David Lee powers up his Nissan Leaf, which he bought to use up the excess energy generated by his PV system at his home in Koloa.
Photo courtesy David Lee

by Jessica Else – The Garden Island

KOLOA — David Lee needed to figure out a way to use some of the extra energy his photovoltaic system generated when Kauai Island Utility Cooperative halved the amount paid to PV owners for excess energy.

He bought a used Nissan Leaf electric vehicle. Now he powers his treks around the island with extra energy generated at home.

“Right now, there is so much PV generation in the daytime, KIUC has a plan to curtail buying from customers when there is too much supply,” Lee said. “Why not use it to charge car batteries?”

Lee explained that it’s a “win-win-win situation,” with KIUC selling more energy, electric vehicle (EV) owners getting 40-80 miles per gallon depending on the rate discount, and a cleaner environment.

Lee is getting the equivalent of 80 miles per gallon on his EV.

That’s calculated by figuring the cost to charge the battery rather than selling the energy to KIUC after driving a known distance and then multiplying that by the current price of gas per gallon.

“In this calculation, instead of buying a gallon of gas, you spend that money to buy the electrical energy,” Lee said. “If gas prices go up and electric prices stay the same, then your equivalent mpg goes up accordingly.”

In addition to great gas mileage, Lee said he’s happy with the fact that his car has zero emissions.

“On the Mainland when you plug in to recharge, most likely you are using energy generated by burning fossil fuels,” Lee said. “But if you charge your car using your PV system, then even that is zero emissions.”

The minimal impacts on the environment are also what drew the attention of KIUC CEO David Bissell.

“Charging a car using PV results in real savings and it helps lessens Kauai’s reliance on foreign oil,” Bissell said. “Charging an electric vehicle using PV is a great use of a homeowner’s system.”

If the cars are charged in prime solar periods between 11 a.m. and 2 p.m., it also helps out KIUC’s grid.

“This helps KIUC avoid curtailing renewable energy which is a waste of resources and increases cost,” Bissell said.

About 12 percent of KIUC customers have PV systems, which means around 3,400 rooftop installations. Lee said his idea would help those homeowners save money and help the environment.

“For non-PV owners, an EV would make much more sense financially if KIUC gives them a rate reduction or if they have a free charging station at their workplace,” Lee said.

He recommended buying a used EV, because the cost is lower. For instance, he paid $9,200 for his used 2013 Nissan Leaf.

“Hawaii is the perfect place to own an EV if you have a PV system and can charge from it midday,” Lee said. “If only there was an EV pickup truck. That would be the perfect vehicle for Kauai. Maybe sometime in the future.”

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