When it came to the transport of goods within local areas, it took decades for the competition among horses, electric vehicles, and gas trucks to shake out.

The substitution of natural gas for coal is not a simple matter. The same concerns about climate and environment remain, along with new impacts.

Burning household trash in massive incinerators saves landfill space, but it also introduces a host of other waste management issues.

Waste-to-energy involves generating electricity by converting waste into gasses. Many are wondering: does it work? And is it scalable?

In the rural Indian province of Bihar, Husk Power Systems is converting leftover rice husks into biofuel. Now they're building mini-power plants around the country, and expanding into Tanzania.

When it comes to nuclear power, one word in particular instills fear: meltdown. But what is a meltdown? Can one be avoided?

Solar panels keep getting lighter and thinner. MIT researchers have created a solar panel so light and thin that it can rest on a soap bubble.

It's not just falling oil prices but any price volatility that makes conservation a harder sell.