FAQ

What is the Twin States Clean Energy Link project?

The Twin States Clean Energy Link (Twin States) is a proposed renewable energy transmission project designed to deliver clean energy from Canada, including hydropower, to all of New England to support our region’s carbon reduction goals and increase our supply of affordable clean energy. As a bi-directional line, Twin States will enable clean energy producers in New England, such as offshore wind, to export excess capacity to Quebec during times of lower domestic demand, providing a critical boost to the region’s clean energy economy. It will also lower costs for customers across New England: Twin States is projected to create over $8.3 billion in wholesale energy market cost savings over the first twelve years of operation alone, according to an independent market assessment based on current project estimates. The proposal is unique in that it utilizes roadway burial and existing transmission corridors in Vermont and New Hampshire to deliver 1,200 MW of clean energy directly to where it’s needed most.

What are the specific components of Twin States?

The Twin States project consists of a new underground high voltage direct current (HVDC) line that will originate in Quebec. The line will connect into the Canadian system at the Des Cantons substation near Sherbrooke, Quebec, before crossing over the U.S.-Canada border to Canaan, Vermont. The line will continue south for approximately 50 miles through Vermont’s Northeast Kingdom, cross under the Connecticut River to Dalton, New Hampshire, and continue south for approximately 26 miles from Dalton to the Comerford substation in Monroe, NH. The HVDC line will be fully buried parallel to existing transportation corridors, along state roads in Vermont and New Hampshire. The project will require a new HVDC converter station and AC substation to be constructed in Monroe, reutilizing a previous facility on National Grid-owned land, along with new 345kV substations in Londonderry and Dunbarton, NH. The project will also necessitate upgrading existing overhead AC lines along the 107-mile route from Monroe to Litchfield, NH, and from Litchfield to Londonderry, all within existing transmission corridors owned by National Grid. This includes:

• Approximately 50 miles of new, underground lines primarily along Vermont Routes 141, 114, 102 and US Route 2.

• Underground crossing into New Hampshire, below the Connecticut River, utilizing horizontal direction drilling (HDD) technology. Approximately 25 miles of new, underground lines along New Hampshire Route 135 in Dalton and Littleton, leading to the Comerford substation in Monroe.

• Nearly 110 miles of upgrades to the existing AC overhead transmission corridor from Monroe to Londonderry in the form of replacement of the existing wires, minimizing visual changes by re-using a vast majority of structures currently operating within the corridor. The first 106 miles of the AC upgrades would consist of replacing the existing wires, reinforcing structures, and undertaking selective structure replacements. The final approximately 2.5 miles of AC upgrades would involve the complete reconstruction of the existing lines in the corridor to allow for the upgraded lines to extend south to a proposed 345kV Substation in Londonderry.

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If this project moves forward, will you need new transmission lines in New Hampshire – even if it is along a pre-existing right-of-way?

The existing National Grid (New England Power) transmission corridor in New Hampshire extends from Monroe to Londonderry. Over a vast majority of that distance, from Monroe to Litchfield, Twin States would simply need to reconductor the existing transmission lines, replace a small portion of the existing structures due to condition, or provide appropriate clearance for the new wires. The vast majority of the transmission structures in place now will remain, with two new wires replacing the existing single conductor and the existing shield wire being replaced. Reconfigurations of the existing corridor for the final 2.5 miles from Litchfield to Londonderry will be required, terminating at a new, proposed substation in Londonderry.

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Why can't the lines be buried underground along the existing rights-of-way in the areas where above-ground transmission infrastructure already exists?

National Grid is committed to mitigating any and all environmental and visual impacts along the entirety of the Twin States route to the greatest extent possible. This means where we can, we will opt to leave existing structures in place and only make absolutely necessary changes based on design considerations including conductor clearance and structural capacity. Additionally, there are some engineering and legal ramifications that prevent our team from using underground construction along our existing right-of-way (ROW). First, typical easement rights do not have provisions for the installation of underground transmission facilities. Second, the terrain in the existing ROW over the full length would make portions of the line un-constructable, resulting in the need to traverse public ways around obstructions and challenges, adding to cost and, in some cases, dramatically increasing construction impacts.

From an environmental perspective, in some cases, the lines currently cross wetlands, streams and other protected habitats that would be nearly impossible for us to avoid with underground construction. Building an underground line along that ROW would possibly entail taking down trees to widen the ROW to accommodate a duct bank, avoiding structure foundations and making electrical clearance for construction equipment. It’s also likely that undergrounding on the ROW, even if legally possible, would require going through more rock and previously undisturbed cultural resources.

Lastly, undergrounding the line would require the construction of permanent roads along the ROW for the installation, routine maintenance/inspections, and emergency response to each manhole, which would have even further environmental impacts to the ROW area.
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How will Twin States help us reach our climate goals?

Twin States will reduce New England’s CO2 emissions by an estimated 1.5 million metric tons per year, resulting in a cumulative reduction of 17.5 million metric tons over the first 12 years of service, according to an independent market report. Twin States will also help further the growth of New England’s emerging clean energy economy, including the offshore wind sector, by allowing regional renewable energy producers to export excess power to Quebec during periods of low customer demand. By working in tandem with New England clean energy producers, Twin States will allow the region to reliably and cost-effectively harness its vast renewable energy potential over the next decade to the benefit of New England customers and workers, and the environment.
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How will it be built?

Twin States is being proposed by National Grid and Citizens Energy Corporation, who have also partnered with the International Brotherhood of Electrical Workers (IBEW) to support its construction. National Grid is the unrivaled global leader in HVDC project development, construction, and operation. As the owner and operator of New England’s largest connection to Quebec, and a local utility that understands the needs of its customers, National Grid is uniquely positioned to deliver a new connection to our Canadian neighbors that will bring maximum value to homes, businesses, communities, and workers.

How many people will this employ during construction? How will it economically benefit the region?

The Twin States proposal is projected to create an average of more than 1,200 jobs per year in New England during construction, including hundreds of construction and manufacturing jobs in Vermont and New Hampshire, according to an updated independent market assessment. It will also provide significant overall economic benefits for the host states and region. During the construction period, Twin States is projected to contribute an annual average of $165 million to New England’s GDP; in Vermont and New Hampshire, it will contribute an annual average of $28 million and $48 million, respectively, to state GDP during this period.

How many people will be employed by this line when it is completed?

Once completed and put into service, Twin States will require regular maintenance and operation services, most notably in the new converter station and substations in New Hampshire, where it is projected to create an average of more than 35 jobs per year. Throughout New England, the economic effects of reduced electricity bills for customers and businesses are expected to create significant economic growth, generating an estimated average of 3,700 jobs per year across the region.

What is the role of U.S. DOE and the Transmission Facilitation Program?

National Grid has submitted this proposal to the United States Department of Energy (DOE) Transmission Facilitation Program, part of the Infrastructure Investment and Jobs Act, which would allow the proposal to receive federal investment and initial cost recovery. The support is critical for the developers to move the project forward within the timelines currently contemplated. In late April, Twin States was invited by the DOE to participate in Phase 2 of the Transmission Facilitation Program’s RFP process, a recognition that they believe Twin States is a viable, buildable project that is potentially eligible for federal assistance. Support from communities, policymakers, and regulators around the proposal at DOE will help to facilitate moving this project forward to final selection.

What will Twin States cost?

The Twin States proposal is estimated to cost under $2 billion to design, engineer, permit and build. This figure is subject to change as we receive more information and conduct outreach to stakeholders.

How will its development costs be paid?

The developmental costs will be paid for by the energy companies that deliver energy over the line; however, the project's energy will result in lower costs for New England energy customers.

Twin States is pursuing selection by the DOE Transmission Facilitation Program, designed to provide Federal support to overcome the financial hurdles in developing large-scale new transmission lines throughout the country.

Where will the power go?

The affordable clean energy delivered over the border from Quebec will interconnect into the New England regional power grid in Londonderry, NH, and will be used by customers across the region.

What are some of the financial benefits for the local communities?

Twin States is projected to generate hundreds of millions of dollars in new property tax revenues to host state cities and towns through which the line passes. It is also projected to contribute millions more in lease payments to Vermont and New Hampshire for underground burial of the lines along state roadways.

In addition, as part of the consideration for the project, National Grid and Citizens Energy Corporation are assembling a $260 million community benefits program, of which at least 40% will be dedicated to disadvantaged communities throughout New England.

We are working closely with communities and local economic development partners to understand how our benefits program can be tailored to support local needs. As part of this process, we are holding detailed listening sessions to understand how Twin States can maximize its benefits for the region, beyond creating jobs, lowering energy costs, and combatting climate change by reducing our dependence on natural gas to generate electricity.

When will the community benefits program go into effect?

National Grid and Citizens Energy are regional energy providers that have a long history of giving back to communities. The $260 million community benefits plan by National Grid and Citizens will come from after-tax profits from Twin States once the project goes into service and is providing benefits to the region.

Will customers in Vermont and New Hampshire have access to the clean power this line will deliver?

Yes.

How will it benefit customers in terms of the electric rates?

Because New England operates wholesale energy markets, the power flowing over Twin States reduces the amount of high-priced power -- usually natural gas and oil-fired generation -- that must be procured to meet energy needs. This lowers energy costs for all New Englanders, to the tune of $8.3 billion in energy market savings over the first 12 years of operation alone, according to an independent market assessment. These savings are based in part by how much power each state uses. The updated independent market assessment shows that Twin States will create annual average energy market savings of $68 million in New Hampshire, $51 million in Vermont, $87 million in Maine, $296 million in Massachusetts, $126 million in Connecticut and $61 million in Rhode Island over its first 12 years in service. Utilities can offer additional savings to customers by directly contracting for capacity over Twin States, thus locking in costs for affordable electricity.

Are there expected environmental impacts when the line crosses the Connecticut River?

The line will be buried underground, below the riverbed via a horizontal direction drilling (HDD) system. As with burial along roadways, the design of this project is intended to minimize environmental and visual impacts.

Are there environmental concerns about having a transmission line near the Connecticut River?

No. We will conduct environmental and archaeological studies throughout the permitting process if the project receives approval from DOE.

What other clean energy projects will connect to this?

The bi-directional nature of Twin States will help further the growth of New England’s emerging clean energy economy, including the offshore wind sector, by allowing regional renewable energy producers to export excess power to Quebec during periods of low customer demand.

Who is supporting this project? Are there partners?

National Grid and nonprofit Citizens Energy Corporation are proposing the project. Citizens has pledged to dedicate $100 million towards community-identified projects in the project’s route cities and towns. If the project were to move ahead, to support its construction, Twin States is proud to partner with the International Brotherhood of Electrical Workers (IBEW). National Grid is also partnering with the Northeastern Vermont Development Association (NVDA) on a significant long-term commitment to supporting their community-driven work in economic growth and advancement for the Northeast Kingdom and beyond.

Is this clean power coming from Hydro-Quebec?

Hydro-Quebec generates the majority of hydropower in Quebec and is one of the largest generators of emission-free power in the world. We are having discussions with Hydro-Quebec and other energy suppliers in Quebec that can deliver power over Twin States. We are also in discussions with U.S.-based offshore wind and other renewable developers about utilizing Twin States’ bi-directional capabilities that will allow them to transmit excess power to Canada when it’s not needed domestically.

It has been recently reported that Hydro-Quebec may soon run out of hydropower export capacity. How can Twin States be assured of having the necessary power supply?

As a bi-directional line, Twin States would essentially act as a “green long-duration battery” for New England and Quebec, sending clean energy, including hydropower, from Quebec to New England to balance New England’s renewable resources during times of peak demand, while also sending surplus renewable power generated in New England—such as offshore wind—to Quebec when it's not needed to meet our own customer demand, such as in the spring and fall months, when energy usage is usually lower. When Quebec receives renewable energy from New England, it allows them to preserve their generation capacity by holding water in their reservoirs that can be utilized later.

The diversity in clean energy supply between Quebec and New England offers a unique opportunity to achieve the promise of the Energy Transition. Twin States offers the potential to catalyze synergies between New England’s future offshore wind generation, Quebec’s vast hydro and wind capabilities, and the electrification plans of both regions, providing a tremendous value proposition to customers through greater transfer capability.

How is Twin States different from the NECEC project in Maine and the New England Clean Power Link (TDI) project in Vermont?

Twin States differs from other proposed large transmission projects in several important ways.

• First, Twin States is a bi-directional line that will deliver 1,200 MW of clean energy from Canada, including hydropower, while also allowing clean energy producers in New England, including offshore wind, to export excess capacity to Quebec during times of lower customer demand. This is a win-win for New England and Quebec as it ensures hydropower resources are available when we need them most while also providing Quebec with renewable energy in the spring and fall that will allow them to preserve their own generation capacity for later use.

• Second, Twin States will be constructed within existing transmission rights-of-way already owned by National Grid and its new lines will be buried alongside state roadways, minimizing any potential environmental and viewshed impacts for host communities.

• Third, by ending in Londonderry, NH, Twin States will deliver this clean energy directly to Greater Boston’s doorstep, where it is needed most and will have the greatest impact on prices regionwide.

• Fourth, Twin States is projected to provide far greater energy savings for New England customers than other projects, according to publicly available data.

What is the Twin States Clean Energy Link’s timeline?

National Grid has applied for the Transmission Facilitation Program at the DOE. We hope to hear the results of this application process this fall. Project construction would occur between late 2026 - 2030 with the project going online in 2030-2031.

Will the line be buried below the frost line and will it adversely impact the quality of the roads? Will roads be closed during construction of the line?

The line will be buried below the frost line. National Grid will be conducting studies and fieldwork to ensure that the line is buried deep enough below the frost line so that there are no adverse impacts on the quality of the roads. The buried line will be a valuable asset and National Grid has extensive construction experience in other cold climate areas. National Grid will work closely with VTrans and NHDOT to ensure the road is inspected and the quality is maintained. National Grid will also work closely with local First Responders to develop Traffic Management Plans, ensuring public safety. Construction will occupy one lane of traffic, allowing for alternating traffic at all times.

How will the manhole covers fare against the snowplows and frost heaves? Will they be noisy when people drive over them?

Manholes will be spaced roughly between 1,500 and 3,000 feet apart along the project route. Manhole covers will be installed flush with the road to diminish potential noise and are designed to withstand snowplows and frost heaves. National Grid will work closely with VTrans and NHDOT to ensure the road is inspected and the quality is maintained, including manhole covers.

Will the buried line emit EMF and be harmful to people and animal health?

The earth itself has a naturally occurring magnetic field and National Grid does not anticipate a perceptible difference in EMF from the Twin States project from that which is naturally occurring from the earth at ground level. We are engaging a third party to perform an analysis of the electric and magnetic fields to ensure this is the case.

High voltage electric transmission lines produce two types of fields, electric fields and magnetic fields. Electric fields are mitigated by the cable sheath, duct bank, and overburden in the case of underground power lines. Magnetic fields drop rapidly with respect to distance, especially in underground circuits where cables are placed near each other within a duct bank.

Research shows that there are no data that demonstrate a correlation between adverse health impacts and the typical electric and magnetic fields created by electric transmission lines. The World Health Organization (WHO) has conducted comprehensive reviews of EMF health-effects research and existing standards and guidelines. The WHO website for International EMF Project states: “[T]he main conclusion from the WHO reviews is that EMF exposures below the limits recommended in the ICNIRP international guidelines do not appear to have any known consequence on health.”

Why isn’t this line being built along the existing VELCO power line in Vermont?

Several years ago, National Grid proposed building a transmission line, (the Granite State Power Link) next to the existing VELCO corridor from Norton south to Concord, VT. The project was not viable for two reasons: it would require significant tree clearing to widen the corridor and the route has conserved private timber lands and state lands that prohibit any commercial activities. The conservation easements in place along the route prohibit the expansion of the existing transmission corridor to construct a new line.

In Vermont and portions of New Hampshire, Twin States will be buried underground along state roadways, which means it will have a much lower environmental and aesthetic impact than the previously proposed Granite State Power Link.

How will this help New Hampshire’s North Country?

Twin States would help solve a decades-long challenge in the North Country of New Hampshire by completing necessary system upgrades in Grafton County, which will allow for new renewable generation opportunities to the north, along the Coös Loop, an existing transmission line that spans a sizable portion of Coös County. With Twin States completing system upgrades to the south, future costs for North Country renewable generators would be reduced; economic development and new job creation are just some of the potential benefits that would be realized by projects on this line.

How will this help Vermont’s Northeast Kingdom?

In Vermont, Twin States will bring extensive and meaningful benefits to the seven communities along the project route. Based upon current tax rates, route communities are projected to receive at least $600,000-$775,000 in increased property tax revenue annually from Twin States. These figures are based upon towns' current tax rates and the value of the proposed line. If communities choose to lower their tax rate with the property tax revenue from Twin States, these numbers would decrease, as would everybody’s property taxes. Alternatively, communities may choose to keep their tax rate the same and have additional funds to spend.

Beyond meaningful property tax revenue, the project has partnered with Northeastern Vermont Development Association (NVDA) to make millions of dollars available to the communities through their grant program and loan fund. Twin States is also working with Vermont Electric Co-op (VEC) to provide community members with an opportunity to lower their electricity bills. This could include funding participation in VEC’s Co-op Community Solar program for route community residents.