A local couple recently installed one of the largest and most
powerful residential solar power systems allowed in California,
resulting in significant savings of both dollars and polluting
carbon emissions.
A local couple recently installed one of the largest and most powerful residential solar power systems allowed in California, resulting in significant savings of both dollars and polluting carbon emissions.
With reductions of more than $2,000 per month in electricity and gas bills, tens of thousands of dollars in rebates from the state and PG&E, and more than $50,000 in federal tax credits, Dr. Salah Werfelli’s solar power system could pay for itself in about four years.
Then he and his wife will be getting free electricity for their three-level, 5,000-square-foot home in unincorporated east Morgan Hill, and contributing power to the grid that serves 15 million customers.
With a capacity to produce up to 20 kilowatts at a time, far more than most households need, Werfelli’s system is among the most powerful residential systems allowed by PG&E, which provides guidance and authorization for solar installations connected to its grid.
With such enticing financial incentives, Werfelli, 54, said “it doesn’t make sense not to have solar power” at one’s home.
However, that wasn’t his primary motivation to install the system for which he paid roughly $170,000 before rebates. His system, which consists of 99 photovoltaic panels occupying about 1,500 square feet of a steep hillside on his five-acre parcel, is part of a “global optimization” strategy to reduce energy consumption at home.
He also installed insulation throughout his house, replaced his gas-fueled heating furnace with a dual system that operates on electricity most of the time, and changed out his gas-powered water heater with an electric one.
“We’ve been thinking about going green for a while,” said Werfelli, an executive for companies that develop semiconductor technology that uses less energy than most existing processors. “We weren’t green (before installing the solar panels). We used tremendous heat in the winter and tremendous cool in the summer.”
Now, Werfelli and his wife, Dr. Sam Appleton, can run all three air-conditioning systems in their house and still have enough sun-powered electricity to keep other appliances going. Their system has kept about 150,000 pounds of carbon dioxide out of the atmosphere in two and a half months.
Since they turned on the solar array and completed the other improvements in April, Werfelli said the home has used no gas. One of two monthly electricity bills they have received in that time was for $2.64 (a decline of an average of $2,000 per month) and a credit for 2,000 kilowatt-hours, or about 20 days’ worth of electricity.
Werfelli’s system does not store power in batteries. Instead, it is connected to PG&E’s grid, which he uses as a “giant battery,” explained Sean Kenny, CEO of Fresco Solar, the Morgan Hill company that installed Werfelli’s system.
On sunny days, Werfelli’s system produces power far in excess of what he and his wife use. That excess goes back to PG&E and is used by conventional customers. When Werfelli’s system is not capable of producing the power his home needs, most notably at night and during cloudy days, it switches over to regular electricity as the couple cashes in the credit they have earned with the electricity they produced previously.
One recent afternoon, Werfelli’s meter showed his system was putting out between 19 and 20 kilowatts at one time. The average household uses between two and 20 kilowatts at a time, with most at the lower end, Kenny said. Thus, Werfelli’s installation usually produces far more electricity than he and his wife need.
There are about 30,000 individual residential and commercial solar installations in PG&E’s service area in northern and central California, representing 223 megawatts of power and almost half of all solar power systems in the country, according to PG&E spokeswoman Jennifer Zerwer. That output is almost equal to half the capacity of a large conventional power plant.
And of those systems, only 44 residential solar power arrays are capable of producing 20 kilowatts of power or more, she added.
The rebates offered through PG&E and the state of California are part of the California Solar Initiative, an effort to promote solar energy as an environmentally friendly option.
One solar kilowatt-hour offsets about one pound of carbon dioxide, Zerwer said. A four-kilowatt photovoltaic system, the average residential size in California, can reduce emissions equivalent to 12,000 miles driven in a passenger car.
“We’re committed to helping our customers to reduce their environmental impact, and we’re committed to adding solar as a way to do that,” Zerwer said.
Werfelli’s rebate through the CSI came out to about $27,000.
When light particles from the sun hit Werfelli’s solar panels, their transformation into electricity that keeps lights on inside the house is instantaneous. Light energy creates a voltage across the tempered glass panels, and three inverters transform the voltage into electrical currents the grid is familiar with, Kenny explained. Copper wire running underground carries the electricity to Werfelli’s house about 300 yards away.
Santa Clara County has about 3,650 photovoltaic sites, more than any other county served by PG&E, Zerwer said. In Morgan Hill, there are 140 solar installations that have a collective capacity of more than 1,160 kilowatts.
People in the industry are excited about the potential growth of solar power. The Bay Area is quickly becoming the center of the world for the solar power movement, Kenny said. Last week he attended the Intersolar trade show in San Francisco, a gathering of solar power industry professionals and enthusiasts from around the world.
“San Francisco is becoming the center for this industry in North America,” Kenny said. “It has the most generous incentives in the country for going solar.”
