By Graeme McNaughton/The Oshawa Express
Following weeks of down time and the region’s waste being sent elsewhere, the Durham York Energy Centre is once again fully operational.
According to emissions data posted on the incinerator’s website, Boiler No. 2 was put back online late in the evening on March 16, while Boiler No. 1 was brought back to life on the morning of March 21.
Boiler No. 2 was the first to be taken offline on Jan. 27 after a damaged water tube was discovered and needed repairs. Boiler No. 1 was taken offline on Feb. 5 to see if it had some of the same problems as its counterpart.
Gioseph Annello, the region’s manager of waste planning and technical services, says the facility’s annual maintenance was pushed ahead when workers found that the boilers were more beaten up than expected.
“Because the water wall tube ruptured, they basically shut down the boiler and advanced the annual maintenance. So what they did then was they did their inspection, they found a lot more wear than they expected,” he says, adding that some of the tubing was replaced with one featuring a nickel-alloy-based coating that protects it from the high heat of the incineration process.
“They’re now better protected from that corrosive environment. So basically, it was a matter of they were cutting out sections of the boiler and replacing it with new sections that had this lining on it.”
Annello says that while the region has not received any feedback from Covanta, the site’s New Jersey-based operator, as to why the tubes were corroding much earlier than expected, the only tubes affected were those not protected by the nickel-alloy coating.
“You can ascertain from there that maybe they should’ve done that when they first started, but based on engineering calculations, they figured it was well protected,” he says.
“The evidence showed differently.”
While the incinerator being back up and running is good news for the region and Covanta, the amount of downtime could come into play for the latter’s 2017 annual report.
According to the project agreement for the incinerator, “unscheduled maintenance shall not exceed six (6) boiler days in any 31 day period and total scheduled and unscheduled downtime shall not exceed 73 boiler days in any contract year.”
A boiler day refers to a day where an individual boiler is offline for the full 24-hour period. If both boilers are not operational on the same day, it counts as two boiler days.
As a result of this latest outage, the two boilers were down for a combined 90 boiler days, with Boiler No. 1 down for 43 and Boiler No. 2 down for 47.
According to the project agreement, this could cost Covanta.
“The performance guarantees are there to make sure that we are not financially harmed by any excessive downtime,” Annello says.
“One of the performance guarantees is that they have to process 140,000 tonnes of waste. If the boiler is down to that amount, beyond availability, they are less likely to meet that. In fact, they can’t.”
According to the project agreement, Covanta is liable for $210 per tonne below that threshold. Producing just one per cent short of that number would cost $4 million, according to the agreement.
Annello adds that due to less waste being incinerated, less electricity is generated, which is another performance guarantee in the agreement, coming in at eight cents per kilowatt per hour per tonne below the guaranteed number. This amounts to approximately $1 million per percentage point.