Thursday, April 1, 2010

The New EPA Fuel Standards: Why MPG No Longer Matters

By Dave Rochlin - originally posted on

I love the ambitious new automobile efficiency targets set by the EPA this week. This is long overdue. As the EPA pointed out, "transportation sources accounted for 28 percent of all U.S. greenhouse gas emissions in 2007, and have been the fastest-growing source of U.S. GHG emissions since 1990."

While the new targets works out to an average of 35.5 MPG by 2016, the rules are actually set in terms of "grams of CO2 per mile." I suspect that it was done this way because of the EPA's new found authority to regulate CO2, but it also highlights that "miles per gallon" is not all that matters when it comes to climate change.

From an oil perspective, setting these aggressive targets may be the single most important action taken to preserve the United States since Robert E. Lee's surrender at Appomattox. Rather than balanced trade, our dependence on foreign oil has created a systematic drain of dollars from the US to the tune of $200 billion per year, with many negative implications to the stability and economic well being of the country. Additionally, our massive military expenditures are driven by the need to protect our overseas oil supplies (see the Carter Doctrine.) And with the looming specter of peak oil - or even just $150/barrel oil - closing the spigot is needed.

But in dealing with climate change, there's a lot more to think about than just how much gasoline gets burned.

The good: Reducing gasoline related emissions.
Assuming a 100,000 mile life, a car getting 25 MPG will burn 4,000 gallons over its lifetime, resulting in 40 tons of CO2 emissions. By raising fuel efficiency to 35 MPG, that car will use 1,100 less gallons of gasoline, keeping 11 tons of CO2 emissions out of the atmosphere.

It also reduces the amount spent on gasoline by almost $4,000! While automobile manufacturers are estimating that the cost to meet the new higher targets will be around $1000 per car, that still puts consumers way ahead of the game. As an old 1987 Honda CRX owner (and how I miss my old pocket rocket), I can say that this does not need to be the case. My CRX was high mileage (40-60 MPG), high performance, and very reasonably priced...and this was 25 years ago. The secret was a small but efficient engine, and a very lightweight design...which brings us to:

The bad: Considering the lifecycle and impact of the automobile.
An awful lot of rubber, steel, plastic and other materials go into making a car. The energy used to power the gigantic factories stamping out parts and assembling it is also significant. The most recent estimate I've seen is that producing a mid-sized sedan results in roughly 7 tons of emissions. I'm guessing that a full-sized SUV with 19 inch wheels and TVs in the seats checks in a lot higher than that.

Unfortunately, automobiles seem to be designed for obsolescence rather than reuse. While many materials are recycled, a more modular cradle to cradle approach to automotive design would be much more eco-friendly.

The support system for automobiles, and consequences of our autocentric culture also have led to the large US emissions footprint. Road building and maintenance, replacing natural habitat with asphalt and sprawl, lack of convenient public transportation...all of these help create an automobile emissions intensive culture. As cars become cheaper to operate, will we simply demand our own version of the autobahn, and drive further and more often?

Avoiding the ugly: Swapping coal for oil?
The biggest battle in the EPA' s new rule was over how to treat electric cars. While the industry likes to use the term 'zero emissions vehicle', a plug-in car requires electricity from the grid. Several estimates I've seen put the amount of energy used in the range of 3 miles per kWH. If you're connected to the hydroelectric-powered clean grid up in Washington, your plug-in would be six times less carbon intensive than a gas powered vehicle. But if you operate that same car in coal-dependent North Dakota, then your 'zero emissions vehicle' would actually be 20% more emissions intensive than if it used gasoline. Of course you can offset this electricity use by supporting wind farms in North Dakota, but the vehicle itself is far from 'zero emissions'.

It's possible that a hybrid Prius, which generates electricity from its braking system, may actually be better from an emissions perspective than a plug-in. In any case, the EPA gave each automobile manufacturer 300,000 'zero emissions' car waivers through 2016, which means the 35.5 MPG figure is actually closer to 34.5 MPG. Beyond that, who knows.

But three cheers for the EPA, for thinking about oil and emissions. Whether we replace gasoline with electricity created from coal, bio-diesel from corn, or hydrogen produced in a refinery, they need to keep the focus on grams of CO2 per mile, not MPG.

It would also be great to start thinking of the the footprint of the actual vehicle and other consumables (tires, oil, other consumables) that go with it. I think we'd be better off with hybrid CRXs rather than than plug in Escalades....Or maybe more light rail, and less of both.

Photo copyright: CC BY 2.0