Green power: what is it and where can we find it?

The interest in commercial green power in the developed world is about 25 years old, starting in the mid-1970s after the first oil shock. Electricity derived from any renewable energy source is considered "green" because of the negligible impact on greenhouse gas emissions. In terms of commercial energy, this list currently includes hydro, wind, biomass, geothermal, and solar. In the 1970s and 1980s, the interest in green power was driven by the goal of replacing fossil fuels to minimize the dependence on oil. Now there is a broader goal: to minimize the emission of CO₂ (the most common global warming gas) that results from the burning of fossil fuels. This article discusses the market potential for renewable resources, green power in the mainstream electric utilities, and the following renewable resources: hydroelectric power, wind power; biomass; solar thermal power; solar photovoltaics; and geothermal power.