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Geothermal Pilot Reference Guide

Geothermal Basics

What is geothermal energy?

Geothermal energy is heat from inside the earth. It is renewable energy that comes from two sources: the sun’s rays that hit the earth and are absorbed, and high temperatures produced deep within the earth’s core that radiate outwards to the surface.

While the deep earth geothermal – thousands of feet deep, 220+ degrees Fahrenheit depending on the area - can be used to generate electricity, the geothermal energy being tapped for our pilot is the shallower (about 500 feet) and lower temperature variety used for heating and cooling indoor spaces and producing hot water in conjunction with geothermal heat pumps. Here in New England, the temperature underground at those shallower depths is a constant 55 degrees year-round.

What is a geothermal heat pump system?

A geothermal heat pump system consists of a geothermal heat pump connected to a series of buried pipes called the “ground loop”. The system moves a heat-conveying fluid, typically water or an environmentally safe antifreeze mix, through the pipes to circulate heat between the ground and buildings.

Geothermal heat pump technology uses electricity to move heat from the ground loop (closed loop design) into a building to warm in the winter and from the building to the ground loop to cool in the summer. This allows it to sustainably heat and cool homes, businesses or other buildings throughout the year.

How is our pilot unique to other geothermal heat pump systems used elsewhere in the U.S. and the world?



Geothermal technology is not new. It has been in use for decades and is a proven technology to heat and cool homes.

Geothermal heat pump systems are in use throughout the U.S. and the world, in all climate zones and for virtually every type of building or facility.

Our pilot is unique because it’s the first of its kind to offer a utility-operated networked geothermal system, meaning multiple geothermal heat pumps will be connected through a shared horizontal piping system with the intent of optimizing the various building loads to reduce the overall size of the loop.  

What are the benefits of a geothermal heat pump system for customers?

  • Low maintenance and cost-effective: Compared to traditional heating and cooling systems, geothermal heat pump systems require less maintenance to operate and are more efficient, therefore, represent a more cost-effective way to maintain long-term energy solution.
  • Reliable: Geothermal energy provides a constant energy supply in all weather conditions. It is always available, day or night, and whether it’s sunny or windy. Geothermal systems have a long life expectancy; geothermal heat pumps are rated to last 25 years or more, while the underground infrastructure is warranted to last up to 50 years.
  • Quiet: Ground source heat pumps are significantly quieter than a traditional compressor used with other types of heating and cooling.
  • Clean: Using geothermal energy for heating and cooling can reduce the average residential customer’s carbon emissions by up to 60%.
  • Renewable and sustainable: Geothermal energy is a sustainable energy source and is continuously replenished by the sun and earth’s core. A properly sized and balanced geothermal heat pump system should have no net change on the earth’s underground thermal environment.

What are the risks of geothermal heat pump systems for customers?

The risks with geothermal equipment are not very different from other heating and cooling equipment.

  • If the power goes out, the system will not operate. This is not any different from existing heating and cooling equipment which will also not operate if the power goes out.
  • As with other buried utilities, there is always a risk of the system being damaged by digging or construction activities.
  • Equipment needs to be maintained and serviced if needed.
  • The circulation fluid that is warmed/cooled by the underground loop is entirely contained within pipes and includes a mixture of water and glycol for freeze protection. This fluid is environmentally friendly and non-toxic. During system operation, fluid levels may need to be periodically maintained and adjusted by Eversource.

Why did Eversource choose to explore ground source heat pumps (GSHP) for this pilot rather than air source heat pumps (ASHP)?

While ASHP can help decarbonize heating and cooling loads, their performance in colder weather regions like New England is not the highest on the market. GSHPs have a coefficient of performance (COP) of 4-5 compared to ASHP’s COP of 2-3. Additionally, with the pilot, networked geothermal could perform with a COP of 6, resulting in even more energy savings for customers.

Framingham Pilot

Why is Eversource doing a geothermal pilot project?

We are committed to delivering New England’s vision of a clean energy future. With this pilot, we’ll be testing to determine if networked geothermal systems are a viable option to affordably heat and cool homes and businesses here. If they are, we may be able to help accelerate adoption of clean energy throughout the region.

Experts believe geothermal technology may be required to help transition to a more renewable energy future.

How was the pilot project developed?

The Massachusetts Department of Public Utilities (DPU) approved the pilot project to install and operate a geothermal network in the gas rate case filed in October of 2020. The NSTAR rate case proposal and approval can be found in docket D.P.U. 19-120.

In June 2021, Massachusetts Attorney General Maura Healey asked the DPU to investigate the future of natural gas companies in the state. The attorney general’s office asked utility regulators to explore the potential for alternatives to heat without using fossil fuels (natural gas, fuel oil, propane), including building electrification, energy efficiency, and “geothermal network applications.” This Future of Gas investigation was aligned with our geothermal pilot that had already been approved by the DPU.  

What are the main goals of this pilot?

The pilot project will evaluate interconnecting a neighborhood using geothermal energy as a potential alternative to complement or replace delivered fuels (oil, propane) and natural gas for heating and cooling.

The project aims to collect information about customer satisfaction and the reliability, scalability, effectiveness, feasibility and costs of geothermal networks.

What streets are included on the project route?

The project route is highlighted in green. A customer’s home or business located on a section of a street within the route with the main passing by is eligible to participate in the pilot.


How large is the project?

The loop consists of approximately one mile of main pipe and 90 boreholes serving 36 buildings (five commercial and 24 residential for a total of 125 customer accounts).

The total volume of conditioned space is about 1,778,147 cubic feet. The theoretical ratio of boreholes to cubic feet of conditioned space is 1:15,736 cubic feet. The total planned heating/cooling capacity for the system is 375 tons. 

The data collected during this pilot will be used to help develop these and other quick metrics for evaluating different building types.

How long is the pilot going to run?

The pilot is intended to run through two heating and cooling seasons (24 months from the start-up of the system).

How did Eversource choose the geothermal pilot project location in Framingham?

We were looking for a location with about 100 neighboring residential, commercial and industrial customers in a relatively dense urban environment. A dense cluster of diverse customers provides a range of data and conditions that the pilot is designed to evaluate.

Participants had to be existing Eversource customers that receive delivered fuels (heating oil or propane) or natural gas services.

The pilot project location was additionally selected based on various criteria including:

  • Community willingness
  • Income diversity among customers
  • Geological feasibility
  • Siting concerns
  • Technical feasibility
  • Nearby environmental features that may pose implementation risks

The final stage of the geothermal pilot route selection involved site visits to the potential properties. The visits involved a survey and inspection of the buildings for the existing heating and cooling systems and any complicating factors, such as lead paint, asbestos or electrical load limits. Properties with certain types of existing ductwork that can transport the heated or cooled air efficiently without the need for major modifications may be preferred.

What would make a town or community a good candidate for new geothermal projects in the future?

  • Community support is an extremely important driver to any project undertaken in the public right of way. The willingness of a town or city to work with us on locating borefields, zoning, permitting and working out the details of an installation can make or break a project.
  • Awareness that projects like geothermal system installation will require construction and disruption to roadways and traffic - all the things that go with installing underground infrastructure - but that the end product will bring you electrification, environmental benefit, and hopefully cost benefit, as well.
  • Depth to bedrock: The bedrock is where you get a lot of good heat transfer in a geothermal system. It is also a question of cost; you must run steel casing down to the bedrock. Shallow bedrock is preferred if possible.
  • A deep water table: We need to make sure we aren't going to see significant amounts of water production while we drill. A very shallow or large water table that produces a lot makes drilling very difficult. 
  • Finally, and most importantly, we are looking for a mix of loads; environmental justice communities with a mix of residential and businesses who have a diverse delivered fuel mix.

How were participants selected?

The general neighborhood was selected through the feasibility/site selection process. Home and business owners became eligible to participate in the pilot based on their proximity to the site route we selected. After speaking with one of our geothermal team representatives in their neighborhood, individual customers then signed a letter of interest. These were used to inform the final loop route and customers living directly on the route were able to sign up to participate.

What percentage of eligible homeowners in the Framingham neighborhood decided to participate in the project?

Approximately 80% of the residential homeowners along the route decided to participate in the pilot. We also received letters of interest from homeowners whose homes ultimately ended up being located on our "alternate route."

How were participants engaged by Eversource during each phase of the project?

Getting customers involved was a combination of getting out and speaking face-to-face to customers in the community and providing them with as much material as we could to educate them on the technology, the reason for the pilot and the process of the project as we moved through each stage.

What environmental benefits will this pilot program have?

The main benefit will be the reduction of direct emissions associated with burning natural gas, oil, or propane to heat homes. Geothermal systems do not produce any direct emissions; therefore, the only emissions are from the electricity generation used to power them.

Additional benefits will involve energy use reduction in summer peak demand and improvement of winter grid utilization for customers.

  • Peak demand is the time when electricity usage is highest during summer heat waves when homes and businesses are using air conditioners and other appliances. Use of geothermal heat pumps reduces demand on the electric grid, which controls costs to customers as well as the chance of power outages.
  • Because geothermal heat pumps pull energy from the earth, they are not impacted by large temperature changes during winter months, which means they operate more efficiently and use less electricity compared to other heat pumps.
  • This pilot represents a significant step towards evaluating technologies that help reduce greenhouse gas emissions from natural gas/delivered fuels that may contribute to climate change and global warming.
  • Geothermal energy also contributes to fuel diversity, providing another option for energy generation. Geothermal ground loop systems provide heating and cooling that is not directly dependent on the price of oil or gas.
  • The applicability of geothermal energy to all building types. Geothermal energy may be utilized by all types of structures, including homes, and commercial and industrial buildings.

Have environmental studies been done and submitted to the City of Framingham? Are they available to the public?

Environmental impacts were screened in the initial site selection work. This involved looking at any potential impact to wetlands or other environmentally significant areas within the geothermal network area. We consulted many geothermal studies as background when developing this project, including the Massachusetts Environmental database and wetlands zoning studies. Those will be available on the Framingham public website.

As the project progresses, the appropriate reviews and permits shall be filed with the city and state to ensure that the work is done safely with as little impact on the community as possible.

Will there be any minimum efficiency standards for buildings in the loop?

There is no set minimum percent efficiency for buildings related to the installation of GSHPs, however the equipment has efficiency standards set by the manufacturer. Data from the pilot may be used to establish building efficiency standards for future projects. Each building will also have Mass Save energy efficiency work done to the extent possible in order to maximize efficiency. 

Are design drawings available to the public?

As of right now, the design drawings are not available to the public. There is a lot of customer data that goes into these designs, so we want to be incredibly careful with what we share publicly. Customer data comes first in terms of data security. However, we will be filing regular updates with the D.P.U where we will be providing all the information that we can. Those filings are available to the public. 

We are also working with several researchers and outside firms that may be able to provide anonymous data that may be publicly available.

What criteria will Eversource use at the end of the pilot to determine if the pilot was successful?

Geothermal offerings following the pilot are not confirmed, yet. The pilot will be evaluated on several criteria points so we can best determine if it is feasible to add geothermal to our customer offerings.

We will be evaluating:

  • Cost to install and operate
  • Benefits to customers
  • Customer feedback
  • Emissions reductions
  • Possible billing structures
  • Expandability

What is a microgrid? How does that relate to the thermal network?

The term microgrid refers to an electric system self-contained to a small area. This would include some type of generation, like solar, and potentially backups like battery storage systems. A thermal network could theoretically interface with a microgrid to create a small area that is mostly energy self-sufficient.

Customer Impact

Eversource will pay for the cost of building and installing the geothermal system. 

For their participation in the pilot, customers will receive any and all work associated with the conversion — construction, old equipment removal, new equipment purchasing and installation, duct work and energy efficiency upgrades — at no direct cost to them. We are also committed to converting customers back to their old system or to an air source heat pump should they choose not to keep the geothermal system after the pilot period is complete.

For the duration of the pilot, customers will only be responsible for a very small service fee and their energy usage costs (electric bill) on a budget billing scale, which is a flat monthly rate calculated by averaging their home/business energy usage data over the 24 months leading up to our evaluation. For our low-income participants, the rate is discounted further.

During the pilot, customers will no longer have to pay for any heating costs related to natural gas or delivered fuels. In this way, their total monthly energy cost may be lower than what they paid before the geothermal system was installed in their home or business. Using air conditioning during the summer will impact customers’ electric bills.

Will participating customers be able to regulate the temperature in their homes and businesses?

Yes. Customers have a standard thermostat that they can set to the temperature most comfortable for them. It is important to keep in mind that temperature setting will also affect the amount of electricity used, and therefore their monthly bill.

How do participating customers switch from summer cooling to winter heating?

There is a switch that controls the mode to heating or cooling in the heat pump. They can either change this manually on their thermostat or allow it to control whether they are in cooling or heating mode.

Will customer's hot water be affected?

We don’t intend to touch any hot water systems, gas stoves or gas dryers.

Will customers keep their current equipment or system during the pilot? What is their option for backup heating?

We will be disconnecting each customer’s existing heating systems for this pilot. Each of the heat pumps we plan to install has electric resistance backup integrated. In the event there is an issue with the loop, customers will not go without heat.

Existing natural gas or delivered fuel service in customers’ homes or businesses will be maintained for other appliances and applications such as hot water and clothing dryers.

At the end of the pilot, if we or customers decide not to continue with the geothermal service, we will replace the geothermal system with the same type of heating equipment they had before the pilot.

Will customers have to change out their appliances for this pilot?

No, the geothermal pilot program only addresses central heating and cooling systems. Other appliances will not be impacted.

Because the network is shared, how is usage calculated individually?

While the loop is a shared asset, each building will have its own individual heat pump system to provide heating and cooling. Customer usage can be calculated from the heat pump data as well as by monitoring the geothermal fluid temperatures entering and leaving the building. 

Will the loop flow and temperature to each building be measured?

We are not going to install specific flow and BTU measurement on every home/business on the pilot route. However, part of the third-party analysis will include installation of BTU and flow monitoring equipment for a representative sample of buildings.

We will be able to take those measurements throughout the loop, know what the flow is in the main, and then, if we have enough data points throughout the residential and commercial services, calculate exactly how much energy specific homes and businesses buildings are using.

How can you ensure equitable Entering Water Temperature (EWT) with a one-pipe system? Will different buildings expect slightly different water temperatures?

One of the main reasons we did a lot of alternatives analysis in the design phase was to ensure equitable EWT. 

With a one-pipe system, we can't guarantee that the EWT is exactly the same across the board. But, when we did alternatives analysis, we calculated what that would translate into for efficiency of customer systems, and ultimately cost for the customers, and determined the variance is so small it wouldn't be noticeable to end-use customers.

What is the best way for customers to manage their electric costs?

Electric usage will increase with a geothermal system, but this will be offset by the reduction in gas or oil/propane costs. The best way to manage this is to understand that the bills are directly tied to how much heating or cooling is used and to set the thermostat appropriately. GSHP systems also operate most efficiently when the temperature is set and left alone rather than frequent changes up and down.

If a homeowner is currently cooling their home with window units, the geothermal system will enhance their cooling from individual rooms to the entire house.

We offer a budget billing option that helps keep monthly bills more consistent throughout the year, which avoids large spikes in the coldest or hottest months. Seasonal energy saving tips are also available.

Was the sequence of construction?

Construction involved three parallel stages:

  1. Drill well fields
  2. Install main in the street/install service Ts for individual homes and buildings
  3. Work in customers’ homes.

Each is not dependent on the other, but all three must be complete prior to starting up the network.

The customers' heating systems will remain operational until the geothermal system has been tested and brought online, so there will not be a risk of no heat for any customers.

Is this on new construction?

There is no new construction on this pilot loop, so every one of these buildings will be a retrofit.

What type of disruption should customers expect in their neighborhood during construction and installation?

The installation of the geothermal ground loops, distribution mains and service lines is like other utility installation or replacement. We will dig a trench in the utility right-of-way for the piping to be installed. Once the pipes are in place and tested, we will restore any roads, sidewalks or lawns impacted by the new utility service.

The biggest difference with this pilot will be the installation of the geothermal ground loops (vertical drill holes), which involve a drill rig and support vehicles that may be working nearby. There will be some construction vehicle noise during approved working hours, but it will be managed as reasonably as possible.

If construction requires cutting through private yards, under fences, etc., who will be responsible for restoring the property?

For construction, we will have to dig on private property to install the service lines and may have to dig under fences or other equipment on customers' property. Following installation of the geothermal system, we will restore customers' property to the same or better condition it was in prior to construction.

Will any trees be removed or disturbed during geothermal system installation?

It is possible that some trees will be affected by the installation of this system, including cutting down trees that are in the direct pathway of the distribution piping. However, there will be no widespread cutting of trees in a neighborhood.

The routing of the service pipe connections from the mains in the street to customers’ heating equipment in their homes and businesses will be adjusted wherever possible to avoid damaging or the need to remove trees on customers’ properties.

What long-term visual impacts are expected from installing a geothermal energy system within the community?

The geothermal loop is underground, just like water, sewer and natural gas utilities. The few access points for pumps, valves and heat exchangers will predominantly be located in the roadways or sidewalks and resemble the same covers used for other underground utilities. There will also be a small utility pump house located within the pilot area that will be designed to blend with other nearby structures.

Can you describe the equipment that will be installed in participating homes and businesses?

It varies depending on the building. We evaluated each building to determine what application works best for the type, size and estimated load. We also determined if the building needed an electrical upgrade (for buildings with older electrical panels) and ducting work.

Overall, the customer equipment will look like and be similarly sized to their current heating and cooling unit. There will be a heat pump unit that will look like and be about the size of a furnace or boiler, an air handler, and ducting and vents throughout the building to distribute the hot or cold air produced. The size of the duct work will depend on the size of the building. It is very similar to a central air system, except the geothermal system can both cool and heat.

There are some situations where running ducting isn’t viable or there are rooms far away from the pump equipment. In those cases, there are options like a VRF system that is similar to a mini-split head that can be incorporated into the customer’s system. 

Outside of the home or business, there will be buried pipes called main lines installed under the streets and additional pipes called service lines to each individual home or business.

Before we make any changes during the pilot conversion process, we will perform all applicable energy efficiency work to make sure every building is insulated and air-sealed for the best geothermal system performance.

Who is responsible for maintenance? Do customers have a choice of who maintains their equipment?

We will perform the maintenance of the geothermal equipment for the duration of the pilot project. Once the project is finished, the equipment maintenance will be the responsibility of the property owner.

What does regular maintenance on the customer equipment look like? What is the expected cost?

The regular maintenance on customer equipment will consist of regular filter changes. For the duration of the pilot, the cost of this maintenance and any repairs needed will be covered by Eversource.

What warranties come with the equipment and who follows up on warranty claims?

The equipment will have a manufacturer's warranty as well as one provided by the installation contractor. These will be handled by Eversource during the pilot period. If the system is turned over to the customer after the pilot, it would then be their responsibility to follow up.

What equipment operation instructions/ training is offered?

Standard operating instructions will be provided by the installation contractor. The equipment will function the same way as the customer's current heating/cooling equipment.

If something goes wrong after the pilot is completed, who do customers call to service their equipment?

The equipment can be serviced by most HVAC contractors, similar to a central air or forced air heating system.

If Eversource decides not to continue to operate the system after the pilot, (either themselves or through a third party), is Eversource going to remove all the equipment they installed?

We will restore customers' home or property in line with the termination option elected. If customers elect to go back to their original heating source, that will mean removal of all installed equipment (excluding things like ducting/venting or weatherization work).

If the pipes last 50 years, who is responsible for the cost when they need to be replaced?

The system, including the pipes, will be owned and operated by Eversource. We are responsible for the pipes and replacing them if needed.

We estimate the pipes will last 50 years. We will be using HDPE plastic pipes, the same type we use for natural gas. Currently, many in use are older than 50 years.

Do you currently have plans to expand the pilot within the Framingham community or beyond the city?

We are excited to explore any and all expansion opportunities. The data that we gather from this initial pilot in Framingham will help us determine operational performance, customer adoption, energy savings and energy costs for the customer. That data will help us determine where and when we can expand. 

In April 2023, Eversource, as part of a larger team with Home Energy Efficiency Team (HEET) and the City of Framingham, was selected for the U.S. Department of Energy’s Community Geothermal grant. We will use our $715,000 award to explore the feasibility of expanding our demonstration pilot in Framingham.

Additionally, our gas company operates in both Massachusetts and Connecticut. Right now, the Connecticut Department of Energy and Environmental Protection (CT DEEP) is developing its comprehensive energy strategy and we are hopeful geothermal will be included in some of the policy strategy moving forward as an electrification option. 

Do you currently have initiatives planned to support individual building retrofits to geothermal heat pumps?

Individual retrofits and private geothermal systems are great in some applications. There are some robust federal and state incentives available (Inflation Reduction Act tax credits and MassSave incentives) that customers can explore. 

Would Eversource consider working with other local gas distribution companies (ex: Berkshire Gas) to establish similar geothermal networks?

We have received outreach from utility companies both in New England and across the nation regarding our networked geothermal work in Framingham. We have already started trading information and trying to get folks up to speed on what we are doing in that community.  

Are there other technologies Eversource is considering to decarbonize gas customers in addition to networked geothermal? 

We have outlined a number of technologies and pathways in our Massachusetts Future of Gas docket. These are currently being evaluated to determine the most effective pathway to a decarbonized future for our customers.

System and Technical Specifics

Was there a minimum number of customers who had to sign up for Eversource to install or continue to operate the system?

There was not a specific number of customers needed for the pilot. The filing with the DPU targeted a 300-ton system, so we planned with that target in mind.

When you determined the load, did you factor in that more people are working from home than in years prior to the pandemic?

Yes, we took into account a large number of people working from home in the modeling. An engineering firm that specializes in calculating thermal usage helped us design the system. We also looked at past utility usage of all the buildings on the pilot route, including usage during 2020. 

How large will the networked system be?

The project route consists of 140 customers: 37 buildings, 5 non-residential and 32 residential buildings.

How many wells will be drilled on the system?

There will be 90 boreholes for 37 buildings. The system was designed based on participation and will be just large enough to accommodate the route. 

What is the depth of the pipe in the street?

5 - 7 feet, deeper than traditional gas main, which is at 3 feet. 

Is this a closed-loop design?

Yes, it is a closed loop design. It is the same concept as a baseboard system in a home.

What is the liquid being used in the system made of? How is the liquid pumped?

The geothermal system will contain a 20%, environmentally friendly propylene glycol additive to prevent freezing and biological buildup. The glycol element lowers the freezing point and ensures the system performs even in the coldest New England winters.

Pumps with variable frequency drives (VFDs) are used to circulate the fluid in a continuous loop through the system, which includes through the borefields. 

How big will the pumphouse be? Where will it be located?

The above ground pumphouse will be approximately the size of a 60-foot container with circulating pumps, instrumentation, etc. We will have back-up heating and cooling in case we need to increase or decrease the temperature on the loop from the central pumphouse.

The pump house will be located somewhere near the central bore field in the Farley Lot on Normandy Road.

Are isolation valves located on private property?

We will position the valves at the sidewalk, by the edge of each property and as close to the main as possible for safety. Exact locations will depend on the facilities in the area and where locating a valve is feasible.

How are loop connections made to the main?

Loop connections are very similar to standard water or gas connections.

There is a "saddle T" connection (a U-shaped piece of plastic that sits on top of the main) that will tap a hole down through the main and then connect the service line so that it can flow down to the customer's heat exchanger and then back to the loop on a second one.

Why not just put stubs/Ts in?

When we install the main, we can put service Ts to every house and business at that time, but it would be an added expense. Because the design is dependent on participation, we might not be able to add a customer after the design is finalized, even if a T is in place on the main.

Is there a blend of cooling dominant loads and heating dominant loads?

Yes, the system will have a diverse set of loads which include both heating and cooling dominant loads.

Is there an analysis of the amount of heat transfer of the horizontal vs. vertical portions of the loop?

The horizontal pipe transfer was taken into account in the thermal modeling of the system. This is one of the factors that was considered in the alternatives analysis to choose the bury depth of the mains

Pump-wise, will the top of the system be more efficient than the bottom of the route?

If we only had wells at the top of the system, there would be a significant temperature drift. To prevent that, we will install satellite fields throughout the route that will help keep the temperature more stable. Wells are located along the route to ensure that the system will be equally efficient at any point on the route.

If a pipe is damaged, does the whole system go down?

It depends on where the damage takes place. Hits typically happen on service lines located on a customer’s private property, so we would be able to isolate the individual service line. It would not affect the whole system. This is similar to how we respond to hits on our natural gas service lines. If a main line hit occurs, the severity will determine if a repair can be made without shutting down the system.

How likely is it that the electric resistance backup will be needed?

We are hoping that it is not needed at all, but there are circumstances we can't control. For example, if a third party digs into our system and we have to temporarily stop the flow to make a repair. Barring a circumstance like that, the overall loop is being designed in such a way that we shouldn't need the backup even on the coldest day of the year.

If the backup is ever engaged, would it just engage for the building requiring it, or for the whole system?

The boiler backup would be for the whole loop. Additionally, each GSHP has to have built-in heating backup for the building where they are installed.

Will the entire system be installed in the public right-of-way (ROW)?

All the mains and services for the networked loop are being run in the public ROW – very similar to how a gas, water or electrical conduit would be run.

For the bore fields, we evaluated potentially putting them in the ROW. There may be a few that will end up located in a public ROW, but for the most part, those will be on private property. Some challenges there would include traffic management and the time it would take to drill in public ROW. In this case, we have very convenient areas and support from the city to locate those bore fields underneath parking lots. We determined that was the best solution for this project.

Tax Credits, Energy Efficiency Benefits, ASHP and Permits

Will the installation of geothermal systems require any permitting or review processes?

We applied for all the necessary environmental, planning and zoning, traffic management and right-of- way permits needed to install the networked geothermal system.

What documents did customers have to sign to permit Eversource to install the system on their property?

Customers were required to sign the customer agreement prior to participating in the pilot. This is a similar document to what would be signed in order to receive natural gas service.

Are customers entitled to any beneficial tax credits, tax treatment, or energy efficiency benefits either when they sign up, or in the case where they take over the system after the pilot concludes? How will they be implemented?

There are energy efficiency credits that will potentially be used to offset the cost of both weatherization and installation in homes and businesses.

Participating homes and businesses will be eligible for weatherization work to improve energy efficiency. This will be done as part of the installation work.

Longer term, the main benefits will be lower energy consumption and the value of the installed equipment.

Can a home with air-source heat pumps (ASHP) be retrofitted to work with a future geothermal loop system?

As of right now, retrofitting ASHPs to work with future geothermal loop systems is challenging in most cases. However, there are new products in development that will be changeable and will very likely be an option in a year or two for homeowners hoping to run on ASHPs until they have a geothermal line.

How do customer costs for loop heat pump installation compare to individual ASHPs?

Although the upfront costs of equipment and installation of ASHP are lower than loop ground source heat pumps (GSHP), ultimately GSHPs offer significantly more savings related to decreased operating costs and longevity of equipment.