UC Berkeley News


UC experts detail new standard for clean transportation fuels
'Low-carbon fuel standard' points way to a 10 percent reduction in warming-related gas emissions by 2020

| 22 August 2007

A much-anticipated blueprint for fighting global warming by reducing the amount of carbon emitted when transportation fuels are used in California was made public earlier this month by University of California researchers.

This "low carbon fuel standard," designed to stimulate improvements in transportation-fuel technologies, is expected to become the foundation for similar initiatives in other states, as well as nationally and internationally.

The new standard was commissioned in January by Gov. Schwarzenegger, who asked UC's top transportation-energy experts to design a standard that would reduce carbon emissions from fuels by 10 percent by 2020. Carbon dioxide and other greenhouse gases trap heat in the atmosphere and are a major cause of global climate change. In California, transportation fuels account for about 40 percent of all greenhouse-gas emissions.

The low-carbon fuel standard's authors are Alex Farrell, a Berkeley associate professor of energy and resources and director of the campus Transportation Sustainability Research Center, and Daniel Sperling, professor of civil and environmental engineering and director of the Institute of Transportation Studies at UC Davis.

In part one of their report, completed in May, Farrell and Sperling evaluated the technical feasibility of achieving the 10 percent cut by 2020. They identified six scenarios based on a variety of different technologies that could meet or exceed this goal, and concluded that the goal was ambitious but attainable. At the end of June the California Air Resources Board voted to start working toward that goal, with the new standard taking effect by January 2010.

In the second part of their report, many of the specific policy issues involved in designing a low-carbon fuel standard are examined. That standard, together with California's vehicle greenhouse-gas standards, will advance automobile technologies and contribute significantly to achieving California's climate-change goals.

"Stabilizing the climate will require major changes in the coming years, and the new fuels that will come on the market in response to the low-carbon fuel standard will be an important part of that change," says Farrell. "One of the key roles for the state agencies will be ensuring that the competition among the different fuels results in real carbon-emission reductions, more consumer choice, and minimal costs."

Highlights of the report:

Gasoline and diesel fuel refiners, blenders and importers

  • The report recommends that the new low carbon fuel standard cover all gasoline and diesel. Gasoline makes up 70 percent of California's transportation energy, diesel 17 percent, and jet fuel 12 percent. (Included in the gasoline and diesel figures are biofuels blended with or substituting for fossil fuels.) Aviation is exempt from regulation by international treaty, although the standard might allow emissions credits for cleaner jet fuels. The point of regulation should be the refiners, blenders and importers of petroleum fuels.
  • All gasoline and diesel fuel providers would be required to track the life-cycle global warming intensity (GWI) of their products and reduce this value over time. (The term "life cycle" refers to all activities included in the production, transport, storage and use of the fuel.)
  • The report suggests that petrofuel providers reduce their greenhouse-gas emissions in a variety of ways, including by blending more biofuel with gasoline and diesel, buying low-carbon fuels and emissions credits from other producers, making refineries more efficient and using lower-carbon sources of energy to run refineries.
  • The authors recommend that the new standard require only modest reductions in carbon intensity in the early years, and greater reductions later, as innovations reach the market.

Non-liquid fuel providers (electricity, natural gas, propane and hydrogen)

  • These firms should be given the option to participate in the low carbon fuel standard, most likely by selling emissions credits to petrofuel providers, the report says.

Low-carbon biofuel providers (fuels from plant and animal sources, such as corn, switchgrass and food waste)

  • The authors anticipate that revenue from selling emissions credits will help these firms recoup investments made in innovation and learning.

Passenger vehicle owners

  • The low carbon fuel standard will bring a greater variety of fuels to the market, according to the authors. Fueling infrastructure will evolve, creating E85 filling stations, dedicated electric vehicle charging stations and meters in residences, hydrogen delivery systems and other innovations. The menu of fuel choices might vary regionally, depending on local availability, so that in some areas of the state, there would be more electric vehicles, in others more hydrogen, and in still others more biofuel.
  • Consumers will be able to keep the gasoline-powered cars they drive today for many years, as fuel providers lower the global warming effects of gasoline. They will also have more options for new vehicles and fuels in the future.

Trucking, construction and farming vehicle owners

  • The low carbon fuel standard should apply to all gasoline and diesel used in transportation, including freight trucks and trains, and off-road machinery such as construction and agriculture equipment, the report says. There are opportunities for double benefits here, such as switching to electricity for freight handling or for overnight truck use, which reduces carbon emissions, air pollution and noise.

Biofuel farmers and manufacturers

  • Growing more biofuel crops (feedstocks) will have mixed effects on greenhouse-gas emissions, the authors say. If biofuels are to be cleaner than fossil fuels, they must use advanced production methods (some of which are available now), be derived from feedstocks grown on degraded land, or be produced from solid wastes or agricultural residues.


  • The California Air Resources Board will require additional resources to develop and enforce the new standard, according to the report. It is imperative that neither the state administration nor the legislature expect low carbon fuel standard administration to be a peripheral set of duties shoehorned into current operations without explicit funding. The California Board of Equalization may play a role. Certainly, the California Energy Commission will; it already manages the Petroleum Industry Information Reporting Act (PIIRA) program, which requires firms that ship, receive, store, process and/or sell crude oil and petroleum products in California to submit detailed, frequent reports on their activities. And the California Public Utility Commission will have to grapple with tricky questions of how regulated local electricity providers should compete with the highly competitive global oil industry, the report says.

Scientists and policy analysts

  • The report identifies many questions that require further study, and also recommends periodic reviews and assessments. These include reviews of protocol and methods (but not, the authors emphasize, of emissions targets); study of the sustainability impacts and lifecycle emissions of existing and new fuels; and a cost analysis of the low carbon fuel standard following the cost-effectiveness approach used in evaluating the U.S. Clean Air Act.


  • In addition to climate change, the report recommends that fuel providers report on the sustainability and environmental justice implications of the low carbon fuel standard. And it calls on the state to ensure that sensitive lands are protected from conversion to biofuel production.

This research was supported by the Energy Foundation and conducted by a team of researchers at UC Davis and UC Berkeley, who coordinated and consulted extensively with the staffs of the California Air Resources Board and the California Energy Commission, and the representatives of many stakeholder organizations.

Additional links for more information:

Full text of “A Low Carbon Fuel Standard for California,” parts 1 and 2

UC Berkeley Transportation Sustainability Research Center

UC Davis Institute of Transportation Studies (ITS-Davis)

Governor's Executive Order S-1-07