Wisconsin Electric Power Co. is nearing a likely approval from the Wisconsin Department of Natural Resources of an air permit allowing the permanent use of coal additives for air emissions reductions at the Elm Road/Oak Creek power plants.
Notable is that Elm Road’s two units, part of the larger Oak Creek coal complex, were built last decade around a design coal out of the Pittsburgh seam in Northern Appalachia. They went into operation in the 2009-2010 period. But lately the utility has been pursuing needed regulatory approvals and equipment upgrades to handle Powder River Basin coal as an additional fuel for the Elm Road units in varying blends with other coal. The Oak Creek units have been using PRB coal for years.
In October 2014, the department issued a research and testing exemption to Wisconsin Electric Power d/b/a We Energies to install and operate temporary refined coal (RC) equipment to apply two additives (MerSorb and S-Sorb) to the coal for the Elm Road Generating Station Units 1 and 2, and Oak Creek Units 5, 6, 7, and 8. Although the research and testing is currently underway, We Energies submitted a construction permit application to obtain approval to make permanent changes to incorporate the RC processes and to increase RC additive rates.
The department is taking public comment until June 24 on a draft air permit covering this permanent use of the additives.
The proposed RC process applies a liquid additive called MerSorb for the control of mercury emissions, and a solid additive called S-Sorb for the control of NOx and SO2 emissions. The permanent RC process equipment will include modifications to existing conveyors and other coal handling equipment. The S-Sorb storage silo and the MerSorb storage tanks will be located near Transfer Tower 4. The refined coal equipment is designed to allow coal to bypass the refined coal process when coal is stacked out or reclaimed through Transfer Tower 4. As a result, the stackout and reclaim processes in Transfer Tower 4 (associated with the planned Outdoor Coal Storage Pile Expansion Project) may be operated independently from the refined coal process.
Particulate matter (PM, PM10, PM2.5) emissions from all of the refined coal processes in Transfer Towers 4 and 5 will be controlled by wet suppression. Emissions from S-Sorb Silo will be controlled by a bin vent dust collector. The MerSorb storage tanks will have essentially no emissions of regulated air contaminants. In addition to particulate matter emissions from RC process equipment, there will be haul truck fugitive emissions as a result of fuel additives for RC process being delivered by trucks.
The department determined that the proposed Refined Coal Project and the proposed Outdoor Coal Storage Pile Expansion Project are separate projects, although the applications for both projects were received by the department on the same day (Nov. 11, 2014).
The Elm Road/Oak Creek plant, with a total capacity of about 2,400 MW, is located in Milwaukee County, approximately 20 miles south of Milwaukee. The site occupies more than 400 acres on the shore of Lake Michigan.
We Energies says expanded storage capacity needed to meet market needs
The November 2014 application for new coal storage hasn’t reached the draft permit stage yet. Said a February 2015 revision to that application: “We Energies is proposing to make changes to the coal handling systems at the Oak Creek site, including expansion of the existing outdoor storage pile, new outdoor storage pile stackout and reclaim systems, new conveyors, and upgrades to the existing fabric filter baghouse for the coal car dumper. This project will include other changes, including the addition of mechanical separators to several existing dust collectors, the addition of coal crackers to the railcar dumper, new mobile equipment and garage, a new administration building, new and relocated diesel fuel oil storage tanks, and additional rail siding.
“Note that We Energies is also proposing the addition of equipment necessary to prepare refined coal which will be part of the Oak Creek Site Bulk Material Handling (SBMH) coal handling systems. However, that equipment is included in a separate project and air permit application.
“In 2013, the Wisconsin Department of Natural Resources issued construction permit No. 12-SDD-047 which authorized modifications to the two Elm Road Generating Station (ERGS) coal-fired boilers to allow the flexibility to combust blends of bituminous and subbituminous coals, called the Fuel Flexibility Project. In the permit application for that project, We Energies stated that although it did not anticipate that physical changes to the coal handling systems would be required to utilize subbituminous coals at ERGS, that if new or modified coal handling equipment is required in the future, We Energies would apply for a construction permit for any new equipment as a part of the Fuel Flexibility Project. That is, any new equipment would be “aggregated” with the Fuel Flexibility Project for purposes of Prevention of Significant Deterioration (PSD) and Nonattainment Area New Source Review (NANSR) applicability.
“After commencement of construction on the Fuel Flexibility Project, We Energies concluded that additional coal storage capacity at the Oak Creek Plant is needed to ensure efficient unit train unloading, adequate fuel supply reserves, and to decrease risks of running low on coal due to market supply or shipping problems.
“We Energies is proposing to expand the outdoor coal storage pile and add new stackout and reclaim conveyors to increase the site storage capacity from 45 to 90 days, to ensure fast, efficient unit train unloading, maintain adequate fuel supply reserves, and decrease the risks of running low on coal due to market supply or shipping problems.
“Since the beginning of 2014, the Oak Creek site focused on increasing coal deliveries beyond the historic delivery rate to meet market demands. However, fuel delivery inconsistencies and unloading challenges impaired generating unit operation at the site in early 2014. The current coal handling systems permitted as part of the original ERGS Project were designed to accept an average of about 9 trains per week, equal to approximately 7.0 million tons per year. Although the anticipated number of rail deliveries has not been consistently achieved to date, We Energies expects that, over time, the rail system congestion will ease and rail capacity will be sufficient to deliver an average of at least eight trains per week.
“An expanded inventory due to the new pile allows for storage of fuel during low demand periods, for future consumption during high demand periods. Together with the new pile, the additional stacker and reclaimer will improve efficiency of how trains are off-loaded, enable more trains to be offloaded, and provide operational flexibility when outages to the existing pile and related equipment occur. For example, at the beginning of 2014, the bituminous and subbituminous coal piles were nearly full. However, bituminous coal train deliveries were heavily curtailed due to rail problems to the East and as a result the ERGS units ran less than expected from January through March of 2014. Subbituminous coal deliveries were also curtailed in February and March due to rail problems from the West and both the OCPP and ERGS ran less than expected in February and March of 2014 and resulting in net fuel cost increases for customers.
“The effect of these curtailments was made worse because the winter of 2014 was colder than normal which affected the entire energy market. Electricity demand was high, natural gas demand for residential and commercial space heating was high, and rail transportation problems were widespread. And although the ERGS and OCPP power plants ran very well, many generating plants in the region had operational problems in the cold weather.
“The OCPP and ERGS are highly efficient, low-cost power plants. The Midcontinent Independent System Operator (MISO) electric energy market is calling upon the OCPP more as its delivered fuel costs have decreased, and ERGS more now that it is fully operational. For the reasons discussed above, this project will ensure consistent operation at OCPP and ERGS.
“A 90-day coal storage inventory for the Oak Creek site based on the normal operation of the Elm Road and Oak Creek units is approximately 1.5 million tons of storage capacity. A primary concern when storing coal is the potential for spontaneous combustion of the coal in the pile due to the self-heating and combustion properties of coal. In an outdoor storage pile, coal can be compacted to minimize entrained air which reduces the potential for spontaneous combustion. However, coal stored in a silo or bunker cannot be compacted. As a result, silos and bunkers must be emptied periodically to prevent fires. A fire is a serious danger to personnel and equipment. Because the purpose of this coal pile expansion is to increase long term storage, and because long term coal storage is susceptible to spontaneous combustion and coal fires, indoor storage is not a safe alternative due to the potential for fire and the resulting danger to operating personnel and equipment.”