The Southeast region emerged ahead of the pack in the country's completion of big solar installations. Projects in the Southeast brought nearly 1.5 gigawatts (GW) of utility-scale solar online in 2019, according to the 2020 update of utility-scale solar data by the Lawrence Berkeley National Lab. The lab regularly analyzes publicly available data on key trends in large-scale solar projects, specifically ground-mounted projects that produce more than 5 megawatts (MW).

Big projects in the Southeast outpaced those in California by about 50% in 2019. Roughly 1 GW of utility-scale solar achieved commercial operations in the Golden State in 2019. The region, with boundaries that closely follow those of the state, took second place in the rankings for the third consecutive year.

The lab focuses on historical data but emphasizes the most recent full calendar year. A pdf of the 2020 update is available for download. For the purposes of the report, researchers divided the country into 10 regions. "Projects are spread across all 10 regions that we track, though more heavily concentrated in the sunniest regions," wrote the authors. You can see the regional boundaries in the map at the bottom of this story, courtesy of the National Renewable Energy Laboratory.

California Still Leads the Nation in Solar

Although California hasn't brought as many megawatts of solar online via utility-scale projects as the Southeast has for three years now, the Golden State remains the number one solar state by far. States in the Southeast aren't even in the top 10. The U.S. Energy Information Administration (EIA) ranked solar's market penetration by state, as seen in this table.

Solar generation as a percentage of in-state generation
State All Solar Utility-Scale Solar Only
California 19.9% 13.0%
Vermont 14.0% 7.5%
Nevada 13.7% 12.0%
Massachusetts 13.7% 4.9%
Hawaii 12.6% 2.4%
Arizona 6.6% 4.4%
Utah 6.6% 5.4%
North Carolina 5.7% 5.5%
New Mexico 4.7% 3.8%
New Jersey 4.7% 1.7%

Most Completed Projects Use Trackers

Also apparent in the 2020 update is the popularity of trackers in utility-scale solar farms. The two methods to mount solar panels to the ground are trackers and racks. Trackers are solar panels that tilt on at least one axis to track the sun throughout the day. In the Southeast and California, the newest solar projects overwhelmingly used trackers. In Florida, for example, only four projects used fixed-tilt racking. Tracking on just one axis can add roughly 5% to a solar farm's capacity in regions where sunlight is plentiful.

Across the country, trackers also outnumber fixed-tilt racking. Single-axis tracking was used in 77% of projects that achieved commercial operations last year.

The Cost of Building Big Solar Continues to Drop

The report said the median installed cost of projects that came online in 2019 fell to $1.4 per watt AC power ($1.2 per watt DC). These costs are down 20% from 2018 and down by more than 70% from 2010.

Jeffrey Sachs, a professor at Columbia University, has watched utility-scale energy projects over the years. "Renewable energy now is at what is called grid parity," he told CBS News. "That means it is no more expensive to put up a solar field than it is to put up a coal plant."

With the 2019 figures in the books, America's cumulative capacity from utility-scale solar climbed to 29 GW.

Regional boundaries used by the NREL in its report.