There are more than a dozen alternative and advanced fuels in production or use today. Although government-regulated and voluntary private fleets are the primary users of these fuels, consumers are showing a growing interest in them. Use of these fuels is critical to reducing dependence on foreign oil and improving air quality. These fuels are defined as alternative fuels by the Energy Policy Act of 1992 and are currently, or have been, commercially available for vehicles:

Vehicle Emissions for any fuel type fall into two categories: "Tailpipe" emissions are the emissions that result from consuming the fuel in a vehicle or engine. "Lifecycle" emissions describe all the emissions associated with a fuel as it is generated, grown or extracted, refined, distributed and consumed. Electricity, for example, has no tailpipe emissions but most electricity in the US is currently produced by burning fossil fuels. The emissions rated here are tailpipe emissions only as produced by a clean, modern, commercially available vehicle today for any given fuel.

Energy Independence addresses the source of the fuel - is it produced overseas or on US soil? Most fuels come from both within the United States and foreign sources. The energy independence of biofuels depends on whether they can be produced on US soil in quantities that satisfy domestic demand.

Renewable fuels are those which can be produced without depleting natural resources or degrading the environment. Fossil fuels, for example, are not renewable and can are depleted completely. Biofuels are renewable in theory but may require more energy to produce than they contain. Large-scale biofuels production may also have significant environmental inmpacts.

Current Technology described the availability of vehicles, engines, parts, service and maintenance, fuel and fueling infrastructure for a particular fuel today in SLO County and California.

Vegetable Oil (WVO, SVO)

Fair

Good

Maybe

Fair

Ethanol

Good

Good

Maybe

Fair

Propane (Liquified Petroleum Gas, LPG, LP Autogas)

Good

Fair

No

Fair

Gasoline*

Fair

Poor

No

Best

Diesel*

Poor

Poor

No

Excellent