SunPower has targeted solar power marketing efforts at municipal water districts and regional water agencies with brilliant results.

The company has installed more than 25 solar systems at water plants throughout the country, most of them in California. It just announced four new ones, totaling 3.8 megawatts of installed solar capacity at two Rancho California Water District facilities in Riverside County, one in Castaic Lake Water Agency’s Rio Vista Water Treatment Plant in Santa Clarita and another at the City of Galt’s Wastewater Treatment Plant.

Water pumping and treatment facilities are notorious energy hogs for municipal governments, and SunPower has successfully pitched cost-savings to local governments.

“Solar power systems are a smart investment for water agencies,” SunPower spokeswoman Ingrid Eckstron said.

There are several reasons that water districts are going solar en mass, she said.

“Water agencies typically have underutilized space suitable for installation of solar power systems,” she said.

She said solar provides a hedge against future rate volatility because it’s onsite. Solar also improves profits and the bottom line as energy is the single highest investment for water agencies. Water agencies are also able to take advantage of government incentives to reduce costs.

The Rancho California district financed its 1.1-megawatt pump station system and 1.1-megawatt reclamation facility system with low-interest Qualified Energy Conservation Bonds through the federal American Recovery and Reinvestment Act.

“Water agencies can also use solar power purchase agreements to finance systems with no initial capital investment and savings from day one,” Eckstrom said.

That’s how the City of Galt paid for its 983-kilowatt system.

Municipalities and water districts are installing enough solar to offset anywhere from half to 95 percent of their energy use, Eckstrom said.

Rancho California will cover 95 percent of its energy need at its district headquarters and 55 percent at the Senga Doherty Pump Station. The system is expected to save the agency approximately $4.3 million over the next 20 years, Eckstrom said.

The City of Galt’s new solar installation will provide 90 percent or more of the facility’s electricity demand.