photos: green wombat
California utility PG&E has given Green Wombat an exclusive look at new
technology that could provide a big boost to both the nascent
electric car market and renewable energy production. In the coming years, the utility plans to buy thousands of plug-in hybrid and electric car batteries once they’ve outlived their usefulness for transportation and install them in the basements of office towers and at electrical substations to store green energy. That will cut peak demand for expensive – and greenhouse gas-emitting – electricity. On a recent morning Green Wombat went down to a sub-basement below PG&E’s (PCG) San Francisco headquarters where the utility parks its plug-in hybrid Toyota (TM) and Mercedes fuel-cell car. Against one wall a nickel metal hydride battery salvaged from a wrecked Prius sat on a metal cart attached to an inverter that converts the battery’s DC power into AC power. The setup is hooked up to an electrical meter, a fluorescent light and a portable heater. (In the photos, the Pruis battery is on the middle shelf; the inverter is on the top left.) "The meter is spinning anti-clockwise right now," says Sven Thesen, PG&E’s supervisor for clean air transportation. "That means we energy is coming out of the building and powering the meter. PG&E is paying for this right now." A minute later the meter begins to spin in the opposite direction and the lights and heater come to life as the 1.3 kilowatt/hour Prius battery uploads electricity into the power grid.
Electric vehicle batteries generally retain 80 percent of their capacity even after they’re no longer good for powering cars. Thesen envisions a time in the near future when banks of EV batteries are charged at night with electricity produced by wind farms, which tend to generate the most electricity in the evening when power demands are the lowest. Normally, that energy is just lost because it isn’t stored. During the day when air conditioners crank up and energy demand rises, electricity can be released from the batteries to take the load off the power grid. In theory, that means PG&E won’t have to build as many planet-warming natural gas-fired power plants to meet peak demand or as an insurance policy against blackouts. It also allows the utility to do "load leveling." Cranking up a power plant to supply electricity when demand suddenly spikes is expensive. EV batteries could release electricity to the grid to smooth fill in the gaps between supply and demand. The same is true if batteries are used at electrical substations. "If we can put in $5,000 worth of batteries and avoid putting in a $50,000 transformer and upgrading the lines then everyone is a winner," says Thesen.
Electric car makers like Silcon Valley’s Tesla Motors and Norway’s Think could be some of the biggest winners. The battery is the most expensive part of the car, and PG&E’s plan would create a significant secondary market for them, especially if other utilities like Southern California Edison (SCE) and San Diego Gas & Electric (SRE) follow suit. A second life for electric car batteries would lower their cost as battery financing syndicates are formed to buy and sell the micro-mini power plants. That would help jump start the market for electric cars by making them more affordable. It would also spur further technological progress in battery development to exend their range and power. "Those batteries have some residual capacity and that residual capacity is actually valuable," Tesla CEO Martin Eberhard told Green Wombat last week. "At a substation you take a whole stack of three-quarter dead batteries and just run them into the ground an then chuck them into recycling." He says there would be no obstacle to re-purposing Tesla’s powerful lithium-ion batteries – which give its forthcoming Roadster super car its 200 mile range and zero-to-60-in-four seconds vroom – for such use.
The chicken-and-egg dilemma, of course, is that PG&E and other utilities will need thousands of EV batteries. Ford (F), General Motors (GM), Toyota and other automakers are not yet making plug-in hybrids. Companies like Think and Tesla, meanwhile, will be selling limited numbers of electric cars over the next couple years. Many EV batteries are expected to last five years or 100,000 miles, meaning it’ll be some time before they’re ready for recycling. Still, the creation of a secondary market for batteries could drive down costs and expand the electric car fleet sooner than anticipated. That will create another source of supply: Inevitably, drivers will crash their cars, leaving behind batteries in mint-condition that utilities can re-deploy.
"By having these out there we donít have to import as much peak power when itís really expensive from places that are far away," says Thesen, who himself drives Prius he had coverted to a plug in. "We move it at the cheapest most efficient time. And for PG&E that also means itís the cleanest. So weíre going to be able to upload more clean power to the grid and itís the cheap stuff. So it’s this wonderful synergistic win-win for everyone and it will make vehicle batteries cheaper because they will have worth. When we make an electric battery cheaper that means more people can afford it; that means we put less demand on foreign oil imports."