Clean energy transition is starting

For the electric power industry, the signs of change are in the air. Power plants are emitting less pollution than in prior years, and renewable power is a bigger part of the energy mix than ever before. That adds up to cleaner air and a more diverse, resilient and lower-carbon electricity system. Ceres assesses the environmental performance and progress of the electric power sector by analyzing the air emissions of the nation's top 100 power producers. This is the eighth edition of the Benchmarking Air Emissions report, and this year, the findings were particularly significant:

• From 2008 to 2010, sector-wide sulfur dioxide (SO₂) and nitrogen oxide (NOx) emissions both fell by over 30 percent.
• Over the same period, carbon dioxide (CO₂) emissions fell four percent and preliminary data show another five percent reduction in 2011.
• Non-hydroelectric renewable energy accounted for nearly five percent of U.S. electricity generation in 2011. Including large hydroelectric projects, renewables now provide over 10 percent of our power.

Those results speak volumes. Cutting SO₂ and NOx emissions by a third in just a couple years is remarkable, and it reflects that a clean energy transition is within reach. The drop in carbon emissions is also encouraging, but it is important to ensure that the trend continues by continuing to emphasize renewable energy and efficiency. What we did with SO₂ and NOx, we can do with CO₂.

What are the drivers of this remarkable change? Primarily, power producers are shifting away from coal-fired generation to natural gas-fired plants and even cleaner, zero-emissions renewable energy resources such as wind, solar and geothermal energy. They have also installed emissions controls for the coal plants they are running, as additional Clean Air Act rules are set to go into effect over the next few years.

In April 2012, coal- and gas-fired generation were equal for the first time ever. As power producers adjust their generating fleets, gas is being swapped for coal in some cases, but in others, coal plants are being retired outright. According to the 2012 Benchmarking Air Emissions report, 12 percent of the nation's coal-fired generation fleet—about 40 gigawatts of capacity—will be retired. And as the plants that are being phased out are largely older, high-emitting generating units.