The solar panels are visible from the air — as is another airport venture, farming. Tenant farmers pay the Denver airport $18 an acre, to plant wheat, corn, millet and sunflowers on 16,000 (of 34,000) acres of airport land.
The airport also drills for oil and gas. There are 71 wells on the property, which produce 18,000 barrels of oil and 400,000 cubic feet of natural gas per year (or enough natural gas to serve 5,333 Colorado households for a year, according to the Natural Gas Supply Association). The city of Denver recently audited the wells and found nearly 30 percent are losing money. The airport agreed with the auditor’s findings and said it was considering changes.
Dallas-Fort Worth airport has also experimented with drilling. The airport said it earned about $2.4 million in natural gas royalties last year.
Active drilling for new wells at the airport stopped in 2009, when the price of natural gas dropped. Beginning in late October 2008, however, the United States Geological Survey recorded the first of more than 175 earthquakes in the area, the largest with a magnitude of 4. Previously no earthquakes had been recorded.
They were traced to wastewater wells, used for the disposal of fluids associated with oil and gas operations. “It’s plausible the fluids migrated onto an old fault,” said Brian Stump, a professor of earth science at Southern Methodist University and co-author of a continuing seismicity study. The earthquakes are still occurring, although they are further apart and smaller in size, Mr. Stump said.
The experience in Dallas hasn’t deterred Pittsburgh International Airport from initiating hydraulic fracturing, better known as fracking. The airport lost passengers and revenue as US Airways began reducing its operations there in 2004. Now merged with American Airlines, it stopped flying there in 2015.
The airport began producing natural gas in 2016. Consol Energy, based in Canonsburg, Pa., 18 miles southwest of Pittsburgh, paid $46 million dollars before the first well was drilled. CNX Resources Corporation, which spun off Consol Energy last year and currently holds the airport development lease, estimates that the airport will receive about $450 million in royalties over the course of the project. CNX expects to invest $500 million over the 50-year life of the project.
These new businesses come with an inherent risk. “As airport operators continue to get into nontraditional lines of business, oversight will be needed to make sure the tenants are doing what they are supposed to be doing,” Mr. Harteveldt said.