This may be psychologically satisfying to some green buyers but it creates no net environmental improvement. Selling existing renewable energy does nothing for consumers who choose green power for non-environmental reasons, discussed later in this paper. Further, selling existing energy fails to extend the availability of fossil fuels for future generations, diversify the resource mix, or satisfy consumers who buy new sources like solar photovoltaics because they want to be in the technological vanguard. There are two reasons for the emphasis on existing renewables in competitive retail markets. The first is the market price of electricity.
Price is always a consideration, even for committed green buyers, and today's supply prices are low.
The current overcapacity in much of the country contributes to depressed short-term market prices. Existing renewable capacity, especially large hydro, is more likely to be competitive than new renewable capacity. A second reason may be that the supply of new renewable capacity falls short of demand. Even if a buyer is willing to pay a higher price for new renewable energy, a supplier usually cannot deliver it immediately and delivering it in six months to two years will not capture market share. Suppliers can only provide what is available when they enter newly-opened markets.