A desire to do things right led Constellation Energy to invest $70 million to convert its 400-MW C.P. Crane Generating Station to burn Powder River Basin coal and develop the culture critical to making that conversion a success. In addition to being named a 2012 POWER Top Plant, the PRB Coal Users’ Group recognized the plant for its efforts with its Plant of the Year Award
In March 2011, Constellation Energy completed a conversion project at its 400-MW, two-unit C.P. Crane Generating Station, allowing it to burn up to 100% subbituminous coal. The project was driven by an effort to comply with Maryland Healthy Air Act (HAA) regulations and resulted in the increased use of subbituminous coal, largely from the Powder River Basin (PRB) in Wyoming and Montana.
The plant was originally developed by Baltimore Gas & Electric Co., which became Constellation Energy, and has been operating as a merchant generator since 2001. The plant is dispatched into the PJM day-ahead market. Crane Unit 2 provides regulation capability, and both units supply reactive capacity. As a condition of Constellation’s 2011 merger with Exelon, the plant—along with two others in Maryland—is being divested for $400 million to Raven Power, a unit of Riverstone Holdings LLC.
Changing More Than Fuel
In converting the Crane Station to burn PRB coal, “they did it the right way,” said Randy Rahm, president of CoalTech Consultants and executive director of the PRB Coal Users’ Group (PRBCUG). In particular, plant operators and senior executives at the company reached out to the industry for advice and best practices through the users’ group. “They had the PRB Users’ Group involved all the way through,” Rahm said. Operators considered a range of opinions and expert advice and made decisions based on experience and best practices. For these reasons, the PRBCUG selected the C.P. Crane Generating Station as its Plant of the Year and recognized its accomplishments during a banquet at the ELECTRIC POWER Conference in Baltimore in May.
|1. Change in culture. A major undertaking was cleaning the plant and eliminating coal spillage due to subbituminous coal’s highly combustible nature. Shown are conditions after the PRB coal conversion made cleanliness a part of the plant’s new operating culture. Courtesy: Constellation Energy |
“A major initiative was to clean up around the plant,” said Bill Butler, Crane Station general manager. That involved washing down systems throughout the plant as well as conducting extensive training on how to safely handle the dust-prone and volatile fuel. That training even extended to first responders in the Baltimore fire department.
“You can’t have a lot of coal lying around in the power plant because of its highly combustible nature,” Butler said. To help control dust inside the plant, C.P. Crane relocated its coal crushers from inside the boiler house to the coal yard and added new fine-grind crushers, a crusher building, interconnecting conveyors and structures. The crushing equipment is isolated from primary air ducts and includes carbon monoxide (CO) monitoring systems and a deluge system that can be activated remotely. What’s more, operators began washing down the boiler house twice a year. Coal-handling equipment is washed down daily (Figure 1).
Modifications also were made to ash-handling systems, including segregating air heater hopper material from fly ash and adding a fly ash treatment system to prevent ash from settling during unloading and transport. Altogether, the conversion cost around $70 million and required extensive environmental permitting and planning. Constellation viewed this expenditure as prudent both to protect the generating asset and the personnel who work there. “The company had the desire to make sure we did this right,” Butler said.