In 2010, the company produced 731 lbs of CO2 per MWh of energy it produced. In 2011, this figure dropped to 651 lbs of CO2 per MWh putting Sempra’s emissions intensity at roughly half the national average. The report attributes the drop to the completion of several renewable energy facilities.
Last year subsidiary company Sempra US Gas & Power dedicated the 250 MW Cedar Creek wind farm in Colorado and turned on 42 MW of solar panels at the Mesquite Solar 1 plant in Arizona. In March 2011, Sempra Generation opened the 48 MW Copper Mountain Solar plant, a facility that the company says is the country’s largest. The Copper Mountain project in Nevada uses nearly 775,000 thin-film photovoltaic solar panels, enough to power about 14,000 homes. In 2011, San Diego Gas & Electric, another of Sempra’s subsidiaries, drew 20.8 percent of its power from renewable sources and signed 17 renewable energy supply contracts, adding 1,482 MW to its capacity, the report says.
Sempra’s absolute carbon emissions dropped around 15 percent year-on-year, from 15.6 million metric tons of CO2 equivalent in 2010 to 13.2 million metric tons of CO2e in 2011. The company attributes the fall to less overall generation of electricity, the divestment of Sempra Generation’s 50 percent share in the Elk Hills power plant, and “other factors.”
Sempra Energy’s business units’ natural gas–fired power plants can generate more than 3,068 megawatts of power. The company says that these plants were built with the best available emissions control technology, minimizing impacts on the environment. In 2011, they
collectively produced nearly 19 million MWh of electricity, emitting some 5.5 million metric tons of carbon dioxide equivalent. That’s roughly half the emissions than would have been produced by coal-fired power plants, the report says.
In 2011, water withdrawal from Sempra’s business units’ facilities totaled 29.1 billion gallons, including the use of 2.3 billion gallons of reclaimed and on-site wastewater, the report says. This represents just under a 17 percent reduction in water withdrawal year-on-year. Nearly 24.8 billion gallons was returned to source in 2011, in compliance, the report says, with environmental permits and water quality laws. The 2011 report includes more comprehensive data from operations, including LNG receipt terminals, office buildings and midstream assets, than previous years, Sempra says.
Initiatives aimed at reducing water use include using photovoltaic cells made from semiconductor materials that convert sunlight directly into electricity without the use of water and installation of low- and no-flow urinals and low-flow shower heads, faucets and flush valves.
In 2011, the company diverted more than 18.7 million pounds of material from landfills. Sempra’s recycling and waste programs generated $9.8 million in revenue last year. The report does not include nonhazardous waste figures for previous years.
Sempra’s hazardous waste production jumped 18 percent year-on-year, from 7,289 tons in 2010 to 8,625 tons in 2011. The company attributes the increase to changes in the amount of manufactured-gas plant site remediation activity performed each year.
In February, Sempra topped a new sustainability ranking and set of stock indices for US utilities, compiled by Target Rock Advisors. The advisory group says this is the first sustainability index focused exclusively on publicly-traded utilities in the U.S.
The main index, called the Target Rock High Sustainability Index, comprises 15 “high performance” domestic energy utilities that score highly for sustainable operations. Their scores are based on their performance related to environment, economy and society.