SOUTH PORTLAND — City officials are scrutinizing a proposal by Central Maine Power Co. to expand a transmission substation on the Fore River — near the Knightville neighborhood and the Casco Bay Bridge — that has sparked concerns about potential public health, environmental and visual impacts.

The company has provided few details so far about the project, which is part of a $214 million effort to improve the power transmission system throughout Greater Portland, including substation proposals in Freeport, North Yarmouth, Cumberland, Gray and Portland.

The plan to upgrade what’s called the Cape Substation comes as the city tries to control development in its increasingly popular waterfront neighborhoods, including a 2014 ban on loading crude oil into tankers that the Portland Pipe Line Corp. is challenging in federal court.

The city has petitioned the Maine Public Utilities Commission to intervene in its ongoing review of CMP’s Brightline Initiative – the company’s long-term effort to meet state and federal requirements for power reliability and develop an energy grid that can support growth in renewable energy.

City officials want to make sure CMP fully considers so-called “non-transmission alternatives,” such as solar power installations and energy efficiency projects, before the PUC approves the company’s plan to expand the power transmission facility on the 25-acre property.

“That substation is sitting on some of the most valuable property on the East Coast,” City Councilor Claude Morgan said. “It’s really hard to imagine that the best use would be to expand a facility that has become a dinosaur. To me that’s anachronistic and doesn’t fit the city’s long-term vision for waterfront development.”

Morgan said he’s concerned that expanding the substation might affect the health and wellbeing of people who live and work nearby, and undermine the city’s efforts to reduce its carbon footprint. In addition to installing electric car charging stations and building a 2,944-panel solar farm on its capped landfill, the city has partnered with Portland to develop a climate action plan that would reduce carbon emissions 80 percent citywide by 2050.

To provide information and answer residents’ questions about the substation project, CMP has scheduled a community meeting on July 18 at 7 p.m. in the City Council chamber at City Hall.

The Cape Substation is on a peninsula that juts into the Fore River and is fed electricity by a submarine cable from Portland. The land is valued at $2.3 million and the substation is valued at $33 million, with a combined annual tax bill of $635,4000, according to the city assessor’s records.

The expansion project would increase the substation’s footprint by about one-third to accommodate the installation of new equipment, said Gail Rice, spokeswoman for Avangrid, CMP’s parent company.

The company would incorporate non-transmission alternatives, such as load reduction, energy efficiency, battery storage and distributed generation, if they proved to be cost-effective, reliable options compared with poles and wires, she said.

CMP is working with the owners of South Port Marine, a marina next door that leases some space from CMP, to mitigate the impact of the expansion on its operations, she said.

The project also would raise the substation in anticipation of sea level increases, said Tex Haeuser, city planning director.

Haeuser said it will take a few years for the Cape Substation proposal to make its way through the entire review process, including site plan review by the South Portland Planning Board, which would ensure it meets city zoning regulations.

In the meantime, the city has developed a master plan for the nearby Mill Creek shopping area that reimagines it with village-style housing mixed in. It also has started working on an update of the Knightville master plan that’s expected to account for growing demand to live and work in the waterfront neighborhood.

Maine’s largest electricity transmission and distribution utility, CMP operates about 23,500 miles of distribution lines and 2,900 miles of transmission lines, serving 624,000 customers in 346 communities in central and southern Maine.

In addition to building or upgrading several substations throughout Greater Portland, the Brightline Initiative calls for upgrading transmission lines through Gray, North Yarmouth, Yarmouth, Freeport, Cumberland, Falmouth, Westbrook and Scarbrough, according to a CMP notice filed this month with the PUC.

Central Maine Power Co. Cape Substation in South Portland. (Derek Davis/Portland Press Herald)

Central Maine Power Co. Cape Substation in South Portland. (Derek Davis/Portland Press Herald)