1. Some possible policy changes—notably, the adoption of policies to limit or reduce greenhouse gas emissions—could change the reference case projections significantly. EIA has examined many of the proposed greenhouse gas policies at the request of Congress; the reports are available on EIA’s web site (see “Responses to Congressional and Other Requests,” web site www.eia.doe.gov/oiaf/service_rpts.htm).

2. The comparison of production levels was adjusted for the entry of Angola into OPEC in late 2007.

3. See Energy Information Administration, Annual Energy Outlook 2007, DOE/EIA-0383(2007) (Washington, DC, February 2007), “Impact of Rising Construction and Equipment Costs on Energy Industries,” pp. 36-41.

4. Vehicles that can use alternative fuels or employ electric motors and advanced electricity storage, advanced engine controls, or other new technologies.

5. Biodiesel is defined as the monoalkyl esters of fatty acids derived from plant or animal matter and suitable for use in a diesel engine.

6. Biomass-to-liquids (BTL) is defined as diesel fuel and other liquid hydrocarbons produced by a Fischer-Tropsch process using cellulosic biomass as feedstock.