timesheraldonline.com | June 16, 2015 –
The Napa Sanitation District signed two contracts expected to save ratepayers millions over the next 25 years, agency officials announced.
Late last month, the district executed contracts with SunPower Corp. to build, finance, operate and maintain a 1-megawatt photovoltaic solar power array on district property north of the Napa Airport and south of Highway 29, officials said. The system is financed through a 25-year power purchase agreement that saves the district a significant amount in long-term electricity costs compared to what utility rates are expected to be, and with no up-front investment, they said. District officials estimate the arrangement will save nearly $3 million over the contract’s term.
“The district is constantly seeking out ways to lower its operating costs to keep rates low for its ratepayers,” said Napa Mayor Jill Techel, Chair of the Napa Sanitation District. “This agreement with SunPower will immediately save money through lower electricity bills, and those savings will continue to grow over time.”
Last year, the district produced 33 percent of its own electricity by running a cogeneration engine using biogas from the wastewater treatment process, officials said. With the solar power project, that will jump to nearly 60 percent, they said.
The District has also contracted with Tesla Motors, Inc., to install a 1-megawatt/2-megawatt-hour Powerpack commercial battery system, officials said, to allow the it to store energy it produces for use when electricity costs are high, thus lowering its energy costs and its demand charges.
“The partnership with Tesla is great for our ratepayers,” Napa Sanitation District General Manager Tim Healy said. “It reduces financial risk to the district, and ratepayers benefit through lower energy costs.”
The SunPower solar power array will use technology which positions the panels to track the sun during the day to maximize energy capture. The system will cover some 4 acres of district property next to the Soscol Water Recycled Facility on Soscol Ferry Road. It’s expected to produce enough power to run 192 households based on the 2013 national average per the U.S. Energy Information Administration, officials said.
Tesla’s Powerpack system will be about 10 feet wide, 10 feet tall and 50 feet long, and will be able to store two megawatt-hours of electricity, which is enough to power the average household for 67 days, officials said.
Napa Sanitation District provides wastewater collection, treatment and disposal services to the residents and businesses in the city of Napa, Silverado Country Club, the Napa County Airport and several adjacent unincorporated areas. It also provides recycled water service to portions of southern Napa County and has been serving the community since 1945, officials said.