In April of 2000, the City Council set a long term goal for Seattle City Light to achieve greenhouse gas neutrality while meeting all of the electricity needs of Seattle. In 2005, Seattle City Light became the first electric utility in the country to achieve zero net greenhouse gas emissions. It has maintained that carbon neutral status every year since.
In 2000, the Utility divested ownership in a coal fired power plant and later terminated a natural gas turbine contract (July, 2006), investing in renewables and increasing our long-standing energy efficiency programs. Seattle City Light was able to make these major operational changes while maintaining an affordable and reliable power system.
Today, Seattle City Light uses hydroelectric resources for the majority of the power it provides, which is one reason its greenhouse gas emissions are so low. Seattle City Light's carbon emissions are further reduced by its aggressive energy efficiency and conservation programs, which help customers save energy and money. Renewable energy projects have been added to the Utility's resource mix, including wind, landfill methane, and wood biomass energy. In addition, the Utility has adopted an integrated resource plan
that relies on only new renewables and energy efficiency to meet future load growth.
Each year Seattle City Light's Environmental Division completes an inventory of the remaining greenhouse gas emissions. The City of Seattle is a founding member of The Climate Registry and each year the Utility submits inventory reports, verified by an independent third party. The largest greenhouse gas emissions source is from market purchases of power, both directly by Seattle City Light and through the Bonneville Power Administration (BPA). Other sources include fossil fuels used in vehicles and equipment; leakage of SF6, a potent greenhouse gas used in electrical equipment; emissions from employees' air travel; and natural gas used for building and water heat and fuel in emergency generators.
Seattle City Light purchases offsets for these emissions. Basically, one offset is created when one metric ton of greenhouse gas emissions (CO2 equivalents) is avoided, reduced, or sequestered. Seattle City Light currently buys offsets that are registered through organizations such as the Climate Action Reserve and the Verified Carbon Standard. Seattle City Light has purchased carbon offsets from varied projects including: biodiesel fuel for Seattle area busses, ferries and garbage trucks; shore power for cruise ships at the Port of Seattle; aerobic composting of local food and yard waste; and methane recapture and destruction at dairy farms, food processing sites, and landfills.