We had an issue last November," Scott recalled. "We had hydro and wind running just like normal. And just over a couple of seconds, all the wind stopped. The wind went from 20 miles an hour to nothing in just a matter of two or three seconds."


But KEA's system was equipped to handle the abrupt change.


"Everything came up. The flywheels fired, the batteries fired, the hydro started picking up over time, and everything worked perfectly," he explained. "And we stayed above our trip points. Because the next line of defense is that you start turning people's power off to keep things stable. And obviously we don't want to go there.


"We've never had to go there due to a wind incident so far," he said. "And we'd rather not have to do that."


After they enlarge the company's workhorse hydropower system, they may consider more wind turbines. At the same time, Scott said he's also watching promising technologies like wave and tidal power.​

Bob Wilson