Public power systems have reduced carbon dioxide emissions 2.4 percent since 2001, despite a 9.4 percent increase in power generation, according to a recent analysis by Target Rock Advisors.
The analysis focused on trends in emissions by 193 public power systems, including municipal, state and federal power agencies, in the ten years from December 2001. The study measured the change in total tons of emissions and rates of production in three key emissions categories: carbon dioxide, nitrogen oxides and sulfur dioxide.
CO2 emissions fell 13.3 million tons to 541.9 million tons in 2011, down from 555.2 million tons in 2001, Target Rock said. Public power systems also improved CO2 emissions intensity rates by 3.7 percent, to a net generation weighted average of 132.2 pounds per million BTUs in 2011.
The carbon emissions reduction trend accelerated in the five years between December 2006 and December 2011. Public power systems cut emissions by 36.8 million tons, or 6.4 percent, over the five-year period. CO2 intensity rates improved 1.2 percent during the same period.
The reduction in carbon emissions was largely due to a shift away from coal to cleaner fuels, said Target Rock Advisors. Over the 10-year time period analyzed in the study, coal-fired net generation fell 10 percent to 56.1 percent of total generation in 2011. Natural gas power rose 63.1 percent to 13.8 percent of the total generation.
Public power made significant percentage increases in renewable energy generation, particularly hydro and wind, said Target Rock Advisors. Renewables now account for 12.6 percent of net public power system generation, which is up 36 percent from 2001. Virtually of all of the added renewable generation came from hydro.
Over the 10-year period, nitrogen oxide fell 57.8 percent from 1.3 billion pounds and sulfur dioxide emissions decreased 55.6 percent from 4.1 billion pounds. Nox and So2 emissions intensity – the rate at which emissions are produced through the generation of electricity – fell 59.3 percent and 57.1 percent, respectively.
The study didn’t cover investor-owned utilities and merchant generators. However, Target Rock Advisors recently released a quarterly update of 10 sustainability and environmental, social and governance indices launched in February. The latest update to the main sustainability index, which focuses exclusively on investor-owned utilities in the US, gave Sempra, Xcel Energy PG&E, Edison International and Avista the highest sustainability rankings.