Inmates at Dublin, California's Santa Rita Jail will soon get a boost to protect them from the energy crisis hitting California.
The jail will be home to the nation's largest roof-mounted solar array.
"The bills have started to go through the roof," said Matt Muniz, energy program manager at the Alameda County General Services Agency. "We were paying $1 million per year for electricity. With the June 1 increases this would go up by at least 50 percent."
The California Public Utilities Commission approved electricity rate increases of up to 46 percent on March 27.
"With the solar array we will be saving about $300,000 per year," Muniz said.
The 70,000-square foot solar array, set to go live on July 15, consists of six panels comprising 4,500 roof tiles. It packs 500 kilowatts of potential power output; a regular household requires only around one kilowatt to supplement its power supply.
It steals the title for the nation's largest solar panel from a 400-kilowatt solar roof system produced by Powerlight Corporation for Arden Realty in Fountain Valley, California.
The world's largest is a 3.3-megawatt ground solar panel in Serre (Naples), Italy. The panel, produced by Enel, was built as a demonstration panel and is used to evaluate the performance of a large solar array.
The Santa Rita panel, also built by Powerlight, does not come with batteries for storing the power because they're too expensive to maintain. Basically when the sun is shining, there is power; when there is no sun, no power.
"We will still be buying power from the utility: 15 percent of the electrical load in the summer and 20 percent in the winter will be from the array," Muniz said.
The system also has the potential to generate more power than needed during the sunniest part of a sunny day.
"This power can be sold back to the grid so it becomes the storer of excess electricity," said Bill Kelly, regional manager for CMS Viron Energy Services. CMS is a design and building subcontractor for Powerlight.
While lightweight -- it weighs about five pounds per square foot -- the solar panel is still tough.
"The cells are protected by tempered glass so they are extremely durable. You could throw a baseball at them as hard as possible, and they still would not break," said Daniel Shugar, executive vice president of Powerlight.
The panel is also low maintenance. "The system is virtually maintenance-free," Muniz said. "Once a year we may need to spray down the panels to wash them off. They come with a 20-year warranty and a life expectancy of 30 years."
The entire project -- which took just under four months to construct -- cost $4.4 million. It's not pocket change, but with the California Energy Commission's current renewable energy buydown program and its offer to pay for 50 percent of the system purchase price, it becomes a viable project.
The jail was a perfect candidate for the solar panel, with its open, 500,000-square-foot flat roof and sunny locale. This, in part, explains why there aren't more solar panels gracing residential rooftops.
Basically, solar panels are harder to attach to a slanted roof than a flat one. You can just sit the panel on a flat roof, but when there are angles involved the panel has to be very firmly attached to the roof or it will slide off.
"You don't see many flat roofs in residential properties. You can install a panel on a slanted roof, but it is more difficult to attach. Then it's best to have a southern-facing panel to get the most from the sun," Kelly said.
Solar panels generate maximum power when facing the sun directly. The fixed position which approximates this ideal over the course of the year is facing due south (in the northern hemisphere) or due north (in the southern hemisphere).
Another problem that Kelly cited is all the hardware needed: a converter to change DC power to AC, all the electrical wiring needed to install the system, and the development and design costs.
A home owner would need to spend around $32,000 for a 4-kilowatt solar panel, said Marwin Masri, manager of the renewable Energy Project for the California Energy Commission.
For it to make economic sense, said William Rukeyser, assistant secretary for the California Environmental Protection Agency, the home would have to be located in a consistently sunny neighborhood and have a suitable roof area.
If the residents qualified, they would then have to apply for the government subsidy and be prepared to stay in the house for 10 to 15 years in order to recoup through the lowered electrical bill what they had spent on the panel.
"It's not a fully mature or economic industry right now," Rukeyser said.
"The activity was very slow last year. We were accepting about 30 applications (for the government subsidy) a month last year -- this has increased by tenfold," Masri said.
"It remains to be seen if this interest will be sustained after the energy crisis is resolved," Masri said.
"The solar panels are not economical when compared to buying power off the grid, if it were not for the grant. But we hope that by generating demand, we will bring the cost of the systems down as production increases," Masri said.
"The price of installing solar is going down while the cost of electricity is going up. I see a brighter future for solar power in California," Muniz said.
