Pacific Gas & Electric’s CO2 emissions rate associated with electricity delivered fell 12 percent between 2010 and 2011, to 393 pounds of CO2 per MWh, according to the company’s latest corporate responsibility and sustainability report.
This latest emissions rate was about one-third the national utility average, the company says. The rate takes into account emissions from both PG&E-owned power generation and power purchased from third parties.
PG&E’s total CO2 emissions from delivered electricity in 2011 were the lowest on record—declining about six percent from the prior year to 14.7 million metric tons. This decline reflected an increase in the amount of renewable and large hydro electricity in its power portfolio and the expanded use of cleaner fossil-fueled electricity, such as the first full year of operations for two natural gas-fired plants.
The company says it is on target to meet the current compliance period of California’s Renewable Portfolio Standard, which requires an average 20 percent renewable energy from 2011 to 2013. In 2012, PG&E got 19 percent of its delivered electricity from renewable sources, primarily from contracts with renewable energy companies. The RPS requires 33 percent renewables by the end of 2020.
PG&E reports its emissions as part of California’s cap and trade system, and to the US EPA as part of mandatory federal reporting. The company’s facilities in the nine-county San Francisco Bay Area also pay a greenhouse gas emissions fee of 4.8 cents per metric ton of CO2-equivalent on emissions from facilities such as fossil-fueled power plants, natural gas compressor stations and emergency generators.
The company reduced its sulfur hexafluoride (SF6) emissions nearly 10 percent from 2011 to 2012. SF6 is an extremely potent greenhouse gas, about 23,900 times more potent than CO2 on a per-ton basis, and is used as an electrical insulating material in high-voltage circuit breakers and gas-insulated substations. Since 1998, PG&E has reduced total SF6 emissions by 75 percent, and its SF6 emissions rate by 87 percent.
PG&E says it avoided the release of 258 MMcf of natural gas—or nearly 100,000 metric tons of CO2-equivalent emissions—in 2012. These savings were achieved primarily by replacing older gas mains, and by a technique called cross compression, where natural gas is transferred from one pipeline to another during large pipeline construction and repair projects.