AUSTIN (KXAN) — A subsidiary of Tesla has quietly been building an enormous battery in Angleton, Texas, a city 40 miles south of Houston and just north of Lake Jackson, according to a new report in Bloomberg. The battery is so large it could power 20,000 homes even on a hot summer day.

The Tesla subsidiary is called Gambit Energy Storage LLC. Workers have covered up most equipment, but Bloomberg confirmed that property records show Gambit shares the same address as a Tesla facility in Fremont, California.

This comes at an interesting time as the state’s power grid and the reliability of that grid is an emergency item for lawmakers this legislative session. The power grid came just four minutes away from a complete collapse during last month’s winter storm.

The Electric Reliability Council of Texas operates and manages the deregulated market for three-quarters of Texas. When it started forcing mandatory outages across the state, millions of Texans lost power — some for almost a week — with sub-freezing temperatures dipping into the single digits.

Tesla founder and CEO Elon Musk, who recently moved to Texas, sharply criticized ERCOT for being unreliable.

The ERCOT CEO and a half dozen board members have already resigned. The chairwoman of the Public Utility Commission of Texas, which oversees ERCOT, also resigned.

Now it appears Tesla plans to help add power to the energy grid with a 100 megawatt battery. Gambit Energy Storage is registered with ERCOT, and ERCOT told Bloomberg the project could be operational as early as June 1.

Prior Musk company SolarCity laid foundation in renewable energy

Musk has long been in the business of using batteries to provide clean energy. In addition to the electric cars Tesla churns out, Musk helped lead the company SolarCity that his cousins founded in 2006.

The company started by providing residential solar power. You could buy solar panels and put them on your house, contributing to the energy grid and lowering your monthly energy bill. But the company’s footprint grew beyond just residential households.

Since 2016, SolarCity has operated as a subsidiary of Tesla and last summer, Tesla claimed “Tesla Solar is the lowest-cost solar in the United States.” Musk has said he believes Tesla Solar will one day be as big if not bigger than the automotive part of the business.

100 MW plant also being built in Travis County

Key Capture Energy is working on a 100 megawatt battery storage project in Travis County, as well as two other smaller projects elsewhere in the state.

This will increase KCE’s battery storage more than 500 percent.

Including Tesla and KCE, there are at least four energy companies building massive battery storage plants in Texas.