The green car definition used by the DC car show encompasses hybrids, plug-in electric vehicles (EVs), fuel cell cars, and advanced internal-combustion cars including clean diesels. One trend that struck me after missing last year's show was that most of the green cars on display this year have become harder to distinguish visually from conventional models. For Volkswagen's eGolf EV, which shared North American Car of the Year honors in Detroit with its gas and diesel siblings, and Ford's Fusion energi plug-in hybrid the differences are mainly under the hood, rather than in the sheet-metal.
Of course some new models looked every bit as exotic as you might expect. That included BMW's i8 plug-in hybrid, which beat Tesla's updated 2015 Model S as Green Car Journal's "Green Luxury Car of the Year", and Toyota's Mirai fuel-cell car. The Mirai is expected to go on sale this fall in California, still the nation's leading green car market due to its longstanding Zero-Emission Vehicle mandate focused on tailpipe emissions.
Many of these cars have electric drivetrains, increasingly seen as the long-term alternative to petroleum-fueled cars. Although Secretary Moniz pointed out that the US government isn't attempting to pick a vehicle technology winner, there seemed to be more emphasis on vehicle electrification and much less on biofuels than in past years.
Another announcement at last Thursday's session addressed where such vehicles might connect to the grid. BMW and VW have partnered with Chargepoint, an EV infrastructure company, to install high-voltage fast-chargers in corridors along the US east and west coasts to facilitate longer-range travel by EV. In making the announcement BMW's representative indicated that EVs will need fast recharging in order to compete with low gasoline prices. With the relative cost advantage of electricity having become a lot less compelling than when gasoline was near $4 per gallon, EV manufacturers need to mitigate the convenience concerns raised by cars with typical ranges of 100 miles or less.
Getting energy to these cars more conveniently still leaves open the basic question of the ultimate source of that energy. Perhaps one reason this isn't discussed much is that unlike for gasoline or diesel-powered cars, there's no simple answer. The source of US grid electricity varies much more than for petroleum fuels: by location, by season, and by time of day. However, even in California, which on average now gets 30% of its electricity from renewable sources and has set its sights on 50% from renewables by 2030, the marginal kilowatt-hour (kWh) of demand is likely met by power plants burning natural gas, due to their flexibility. That's especially true if many of these cars will be recharged near peak-usage times, instead of overnight as the EV industry expects.
Based on data from the EPA's fuel economy website, most of the plug-in cars I saw at the Washington Auto Show use around 35 kWh per 100 miles of combined driving. That reflects notionally equivalent miles-per-gallon figures ranging from 76 for the BMW i8 to 116 mpg for the eGolf. On that basis an EV driven 12,000 miles a year would increase natural gas demand at nearby power plants by around 30 thousand cubic feet (MCF) per year. That equates to 40% of the annual natural gas consumption of a US household in 2009.
To put that in perspective, if we attained the President's goal of one million EVs on the road this year--a figure that may not be achieved until the end of the decade--they would consume about 30 billion cubic feet (BCF) of gas annually, or a little over 0.1% of US natural gas production. With plug-in EVs making up just 0.7% of US new-car sales in 2014, they are unlikely to strain US energy supplies anytime soon.
It's also worth assessing how much gasoline these EVs will displace. That requires careful consideration of the conventional models with which each EV competes. While a Tesla Model S surely competes with luxury-sport models like the BMW 6-series, thus saving around 500 gallons per year, an e-Golf likely replaces either a diesel Golf or a Prius-type hybrid, saving 250-300 gallons per year. A million EVs saving an average of 350 gallons each would reduce US gasoline demand by 22,000 barrels per day, or 0.25%.
At this point the glass for electric vehicles seems both half-full and half-empty. The number of attractive plug-in models that average consumers would consider real cars expands every year, as does the public recharging infrastructure to serve them. However, they still depend on generous tax credits and must now compete with gasoline near $2 per gallon. More importantly, at current levels their US sales are too low to have much impact on total emissions or oil use for many years.