The growth in renewable energy over the past decade has been almost entirely in expanded wind capacity. The bar chart at left shows the growth of four renewable sources - solar, geothermal, biomass and wind - over the last decade. Solar's role is insignificant, although it does become visible in the last year. Geothermal and biomass have remained almost the same. (Most geothermal is in California and Hawaii and has been operating since the 1990s. Biomass is mainly the ethanol program plus some wood burning in homes and power plants.) All the growth has been in wind, which has grown from only 5 million megawatt-hours in 2001 to 140,000 in 2012.
The bar at the right compares new sources of power built over the past year in megawatts, with all sources included. Wind surpassed natural gas last year for the first time. Coal is still being built and surpassed solar. The biomass addition is now mostly wood and other organic wastes replacing coal in power plants. It should be recalled once again that wind only GENERATES electricity at about one-third of its "nameplate" capacity (the basis for the chart) and solar generates only about one-fifth. Thus their actual contribution to the grid is highly exaggerated.