Despite the looming threat on the financial bottom line, few electric power companies around the world are confronting the burning issue of greenhouse gas emissions.

Moreover, only six of 25 major generators have taken significant steps that ultimately would create long-term wealth for their shareholders, according to a report released Monday by the influential California Public Employees' Retirement System and the California State Teachers' Retirement System.

The study attempts, for the first time, to craft an economic report card on electric utilities worldwide based on efforts to rein in carbon dioxide emissions that contribute to global warming.

The analysis looked beyond traditional profit and loss numbers and weighed the environmental consequences of carbon emissions and whether companies are seizing business opportunities such as wind power projects.

"These utilities pay to dispose of solid waste and wastewater, and at some point, they will be required to pay for the disposal of gaseous waste," CalSTRS Chief Investment Officer Christopher J. Ailman said in a statement. "Those costs need to be factored into their valuation."

Over the years, CalPERS and CalSTRS, with combined assets of more than $380 billion, have been among the most active and vocal public funds to prod corporations to recognize the potential economic costs tied to global warming.

Fund leaders say corporate executives face increasing pressure to reduce greenhouse gases. In California, the state already has imposed a crackdown, and there is a growing cry to impose federal limits. New mandates could be profound for electric utilities, which account for about 25 percent of carbon emissions.

"Utilities would be the first sector subjected to regulations," said Matthias Kopp, head of finance and energy for the World Wide Fund for Nature in Germany, the group that financed the CalPERS-CalSTRS study. "We think this is very important for investors to take a strong focus on this kind of analysis."

The message is spreading to Wall Street, too.

"Financial analysts on Wall Street are starting to provide more in-depth analysis of climate change," said Dan Bakal, director of power programs for Ceres, a Boston-based coalition of investor, environmental and public interest groups. "Investors are definitely waking up to the risks and opportunities."

The pension funds' Electric Utilities Report was based on responses from 112 global power companies in a carbon disclosure project commissioned by 225 institutional investors. About 43 percent of 78 U.S. power companies answered the questionnaire. By contrast, none of the 32 companies in China responded. The analysis included environmental costs to determine the economic value of utilities.

For the California funds, the stakes are significant. CalPERS has $3.7 billion invested in electric utilities and CalSTRS has $2.6 billion in power companies.

In the report, only 25 companies provided enough emissions information to be ranked. The analysis measures operating profits against the cost of carbon emissions, which has been established in Europe at a rate of $22 per ton.

The results showed San Francisco-based Pacific Gas and Electric Co. with the highest ranking, with an economic value of $404 million. PG&E fared well because it doesn't rely on coal-fired plants for its electricity. In addition, PG&E is investing $1 billion through 2008 on energy-efficient programs and initiatives to curb emissions.

On the other end, Ohio-based American Electric Power, a large coal-based power generator, came in at -$3.56 billion in value.

But American Electric officials pointed out the company has launched a major climate change campaign to reduce emissions by 6 percent by 2010 and to invest $1 billion to build the world's first nearly emission-free coal generator plants.

"We have been actively involved in the climate change debate since the early 1990s. There are a lot of areas where coal is the most viable fuel source," said Melissa McHenry, an American Electric spokeswoman. The company is moving "forward to use coal in a cleaner way," she said.