The City of Portland is exploring ways to reduce the carbon emissions of large cruise liners while docked in port.
The city asked Central Maine Power to study the feasibility of creating a transmission system that would allow 3 cruise ships to get power off the grid and shut down their engines.
CMP'S Meg Sullivan told members of Portland's Sustainability and Transportation Committee meeting Wednesday that its existing transmission system could not accommodate the required 25 megawatts of power. But she said the company is finalizing a grid upgrade that could handle shore power and increasing demand in the area.
"We are creating solutions for the Portland area that would accommodate the 25 mw of shore power plus some of the additional electrification and growth that we are expecting in the area," Sullivan said.
Sullivan said that project would take 10 or more years to complete at a cost to the city of $60 million dollars. CMP would incur at least 500 million dollars for the build-out.
Expediting a second option that would include a new substation and transmission line would cost 346 million dollars and take more than 7 years to complete.
The Air Quality Bureau of the Department of Environmental Protection in 2023 released data from the Environmental Protection Agency's National Emissions Inventory that shows mobile commercial marine vessels are a smaller contributor of emissions than land-based trucks and trains.
Stacy Knapp of the DEP said federal regulations restricting sulfur in fuel have lowered the Sulfur Dioxide emissions of marine vessels.
"Once I looked at the entire fleet of commercial marine vessels and related that data to what we see elsewhere in the state, I was less alarmed. We still want to look at this, but I'm much less alarmed knowing what those data tell me," Knapp said.
Knapp said the DEP is moving an air monitoring station from Deering Oaks Park to Ocean Gateway in Portland to better track air quality on the waterfront. She says the state also wants to put low-cost sensors and other monitors in the port area to truly assess the air quality impact of cruise ships.
The DEP's 2023 report says a single engine on a cruise or cargo ship would require mandatory emissions controls if it were land-based, and the state cannot disregard marine vessels as an important emissions source.
