The winter of 2010 paralyzed Europe’s air traffic system. Snow and ice piled up around terminals and closed runways for days. At its peak, 9,500 passengers were stranded in London’s Heathrow airport after a heavy snowfall on December 18. The flights backed up until Christmas, as 4,000 canceled flights had to be rescheduled. It was the third year in a row that snow and ice shut down one of the world’s busiest airports.
One obvious response has been to invest more in clearing equipment and deicing chemicals such as urea and glycol. But another tactic has caught airports’ attention: building heated runways and aircraft parking stands.
Since then, Heathrow has been exploring a proposal to install a heating system that will keep its runways or parking stands warm and ice-free year round. And airports in America have recently started work on similar projects. The energy requirements to keep a space of ground as big as a runway hot enough to melt ice seem enormous. The genius part of this proposal is that almost all of it comes free and clean courtesy of the sun — and even heating smaller areas can make big difference if parked planes are blocked by snow.
Called inter-seasonal heat transfer, the heating system uses a network of fluid-filled pipes laid under the pavement to collect heat during the summer months, when runways may reach 122 degrees during the day. These pipes transfer the energy to subterranean "thermal banks" where the ground insulates stored heat. During the long winter, the summer’s solar energy can be tapped by using heat pumps to bring warm fluids back to the surface. Even the heat produced by an airport’s air conditioning system, rather than venting to the atmosphere, can be piped into underground storage adding still more heat to the system.
The concept has been around since the 1970s, but it has never gained traction. Cost-conscious airports had an easy solution in deicing chemicals and snowplows. But a string of violent winters, and growing concern about dumping deicing chemicals into the environment, has made inter-seasonal heat transfer increasingly attractive relative to investing in yet more heavy equipment and deicing capacity.
Given that U.K. airlines alone lost more than $50 million during the disastrous winter of 2010, the cost of installing the system (estimated at less than $8 million by ICAX, a company that builds them) seems small. In the U.S., the FAA just awarded its first grant to test a small inter-seasonal heating system at the Greater Binghamton Airport in New York, to be built this year.
But not everyone is on board. U.S. airports wary about the costs are urging the FAA to clarify that it is not an economical application for entire runways, and the agency itself remains skeptical, according to Jane’s Airport Review (PDF): "We can say there is technology available that works" says the FAA. "The problem is whether it is cost effective when you’re talking about clearing a 10,000-foot runway."