Wind energy was designated the top renewable source in sales, followed by solar and biomass. With current energy costs being so volatile, there is some appeal to supplant or add to energy production. One advantage of renewable energy is that fuel costs are very stable and predictable. A growing number of states have passed mandates requiring a percentage of the energy produced to come from renewable sources.

The U.S. is not alone in leading the charge. The largest installed base for generating energy from wind is in Germany, with the United States second. California produces over 2000 MW from wind. Solar energy usage has grown by 30 percent per year with Germany and Japan having the largest grid connected systems. Japan manufactures 48 percent of the world's photovoltaic panel systems while the U.S. contributes 11 percent.

Biomass is often co-fired with coal to reduce NO_X emissions. Biomass is the leading renewable energy source used in the U.S. and is derived from plant material. In addition to being burned for its energy, it is also used to produce other energy sources such as ethanol and biodiesel.