The Environmental Protection Agency (EPA) defines electricity produced from solar, wind, geothermal, biogas, eligible biomass, and low-impact small hydroelectric sources as green power. Green power is renewable energy and represents those renewable energy resources and technologies that provide the highest environmental benefit.
Because utility companies struggle to create enough energy from green sources on their own, renewable energy credit (REC) programs allow them to buy documentation of renewable production and “take credit” for that generated power. One REC refers to one megawatt-hour (MWh) of energy produced or 1,000 kilowatt-hours (kWh). REC represents the environmental and social benefits that distinguish clean, renewable energy from conventional sources of energy, like coal. RECs make it possible for organizations to know that the electricity they are using is green with the Renewable Energy Certificates. The certificate proves that 1 MWh of renewable energy was generated. This video explains RECs.