ORRINGTON — Repairs at the Penobscot Energy Recovery Co. (PERC), which takes in much of the waste from Hancock County and surrounding counties and burns it to generate electricity, are turning out to be “a lot more extensive than we anticipated,” said Plant Manager Henry Lang in an email last week. Because of that, the plant will be combusting trash but won’t be generating electricity for more than a month.
The facility was closed for maintenance from April 5 through 25 as Versant Power worked on the 115,000-volt lead line coming into the plant. PERC staff took advantage of that time to undertake a major turbine overhaul, which proved more complicated than expected.
“The owners have decided to forge ahead with some very costly repair options to ensure that the turbine and generator are in good shape for years to come,” said Lang. “The plant will restart on time with one caveat — it will not be generating electricity for approximately 35 days.”
While the turbine/generator is undergoing repair and overhaul, PERC will still be combusting trash to reduce its volume, with the heat generated released to the atmosphere, which it has been designed to do, said Lang. “This will not change the plant’s flue gas emissions but does mean that the water going to our cooling tower will carry more heat away to be exchanged to the air that is drawn through the cooling tower.”
The bypass condenser has been used in the past, said Lang, when the plant was first started up. It also functions as a relief system for steam pressure. “For a period of time we will be using it for its original purpose, which is to allow plant operation without the electrical generation.”
The PERC plant took in 194,912 tons of waste in 2020, which works out to around 16,242 tons each month. Roughly 60,000 tons of that, all from commercial sources, were sent to the landfill, while the rest was burned to generate electricity.
Apart from its usual contracts, PERC has also taken in waste from towns that are part of the Municipal Review Committee (MRC) while the group prepares for the reopening plan for its plant in Hampden, which shut down in late May of 2020. To be able to handle the additional waste, said Lang last month, PERC essentially “bypassed our commercial contracts so that we could accept the MRC material.”
Lang said burning waste without generating electricity “isn’t the best use of this facility, but during the period of time that the electrical generation equipment is unavailable, it allows PERC to maintain its service to the communities that send their waste here.”