The Maryland Energy Authority's (MEA) Grant Changer program supports the state's first commerical solar microgrid that "brings Maryland closer to reaching its goal of increasing in-state renewable generation to 20 percent by 2022, combines the strengths of Maryland’s booming solar energy market and the power of grid resiliency. In the event of a conventional power grid outage, the innovative solar PV array will stay online through the power of an advanced energy storage system. If grid power grid goes down, the system batteries will keep a “critical load” of 50 kW online for just over four hours at night and recharge the next day."

See the source: http://www.baltimorenewsjournal.com/2013/10/15/gov-omalley-celebrates-completion-of-states-1st-commercial-solar-microgrid/