Arizona Public Service (APS) said recently it has become the first utility outside of California to surpass 1 gigawatt of solar energy capacity.

When generating at full 1-gigawatt capacity, APS generates enough power to meet the partial daytime needs of 250,000 homes in Arizona.

APS said its total investment in solar energy is approximately $2 billion and its solar portfolio is almost half rooftop systems and half grid-scale projects.

“APS customers benefit from the fact that when you include energy from APS’s other renewable energy sources — wind, geothermal, biomass and biogas — and the Palo Verde Nuclear Generating Station, nearly half of all the power on APS’s system is carbon-free,”  Tammy McLeod, APS vice president of resource management, said. “A cleaner energy mix is a top priority for us, with solar playing an important role.”

APS generates grid-scale solar power from APS-owned systems and through power purchase agreements. APS owns and operates nine solar plants in Arizona. The rest of APS’s grid-scale solar power comes from long-term purchase agreements with independent plants across the state.

Most of APS' rooftop-generated solar power comes from systems owned by homeowners or leasing companies.