Emissions down as power sector moves toward gas and renewables

Ceres provides benchmarks for 2010 and 2011

Bill Opalka | Aug 09, 2012

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Renewable energy use is increasing. Natural gas is quickly expanding its influence and coal is in retreat as emissions decline. None of this is surprising, but a new report spells out to what extent.

The Ceres 2012 “Benchmarking Air Emissions” report was just released. It shows that CO2, SO2 and NOx emissions are significantly down in 2010 and 2011 as the power sector moves away from coal to natural gas and renewables.

Renewable energy (excluding large hydroelectric projects) accounted for nearly 5% of U.S. electricity generation in 2011. Renewable energy production more than doubled from 83 million MWh in 2004 to 195 million MWh in 2011.

Wind energy, in particular, has been rapidly expanding over the past several years. In 2011, the U.S. wind energy industry added over 6,800 MW of new wind power
capacity, bringing the nation’s cumulative total to over 47,000 MW.

The report says high wind capacity in the ERCOT (Texas), Colorado, and the Midwest ISO areas have led to record high contributions by wind to the total grid mix; Xcel Energy, for example, reported greater than 50% of its total Colorado load being served by wind in early 2012.

Solar energy has also been rapidly expanding. Although a number of companies have planned or started utility scale projects, projects less than 6 MW (below utility scale) account for a large share of capacity added, owing to shorter development times and ease of interconnection.

But the renewable energy outlook is uncertain. The production tax credit (PTC) for wind energy is set to expire at year’s end and needs Congressional action to be extended. After several years of steep growth, market players anticipate a relatively modest 2 GW of wind capacity additions in 2013 without continued incentives. Momentum at the state level is mixed.

The report examines and compares the air pollutant emissions of the 100 largest power producers in the United States based on their 2010 generation, plant ownership, and emissions data. The report also includes analysis of certain 2011 emissions data.

These producers include public and private entities that own roughly 2,500 power plants and account for 86% of reported electric generation and 88% of the industry’s reported emissions.

Coal is still the leader, but its share of generation is declining. It accounted for 45% of total power production, and the remaining fossil fuels -- natural gas and
Oil -- accounted for 24% and 1%, respectively. Nuclear power, the largest non-fossil fuel energy source, generated 20 % of U.S. electric power. Hydroelectricity accounted for about 6 % of total power production and non-hydroelectric renewables (such as wind turbines and solar photovoltaic cells) accounted for almost 3%.

Natural gas prices have fallen significantly from their peak in 2008, leading to increased natural gas use within the electric sector. Government data show that for the first time, since they started keeping records, electricity generation from natural gas-fired plants was virtually equal to the generation from coal-fired plants, with each fuel providing 32% of total generation in April 2012.

Since January 2010, plant owners have announced about 40 GW of coal plant retirements or roughly 12% of the nation’s coal-fired generating fleet due to changing market conditions, including low natural gas prices, and the costs associated with new environmental requirements.

Renewable energy and energy efficiency have shown increased growth and investment. Renewable energy production more than doubled from 83m MWh in 2004 to 195m MWh in 2011. Utility efficiency budgets have increased 26% from $5.4 billion in 2010 to $6.8 billion in 2011.

Electric industry emission trends include:

•    Since 1990, power plant emissions of SO2 and NOx have decreased and CO2 emissions have increased.
•    In 2010, power plant SO2 and NOx emissions were both 68% lower than they were in 1990 due in large part to programs implemented under the 1990 Clean Air Act Amendments. SO2 and NOx emissions have continued to decline in 2011 and 2012.
•    In 2010, power plant CO2 emissions were 24% higher than they were in 1990.

The report was a collaborative effort among Entergy, Exelon, Bank of America, Tenaska, Ceres, and the Natural Resources Defense Council (NRDC).

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Comments

Run the numbers

I did some calculations utilizing numbers from the US EIA for generation by energy source, CO2 emissions etc and then plotted curves based on the data.  This covered roughly the last decade as there are some gaps yet for 2011.  Once the figures are normalized by setting one of the years as a base, it becomes readily evident that the decrease in CO2/MWh generated is driven almost exclusively by the increase in the proportion of generation by natural gas.  The increase in generation by wind and solar compared to the increase in installed capacity is pitifully small--a function of their poor capacity factors.  When it is considered that every single MW of wind or solar installed that must be reliable has to be backed up by some form of thermal generation one has to wonder about the wisdom of all the incentive programs particularly when one considers the uncertainty subsidized wind and solar add to an energy market can readily discourage investment in newer, more efficient, cleaner burning facilities to replace the older plants kept in operation to provide instantaneous backup for wind and solar in order to keep the grid stable.