Roof of Former Steel Mill Outfitted Entirely With Solar Panels

By Lauren White, RCS Reporter.

Mill 19 becomes the new home to tech and manufacturing companies, powered by solar.

A 1,500-foot long, 110-foot wide, 10” bar steel, former mill site, occupying 12.5 acres in Pittsburgh, Pennsylvania is getting converted into a technology and manufacturing facility.  With thousands of solar panels covering the entire roof, this is one of the largest solar installments in the United States.  

Mill 19, one of two original buildings from the Jones and Laughlin steel mill, was built around 1943.  Situated along the Monongahela River, the mill used to manufacture 10” bar steel. This state-of-the-art facility will serve as the anchor of the 178-acre industrial park located at Hazelwood Green.  The first of three buildings will be constructed inside the skeleton of the J&L mill building. 

Now, Mill 19 will be home to companies focusing on artificial intelligence, automation, robotics, and other manufacturing innovations.  Companies include: Aptiv PLC, the Advanced Robotics for Manufacturing Institute, Catalyst Connection and the Manufacturing Futures Initiative of Carnegie Mellon University.  There will also be a rotating group of outside partners that will work in the three-story building.

“The building is owned by the Regional Industrial Development Corporation (RIDC). The Richard King Mellon Foundation provided a gift of $20 million for construction costs,” Next Pittsburgh reported.  RIDC is “a private, not-for-profit organization that catalyzes and supports economic growth through real estate development and the financing of projects that advance the public interest,” according to PGFTech Fuse.  They are developing the property with Scalo Solar Solutions, the designer and builder of this project.  

This “building within a building” will serve as an example of how solar can work for commercial use.  The solar panels are being installed on top of the original steel skeleton that once served as the roof for the steel mill.  “We are very fortunate that the existing mill structure had almost a perfect orientation for solar, so it’s very well suited for this application and we’ll also end up having, we believe, the largest rooftop solar installation in all of Pennsylvania,” Don Smith, the President of RIDC, told KDKA CBS Pittsburgh.

Each solar panel is approximately six feet long and three feet wide and are individually fabricated.  These panels are then “attached to rails in three-by-three arrangements. That larger singular unit is then hoisted more than seven stories into the sky for permanent installation on the roof,” KDKA CBS Pittsburgh reported.  Instead of using scaffolding, workers are using nets for safety while they install the solar panels, according to the Pittsburgh Business Times.  

“This solar array will produce an energy offset equivalent to 773 tons of coal every year, which is enough to power 169 homes every year for 25 years,” Michael Carnahan, Scalo Solar Solutions General Manager, told PGTech Fuse.  The solar array consists of 110,000-square-feet of solar panels which will produce more than two million kilowatt hours (kWh) per year, making it “one of the largest single-surface, sloped roof solar arrays in the country,” PGTech Fuse reported.  

There’s a lot to look at with this superstructure.  One design element was to leave the trusses and columns of the original building exposed.  That way tenants and visitors will be able to appreciate and gawk at the magnitude of the former steel mill.  “The solar panels look nice above and below, which adds to the aesthetic,” Mike Carnahan from Scalo Solar Solutions told Pittsburgh Business Times.  The building team also utilized mill artifacts and converted “...I-beams into swings and [used] sections of the mill’s concrete floor as part of the landscape, which includes a south porch with seating made from steel beams and concrete salvaged from the original building,” reported PGFTech Fuse.

Going forward, Mill 19 will serve the academic community.  Students will be able to work directly with professional engineers from the government and private sector.  “We wanted to make this different— a special place where we can attract more students,” Professor Gary Fedder, faculty director of the Manufacturing Futures Initiative, told Next Pittsburgh.  Professor Fedder would like to see multiple interdisciplinary teams working together in the building.

“Mill 19 is not just a symbol of Pittsburgh’s prosperous industrial past...It is also a symbol of our present and future economy.  The rooftop solar array is a part of an eco-friendly and sustainable design that is a hallmark of our city’s environmental and economic renaissance,” RIDC President Donald Smith shared in his interview with PGTech Fuse.

Mill 19 is getting put to good use while also maintaining the aesthetics and the history of the former steel mill.  By covering the entire roof in solar panels, the building meets LEED Gold standards and shows what is possible with commercial properties and solar.  Students have an opportunity to work with professionals and gather data in real time, gaining exposure to the world of tech and manufacturing. The redesign and repurposing of Mill 19 is helping create jobs, develop the land of the industrial park, and make Pittsburgh more environmentally friendly and sustainable. 

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Photo By Jesse Ament/Scalo Solar