Here is a simple chain of reasoning: No Central Maine Power corridor, less electrification of the economy, more offshore wind for New England and more global warming for the world. Electrification of the economy may be necessary to achieve deep decarbonization while maintaining a robust modern economy, which may require greater interconnection of the electric transmission grid.

Limiting global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) is not going to be easy. The U.N.’s special report on global warming says, in essence, that the consequences of not controlling carbon emissions in the next 12 years will be severe. Limiting global warming to 1.5 degrees C would require “rapid and far-reaching” transitions in land, energy, industry, buildings, transport and cities. We (the planet Earth) may have as few as 12 years to meet this target.

Massachusetts has selected a Hydro-Québec project that uses existing hydroelectric resources to generate 9.45 million megawatt-hours per year at 5.9 cents per kilowatt-hour delivered via a 145-mile electric transmission line. The CMP transmission corridor would be physically located in Maine and therefore required Maine Public Utilities Commission approval.

But for the CMP corridor, southern New England would need to commit to even more offshore wind. Connecticut, Massachusetts and Rhode Island have already selected 1,700 MW of offshore wind resources in recent request-for-proposal solicitations.

The Cape Wind project off the coast of Cape Cod – proposed in 2001, approved in 2010, but canceled in 2017 – is a cautionary tale. Southern New England’s offshore wind commitments may benefit New England over time, but there are risks as well.

With the Hydro-Québec project, on the other hand, existing hydro resources would be used. The end users would be in Massachusetts rather than New York, a state that has ambitious goals for renewable and low-carbon resources and better access to the energy markets than does New England.

Local concerns can dominate more abstract issues, such as global warming. New England’s geographic distance from energy resources such as oil, coal and natural gas has led to higher electricity rates compared to most U.S. states. New England has some hydroelectric resources, but increased interconnection with Hydro-Québec would provide southern New England with access to lower-cost, renewable and zero-emissions electricity.

To achieve deep decarbonization, electrification of the economy may be desirable. Environmentally beneficial electrification would expand the use of electricity – often generated from renewable and/or zero-emissions sources – in space heating, water heating and transportation. Incentives – not mandates – can be used to incentivize electrification.

An interconnected electricity grid can better balance resources and loads. For example, a car with a combustion engine fueled by gasoline is defined by these fixed characteristics, while a battery-electric vehicle is recharged via the electric grid, which is increasingly reliant on “green” resources.

People say they want 100 percent renewables. Polling found that 70 percent of respondents support producing 100 percent of electricity from renewables and 50 percent say that they still support 100 percent renewables even if this raises utility bills by 30 percent. Many states have a “renewable portfolio standard” target, and a number of states are also beginning to focus on achieving a “zero-emission resources” target.

The Hydro-Québec transmission corridor runs through Maine, but will ultimately be supported by payments by electricity users pursuant to power-purchase contracts between Massachusetts utilities and Hydro-Québec; therefore, most of the net benefits of the CMP corridor will flow to Massachusetts and Hydro-Québec. That fact presented a challenge for Maine public utility regulators.

One net benefit of the CMP corridor might be that but for the Hydro-Québec line through Maine to Massachusetts, more offshore wind in southern New England would be needed. How can this benefit Maine ratepayers? It could if a portion of the margins made from transmitting power via the CMP corridor goes to Maine.

Is a Hydro-Québec transmission line through Maine likely to support decarbonization of Massachusetts and society generally while at least not harming Maine ratepayers and providing net benefits to the state? In approving the CMP corridor and the $258 million settlement, the latest word from Augusta is that the answer is yes.