In the past, meeting California's electricity needs was relatively straightforward: Build a generating plant, most likely powered by natural gas to comply with the state's strict air-quality standards, and wire it to the grid.

Carbon-based fuels, however, are decidedly out of favor in California in these days of heightened concern about global warming, and new laws are forcing providers to explore greener energy alternatives. But as utilities try to find and tap environmentally superior electricity sources, they are finding that even "green" power development often has a price tag environmentalists and their supporters are unwilling to pay. Californians are relatively thrifty when it comes to electricity consumption, using less on a per-capita basis than residents of any other state. The average Californian consumed 7,032 kilowatt-hours of power in 2005, according to the California Energy Commission. That's not much more than half the U.S. average and about a quarter the power consumption of the average resident of Wyoming, which leads the nation in per-capita use.

Still, population growth of nearly half-a-million people per year is driving an increase in overall electricity demand, prompting California's utilities to search for new energy sources.

Under a law passed last year — SB107 by Sen. Joe Simitian, D-Palo Alto, and Don Perata, D-Oakland — California must obtain 20 percent of its electricity from renewable energy sources by Dec. 31, 2010. The law defines those as biomass, solar thermal, photovoltaic, wind, geothermal, fuel cells using renewable fuels, small hydroelectric generation of 30 megawatts or less, digester gas, municipal solid waste conversion, landfill gas, ocean wave, ocean thermal, or tidal current.

Of the state's five major investor-owned utilities, only Southern California Edison — which derives 16 percent of its electricity from renewables — is anywhere close to meeting the SB107 mandate. Pacific Gas and Electric, serving Northern California, is next at 13 percent, followed closely by the Sacramento Municipal Utility District at 12 percent. At the back of the pack are San Diego Gas & Electric at 8 percent, and the Los Angeles Department of Water and Power at 6 percent.

So far, most of the utilities' efforts have focused on transmission lines, long the Achilles' heel of the statewide power grid, and assuming even greater importance as renewables move to the forefront.

Unlike the natural-gas-fired generators that historically have provided the biggest share of California's electricity, power plants using many of the most promising renewable technologies cannot be sited just anywhere. Wind power, for example, can only be generated where there's lots of steady wind.

Solar cells work best in the deserts and hot valleys of the interior. Small hydro plants requires running water.

Utilities gambling on renewables must, in effect, go find the power — typically in relatively remote rural areas — and obtain regulatory permission to install transmission lines connecting them to the state's major urban areas, where most customers live. Southern California Edison, for example, recently won permission from the Public Utilities Commission to construct key segments of a new transmission line needed to move electricity from a new wind farm in the Tehachapis to the utility's distribution system.

In a state as populous and environmentally conscious as California, however, it's difficult to find routes for transmission lines that don't cut through sensitive habitat or impinge on rural communities. Perhaps the most contentious "green" power proposal currently before regulators is the Sunrise Powerlink. Portrayed by its proponents as a way to tap "clean, renewable energy sources" in or near the Imperial Valley, the 150-mile transmission line would allow SDG&E to import 1,000 megawatts of electricity, enough to serve about 650,000 homes.

The preferred transmission corridor, however, would cut through several prized natural areas including Anza-Borrego Desert State Park, a sprawling swath of arid canyons, mountains and valleys that are popular with recreational users and home to numerous protected species.

Although SDG&E has proposed installing the new line along an existing utility corridor, the project would require replacing a series of 50-foot wooden power poles with steel towers up to three times as tall.

Consequently, the proposal has drawn fierce opposition from the Sierra Club, the Center for Biological Diversity and other environmental advocates struck by the incongruity of a "clean" energy project that would disrupt a relatively pristine landscape.

— John Krist is a senior editor and Opinion page columnist for the Star. E-mail address: jkrist@VenturaCountyStar.com.