Parking Office to 95% decarbonize with largest City-owned solar array and more – final 5% to come over time

SOMERVILLE—The aging gas-fired boilers and cooling system at the City of Somerville Parking Office building will soon make way for new, green solutions including solar and heat pumps, making it the first city-owned building to essentially decarbonize. The project will not only deliver energy cost savings and advance the community’s climate goals but will also give city staff experience operating and maintaining the kind of electrified building systems envisioned for all of the City’s buildings in time.

“Our buildings make up the largest portion of the City’s fossil fuel use and decarbonizing these structures is a monumental undertaking — but you don’t wait for the perfect moment or try to do it all at once,” said Mayor Jake Wilson. “You take the next right step. Our Parking building is running on ancient boilers and a leaking cooling system. Soon it will be powered by 95% clean energy and can serve as a model for what comes next. That’s how this City turns challenges into steady steps forward. This is us walking the walk on climate action.”

The building on Holland Street in West Somerville is a prime target for sustainable upgrades. The structure is currently served by three gas-fired boilers and a traditional rooftop cooling unit. The boiler plant is beginning to fail, with numerous piping leaks, and the boilers are beyond their useful life. But the building is also unique among City-owned buildings: it already has electrical service from the utility capable of handling the added electrical load of an electric HVAC system.

To decarbonize the building, three projects are planned for this summer (2026) including a new 67 kilowatt DC rooftop solar array that will be the largest City-owned solar installation (larger leased arrays exist on the East Somerville Community School and the High School). The gas-fired boilers and old rooftop unit will also be replaced with a new heat pump air handler and basement heat pump units for heating and cooling. Finally, weatherization and improvements to the building’s exterior aim to improve staff comfort in the basement work areas, where the City’s street signs and parking meters are maintained.

Combined, the three projects will bring the building to approximately 95% decarbonized. The final 5% will be achieved when the current relatively new gas-fired hot water heater (similar to those found in residential homes) reaches the end of its useful life and is replaced with an electric-powered unit.

As the charts farther below detail, the three projects are expected to collectively produce more than $18,000 per year in energy cost savings. Total reductions in fossil fuel use are also projected to equal the total energy use of eight Massachusetts homes or the gas consumption of 38 passenger vehicles.

The upgrades are funded by the city’s Energy Stabilization Fund. The fund sets aside money for projects that reduce carbon emissions and energy costs for City operations. This project is a prime example of how the fund can effectively be used to work toward the community’s Climate Forward municipal decarbonization goals. Learn more about Climate Forward at somervillema.gov/climateforward.

Annual Energy and Cost Savings from Decarbonizing the Traffic and Parking Building

Gas Savings in Therms
Electrical Savings in KWh
Gas Savings in Dollars
Electrical Savings in Dollars
Totaled Projected Annual Savings
6,422
32,932
$10,468
$8,365
$18,833
*Based on current utility costs at 133 Holland $0.254/kwh and $1.63/therm

The projects interact to produce annual Green House Emissions Savings in the following ways:
Project
Gas Savings and Green House Gas savings
Electric Savings and Green House Gas savings
Total Project Green House Gas Impact
Boiler to Heat Pump Work
6,230 therms
73,069 lbs
-49,329 kwh
-27,682 lbs
About 5 MA homes total energy use
Weatherization Work
192 therms
2,252 lbs
75 kwh
42 lbs
About 1/4 of a MA passenger vehicle’s annual energy use
Solar Arry Installation
N/A
82,186 kwh
46,120 lbs
About 3 MA homes total energy use
All Projects Collectively
6,422 therms
75,321 lbs
32,932 kwh
18,480 lbs
8 Homes or 38 Passenger Vehicles total use
*Using Massachusetts Leading By Example GHG Emissions Calculator https://www.mass.gov/doc/lbe-conversions-and-ghg-emissions-calculator/download

For more information and updates on Somerville’s progress on decarbonization visit the Climate Forward dashboard at http://www.somervillema.gov/climatedashboard. Sign up for the SustainaVille newsletter at somervillema.gov/subscribe to stay up to date on all of OSE’s decarbonization efforts and sustainability initiatives.