Solar and Passive House:
Multiple Solutions
2Life Communities - JJ Carroll House | Brighton, MA
About the Customer
J.J. Carroll House is 2Life Communities’ first certified Passive House building, the largest multifamily Passive House building in Massachusetts and in the top 10 in the United States and Canada. Core elements include an airtight building envelope, high-quality windows and doors, solar energy, and high-performing ventilation systems to improve indoor air quality and comfort. Passive House is the highest standard for energy efficiency, using the building envelope to better retain warm air in the winter and cool air in the summer.
Customer Situation
Originally built in 1966 and operated by the Boston Housing Authority (BHA), JJ Carroll Apartments was a 64-unit federal public housing development on Chestnut Hill Avenue in Brighton that served seniors and persons with disabilities. Over time, the buildings became obsolete with systems that were expensive to maintain and lacking accessibility features.
In May 2019, BHA issued a Request for Proposals for the redevelopment of the JJ Carroll development. BHA designated 2Life Communities, a nonprofit senior affordable housing developer, owner, and property manager with properties across eastern Massachusetts, as the developer. 2Life Communities worked with JJ Carroll residents and BHA on a plan to replace the site with new, energy-efficient and accessible buildings housing 142 new, modern, energy-efficient apartment homes. Because 2Life already owned and operated 763-apartment senior housing directly adjacent to the property, the new JJ Carroll was able to be fully integrated into the 2Life Brighton campus.
Given the Passive House Institute US (PHIUS) compliance goal and interest in pushing the envelope in sustainability, as well as other expectations that were set with the funders and a strong interest in substantially lowering the development’s electric bills, solar was always a key consideration for this new construction project. However, finances were a key barrier, and 2Life sought a no-cost solution.
As a leading provider of solar, Resonant works with a variety of key players in the market, and through its relationships with the Massachusetts Association of Community Development Corporations (MACDC) and Local Initiatives Support Corporation (LISC) in the STAR Program, Resonant was introduced to 2Life Communities and the JJ Carroll development.
2Life had been exploring options to meet the construction requirement for solar at the building. They had previously been discussing installing a solar PV system to be owned by the building, but the cost of owning the system was out of budget for the total development. Resonant presented a creative no-cost Power Purchase Agreement (PPA) option, which was the ideal opportunity to give the project the financial and clean energy benefits of solar (to meet the Passive House requirements) without an impact on the constrained development budget. 2Life then made the decision to move forward with Resonant Energy for the solar implementation.
Resonant Solution
Resonant Energy carefully reviewed 2Life’s requirements for JJ Carroll House and developed a recommended solution, consisting of:
156.17 kW DC rooftop system made up of 322 PV modules (solar panels)
Expected production of 183,258 kWh/year, offsetting 80.9 tons of CO2 annually
PPA with Sunwealth, providing a 50% discount on a portion of JJ Carroll House’s energy needs, with a locked-in 1% annual increase
Extensive coordination with the general contractor on-site throughout the construction process
All of the necessary steps to meet the property insurer’s rigorous insurance requirements
The system was installed and fully operational by the project deadline.
Results
The grand opening of the new solar-equipped JJ Carroll House was celebrated in March 2024, by Boston Mayor Michelle Wu, Massachusetts Senator Elizabeth Warren, Representative Ayanna Pressley, Lieutenant Governor Kim Driscoll, and Boston City Council President Ruthzee Loujeune, among other dignitaries from the Massachusetts Executive Office of Housing and Livable Communities, Massachusetts Executive Office of Health and Human Services, U.S. Department of Housing and Urban Development, and MassHousing.
While the total electric use at this all-electric master metered site is larger than the solar output possible in a rooftop of this size, the cost savings are still very significant:
In 2025, the 50% discount on a portion of JJ Carroll House’s electricity generated expected savings of $23,071.
Because the PPA rate is locked into a 1% annual increase at a time when Eversource’s rates have been increasing 3-5% annually, the discount will continue to increase over time.
Resonant Energy expects this initiative to lead to JJ Carroll House saving over $620,000 in energy costs over 25 years.
Note: Given new financing options available since this project, most new construction projects are now favoring direct ownership, which can often fit into the overall construction costs, rather than PPAs. Resonant will, of course, fully explore all available options with any new construction developers, as well as with existing buildings.
“A project of this scope involves tremendous complexity, especially given the Passive House goals we were committed to achieving. Solar brought huge opportunity, but it was potentially cost-prohibitive. Resonant Energy came to the table with a no-cost PPA option, and we were able to move forward and achieve all of the benefits of the solar array. Resonant rose to the challenge, becoming a trusted partner with strong ongoing communication and coordination throughout the J.J. Carroll project, which now continues with other projects in the 2Life portfolio.”
Zoe Weinrobe
Chief of Real Estate