New plan to join wind power with hydropower enters the mix of New England electricity proposals 

National Grid has joined with a Boston developer of transmission lines in seeking to build an undersea power line that would combine Canadian hydropower with Maine wind power and bring it to Boston – even as another partnership moves ahead with a huge power line beneath Lake Champlain in Vermont that would bring Quebec hydropower into New England.

These two separate projects, each of which would cost at least a billion dollars and not be ready until 2019 at the earliest, are part of the large-scale debate over how New England should deal with spiking winter electricity rates, a function of the region’s dependence on natural gas.

About half of New England’s electricity is produced by gas-fired power plants. In winter, when much natural gas is used for heating, the supply of gas in New England gets tight and the coast soars, pushing up electricity prices. Several utilities that buy gas on the open market have said their winter power rates will rise by one-third to one-half this year, although PSNH has not yet proposed its winter rate.

This issue is also behind the attempt by PSNH’s parent, Northeast Utilities, to build the Northern Pass power line, which would bring Quebec hydropower through New Hampshire. Northeast Utilities has long painted the project as a necessary response to the region’s natural gas bottleneck.

Much or all of the cost of whichever power line is built – and it’s not clear whether all of them are needed – would be covered in the region’s electric rates.

The winter gas shortfall is also why Texas energy giant Kinder-Morgan wants to build a large, multibillion-dollar interstate gas pipeline through southern New Hampshire.

All of these projects face large regulatory obstacles, and even if all goes well, none will have any effect on New Hampshire’s power supply or electricity rates for at least four years.

The latest player was announced Tuesday, when National Grid, which provides electricity in parts of southeast New Hampshire as well as large swaths of Massachusetts, said it was “partnering” with Anbaric Transmission of Boston. They want to develop power lines that would take as much as 2,800 megawatts of power from online wind farms and dams up north and bring it into eastern Massachusetts.

The only project announced Tuesday is a proposed 1,000-megawatt undersea line that would carry electricity produced by wind farms in Maine, as well as dams in Maine and eastern Canada, and bring it to the Boston area. It’s called the Maine Green Line and could go into effect by 2020, officials said.

“Large-scale hydro will not solve the problem. We need to combine wind with hydro. It is the most efficient combination, provides the greatest price release and the greatest amount of REC-eligible supply,” said Ed Krapels, co-founder of Anbaric, in a media conference call. He was referring to Renewable Energy Certificates that measure state compliance with renewable energy requirements.

Large-scale hydropower by itself is the idea behind so-called New England Clean Power Link, which would bring electricity from Quebec, which has huge supplies of hydropower, into Vermont via a line running partly along the bottom of Lake Champlain, where it would connect into the New England grid.

An industry consortium called TDI New England announced Tuesday that it has filed a Vermont permit application seeking approval of the project, which would also carry 1,000 megawatts of electricity. It could go into service by 2019.

Large-scale hydropower is also the idea behind Northern Pass, proposed by an alliance including Northeast Utilities. It would carry 1,000 megawatts of power from many huge power dams in Quebec, going through New Hampshire and connecting to the regional grid in Deerfield. It could not be in operation before 2018 at the earliest.

All three of these projects would cost at least $1 billion each and involve high-voltage direct-current lines, usually operating at 320 kilovolts, which are much more efficient than the alternating-current power lines that are the usual component of the power grid. However, they are also more expensive and more difficult to integrate into the grid.

They’re not the only transmission projects on the table, either.

Unrelated to these is an alternating-current project proposed by Northeast Utilities and National Grid that would run through Hudson and Pelham. It is designed to shore up the existing power grid, not bring in new sources of electricity, and faces competition from NextEra Energy, which owns the Seabrook Station nuclear power plant.

NextEra wants to boost the grid with an undersea link between Seabrook and a transmission station in Everett, Mass. Each of those plans would cost half a billion dollars or more and not be ready until 2018.