Oct. 29--A 2-year-old PG&E program to help customers offset the size of their carbon footprint has drawn little interest and consumer advocates are arguing it should be allowed to expire at the end of the year.

Only 30,000 households and businesses have enrolled in "ClimateSmart," which allows residential and commercial customers of the San Francisco-based utility to add a tax-deductible "donation" to their monthly bill that allows PG&E to buy carbon offsets.

But with California's unemployment rate at 12 percent and many households struggling each month to stay on top of mortgages and other bills, persuading people to give extra money to PG&E has been a hard sell.

Some consumer advocates think the program is a waste of money and should be scrapped.

ClimateSmart charges customers to have the carbon emissions footprint of their gas and electricity use calculated. A small fee -- the average is less than $5 a month -- is then added to their monthly bill. The revenue generated by ClimateSmart allows PG&E to buy carbon offsets from a variety of projects, including forest conservation efforts in the Santa Cruz Mountains.

"When you plug something into the wall here, you're generating greenhouse gas emissions somewhere else," said PG&E spokeswoman Katie Romans. "We're hoping to make that connection."

PG&E has 5 million "customers of record," or billing addresses, and serves 15 million people from Eureka

to Bakersfield.

But so far, only 30,000 customers -- 0.6 percent -- have enrolled. The largest concentration of ClimateSmart customers is in San Francisco. There are about 4,000 enrolled customers in Silicon Valley, including businesses like Fresh Choice, eBay, the Palo Alto Medical Foundation, IKEA and the San Jose Convention Center.

PG&E has asked the California Public Utilities Commission for permission to extend the program, which is set to expire at the end of the year, in hopes that it can increase enrollment.

But consumer advocates with TURN, The Utility Reform Network, say PG&E should just pull the plug.

"The numbers are abysmal, and we think PG&E should just scrap the program altogether," said Mindy Spatt of TURN. "This is not a good deal for consumers."

TURN says that while only 30,000 PG&E customers have enrolled in ClimateSmart since it launched in 2007, all PG&E customers subsidize the costs of the program through the rates they pay. Since its launch, ClimateSmart has collected approximately $4.5 million in contributions from residential, commercial, and municipal customers. TURN argues that PG&E has allocated $12 million for marketing and advertising with little results.