US solar output 50% higher than official figures suggest, report finds


Almost 50% of the solar electricity generated in the U.S. remains unaccounted for in official Energy Information Administration (EIA) figures, finds a recent study by GTM Research and kWh Analytics – the largest independent database of solar production data in the U.S.

According to a joint study involving the Solar Energy Industries Association (SEIA), GTM Research and kWh Analytics, behind-the-meter solar electricity production – solar PV power generated by the country’s 700,000 customer-sited systems – represents 9.2 GW of capacity.

This figure is some 45% of the nationwide solar electricity generation capacity, but such data remains absent from the EIA’s official figures. Equally, in California – the state with the highest volume and penetration of solar power – the California Independent System Operator (CAISO) reports on utility-scale generation, but does not include distributed generation (DG), the study finds.

The EIA analyses data gleaned only from those solar plants greater than 1 MW AC in size. This approach to measuring the nation’s energy output made sense when the fledgling U.S. solar sector was predominately rooted in large-scale plants.

However, as the residential and commercial solar sectors have grown to around 700,000 customer PV systems, a huge chunk of data is overlooked by these official figures. To ascertain more exact output data, kWh Analytics delved into its database to deliver monthly solar production figures based on state and market segment.

Combining these data with SEIA’s detailed capacity generation figures, and allied to EIA’s estimates for utility scale production, the study found that solar energy systems in the U.S. generated 30.4 million MWh of electricity – 50% more than EIA’s utility-only estimate of 20.2 million MWh. This data was drawn from a 12-month period ending March this year.

Broken down further, GTM Research reports that solar’s actual capacity in the U.S. is enough to supply the yearly electricity needs of Hawaii, Rhode Island, Alaska and Vermont. Put another way, solar electricity generation is now greater annually than the consumption of 16 individual states, as well as the District of Columbia.

Furthermore, there are now three U.S. states where solar electricity has greater than 5% penetration: California, Arizona and Hawaii. The report outlines the importance of accurate data gathering, particularly for a still-young industry such as solar.

Policy decisions taken by a PUC or FERC rely heavily on energy data, while the Environmental Protection Agency’s (EPA) Clean Power Plan relied upon 2012 EIA data on solar (4.3 million MWh) when drafting its Alternative Approach plan. In it, EPA outlined a solar contribution target of 8.7 million MWh by 2030 – a figure that is less than one-third solar’s output already in 2015.

Cumulatively, GTM Research has found that the U.S. has more than 20 GW of solar PV capacity currently deployed.