Glossary
This glossary is a resource, with a broad set of definitions that may be found in literature and other discussion of policy, science, and engineering behind low-carbon fuel standards.
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Carbon intensity (CI)
The total amount of carbon emitted per unit of fuel energy. Generally measured in grams of CO2 equivalent per megajoule (gCO2e/MJ).
Energy economy ratios (EER)
Factors applied to a LCFS fuel that account for the differing energy efficiency of powertrains that use various fuels, such as powertrains powered by electric motors or those powered by combustion engines.
Leakage
Actions taken by fuel producers or suppliers that may involve modifying production and sales in ways that meet requirements but do not result in any net change of emissions. There is risk of this occurring when fuel producers or suppliers have operations both in regions with a LCFS and in regions without.
Low Carbon Fuel Standard (LCFS)
A policy that requires transportation fuel producers and suppliers to lower the carbon intensity (CI) of their fuels over time to reduce transportation emissions.
Baseline-and-credit scheme
An emissions trading scheme in which fuel credits and deficits may be bought and sold by fuel producers and suppliers. Fuels above a standard generate deficits, and fuels below generate credits.
Cap and trade
Policy that sets a limit on the total amount of carbon that can be emitted in a certain period. Entities may buy or sell carbon credits on a market to meet requirements.
Carbon tax
A pre-determined tax on carbon emitted during a certain period.
Complementary measures
Policies that are designed to enhance market mechanisms and generate investment in a certain sector of the economy or particular type of emissions-reduction activity. Examples include the Renewable Fuel Standard (RFS), Corporate Average Fuel Economy (CAFE) Standards, and subsidies to particular technologies.
Compliance costs
Expenses required to meet a government regulation.
Corporate Average Fuel Economy (CAFE) Standards
Regulation on the distance vehicles must be able to travel on a gallon of fuel.
Market-based measures
Policies that set a requirement across an entire region or sector(s) and let the market respond accordingly. Examples include carbon tax and cap and trade policies for carbon emissions reduction.
Price cap
An upper limit set on a market price, such as a carbon price, that is established and enforced through regulation.
Renewable Fuel Standard (RFS)
A federal program that requires transportation fuel sold in the United States to contain a minimum volume of renewable fuels.
Biodiesel
A renewable fuel produced from vegetable oils, grease, or animal fats.
Diesel
Refined petroleum fuel product for specific use in diesel engines.
Electricity
In transportation, an alternative fuel generated by coal, natural gas, or renewable sources that powers a vehicle through an electric motor.
Ethanol
Renewable alcohol fuel derived from corn and other plant materials.
Gasoline
Refined petroleum product commonly used as fuel for spark-ignited internal combustion engines.
Heavy duty
Classification of on-highway vehicles with a gross weight of 26,000 lbs or greater, such as city buses and semi-tractors.
Hydrogen
An alternative fuel produced from a variety of sources that generates only water when consumed in a fuel cell.
Jet fuel
Refined petroleum fuel product for specific use in aircraft powered by gas-turbine engines.
Light Duty
Classification of on-highway vehicles up to a gross weight of 10,000 lbs, such as pickup trucks and vans.
Medium duty
Classification of on-highway vehicles with a gross weight between 10,000 and 26,000 lbs, such as delivery trucks and school buses.
Natural gas
Naturally occurring fuel extracted from underground resources that is primarily methane (CH4).
Off-highway
Classification of vehicles not used on public roads or highways. Applications include construction and agriculture.
Renewable diesel (RD)
A renewable fuel chemically similar to petroleum diesel produced from vegetable oils or animal fats.
Renewable natural gas (RNG)
Natural gas produced from organic waste material.
Book & Claim (BC)
A carbon accounting approach that does not require physical tracking of a product. Rather, attributes such as Renewable Energy Certificates are used to represent the ownership and transfer of transportation fuel under the LCFS.
Chain of Custody (CoC)
A carbon accounting approach that requires physical tracking throughout the production and use of a product.
CO2 equivalent
A measure of GHG standardized to a unit mass of CO2 using factors based on a gases’ lifetime and contribution to the greenhouse effect in the atmosphere.
Greenhouse gas (GHG)
A gas that contributes to the greenhouse effect in the atmosphere, such as carbon dioxide (CO2) and methane (CH4).
Indirect land-use change (ILUC)
Changes in land use that may result from increased agricultural production or other activities. For example, increased biofuel production may divert food products grown on existing agricultural land, such as corn for ethanol. This may result in the conversion of other land to agricultural uses to meet demand, such as forest or wetlands. When this land is converted the natural carbon stored is released into the atmosphere.
Lifecycle emissions
Total greenhouse gas (GHG) emissions generated during the life of a product, including all stages from production to end-use or disposal.
Well-to-wheels
A common description for the full lifecycle of transportation fuels. “Well” represents the extraction of crude oil, and “wheels” represents fuel use in a vehicle.