Solar energy is one of the smallest contributors to the power grid in Texas, providing just 2.2 percent of generation capacity this year. But it's also projected to be the fastest growing over the next three years.

Solar developers in Texas are expected to add 3.5 gigawatts of capacity from new utility-scale solar projects this year and 5.5 gigawatts next year, according to the Electric Reliability Council of Texas, the state grid manager. One gigawatt provides enough power for about 700,000 homes.

The projections reflect projects in the pipeline that have signed interconnection agreements with ERCOT, an indication they'll likely be completed.

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Most of the planned solar projects with interconnections deals in place are expected to come online before summer 2021, ERCOT said.