Solar Roofs Brighten Utilities

Bill Opalka | Jun 08, 2011

 

Can the cost of utility scale solar projects be driven down to reach grid parity? In California it’s not an academic question as the state embarks on its aggressive program to reach 33 percent renewables on the grid by the next decade.

Southern California Edison is trying to meet that challenge by reducing the overall costs of its solar photovoltaic (PV) operations. SCE's 25O-megawatt Solar Photovoltaic Program (SPVP) is designed to install 1- to 10-megawatt roof and ground mounted PV projects at an average cost of $3.50/watt.

The topic was recently addressed by the Solar Electric Power Association in a webinar, “SPVP The Pathway to Grid Parity.”

So far, the program is starting to meet that challenge, said Rudy Perez, program manager for SCE solar photovoltaic program.

“One of the key parts of the program was to have an average cost of $3.50 per watt, around that number with a 10 percent (inflation) adder $3.85 in 2008 dollars,” he said. “Today we’ve managed to do that so our total direct capital costs we’re averaging $3.85 and ground mounts are at $3.30.”

One reason the program has been able to keep costs down is the lower costs for solar panels and modules that have swept through the industry in recent years.

“Prices were higher before so there weren’t many independent power producers bidding, but now there seems to be quite a few,” Perez said.
Primarily, the sites are one to seven megawatt per rooftops, with the program allowed 10 percent of the total to be ground mounts.

Locating the program on large commercial solar rooftops from 200,000 square feet to 1 million square feet was the intent of the program a total of 250 megawatts from 50 to 100 individual sites.

Integration challenges remain, though valuable experience has been gained. One key area is that individual rooftops interconnect onto the distribution circuit. The rooftop arrays don’t serve building load, so essentially they’re like independent power plants, Perez said.

On the construction side, some growing pains were experienced, which the utility thinks experience has helped solve.  Lease negotiations took several months as questions about liability had to be addressed; fire departments had to be assured that roof access would be maintained; and there are the typical environmental and siting permits to be had.

One downside of the program: “Even within our cost cap, we’re still at 26 cents per kilowatt-hour power, which is much more expensive than other sources of generation today,” Perez said.

One change in the program started earlier this year was the filing of a petition to regulators to lower the utility-owned component. SCE asked to cut program in half, to 125 megawatts, with the other 125 megawatts turned over to independent power producers, which in turn would sign contracts with the utility.

“This is in order to save customers money, switch to more IPPs to have goals met through program,” Perez said, without the costs incurred and passed into the rate base.

In short, even with the initial successes, there’s room for improvement.

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