San Antonio, Texas-based public power utility CPS Energy is pursuing a so-called “Flexible Path” approach to energy, one that incorporates new energy storage technology to guide its ongoing transition from fossil fuels to renewables.
"We want to look into new technology, innovation," says CPS spokesman John Moreno. "We want to reduce our dependence on coal." CPS serves 804,000 electric and 343,000 natural gas customers in San Antonio and seven surrounding counties.
The utility is working with local universities, Moreno says, to "point us in the right direction" and is partnering with the Southwest Research Institute on a $16.3 million project to install a 5-MW solar array with 10 MW of battery storage on Southwest's property in northern San Antonio.
The Institute is one of the oldest and largest independent, non-profit applied research and development organizations in the United States.
Construction on the battery storage project is expected to start in October, with completion targeted for April 2019, according to James Boston, CPS manager of marketing intelligence.
The utility believes battery storage can go hand in hand with renewables, to which it is no stranger. CPS currently has an estimated 1,500 MW of renewables, including 1,000 MW of wind energy and 500 MW of solar energy. It also has about 90 MW of distributed solar.
Gas represents 46% of the CPS energy portfolio in 2018, up from 39% in 2010. Coal, meanwhile, has fallen from 32% eight years ago to 14% today.
It is destined to diminish even more in the years ahead if CPS can stay on its Flexible Path. By 2040, coal could account for only 9% of the portfolio under the "flexible" scenario compared to 11% under a more traditional path.
Indeed, David Jungman, the utility's senior director of business and economic development, says the CPS energy strategy “is all about being flexible with our generation selection in the future. We will need to continue using our fossil fuel generation until new technology allows us to adopt cleaner sources of generation.”
At present, CPS is "long on generation . . . we have more generation than what we need," says Jungman. So, rather than spending millions of dollars to build more generating plants, most likely fueled by gas, CPS is saying "Let's be flexible and look at this [storage] technology."
Ideally, the utility eventually would like to rely on battery storage, in combination with solar energy, to serve its peak demand load typically between 5-7 p.m, when people usually are home from work and using air conditioning to get relief from the often-oppressive San Antonio heat.
"Instead of using fossil fuels in that two-hour time period, we're going to discharge with batteries," Jungman says.
In terms of generation, "We see things changing from central plant to distributed generation," Jungman says. "We'll have community solar. We can see a time where we're putting smaller plants in within our service territory."
And, if CPS is successful, the Flexible Path could help it get there sooner rather than later.