Texas remains a solar and storage hotspot, but transmission gaps could hamper growth


The pipeline for utility-scale solar development in Texas is being turned on as nearly 3 GW of projects with signed interconnection agreements are slated to be added by the end of the year.

Battery energy storage additions are expected to reach 1,770 MW over the same time period, up from the 552 MW already installed.

The data was reported by the Electric Reliability Council of Texas (ERCOT) in its May report on capacity changes by fuel type. The report forecasts new solar projects with signed interconnection agreements to total 2,937 MW of new capacity from now until year’s end, landing at a total cumulative 2021 capacity of 10,542 MW.

The three largest solar projects will add a combined 1,883 MW of capacity. The top spot goes to Dawn Solar in Deaf Smith County west of Amarillo, sized at 515.66 MW. Close behind is Plainview Solar, at 514 MW, and Eunice Solar at nearly 427 MW.

The largest battery project is the Crossett Power Battery system, a 203 MW storage facility that has a target operation date of August. Also coming online this year is the Vortex BESS, and Silicon Hill Storage, at 122 MW and 105 MW, respectively.

Wind remains the dominant source of renewable energy in ERCOT. Cumulative wind capacity currently stands at 31,836 MW currently and will increase by another 3,891 MW to 35,727 MW by the end of this year. Texas can expect the High Lonesome Wind project to begin operation this year, adding almost 450 MW to the grid.

The increase in capacity of solar represents a 38% addition of cumulative capacity added from June through December. Wind will add 12% in the same period, and batteries will add an additional 220% of new capacity to what is currently in place.

Transmission remains problematic

While growth in renewable capacity is occurring, constraints around current and future transmission capabilities could hamper growth. In its 2020 Long Term System Assessment, ERCOT said the scale and location of wind and solar generation additions are dependent upon sufficient transmission capacity between resource-rich regions and demand centers.

ERCOT estimated if current transmission constraints do not improve, the state could see 7,000 MW less of solar and wind generation through 2035.

ERCOT said it expects the construction of gas generation sources closer to loads to make up for the loss in renewable generation. Another solution under consideration for solving the transmission problem is to add more energy storage, which can help relieve localized congestion.

Solutions that address both regional transfer limits and local constraints closer to urban demand centers are required to accommodate large-scale renewable generation transfers, said ERCOT. Its 2020 Regional Transmission Plan outlined several placeholder projects for areas in the most need, but there is no major economic project currently planned. The grid operator will review the projects again later this year.

Guiding force

As is the case with most grid operators, the need for storage has come under the spotlight for ERCOT. In 2019, it formed a Battery Energy Storage Task Force (BESTF).

The BESTF evaluates operational and market design policies that may be implemented in a two-step approach. It examines rules that can be implemented in the short-term to integrate battery Energy Storage Resources under a “combination model” structure. Then, it examines rules that can be implemented on a longer timeline to integrate battery energy storage resources under a “single model” structure.

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