They have to be maintained, spare parts manufactured, fuel produced.

For spaceflight use, the fuel must produce a large amount of power per mass and volume (density).

Ignition and fuel produce nothing if oxygen is removed from the equation.

If enriched, the fuel Libya obtained could produce a single nuclear weapon, experts say.

Fossil fuels produce a lot of pollution when burned.

The fuel produces 78 percent less carbon-dioxide emissions than standard diesel.

At first, the uranium was leased with the explicit provision that any spent fuel produced had to be returned to this country.

The fuels we produce serve our economy in many ways.

Any hydrocarbon-based fuel when burned produces more air pollution than hydrogen.

The fossil fuels can produce greenhouse gases, such as carbon dioxide and others.