Dive Brief:

• The U.S. Energy Information Administration has begun including data on small scale solar PV installations in its Electric Power Monthly reports, noting that the systems "have grown significantly in the United States over the past several years."
• Previously, the agency only reported the data in annual analysis because of the difficulty in finding behind-the-meter installations and concerns about the accuracy of the numbers, PV Magazine reports. 
• But in its first report including smaller installations, which EIA defines as 1 MW, the generation accounted for one-third of the country's solar capacity with the bulk of it located in California.

Dive Insight:

Concerns about the accuracy of data on small-scale solar production have finally given way to the fact that there's just too much of it to ignore. EIA will now include estimates in its monthly data, and its first crack at the numbers show a full third of the United States' solar generation – PV and thermal – is coming from smaller distributed systems.

Although each distributed PV system is very small, EIA noted that "there are hundreds of thousands of these systems across the country that add up to a substantial amount of electricity generating capacity."

The agency this week estimated that total U.S. solar generation was 3.6 million MWh in September 2015, with 33% of that total coming from small-scale solar PV. In total, U.S. solar generation was equivalent to about 1% of total reported electricity generation from all utility-scale sources in September 2015, the agency said.

Almost 40% of the small-scale solar is located in California, and EIA said the next nine states combined to account for another 44%. The remaining 40 states and the District of Columbia combined have the remaining 16%.

California's dominance in the solar industry is not unexpected, EIA said. It is "not only the most populous state, but it is also home to other factors that encourage distributed PV generation: high electricity prices, strong solar resources, and state policies and incentives that support solar PV," the agency said.

EIA also looked at how much power different types of solar PV generated, as a percentage of capacity. The agency estimated monthly generation rates for small-scale solar PV installations were almost identical to generation rates reported to EIA by third party owners. Utility-scale solar PV systems, however, have higher generation rates than small-scale solar PV systems, "likely because of more favorable siting and orientation, better maintenance practices, and a higher proportion of systems with sun-tracking features that allow for increased generation."