A historic building in Denver is boasting a dual milestone in intelligent building design and renewable energy development. The 1940s-era Hangar 2 building, a former U.S. Air Force base and training center at the heart of the Denver’s Lowry neighborhood, is now host to Denver’s first community-owned solar garden and becomes the nation’s largest building integrated PV (BIPV) installation on a historic landmark. The 400 kW Denver/Lowry Solar Array, developed by community solar pioneer Clean Energy Collective (CEC), was built into the curved roof of Denver’s iconic Hangar 2 building, which now serves as a mixed-use/self-storage project. The utility-scale solar PV array was integrated with an existing 106 kW array, initially fashioned to replicate the appearance of the hangar’s original skylights, to partially offset the building’s electricity demand. The Hangar 2 building was the first structure built at Lowry Air Force Base in 1939 and sits right in the middle of the Lowry neighborhood. It has a special place in Denver’s history, so finding a way to repurpose the building to be productive and where the community could actually use it seemed like the right solution. Designed by architect and CEC Vice President of Strategic Development Jim Hartman, the project met the strict requirements of Denver’s Landmark Preservation Commission by ensuring the 1,638 solar panels would closely resemble the industrial-looking existing metal roof of the historic structure. In most light conditions and from typical public vantage points, the solar panels reflect the sky and are a grey color similar to the metal roof. The panel layout integrates with the existing segmented roof layout and details so that the panels provide as monolithic an appearance as possible.“We’ve turned this drafty old hanger into a symbol of Denver’s innovation in renewable energy and commitment to sustainable design,” said Hartman. “It’s now a solar-powered, energy-efficient landmark.”The Lowry Hangar 2 building is 100,000 square feet and the community solar array crowns one of the largest attics in the world. Installing the large solar array on the steep roof contour required crews to use rock-climbing safety gear and rappel down to reach the array’s lower sections. A similar challenge was the renovation permitting and approval process, requiring consent from eight different community groups and governmental agencies.One of 11 community-scale PV facilities CEC is building as part of Xcel Energy’s Solar Rewards Communities program, the Denver/Lowry Solar Array will serve 150 to 200 Xcel Energy customers in Denver County interested owning locally-made clean energy production but can’t or prefer not to install a system on site. Customers in the shared-array receive all of the same tax credits and incentives as home-sited systems, and are similarly credited directly on their utility bill.In addition to the community solar installation, this historic building uses 50 percent less energy than a new building of the same size through the execution of extensive energy efficiency strategies like super-insulation, day-lighting, natural ventilation, motion-controlled lighting, sophisticated HVAC systems, etc.Combining the cultural significance with energy efficiency and sustainability has garnered many awards for the project, including the 2013 community preservation award and the 2011 Mayor’s design award spurred by the first solar retrofit. A key part of the renovation financing was a $2 million grant from the Denver Urban Renewal Authority. Hangar 2 is a community project on many different levels. In addition to the community solar array that serves residents throughout Denver, it houses a Montessori school, fitness studios, a coffee shop, a Beer Garden, four full-service restaurants, community offices, the Lowry Recycling Center and a state-of-the-art storage facility that you can drive a truck into for loading/unloading out of the weather. Martifer Solar USA served as EPC for the development and E Light Electric managed installation.