ReDevelopment Traditional and Emerging Energy Innovation

Largest Single Sloped Solar Array in the U.S. Completed atop Pittsburgh’s Mill 19

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$5 million project part of sustainability vision at 178-acre Hazelwood Green site 

August 12, 2020 — The last of 4,784 silicon solar panels that will power Mill 19 at Pittsburgh’s Hazelwood Green site have been placed, marking the completion of the largest single sloped solar array in the United States. The $5 million project, completed by Scalo Solar Solutions, comprises a massive scale, covering 133,000 square feet across the frame of Mill 19.  The project is made possible by the Richard King Mellon Foundation and the other foundations that comprise Almono LP, the owners of the Hazelwood Green site. 

The panels were installed using an innovative access platform netting material, aptly called the Spider WorkWeb, and attaching it to the Mill’s existing steel structure in a manner taut enough for the installers to walk on.  Each of these LG solar panels were preassembled and tested on the ground, then lifted and fitted into place.  The slope of the roof is 20 degrees, a great angle to capture the majority of the sun’s rays.  This array will generate over 2 megawatts of power and produce enough energy to power 264 homes annually. 

The over quarter-mile long Mill 19 structure includes the steel skeleton of the original mill building, formerly built by the Jones & Laughlin Steel Company in 1943.  The tenants of this site include Carnegie Mellon University’s Advanced Robotics for Manufacturing (ARM) and Manufacturing Futures Initiative, and Catalyst Connection in Building A. Building B houses Aptiv, which recently entered into a joint venture with Hyundai to create autonomous or ‘self-driving’ vehicles.  

A former brownfield site, Hazelwood Green is envisioned as a model of sustainable development. Mill 19 has been designed with the goal of achieving LEED v4 Gold certification, with a high-performance envelope providing maximum thermal efficiency and up to 96% daylight autonomy. 100% of the complex’s total electricity usage will be offset by energy generated on site and storm water will be conveyed through a rainwater garden to centrally located infiltration basins. Captured rooftop rainwater will be reused in the cooling tower and for flushing in the restrooms. 


Media Contacts:  Laura Ellis, Veritas Communications Advisors  

412.952.7844 /  

Jesse Ament, Scalo Solar Solutions 

Direct: 412.458.3801 /Mobile: 412.266.5142 / 


Editor’s Note: Log on to for emerging stories detailing Pittsburgh’s ongoing environmental transformation, as well as connections to Pittsburgh’s green instigators, expert sources, and video and photography assets. Pittsburgh Green Story is a collaborative and growing partnership of organizations who are champions of Pittsburgh’s legacy, and its current, and future green story; its purpose is to share Pittsburgh’s green stories with reporters and editors. is a project managed by the Green Building Alliance and funded by the Richard King Mellon Foundation. 

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