The Clean Energy Corridor Clarified

You have seen the signs and the TV ads regarding the New England Clean Energy Corridor (NECEC), aka the transmission line from Quebec to just above Lewiston.

While the following goes into some detail about the Corridor, the bottom line to voters is simply this: by allowing the Corridor to operate, voting “NO” assures as much as a 15% immediate reduction in the carbon content of electricity delivered to New England customers. A YES vote assures a significant number of natural gas power plants, which emit carbon, will continue to operate.

We hope the information below will lead to an informed choice when voters decide this issue in November.

The delivered electricity does not go directly to Massachusetts.

When the power leaves the NECEC just north of Lewiston it enters the six-state New England Power Pool and is instantaneously blended with all the power in the system. It is pohysically impossible to inject power into the grid and have it go to one state or confine it to any state. There are no direct paths to Massachusetts or any other states; there are no state grids. It is all interconnected. Massachusetts residents are paying for that power and getting most of the environmental credit, but many people do not understand that in power grids, dollars do not flow with electrons.

One way to think of this system is to visualize a very large bathtub that has multiple faucets filling it and multiple drains emptying it. The tub is the grid, and grid operators must constantly match “water” coming in from power plants and other transmission lines with water draining (consumption) to keep the level of water perfectly level. The NECEC is just one more faucet, and when its water is released it blends with everything there. This “bathtub” is the six-state region of New England. There are no state “bathtubs.” When the power enters the bathtub in Lewiston, it is instantly blended with all the other power sources: NECEC power goes to every customer in New England.

Greenhouse gas content of New England grid electricity is reduced.

When this new NECEC faucet adds a huge amount of water into the tub, but no new drains are added, an equal amount of water (electricity) that had been pouring into the tub needs to be shut off. The operators turn off units, highest cost first. In the New England pool, the units displaced would all be natural gas fired plants.

These natural gas plants emit about 4.3 million tons of greenhouse gases. In 2019, the New England grid emitted 30 million tons; by displacing them with zero emissions electricity, the NECEC could lower greenhouse gas intensity by between 10% and 15%. Millions of dollars from natural gas power plant and pipeline operators are funding opposition to the line, as it represents a real threat.

The details of ISO-NE operations are described best here:, but briefly put, the operators are constantly trying to both monitor and forecast energy needs.

ISO-NE operations are described in more detail here, but briefly put, the operators are constantly trying to both monitor and forecast demand. They then dispatch generation, according to cost from low to high, to meet that demand. Since there is always some level of demand, many generators run 24/7.

At a capacity of 1.2 Gigawatts, NECEC will import 10.5 billion kilowatt hours (kWh) annually. ISO-NE consumption in 2019 was 97.8 billion kWh. Coming in all at once, and without reducing demand, an equal amount of generation will need to be turned off. The following chart shows which type of units were dispatched to meet that load last year.

Natural gas units are the ones that will be displaced.

There are 89 natural gas fired power plants in ISO-NE that operated in 2019. Their carbon emissions vary widely from plant to plant, irrespective of size. Not all these plants would necessarily shut down when the NECEC operates, because some are only used to meet a few hours of high peak demand. The top 85% largest units have an emissions average of .00056 tons/kWh. However, the system average for all of these plants, according to EPA data, is .0005 tons CO2 per kWh. The largest of these units (Lake Road in CT and Fore River in Mass) , emit .00043 and .00044 tons/kWh. Using the metrics from these two largest plants, the NECEC offsets 10 billion kWh, or about 4.3 million tons of CO2. The ISO-NE system emitted 30 million tons in 2019, so the NECEC would cause a 15% reduction.

Another analysis concluded that the minimum reduction would be 3 million tons, or about a 10 % reduction.

Reducing Maine’s baseline carbon intensity for grid electricity is therefore between 10% and 15%

Maine ratepayers do get lower electricity costs.

Whenever electricity moves around the grid, the amount flowing depends on where the demand might be. Putting all this new capacity into the grid in Maine will reduce the amount of power flowing north, thereby reducing transmission costs for Maine ratepayers. According to the Maine Public Utility Commission, the NECEC will save customers power costs and other charges between $23 and $63 million annually for 20 years and the State will receive a benefits package of $258 million for a low-income customer benefits fund, a  rate relief fund, a broadband fund, a heat pump fund and funding for electric vehicle charging stations.

These values do not include this addition:

When Quebec Hydro exports this power, it will not replace it with fossil units.

           Hydro Quebec has the capacity to generate over 37 billion watts, of which 0.4 billion watts is fossil – less than 1%. This generation serves its domestic load, including exports and has enormous excess hydroelectric capacity. The NECEC export is about 1.2 billion watts. The New England grid is part of a larger network that includes New Brunswick, Quebec, Ontario and New York. Hydro Quebec adds 1.2 billion watts to its output and sends it to New England, where 1.2 billion watts of natural gas power is turned off. It is that simple.

The details

Hydro Quebec’s energy generation sources include the following (source: Canada Energy Regulator):

Data on surpluses:

The pristine forest is not pristine and is not a huge loss of carbon absorbing trees.

Only 53 miles of the corridor is newly clear-cut, a 54-foot-wide swath. That stretch is commercially logged land, already crisscrossed with roads. The remainder of the line is already cut and will be slightly widened. This 53 miles of corridor is about 349 acres. Maine’s forests absorb about 2.5 to 4 metric tons of carbon per acre. That “lost” forest would have absorbed between 872 and 1,396 metric tons of carbon a year. When the NECEC operates, between 3 million and 4.5 million metric tons of carbon will not be emitted from natural gas power plants.

The tradeoff.

Replacing fossil fuels with decarbonized grid electricity is a key strategy to achieve Maine’s, and the region’s, climate goals. The NECEC is critical to effective climate action: it will substantially reduce the greenhouse gases now emitted by New England grid electricity. The tradeoff is a small price to pay for the enormous reduction in harmful emissions.