125 Broad Street – New York, NY

Central Utility Plant Transformation for a Class A Mixed-Use Property

125 Broad Street, a 1.45 million square-foot Class A mixed-use building in Manhattan’s Financial District and global headquarters of Sullivan & Cromwell LLP, required a resilient onsite energy solution to address both grid reliability concerns and New York City’s Local Law 97 (LL97) carbon reduction mandates.

Unison Energy transformed the property’s energy infrastructure into a fully integrated onsite central utility plant, under a long-term Energy-as-a-Service (EaaS) agreement, enabling the property to achieve emissions reductions, improve resilience, and stabilize long-term energy costs—without upfront capital investment.

Client Goals: Ensure resilient, compliant, and cost-stable energy for a critical commercial asset.

• Onsite CHP system supplies approximately 55% of the building’s annual electric load
• Integrated system designed to deliver 100% of building cooling demand through absorption and electric chillers
• CHP system captures and utilizes waste heat to provide approximately 62% of the building’s thermal (hot water) load
• Estimated 30%+ reduction in annual carbon emissions
• Delivers ~37% annual savings in avoided Local Law 97 penalties (based on NYC Building Energy Exchange modeling; subject to legislative updates)
• Enables island-mode operation, maintaining power, heating, and cooling during grid outages
• Long-term Energy-as-a-Service agreement provides predictable energy pricing with no upfront capital investment
• Monetization of Federal Investment Tax Credits enhances project economics
• Supports 24/7/365 high-reliability operations with continuous monitoring and predictive maintenance

Integrated Power, Heating, and Cooling Delivered Onsite

Project Details:

In 2025, Unison Energy acquired and assumed full ownership and operation of the onsite energy system at 125 Broad Street, transitioning the building to a comprehensive Energy-as-a-Service model.

The system functions as a central utility plant, delivering electricity, heating, and cooling from a single integrated platform. At its core, the CHP system generates electricity while capturing waste heat to produce hot water and drive absorption-based cooling. This is complemented by high-efficiency electric chillers, together meeting 100% of the building’s cooling demand. The system is fully integrated with new 480V switchboards, enabling seamless interconnection with the building’s existing electrical infrastructure.

This configuration replaces an outdated district chilled water loop and significantly improves overall system efficiency. By producing energy onsite and utilizing recovered thermal energy, the system reduces dependence on grid electricity while lowering emissions intensity.

Resilience is a central component of the design. With island-mode capability and load-following performance, the system can continue to provide power, heating, and cooling during utility disruptions – an essential particularly valuable in Lower Manhattan, where major outage events such as Superstorm Sandy demonstrated the importance of resilient onsite energy.

The project also helps the building comply with New York City’s Local Law 97. Based on NYC Building Energy Exchange modeling, the system is expected to reduce emissions sufficiently to avoid substantial penalties, delivering meaningful annual cost savings.

Financially, the project provides immediate and long-term value to ownership. Through Unison’s Energy-as-a-Service ownership model, Federal Investment Tax Credits were monetized as part of the acquisition, and the long-term ESA structure eliminates the need for upfront capital while providing predictable energy pricing over time.

The system is also designed with future flexibility in mind, including compatibility with evolving lower-carbon fuels and potential integration with carbon capture technologies, ensuring a pathway for continued emissions reduction.

“125 Broad Street’s partnership with Unison represents a major step forward in future-proofing our building’s infrastructure with a resilient power source. The efficiency gains and reliability of the energy system, coupled with fixed-priced electricity, heating, and cooling under Unison’s ESA, provide much-needed stability in the face of increasingly volatile power markets in the Northeast.” Rob Schlein, Partner at Sullivan & Cromwell LLP