When you install solar power, you are helping to reduce greenhouse gas emissions. This entitles you to create environmental credits called Small-Scale Technology Certificates
or STCs for short. “Renewable Energy Certificates” (RECs) was the original term, which was replaced by “STCs” in January 2011; however it is still an umbrella term covering both Small-scale and Large-scale certificates.
Like other commodities, the price of STCs is not fixed and varies with supply and demand. Prior to January 1st 2011 the price of Renewable Energy Certificates (RECs) would fluctuate daily. Now these commodities have been renamed Small-scale Technology Certificates and regulation has been put in place to stabilise their price. One STC equals 1MWh of generation from a renewable source and is part of the Mandatory Renewable Energy Target.