Rosemead, Calif., June 13, 2011 — The design of traditional circuits that carry electricity through communities served by utilities like Southern California Edison is changing for the first time in more than 100 years.
These distribution circuits have been one-way routes for electricity channeled from neighborhood substations to some 1,200 nearby homes and businesses each. Components built into these power paths compensate for the natural drop-off in voltage, ensuring that the customer at the end of a circuit receives the same stable voltage supply as the one nearest the substation.
SCE has begun connecting large multimillion-watt solar power stations, with their fluctuating outputs depending on time of day and cloud conditions, to the middle of such circuits. To support this advance in distributed renewable generation, the utility's grid engineers have launched the first major redesign of this aspect of the traditional power delivery system.
One example of this work is the inverter testing program at SCE's Pomona, Calif., laboratory. Inverters used to convert the direct current output of solar panels to the alternating current customers use are connected to a grid simulator and subjected to real-world conditions.
SCE engineers are collecting and analyzing data to determine how best to enable the safe and effective deployment of inverters on the utility's distribution circuits.
Lessons learned as SCE deploys its network of 1-to-10-million-watt community solar plants, and upgrades its power distribution system, are being shared with other utilities and the solar industry to foster similar advances elsewhere.
SCE also announced today that four new solar power plants capable of providing 7 million watts of peak generating capacity (AC) – enough to serve 4,550 average homes – have been connected to the utility's Inland Empire grid, enlarging SCE's community solar network to 15 stations.
These new rooftop solar photovoltaic stations in Fontana and Redlands, Calif., join 10 others, which have been serving the utility's Inland Empire customers for up to three years, plus the utility's first large ground-mount installation recently completed in the Central Valley.
Construction of the solar plants created 192 temporary Southern California jobs. SCE estimates its five-year solar project will result in 75 to 100 roof- and ground-mount facilities and up to 1,200 new construction jobs.
The Fontana installations involve three solar stations on more than 1.9 million square feet of leased warehouse roofs owned by Prologis and 35,000 photovoltaic panels.
In Redlands, SCE has built an additional solar station with 5,900 panels spread over 259,000 square feet of Prologis warehouse space.