Solar rebates help to reduce the cost of installing a solar power system. The discount ranges from $1500 to $4000 for residential solar system and up to $20 000 for commercial solar systems. The term used for the Solar Rebate is the STC or Small Scale Technology Certificates. Each certificate equals one megawatt of electricity displaced over 15 years. The number of certificates and value is set by the government based on size system installed and what location each system is installed.