Coal-fired power plants are a key component of our mix of electric generation resources detailed in our Balanced Energy Initiative (BEI).
As America’s most abundant fossil fuel, and with appropriate air pollution controls, coal provides the most cost-competitive means of producing electricity for our customers. This is critical to keeping electricity affordable for both business and residential customers, and also for enabling new technologies such as plug-in electric vehicles (PEVs) and plug-in hybrid electric vehicles (PHEVs).
We burn a variety of coals in varying combinations at our electric generating plants in an effort to minimize our production costs and meet regulatory requirements. A blend of low-sulfur eastern, mid-sulfur eastern and low-sulfur western coal is included in the fuel mix. On a system-wide basis, we expect to burn approximately 8.2 million tons of western coal, or approximately 85 percent by weight of our total coal burn requirements, in 2011 compared to approximately 1.5 million tons of eastern coal (approximately 15 percent by weight of our total burn requirements).
Burning coal to produce electricity creates an ash residue, also known as a coal combustion byproduct (CCB). Fly ash — tiny particles removed from our flue gas by emissions control devices — is transported and placed in the landfills in a dry form, which substantially reduces the risk of storage area dike failures and leakage. Bottom ash and slag are collected in the bottoms of boilers using a wet slurry method.
We have been proactive in our ash management for many years. All of the company’s fly ash handling systems have been converted to dry systems at a cost of about $80 million over the past decade. The original wet handling systems mixed water with CCBs to create a wet mixture that could be pumped to the land disposal areas. Dry systems reduce water entering the landfill by 90 percent and significantly reduce the potential to release contaminants into the environment.
Consumers Energy uses 100 percent of its bottom ash (up to 100,000 tons annually) in the manufacture of Portland cement or to replace native materials in landfill construction. Bottom ash is an acceptable replacement, as it is similar in nature to native materials used for Portland cement manufacture. CCB-based cement has been in use for decades and there is little to no health risk.
About 25 to 30 percent of company fly ash (up to 125,000 tons annually) is used in ready-mix concrete or in Portland cement manufacture. Consumers Energy CCBs are not used for land or other agricultural applications.
At the Campbell, Karn/Weadock, and Whiting generating plant sites, fly ash, bottom ash and boiler slag are safely managed in Type III waste disposal landfills. Several of these landfills are former coal ash impoundments that have been dewatered and will be operated and closed as landfills. Bottom ash continues to be handled wet in surface impoundments. All surface impoundments have been inspected, and are subject to continued inspection by registered professional engineers to assure their safety.
Groundwater at the operating landfills is subject to quarterly monitoring requirements under Michigan Department of Environmental Quality (MDEQ) approved monitoring plans.
At the Whiting plant in Erie, Mich., Consumers Energy monitored groundwater quality at the coal ash landfill from 1982 through the third quarter of 2009. MDEQ then granted a waiver from groundwater monitoring requirements based on a successful demonstration by the company that site geological conditions -- more than 60 feet of very low permeability clay over a confined, artesian aquifer -- prevented contamination of the aquifer if any leachate were to penetrate the compacted clay liner.
The recently closed landfill at the Cobb plant near Muskegon, Mich., is monitored semiannually and will continue to be monitored for at least 30 years post-closure.
Because CCBs are a product of high temperature combustion, the groundwater monitoring parameters are primarily “trace metals.” We use U.S. Environmental Protection Agency-approved testing protocols to determine the parameters that we monitor in our groundwater wells. We also monitor site-specific indicator parameters such as pH and conductivity that may indicate a leak in the landfill. A representative monitoring program might include the following compliance parameters and detection limits:
Other parameters that are considered annually in testing and analysis, but are not monitored because they are either undetectable or yield results below regulatory compliance criteria, include barium, beryllium, cadmium, cobalt, copper, lead, mercury, silver, thallium and zinc.
The extensive groundwater monitoring programs generally show compliance with regulatory criteria on a quarterly basis.
At the Campbell landfill in Ottawa County, Consumers Energy operates a groundwater remediation system. The system intercepts groundwater and transmits it to retention ponds at the active landfill where it is handled as part of the leachate management program. Monitoring wells adjacent to surface water demonstrate compliance with MDEQ discharge criteria.
Closure plans approved by the Michigan Department of Environmental Quality (MDEQ) are in place for all Consumers Energy coal combustion byproduct landfills. To ensure the environment is protected long after a landfill is closed, Consumers Energy maintains a $1 million bond for each area with the MDEQ as a beneficiary and maintains a perpetual care fund with defined contributions made quarterly.
After the coal fly ash slurry spill at the Tennessee Valley Authority’s (TVA) Kingston Fossil Plant in December 2008, Consumers Energy had a comprehensive assessment of disposal area dike and embankment stability conducted throughout our company. The assessment determined that while none of the disposal structures at our facilities presented significant safety issues, certain upgrades were recommended. The reviewing team also made some recommendations to improve operations and reliability of the structures. Upgrades were initiated in 2010 and are on track to be completed in 2011.
On June 21, 2010, the EPA proposed a rule for disposal of CCBs from electric utilities. While we support regulation of ash impoundments, we believe coal ash should not be reclassified as a hazardous waste. Many state regulators and policymakers agree with our position and have shared their views with the EPA. This is an important issue for our company since coal-fired generation, as outlined in our Balanced Energy Initiative, remains an important component of our energy mix.
At the same time, we understand that following the Tennessee Valley Authority incident the public is legitimately concerned about safely managing coal ash. In addition to all of the improvement actions we have undertaken, we remain committed to being responsive to public concerns about landfill safety and to openly communicate.
For more information, please see Coal Combustion Byproducts Management.
Updated December 2011