[United States] Renewable Energy Certificates (RECs), also known as Green tags, Renewable Energy Credits, Renewable Electricity Certificates, or Tradable Renewable Certificates (TRCs), are tradable, non-tangible energy commodities in the United States that represent proof that 1 megawatt-hour (MWh) of electricity was generated from an eligi... Found on http://en.wikipedia.org/wiki/Renewable_Energy_Certificate_(United_States)
(REC) A REC is the property right to the environmental benefits associated with generating renewable electricity. For instance, homeowners who generate solar electricity are credited with 1 solar REC for every MWh of electricity they produce. Utilities that have to fulfill an RPS requirement can purchase these RECs on the open market. Found on http://www.cleanenergyresourceteams.org/glossary