In the last 35 years, DTE Electric Company has dramatically reduced emissions while customer demand for electricity has escalated.
Approximately 76 percent of our annual electricity production is generated from fossil fuel, primarily coal. Our Fermi 2 nuclear plant accounts for most of the remaining generation.
Our 35-plus year track record shows dramatic reductions in regulated air emissions. At the same time, customer demand has accelerated.
DTE Electric has reduced annual particulate matter (PM) emissions 95 percent, sulfur dioxide (SO2) emissions 78 percent and nitrogen oxide (NOX) emissions 77 percent below 1974 levels. During this same period, total annual generation increased 16 percent.
We submit each year's Toxic Release Inventory (TRI) information in June of the following year. As expected, there are variations each year in the emissions due to the concentration of elements in the coal and the amount of electricity generated.
As part of the EPA Acid Rain program, continuous emissions monitoring of carbon dioxide (CO2), nitrogen oxides (NOX) and sulfur dioxide (SO2) has been conducted since 1995. EPA regulations specify how each monitor must be operated and meet data quality requirements. Affected utilities must submit quarterly reports to the EPA. Reports are available from the EPA Clean Air Markets Division for each utility unit nationwide.
DTE Electric Interruptible Load Program Emissions Effects
DTE Electric customers who participate in the Interruptible Load Program contribute to reducing CO2 emissions, SO2 emissions, NOX emissions, particulate matter emissions and mercury emissions.
DTE Electric burns about 50 percent more coal today than 35 years ago. The company burned 12.3 million tons of coal to generate electricity in 1974. All of this coal was from the eastern U.S. Shortly thereafter, the company switched from using all eastern bituminous coal to a blend of eastern bituminous and western sub-bituminous coals to reduce SO2 emissions. Today more than 80 percent of the 18 million tons of coal burned in DTE Electric power plants is lower sulfur western coal.
Overall coal consumption grew rapidly between 1974 and 1987 due to a large increase in customer demand for electricity. Another contributing factor is the heating value of western coal - more coal must be consumed to produce the same amount of heat for steam generation. Within our fuel mix our annual coal consumption has averaged 20.5 million tons per year since 1987.
DTE Electric coal consumption is expected to remain relatively stable in the near future (plus or minus 1 million tons). Any increase in the percentage of western coal used or additional load growth could raise total consumption.
DTE Electric generated about 35,000 gigawatt hours (GWh) of electricity in 1974, which is equivalent to 35 billion kilowatt hours (kWh). All this electricity was produced from the combustion of fossil fuel.
Fossil generation peaked in 1987, the same year the Fermi 2 nuclear unit began commercial operation. DTE Electric produces as much electricity as possible from nuclear generation and the remainder with fossil generation.
Carbon dioxide emissions are directly related to the amount of fossil fuel (coal, oil, natural gas) consumed in a given year. Emissions of CO2 are not limited or capped under current federal or state regulatory programs.
In 1974, CO2 emissions from DTE Electric power plants totaled about 37 million tons. This increased to about 49 million tons in 1987, when fossil generation peaked. In 2012, DTE Electric power plants emitted almost 38.1 million tons of CO2 - a 2 percent increase from 1974, but an 21 percent decrease from 1987, and a 4.4 percent decrease from just 2011.
There is currently no emission control technology available to cost-effectively remove CO2 from power plant emissions; however, DTE Electric is taking several voluntary actions to reduce, avoid and sequester greenhouse gases.
In the 1970s, DTE Electric pioneered the use of low-sulfur western sub-bituminous coal to reduce SO2 emissions. At that time, all of DTE Electric's coal-fired power plants were designed to burn eastern high-sulfur bituminous coal. Emissions of SO2 in 1974 were about 600 thousand tons.
Thirty five years later, approximately 80 percent of the 18 million tons of coal burned at DTE Electric power plants was western sub-bituminous coal. In addition, two new flue gas desulfurization (FGD) units came on line at our Monroe Power Plant in 2009 to reduce SO2 emissions even further in preparation for anticipated federal regulations. Sulfur dioxide emissions were 133 thousand tons in 2012 - a 78 percent reduction from 1974.
Nitrogen oxides are a product of fossil fuel combustion. As more coal is burned, NOx emissions increase. This was the historical trend in NOx emissions from DTE Electric power plants during the 1970s and 1980s. In 1974, DTE Electric NOx emissions were about 165 thousand tons, which grew to nearly 193 thousand tons in 1987.
The 1990 amendments to the Clean Air Act established the Acid Rain Program to reduce power plant NOx and SO2 emissions. Low NOx emission burners were installed at Monroe Power Plant in the mid-1990s (five years before the compliance deadline) to satisfy these requirements.
In recent years, DTE Electric has invested more than $550 million in additional NOx control technology to meet the new EPA reduction requirements at its power plants. In 2012, DTE Electric NOx emissions were about 37,300 tons - a 77 percent reduction from 1974 and 80 percent reduction from 1987 levels.
When DTE Electric moved away from using strictly bituminous coal in the 1970s, it was necessary to upgrade some particulate control (removal) equipment. Particulate matter emissions in 1974 were estimated at just over 25,000 tons. In 2011, these emissions were about 1,290 tons - a 95 percent reduction from 1974.
From 1974 through today, DTE Electric voluntarily took steps to reduce mercury emissions even though there were no specific environmental regulations that required it. As a result of our aggressive move to low-sulfur western coal and our supplier's actions to better clean eastern coals, total power plant mercury emissions have not increased proportionally to the 50 percent increase in coal consumption since 1974. The 2009 addition of the flue gas desulfurization (FGD) units in combination with existing control equipment at Monroe Power Plant is expected to even further reduce mercury stack emissions. DTE Electric is also developing plans for future reductions in mercury emissions to meet the mercury reduction requirements under the 2012 federal Mercury and Air Toxics Standard.