Renewable Energy Certificates (typically referred to as “RECs,” and also known as “green tags” and “tradable renewable certificates”) are at the heart of sales of renewable electricity. A REC represents the environmental attributes, but not the electrons, of 1 MWh of renewable energy generation on the electricity grid. They are used to track when and where renewable energy is generated, who it is sold to, and who is using it. When electricity is generated, the electrons are all mixed together on the grid, and there is no way to know the sources from which they were generated. RECs make it possible for consumers and businesses to choose clean energy and not have it be claimed by anyone else.