Most states require or will soon require electricity suppliers to provide a percentage of their electricity sales from solar generation as well as other renewable forms of energy through Renewable Portfolio Standards. This means that utilities have to construct their own renewable energy plants to provide sustainable electricity, or they will purchase these credits from other suppliers like residences and businesses who have renewable systems such as solar. If a utility does not buy enough SRECs to meet their annual, legislated quota they will pay a penalty, called an ACP (Alternative Compliance Payment). If you are a solar photovoltaic owner you will produce one SREC per each 1,000 kwh your system produces. These SRECs (solar renewable energy credits) are sold on the open market, and vary in price.