Purchasing green certificates allows you to contribute to the generation of clean, renewable power, even if you can't buy clean power from your current power provider or from a clean power generator on the competitive market.
An increasing number of clean power generators are now separating the power that they sell to power providers from the environmental attributes associated with that power. These environmental attributes, called green certificates (also known as green tags, renewable energy certificates, or tradable renewable certificates), are then sold to companies and individuals who want to help increase the amount of clean power entering our nation's electricity supply.
By separating the environmental attributes from the power, clean power generators are able to sell the electricity they produce to power providers at a competitive market value. The additional revenue generated by the sale of the green certificates covers the above-market costs associated with producing power made from renewable energy sources. This extra revenue also encourages the development of additional renewable energy projects.