Southern California Edison is creating a smorgasbord of alternative energy courses, and some will turn out to be better than others.

But the company is also under deadline pressure to meet a legal mandate, so all of them will become part of the mix of power generation processes of the future.

Over the past year alone, the Rosemead-based utility has signed more than a dozen agreements with renewable-energy developers in at least five categories: solar, wind, hydroelectric, geothermal and biological waste.

The latest is its plan announced last week to buy 245 megawatts of electricity from solar plants to be built in the Antelope Valley by eSolar Inc., a Pasadena startup backed by Google.org. The plants will use thousands of mirrors to direct solar rays to heat water in tanks. That process creates steam that will spin turbines and provide enough electricity to light about 160,000 homes.

The solar initiative follows Edison's big push for wind energy. In March, the utility announced a $1.8 billion transmission upgrade to carry power generated by windmills in the Tehachapi Mountains to its Los Angeles-area power grid.

Edison's suite of renewable energy sources comprises 17 percent of its energy mix. California mandates that utilities draw 20 percent of their power portfolios from renewable energy sources by 2010.

Edison's sweeping approach to emerging technologies makes business sense, said Mark Bernstein, managing director of USC Energy Institute.

"You don't want to depend on one supply for all your needs," Bernstein said. "Individually, none of the technologies will account for a major portion of electricity, but together can form a good portion of a portfolio. The future of energy will be dependent on a broad suite of technologies."

Some of these technologies are so new that no one knows which one is going to be a winner over the long haul, said Stuart Hemphill, who heads Edison's renewable and alternative energy department.

For example, wind power, which costs up to 8 cents per kilowatt-hour to generate, used to be considered expensive. But the cost of natural gas has doubled since last year, up to 6 cents per kilowatt-hour. Suddenly, wind has become cost competitive.

Solar is relatively more expensive, costing up to 20 cents per kilowatt-hour to generate. But in the hottest months of the year, during afternoon peak hours, some large commercial customers in Southern California pay about the same rate for electricity, Bernstein said.

Another major source of renewable energy is geothermal technology. Edison gets its geothermal energy, which uses heat from within the Earth to generate electricity, from installations near the Salton Sea, Imperial Valley, Mammoth, Geysers and Western Nevada. About 60 percent of Edison's renewable energy portfolio comes from these plants.

In the past, none of these renewable energy technologies, including wind, solar and geothermal, made economic sense. But the cost structure of maintaining conventional utility facilities began to increase dramatically recently, and the cost of gas and oil has doubled or tripled in the past few years.

"The cost of renewable technologies, due to tech improvements, has all come down," Bernstein said. "Conventional technologies, because of the rise in fuel and material costs, have become expensive."

Changing approaches

Meanwhile, emerging technologies keep getting more creative. Tidal power is an area of research gaining traction at universities. Solar technology has varying forms, including nanotechnology, which improves the efficacy of heat-generation in solar power.

Technological advancement in these areas is something to celebrate, but it will not ease the energy crisis in the short term, said Jack Cox, a research director for a joint-study by Arizona State University and Penn State on Arizona's long-term energy future.

Every megawatt of solar energy, for example, requires a backup from conventional sources for 90 percent of that megawatt, he said.

"It's just not reliable. When it's not sunny or windy, you have no energy," Cox said.

Rob Rogan, executive vice president at eSolar, said adding solar power into the energy mix makes the electricity grid more reliable. Solar plants produce power when people need it most in California during the hot summer months, in the middle of the day. Plus, since eSolar's installations are modular, it's more cost effective than most solar plants.

"The unit modularity means simpler and more rapid construction, while our smaller footprint smoothes the siting and permitting process," Rogan said.

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