California grid preparing for greener future

HOUSTON (Reuters) - Six or more major new transmission lines will be needed to meet California clean air and clean water standards that affect the changing production and use of electricity, the state's Independent System Operator said in its five-year outlook on Thursday.

The grid agency's strategic plan "addresses the dramatic changes required of the electricity industry in California over the next decade," said ISO Chief Executive Yakout Mansour.

"We engaged stakeholders and tested our vision with experts as part of a collaborative process to envision a future that ensures a reliable grid that also enables ground-breaking environmental goals," Mansour said in a statement.

The report outlines the ISO's strategy to help the state meet its ambitious goals to boost use of electricity from sources that cut emissions of carbon dioxide, a greenhouse gas blamed for global warming; to adapt to a more intelligent power grid and the use of electric vehicles and electric storage devices.

"We need to anticipate and adapt to the uncertainties that come from shifting to a smarter, greener grid, staying one step ahead of any reliability implications as we clear the path to reaching environmental goals," the report said.

California will need 55,657 gigawatt-hours of new renewable generation to meet the state's 20 percent standard by 2013 and more than 100,000 GWh to meet the 33 percent standard by 2020, according to the ISO report.

One gigawatt-hour equals 1,000 megawatt-hours. One megawatt-hour can serve about 1,000 homes for one day.

Since large-scale renewable resources, like wind and solar generation, are located far from cities, California will need many new power lines to deliver power long distances to reach its renewable energy targets.

According to the ISO's preliminary studies, meeting the 33 percent renewable goal will require more than 800 miles of 500-kilovolt transmission lines in operation by 2020.

The ISO said the weather-dependent, intermittent nature of wind and solar resources place new demands on the electric system to prevent power disruption.

Another major regulatory change under consideration in the state is a once-through-cooling water use regulation that will affect more than a dozen coastal power plants that currently use ocean water for cooling.

The ISO said the change, if implemented, may force the retirement or repowering of nearly 19,000 megawatts of existing generation -- more than one-third of the grid's installed capacity -- located near coastal communities by 2024.

"The grid may need replacement generation in the same areas or transmission additions to deliver new supply from elsewhere on the system to maintain reliable electric service," the report said.

(Reporting by Eileen O'Grady; Editing by Gary Hill)