|Maryland (light green) is about to join the other 11 states (dark green) that have adopted the CA LEV program. Click to enlarge.|
The House of the Maryland General Assembly has passed the state’s Clean Cars Act (HB 131 / SB 103) by a vote of 122-16. The bill adopts California’s Low Emissions Vehicle (LEV) standards which include the greenhouse gas reduction targets for new cars, beginning with the 2011 model year.
The Maryland Senate is voting on its version of the bill this week, with support from Gov. Martin O’Malley and Senate President Thomas Miller, according to the Baltimore Sun. Passage and enactment seem likely. Maryland would thereby become the 12th state adopting the California LEV program.
The other states, in addition to California, are: New Jersey, Connecticut, Rhode Island, New York, Oregon, Washington, Massachusetts, Vermont, Maine and Pennsylvania.
Under the regulations, auto manufacturers would be required to reduce the emissions of greenhouse gases by their fleets by around 30% by 2016. In California, the CO2 reductions are due to begin in 2009. Automakers have challenged the regulations in federal court, the state of California has initiated a suit against the automakers, and the US Supreme Court is addressing the issue of regulating CO2.
The California regulations are expressed in terms of CO2-equivalent emissions, taking into account the global warming impact of the different pollutants. Accordingly, there is a CO2-equivalent fleet average emission requirement for the passenger car/light-duty truck 1 (PC/LDT1) category, and another for the light-duty truck 2 (LDT2) category, just as the California LEV program currently has fleet average NMOG emission requirements for both categories of vehicles.
Assuming a start date of 2009, when fully phased in, the near term (2009-2012) standards will result in about a 22% reduction as compared to the 2002 fleet, and the mid-term (2013-2016) standards will result in about a 30% reduction.
|CA LEV CO2-Equivalent Emission Standard|
The 2012 PC/LDT1 standard of 233 g CO2e/mile is equivalent to 144 g/km; the LDT2 standard of 361 g/mi is equivalent to 224 g/km. By way of comparison, the EU is proposing legally binding fleet average CO2 emissions of 130 g/km from 2012 onward based on the NEDC, with a further reduction down to 120 g/km from the use of other measures such as biofuels. (Earlier post.)
The exact amount of CO2 generated by burning a gallon of gasoline depends on the precise properties of the individual fuel. In the US, the composition by weight of carbon in gasoline ranges from 85 to 88%, and the density of gasoline in pounds per gallon ranges from 6.0 to 6.5 pounds, according to the Department of Energy.
For some rough calculations, we’ll take the mean value of each (86.5% carbon by weight and 6.25 pounds per gallon) to yield an average carbon content of 5.4 pounds per gallon, or 2,449 grams of carbon per gallon.
Each single molecule of CO2 has an atomic weight of 44 (12 from the carbon atom and 16 from each oxygen atom). To calculate the amount of CO2 produced from a gallon of gasoline, multiply the weight of the carbon in the gasoline by 44/12 or 3.7. Applied to the number above, that yields roughly 9,061 grams of CO2 per theorectical average gallon of gasoline.
On a CO2 only basis (no equivalents, thus leaving out the other greenhouse gas emissions from an auto), that works out to gasoline fuel economy of about 39 miles per gallon to hit the 233 g/mile target in 2012. The 205 g/mile target for 2016 would result—again, just on the basis of considering CO2—in about 44 miles per gallon.
The heavier category, which would include large SUVs, would need gasoline fuel economy of about 25 mpg on a CO2-only basis to hit the 361 g/mile target in 2012, and about 27 mpg to meet the 332 g/mile target in 2016.