Across the US, over 17,500 megawatts of distributed generation has been installed and interconnected with the electric grid. The State of California has approximately 3,500 MW (20%) of this installed DG capacity as shown in the figure.
Sources: California Energy Commission (Scott Tomashevski), DG Monitor March/April 2004
These market numbers reflect only distributed generation devices that are interconnected to the electricity grid and do not include emergency or other non-interconnected DG. EPRI reports that the total US DG capacity may be as high as 147 GW, including non-interconnected DG with sizes up to 10 MW. If the same ratio holds for California, the total DG could be as high as approximately 30 GW.