One year ago, Pittsburgh International Airport became the first airport in the nation to get all of its power from a solar and natural gas microgrid. Today, it’s got 1 million extra dollars to show for it.
In an interview with Microgrid Knowledge last week, Tom Woodrow, the airport’s senior vice president for engineering and intelligent infrastructure, explained how the airport achieved the savings.
“I don’t know if it was luck or skill or both,” Woodrow said.
It began when the Pennsylvania airport decided to install five natural gas generators and 9,360 virtually net-metered solar panels to create a 23-MW microgrid, which it accomplished in July 2021.
The microgrid is part of a larger sustainability effort by the airport that includes employing alternative fuel strategies, repopulating the honeybee population and striving for LEED Silver Certification in its terminal modernization program.
“We are looking at using any and all materials in our new terminal that come out of, for example, ripping up the ramp and crushing the concrete — that will be the base layer of our roadway system,” said Christina Cassotis, CEO of Pittsburgh International Airport.
The airport also found use for a closed landfill, installing the solar panels on it.
Its efforts on the energy side have cut carbon dioxide emissions by about 8.2 million pounds per year, half of what they would be otherwise.
But it is the $1 million in energy savings, achieved in its first year of operation, that is most eye popping.
Microgrids can achieve cost savings in various ways, among them load management, participation in demand response and ancillary services and price hedging against grid or fuel prices.
For the airport, the key to its economic success is a 20-year energy service agreement with Peoples Gas and a fortuitous decision about the future price of natural gas.
When the world was still normal
The airport began contract negotiations with Peoples in 2019 when the “world was still normal,” as Woodrow put it. Natural gas prices were low, but unbeknownst to Woodrow — and the rest of the world — they were about to skyrocket. A combination of forces, among them COVID-19 and war in the Ukraine, would spike gas prices to levels not seen in a decade.
Natural gas makes up 30% of the cost of each kilowatt-hour the airport uses, so it made sense to lock in at the low price for five years, he said, and avoid the worry of constantly monitoring market changes. After the first five years, the energy services agreement with Peoples allows for a modest annual increase.
“We got a great, great price on gas,” Woodrow said. “We’re locked in for five years without any rate increases whatsoever. I know exactly what we’re going to pay for a kilowatt-hour for the first five years.”
Had the airport not locked in prices, “We likely would have seen rate increases of at least 15% or 20% according to our consultant,” he said.
The $1 million savings estimate is conservative, he added. “I am very, very comfortable with that, and it’s probably higher than that.”
While the microgrid is grid connected, the airport generally takes all of its energy from the microgrid and exports excess energy to the grid.
The microgrid overgenerates as a matter of course to ensure that the aiport has enough power for its people mover trains, Woodrow explained. Every time the trains start, they cause a two to three megawatt surge in demand. To meet the demand, and avoid importing grid electricity, the microgrid overgenerates continuously, he said.
Solar panels separate
The solar panels do not play into the microgrid savings because they operate under a separate financial arrangement, a virtual net-metering agreement with about 20 tenants on the airport perimeter, including a 911 call center. Woodrow hopes to expand the solar field as more tenants become interested in subscribing.
“We are really proud of the microgrid and we see this just as one example of the work we are doing in sustainability,” said Cassotis. “It’s really led to a reconsideration by the industry of what’s possible. We all need aviation and a lot of us want it to be more sustainable, so we want to be at the forefront of making that happen and we are doing it right here.”
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