DTE Energy (NYSE: DTE) announced June 8 that it will retire eight coal-fired generating units at three sites in Michigan within the next seven years.
Slated for retirement between 2020 and 2023 are the River Rouge, St. Clair and Trenton facilities. Combined, these three plants generated about 25% of the electricity produced by DTE in 2015. These plants are operated by DTE Energy’s regulated DTE Electric utility subsidiary.
The retirements are part of an overarching fundamental transformation in the way DTE will produce energy for Michigan, the company said. Earlier this year, DTE retired three coal units due to age and projected future costs. With the June 8 announcement, the company will retire 11 of its 17 coal-fired units by 2023. The primary plant that will stay in operation is the big, emissions-controlled Monroe coal plant.
“The way DTE generates electricity will change as much in the next 10 years as any other period in our history. We will replace 11 aging coal-fired generating units at three facilities built in the 1950s and 1960s with a mix of newer, more modern and cleaner sources of energy generation such as wind, natural gas and solar,” said DTE Energy Chairman and CEO Gerry Anderson. “DTE Energy will work with the state of Michigan on a plan that ensures electric reliability for our 2.2 million customers, places a premium on affordability, and is seamless for our employees and the communities that are home to these plants.”
DTE is also working on legislation to ensure the state has adequate generating capacity as power plant closures (mostly coal-fired) continue in Michigan and across the broader region. Fellow Michigan utility Consumers Energy, for example, retired its “Classic 7” coal units earlier this year. DTE said this legislation is important given that 10% of Michigan’s power is supplied by marketers who depend upon excess supply from plants like those being retired.
The company has already taken steps toward transforming its energy generation. Over the past five years, DTE has built significant renewable energy production which now accounts for 10% of the company’s total sales. In recent months it broke ground on one of the largest solar arrays east of the Mississippi River located in Lapeer, Mich., and announced plans to develop a solar array on vacant land in Detroit.
Notable is that the Michigan Department of Environmental Quality (DEQ) on May 31 submitted its plan to reduce SO2 emissions in heavily-industrialized southern Wayne County to the U.S. Environmental Protection Agency for final approval. The agency said this State Implementation Plan (SIP) ensures the air in Detroit and surrounding communities meets a health-based National Ambient Air Quality Standard (NAAQS) for SO2. It requires four industrial sources in the area to make substantial reductions in SO2 emissions during the next 2.5 years. This includes:
- DTE Electric’s coal-fired River Rouge Power Plant is required to permanently shut down one of its two coal boilers by the end of the year.
- DTE’s Trenton Channel Power Plant permanently shut down four of its five coal-fired boilers in April 2016.
Details of the DTE plants affected are:
The River Rouge plant is located in the city of River Rouge. When SIP development began, the River Rouge plant had three generating units. Unit 1 is a 2,400 million British thermal units (MMBtu) per hour natural gas-fired boiler that is not part of this analysis. Units 2 and 3 were solid fuel-fired boilers rated at 2,280 and 2,670 MMBtu per hour, respectively. Units 2 and 3 had nameplate capacities of 292 MW and 358 MW, respectively. Both of these boilers were permitted to fire pulverized coal, natural gas, blast furnace gas, and COG and exhausted to separate stacks. For the SIP, Unit 2 was removed as an emissions source.
River Rouge has a capacity of 651 MW. The plant was constructed in 1957 and 1958. The plant burns coal of varying sulfur content and has been increasing its use of western low-sulfur coal over the last few years. This coal is lower in Btu value than eastern coal but is currently cheaper per Btu. The power plant primarily burns eastern coal on the days when electricity demand is the highest, typically during summer months. The SO2 is emitted from the power plant’s two 400-foot stacks.
To address the unacceptable combined hotspot impact northeast of the facility, DTE has agreed to permanently shut down Unit 2, achieving an additional 45% reduction in SO2 emissions from the River Rouge plant. This change is included in a Permit to Install which was approved on May 3, 2016.
The Trenton Channel plant is located in the City of Trenton. When SIP development began, the Trenton Channel plant consisted of five coal- and oil-fired boilers and five oil-fired Slocum peaker units. Boilers 16, 17, 18, and 19 were similar, tangentially fired coal-fired boilers with a combined heat input capacity of 3,023 MMBtu per hour for all four boilers. Boiler 9A is a coal-fired boiler with a rated heat input capacity of 4,530 MMBtu per hour serving an electric generator with a nameplate capacity of 520 MW. Boilers 16, 17, 18, and 19 were exhausted to a common stack and Boiler 9A is exhausted to a separate dedicated stack. Only Unit 9’s emissions are covered under the new SIP for continued operation.
Trenton Channel has a capacity of 776 MW. The existing plant was constructed in 1950, with a newer section added in 1968. The plant burns coal of varying sulfur content and has been increasing its use of western low-sulfur coal in recent few years The power plant primarily burns eastern coal on the days when electricity demand is the highest, typically during summer months.
DTE has agreed to permanently shut down Units 16-19 at Trenton Channel and to retain the emission limit for Unit 9 contained in the original Permit to Install. The change is included in a new Permit to Install which was approved on April 29. Notable is that a Permit to Install issued on April 29 allows DTE to install five permanent natural gas-fired package boilers which will replace four existing coal-fired boilers (Units 16-19) at Trenton Channel.
DTE Energy is a Detroit-based diversified energy company involved in the development and management of energy-related businesses and services nationwide. Its operating units include an electric utility serving 2.2 million customers in Southeastern Michigan and a natural gas utility serving 1.2 million customers in Michigan. The DTE Energy portfolio includes non-utility energy businesses focused on power and industrial projects, natural gas pipelines, gathering and storage, and energy marketing and trading.