Solar microgrid keeps flights on time at Pittsburgh International Airport

More than 8 million people took a flight from Pittsburgh International Airport in 2022, but they likely didn’t know the airport’s terminals, shops, restaurants, trams and other facilities are all operating on a separate electrical grid powered by a solar array and natural gas-fueled generators.

PIT is the first airport in the country to use a dedicated microgrid. Its development was motivated by an 11-hour blackout at Hartsfield-Jackson Atlanta International Airport in Atlanta in 2018, which called into question the energy resiliency of airports across the country.

PIT has nonstop flights to 125 locations and on average saw more than 20,000 passengers a day in December 2022. A delay in operations could be logistically and economically catastrophic.

Today, PIT is powered by this dedicated solar + generator microgrid, but the airport and project developers had to lay new runways for energy resilience in the aviation industry for it to happen.

Clear for construction

Despite an immediate desire to build energy resilience into the airport, it was several years after initial discussions that this microgrid project was permitted for construction. That permitting process lasted through the early COVID-19 pandemic and the several months that Pennsylvania designated solar construction as non-essential work.

Peoples Gas, a multi-state gas utility, was hired to develop the microgrid project and worked with IMG Energy Solutions, EIS Solar and Hanlon Electric Company to bring the project to fruition. They were finally granted permission to start construction on January 1, 2021.

“We started construction literally 48 hours later — we were ready to go,” said Tom Woodrow, senior VP of engineering and intelligent infrastructure for the Allegheny County Airport Authority, the municipal authority that manages PIT. “Those guys built that thing during the height of the pandemic from January and were online and flipped the switch the second week of July.”

An unusually dry Pennsylvania winter allowed installers to work through that typically tough season. The total microgrid is 20 MW, with solar contributing 3 MW. The array was installed on the southern edge of the airport’s property that borders Interstate 376 — on a hillside site originally used as a landfill for construction debris from when the airport was rebuilt 30 years ago.

“Part of our sustainability aspect of this project is we were able to build a renewable energy facility on top of land that is otherwise unable to be developed,” Woodrow said.

Another first for this microgrid endeavor was the Pennsylvania Department of Environmental Protection (DEP) had never permitted a solar project on a landfill. Woodrow said the DEP has since used its experience with the PIT solar landfill array as a touchstone for similar projects.

Foundations on the solar array are a combination of driven piles and concrete ballasts. The airport’s landfill isn’t capped like those containing organic waste, so installers could make ground penetrations without risk of contamination.

“Because it’s a landfill, occasionally you’re going to hit something,” said Mike Brady, CEO of IMG Energy Solutions. “Some of the ballasts near the edge of the landfill cap, we didn’t have enough depth there that we felt that it was safe to drive a post, because if they do sink it could compromise the bottom of the landfill.”

Given that the landscape is on both a hill and a landfill, solar installers used skid steers and smaller models of pile-driving machines to minimize surface impact on the site.

The solar array uses 9,360 VSUN 390-W bifacial panels, RBI Solar (now Terrasmart) racking and Sungrow SG125HV string inverters. Installers poured a concrete foundation and hung the inverters on support beams under a covered wooden roof to protect them from the elements.

An apiary of several beehives is also located across the road from the solar array, so developers planted native vegetation on the site to assist the pollinator habitat.

Sustainable flight path

PIT signed a 20-year energy service agreement with Peoples to pay for the energy produced by the microgrid, and IMG owns and handles maintenance of the solar project. In almost two years, the airport has already saved more than $1 million on energy costs by using the microgrid.

The solar portion of PIT’s microgrid supplies about 5% of its total energy output, with the natural gas generators handling the rest. The airport set aside 20 acres for solar, but the 3-MW array only covers eight due to earlier regulatory limits on solar array sizes. However, there are already plans in the works to expand the facility with new approval from PJM.

In the meantime, PIT is building a new terminal that will pursue LEED certifications with considerations for reducing waste, water, emissions and energy production. And perhaps there will be some more solar for Pittsburgh International Airport in the future.

For now, the airport has more than one reason to hope for clear skies.

“I think that any piece of land that doesn’t have another use or any rooftop that doesn’t have anything on it should be covered with solar panels because it reduces the amount of power that we have to place on power plants and infrastructure,” Brady said. “As we look to electrify everything, if that’s truly where we’re going, you’re going to have to find solutions like this, where you’re building on available land and in a fuel-free type of energy supply.”