Plug-In Vehicles and the Smart Grid

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Transportation accounts for about a third of all carbon dioxide emissions in the U.S., and there is a powerful case to be made for cleaner cars. In “High Voltage,” science and energy writer Jim Motavalli gives a behind-the-scenes narrative of the robustly competitive market for electric cars.
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 Tesla’s Model S electric sports car combines luxury and sustainability.  

Plug-in charging stations and smart grids seem like something still far off in the future, but by 2020, the auto industry will look very different from today’s field of troubled auto giants. In High Voltage(Rodale Books, 2011), Jim Motavalli captures this period of unprecedented change, documenting the evolution from internal combustion engines to electric power. The following is excerpted from the beginning of Chapter 6, “The Smart Grid.”

As the huge piles of snow from a record 2011 winter finally melted, my local utility came by and installed a smart meter on the side of my house, replacing one whose design had changed little for a half century. It’s great that this state of affairs employed thousands of meter readers, but there was no reason for them in the modern era–my meter should be readable from the billing office. And now it is.

A smart meter not only enables the utility to measure my electric usage and note the bump when I plug in my EV, but also empowers me. On my computer, I can now dial up software that shows me exactly how much juice each of my appliances is using, and choose to shut some of them harmlessly down during peak power demand times (heat waves, for instance).

Smart meters are a huge advance and are fortunately going mainstream at the same time that electric cars are hitting the road. The two can work together closely. When it’s plugged in, your electric car is just another household load–and a pretty big one, sometimes doubling electricity consumption. If we get really smart about this, we can create home networks that empower consumers to manage and reduce their power needs–and save money in the process. The smart home is finally coming to America, and it’s also making huge strides in Japan.

The car I saw parked in the garage at Panasonic’s Eco Ideas House in downtown Tokyo was a plug-in hybrid Toyota Prius, and it’s part of a singularly green home energy management system. The house, presided over by a poised tour guide with a sing-songy delivery, combines a five-kilowatt solar panel on the roof and a one-kilowatt hydrogen fuel cell in the backyard to generate electricity, and a stationary five-kilowatt-hour lithium-ion battery to store it. The net result: zero carbon emissions.

Holistic systems that use sophisticated power management electronics like this are all the rage in Japan, thanks to a combination of a growing green consciousness, corporate commitment, and financial support from the government.

If one of your worries is that electric cars will fuel up from a dirty grid powered by a lot of coal, reducing “zero emission” claims to “lower emission,” then it’s worth taking a closer look at the smart home of the future, which may make all of its own electricity in a completely green energy loop. As it turns out, even coal-fueled EVs are cleaner than today’s 25-mile-per-gallon cars, but electricity with far fewer emissions attached is clearly helping to drive international support for EVs.

Nobuo Matsuo, manager of Panasonic’s strategic planning office, told me that the company hopes to produce all the technology in the smart house by its 100th anniversary in 2018. It makes a lot of it now, including the energy-efficient home appliances in the Eco House’s laundry room and kitchen, the solar panels, and the fuel cells.

Even wilder appliances are in the planning stages: I’d love to have Panasonic’s smart air conditioner, which can scan the room it’s in, determine how many people are present and what they’re doing (because, for example, reading needs less cooling than working out), and adjust the temperature accordingly. How about a refrigerator that learns its family’s patterns and goes into eco-mode during low usage times?

Americans may think of 3-D televisions and cameras when the name Panasonic comes up, but the company has a different image in Japan. I visited a sprawling recycling facility where Panasonic dismantles many of its home electronics products, and strolled through its environmentally themed displays at the giant CEATEC electronics show.

Panasonic has sold 2,000 of its home fuel cells, which can supply 60 percent of a family’s power needs. General Electric, in cooperation with a company called Plug Power, had planned to sell its own home fuel cells to Americans in the early 2000s. Plug Power even had its own version of the Eco House, entirely powered by hydrogen. But without federal subsidies, the economics weren’t there–the fuel cell would have produced electricity at a cost higher than that of grid power.

The Japanese Ministry of Economy, Trade and Industry subsidizes a third of the $34,000 price of the home cell. But even with that support, the savings in electricity and gas costs are only about $500 annually, so it may be several decades before the fuel cells pay for themselves.

Panasonic is in no way alone in its smart-grid approach. In September of 2010, Toyota (with Hitachi and Panasonic as partners) unveiled its Smart Grid Village in the tiny Japanese hamlet of Rokkasho. The complex includes six eco-efficient homes and eight Prius plug-in hybrids. The homes are equipped with ultrasophisticated energy management systems and smart meters, as well as efficient EcoCute water heaters. The village, a two-year experiment, uses electricity exclusively from renewable sources, including wind turbines.

Toyota’s village incorporates a version of its Smart Center home smart-grid system, which allows homeowners to easily monitor the consumption of all their appliances via computer, and manage their cars’ charging, too. Toyota claims that a well-managed home energy management system that seamlessly incorporates a car like its plug-in hybrid Prius could result in a 75 percent reduction in electricity consumption.

Looked at in one way, the Prius in the Eco House garage was just one more energy consumer, using up approximately 30 percent of total family consumption. And there will be lots of different approaches to feeding it the electricity it needs, helped by what many hope will be a smarter grid. Without that, EV charging faces some challenges.

The Power Grid: Up to the Challenge?

Britta Gross of General Motors says that a Chevrolet Volt, charging from a 240-volt, 3.3-kilowatt charger in a garage, will present a load roughly equivalent to that of an electric clothes dryer–but a dryer that’s on for four hours at a time. It’s a big load, but not an unmanageable one–the Volt incorporates, as do most electric cars and plug-in hybrids, a feature that lets the owner easily dial in a late-night, off-peak charge time that takes advantage of underutilized grid capacity.

A 2006 Department of Energy study estimated that the existing power grid could fuel as many as 180 million plug-in hybrid cars, assuming that they plugged in at night when a lot of the generated electricity goes unused. Those 180 million are 84 percent of the country’s vehicles.

The study looked at plug-in hybrids, though, and they don’t need as much electricity as battery electrics. President Obama wants a million electric cars (including plug-in hybrids) in the United States by 2015, so what would that do to the grid? According to a 2010 assessment by a coalition of US and Canadian companies, it’s quite doable.

That study says that if 684,510 electric cars all charged at the same time, the load would total 3,785 megawatts, or the output of three or four large power plants. But if that same load were spread out over an eight-hour period, it would be reduced to 819 megawatts at any one time. Stagger it over 12 hours, and only 546 new megawatts need to be found. As Treehugger points out, “That’s nothing! One medium-sized power plant could provide that, and if it’s during the night, you won’t even have to build a new power plant since there’s more than enough extra capacity off peak.”

JD Power and Associates, the respected rating firm, doesn’t think the United States is going to get anywhere near 1 million plug-in cars by 2015. In fact, it predicts that electric vehicles globally will total 500,000 that year, with half of them in China. Add in regular hybrids, which don’t plug into the grid, and you get to 3 million worldwide sales annually, or 3.4 percent of global light-vehicle sales, Power said. A Department of Energy study based on manufacturers’ stated intentions is much more optimistic, predicting that the United States will succeed in reaching President Obama’s goal of a million plug-in cars by 2015.

There’s still some dispute over volume, but it helps to consider the power requirements of battery cars as equivalent to those of 2 million plasma television sets, spread across the global grid. A two-kilowatt EV charge load is roughly equivalent to four or five of those sets. And those TVs aren’t only on late at night. Utility executives from Bangkok to Boston aren’t likely to lose sleep over that scenario–in fact, they’re eagerly anticipating it, because their product, not the oil companies’ gasoline, will become America’s transportation fuel.

Mike Rowand, director of advanced customer technologies at Duke Energy, told me the utilities can handle millions of EVs without breaking a sweat. “We managed two computers in every house,” he said, “and we handled air-conditioning–two things that had a bigger impact than EVs. Plug-in vehicles will be manageable, but I don’t want to minimize it as an issue.”

Duke’s load will be manageable, but I was curious what utilities in California would say, since EV deployment is going to hit hardest there. Doug Kim directs the EV readiness program at Southern California Edison, which is a big green car booster, and he told me that his 50,000-square-mile, 400-community service area could have 450,000 EVs plugging in by 2020. But he’s also confident the utility can handle it, especially as it rolls out rates that give consumers big incentives to charge in the evening.

This excerpt has been reprinted with permission from High Voltage, published by Rodale Books, 2011.

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