A 600,000-square-foot Fontana, Calif., distribution warehouse roof fitted with 33,700 panels. (Photo courtesy of Edison International)

As part of its 500 megawatt solar PV program, Southern California Edison has awarded a 200 megawatt contract to SunPower for rooftop solar installations

On a recent flight into Los Angeles International Airport, I was struck by what appeared to be a region being virtually consumed by giant warehouses. In fact, if you have flown into any of southern California's major airports, one thing you may have noticed is that there is no shortage of prime rooftop real estate. And one of the largest utilities in the U.S., Southern California Edison (SCE), is taking advantage of that available real estate with an ambitious project to bring 500 megawatts of new solar capacity onto the grid over a five year period.

In a partnership with San Jose-based solar panel maker SunPower inked just last week, SCE will lease rooftop acreage for 200 MW of new solar PV generating capacity -- most of which will come in the form of 1-2 million watt rooftop installations.

Under California law, investor-owned utilities are required to secure 20 percent of electricity from renewable energy sources by 2010 and 33% by 2020.

The payouts to the property owners for their otherwise unused roof space will be nothing to sneeze at either. SCE will lease each roof for about $40,000 per year.

The project is part of SCE's larger 5-year, 500-megawatt solar PV plan just approved by the California Public Utilities Commission in January. In that amended plan, 250 megawatts of solar PV will be owned and operated by SCE with at least 80% coming via this warehouse roof leasing program. The other half in the plan will com from solar installations that are owned and operated by independent power producers.

Eventually, the two installation tracks will add a total of 500 megawatts to the solar generating capacity of Southern California’s power resources – making it the largest U.S. photovoltaic program ever undertaken.

"The SunPower cost structure will allow us to meet our commitment to increasing our customers’ supply of renewable energy while reducing the cost of installed solar photovoltaic power in California," said SCE communications manager Gil Alexander in a phone interview on Friday.

"In other words," said Alexander, "we have estimated a final cost of $3.50 per installed watt vs. the state average of $7. The SunPower agreement means we are on target to fulfill that commitment."

SunPower T5 Solar Roof Tiles chosen for light weight, efficiency

For eighty percent of Southern California Edison's 250MW commitment, the utility opted to purchase the SunPower T5 Solar Roof Tile product. The T5 is one of the lightest products and considering the load bearing characteristics of the roofs are not designed for massive solar installations, overall weight is important.

The T5 was also selected, because its design is ideal for flat or low-slope rooftops. The T5 is made from an engineered glass-filled polymer that is non-reactive, integrating solar panel, frame and roof mounting system into a single unit and eliminating the need for electrical grounding of the array.

In essence, the solar tiles require no framing or rack to fasten to the roof, they are the rack. And when you're talking about installations of 1 million to 2 million watts, efficiency in the installation process is paramount. (Continued...)