These lamps provide a clean source of light at a cost that is much lower in the long run.

It was not diversity for environmental reasons, towards a cleaner source of energy.

Instead, all the focus seems to be on finding new clean sources of energy.

Category 1 is water from a clean or sanitary source.

For these reasons, most tea masters will use a good clean local source of spring water.

America should also expand a clean and unlimited source of energy: nuclear power.

Ford also believed in using clean and readily-available sources of power.

They still have many challenges to overcome before it can be used as a clean source of energy.

In this way we could obtain up to 14% of our energy from clean sources.

Others always thought it was a reliable, cheap and clean source of electricity.