MASSENA — A New York Power Authority project that’s expected to begin in 2020 will have the capacity to bring enough clean electricity to power 720,000 to 900,000 average-sized homes.

The rebuilt lines that will be part of the $440 million Moses-Adirondack Smart Path Reliability Project — 86 miles of lines from Massena to Croghan — are currently rated to carry 900 megawatts during the winter months, which NYPA officials say is enough electricity to power those thousands of homes.

The line includes 78 miles that were originally constructed by the federal government in 1942 and acquired by the Power Authority in 1950.

Power Authority officials say they’ll have the ability to increase the voltage when demand requires it, making it a cost-effective way to add more renewable power along the transmission line.

The application for the proposed project was filed this week with the state Department of Public Service. The state’s Public Service Commission reviews the environmental, public health and safety impacts for major electric transmission projects; other state agencies, as well as the general public, have an opportunity to provide input.

When the process is complete, the PSC will issue a Certificate of Environmental Compatibility and Public Need for the Smart Path project, a process expected to be done sometime within the next year.

With approval by the PSC, NYPA plans to replace existing wide, wooden H-frame poles with single steel monopoles. The single steel poles require significantly less space than the H poles, extend the distance between poles and minimize the use of space on the right-of-way.

“Basically, what we will be doing is changing the two-pole structure or three-pole structure to a single pole structure, which decreases the footprint of the tower itself,” said John Finnegan, transmission supervisor for the New York Power Authority. “We’re not expanding into any new right-of-ways, any new areas. We’re staying on the same right-of-way as it is.”

The Moses-Adirondack Line starts in Massena and carries electricity from the St. Lawrence-FDR Power Project to the Adirondack substation in Croghan.

“It’s about 86 miles from here. The portion that we’re talking about rebuilding is the one portion of the line which is approximately 78 miles long,” Finnegan said.

The Moses-Adirondack Line transmits enough power to provide backup to the Power Authority’s 765-kilovolt transmission line, and is a key part of the New York Independent Systems Operators power restoration plan.

“This is an integral part not only to the authority, but to the region and the United States as a whole,” said Edward A. Rider, NYPA’s Northern New York regional manager.

What project organizers are currently facing, however, are many conductors and H-frames of the existing line that are more than 70 years old, past their useful life and in need of replacement or rebuilding.

“These transmission lines have been consistent workhorses in the Power Authority statewide transmission and generation power network,” Gil C. Quinones, NYPA president and CEO, said in a statement.

“After the Public Service Commission’s review, we hope to give these transmission lines new life so they can continue to provide New York with cost-effective, clean electricity. As the utility sector of today undergoes dramatic change, we are investing in our transmission infrastructure to prepare New York’s energy highway for many more years of reliable service,” he said.

“Realistically, you should be looking at 50, maybe 70 years for your transmission assets until they need total replacement, and that’s what we’re dealing with right now,” said Jordi Parisian, NYPA’s transmission asset manager.

The rebuilt lines will be taller, but stronger, less susceptible to failure, and able to withstand ice storms with the new aluminum conductor and steel poles.

NYPA officials said they will use local resources when possible and encourage local firms to bid during the procurement process.

“The corridor from Adirondack up through all the communities, right to Massena, should see a little bit of a benefit from the construction,” Mr. Rider said.

The project will strengthen the state’s electric power grid, which will allow more upstate renewable energy to connect to the power system throughout the state. It will also help the state meet the governor’s Clean Energy Standard that mandates that 50 percent of New York’s consumed electricity comes from renewable energy sources like wind and solar by 2030.