Salt River Project (SRP) announced on Wednesday that is has plans to add an additional 1 GW of utility scale solar power to their power grid by the year 2025. The Arizona electricity and water cooperative, serving 1 million customers, plans to add 200 MW a year. Currently, the utility hosts 106 MW of rooftop solar power and 200 MW of utility scale solar.

The utility has 2020 goals of reaching 20% of their retail energy requirements from “sustainable” sources, including biomass, hydropower, geothermal, solar & wind. As of the end of April, SRP was at 17% “sustainable” energy, with solar power supplying 467 gigawatt-hours (GWh) of the just over 5,000 GWh noted as sustainable – about 1.6% of its total electricity. Almost 3/5 of the “sustainable” volume is from energy efficiency savings – not clean energy generation.

Of course, its not all sun and games at SRP. The board of the utility approved a $50,000 donation to fight a ballot initiative to move the state to 50% renewable electricity by 2030. It is notable that SRP would not be subject to the mandate, but that it is a partial owner of the massive Palo Verde nuclear power plant.

The initiative failed. And last year, when the company thought they might lose a case against solar power proponents in the Supreme Court, they settled out of court and agreed to buy a 25 MW battery from Tesla – but not to revert the charges that it was sued for, successfully, in court, and which devastated the rooftop solar market in its service area.

The utility is offering residential customers up to $1,800 for installing energy storage. The program was launched in May with 4,500 reservations available, and initially, over 1,000 people signed up right away. However since then the number of reservations spoken for has actually fallen back to fewer than 500.

The utility recently announced – above – the installation of Arizona’s largest solar plus storage plant – which stars Tesla, First Solar and NEXTracker hardware. The NextEra-built facility, the Pinal Central Solar Energy Center, is a 20 MW solar plus 10 MW/ 40 MWh energy storage power plant. The project costs approximately $50 million.

SRP suggested that it decided to make this move because the pricing of solar power had fallen far enough, and specifically because “utility-scale solar projects that have higher solar capture efficiencies and therefore provide optimal value for our customers”.