There are two ways that you can get credit for your extra energy production. Net metering allows you to get credit on your utility bill that you can use when your solar is not producing as much power as you are using. You can also get paid for your extra energy in the form of Renewable Energy Credits, or RECs. The REC market is already established in MD and DC and will soon be available in VA as well. Read more about Renewable Energy Credits (RECs) here, and learn more about net metering here.