Designing a net zero building for all day, every day of the year
How do you design a net zero public safety facility that never shuts down?
Recent Perspectives
The Hennepin County Sheriff’s Office Public Safety Headquarters
Hennepin County, Minnesota, needed a new headquarters for its Sheriff’s Office Public Services Division, which serves nearly 1.3 million people. The county leadership didn’t want a basic headquarters — they needed an energy efficient, wellness-forward space for sheriff’s deputies to train, perform administrative tasks and meet with the public.
The result: A daylight-filled facility designed with both security and wellness in mind, that’s designed to meet net zero energy use even while operating 24/7, 365 days a year. Sustainability features include an array of photovoltaic panels over the garage, a green roof over the office portion, a groundwater-based geothermal heat recovery chiller system, chilled beam HVAC system and storm water reuse system.
The previous headquarters, located in Brooklyn Park, was cramped and unsuitable for a modern law enforcement department, and in fact it was intended to be a temporary home.
On a site centrally located to support all of Hennepin County, this new building allows deputies quick access to respond to emergencies in all corners of the county. The new facility supports the sheriff’s department with modern spaces that include an armory, SWAT team, K-9 accommodations and storage for over 115 vehicles.
Darcy geothermal well: using new technologies and tested strategies to design to net zero
This project uses the innovative Darcy well geothermal system to dramatically reduce environmental impact while maintaining operational efficiency.
Minnesota’s geological conditions enabled the design team to leverage this innovative geothermal system, which reduces the quantity of borehole wells from approximately 150 traditional vertical geothermal wells down to just 2 Darcy wells, significantly reducing the impact on the site and the amount of materials in the system. This revolutionary reduction in drilling requirements demonstrates how advanced geothermal technology can be adapted to work more efficiently with local geological and climatic conditions, making sustainable energy solutions more feasible for large-scale public safety facilities.
The Darcy system is integrated with other high-performance mechanical systems including chilled beams and energy recovery ventilators in key areas to maximize both improved air quality and energy reduction throughout the facility.
The system represents a critical component of the facility’s sustainability strategy, working in conjunction with the 858 kW photovoltaic array and other green infrastructure elements to create Minnesota’s first mission-critical facility designed to achieve net zero energy usage while supporting continuous law enforcement operations.
A focus on wellness
The design takes advantage of the site to create a wellness-infused space for officers to decompress.
A key wellness feature is the integration of natural materials and views to nearby Parkers Lake, fostering connections to nature that support mental and emotional wellbeing. The facility maximizes access to daylight and outdoor connections in a secure manner, recognizing that connections to nature serve as a means of improving employee wellbeing, especially during times of high stress. This biophilic design approach helps reduce stress levels and creates a calming environment for staff.
The facility also includes dedicated spaces for decompression and interaction, creating environments where officers can “feel safe” and have the space for sound thinking and continued service. These areas are specifically designed to provide moments of distance and separation from the gravity of daily tasks, allowing officers to decompress after difficult cases or long shifts. The design philosophy acknowledges that even the most highly trained officers require spaces to bond together, celebrate case closures, or share information informally.
Hennepin County held a ceremonial ribbon-cutting for its new Public Safety Services Headquarters in Plymouth in May 2025, and the building is fully operational.