A Fire Plunged Heathrow Into Darkness. A Nearby Data Center Kept Humming. Why?

A gleaming new data center sits less than half a mile from the electric substation where a fire plunged Heathrow Airport into darkness last week. The data center’s own power was also cut that day. But no one who relied on it would have noticed, thanks to a bank of batteries and backup generators designed to kick in instantly.

Meanwhile it took officials at Europe’s busiest airport close to 18 hours to bring its terminals and runways back into operation, causing global travel delays and underscoring the vulnerability of Britain’s infrastructure.

It is a striking contrast that energy experts say can be explained largely by one word: Money.

“The data center industry is relatively young. They are more attuned to the cost of a catastrophic failure,” said Simon Gallagher, the managing director at UK Networks Services, which advises clients on the resilience of their electricity networks. He said most of the world’s airports — including Heathrow — have not been willing to make the big investments necessary to build total backup systems.

Even at an airport the size of Heathrow, which officials have described as equivalent in power use to a small city, it is possible to create backup systems robust enough to maintain normal operations during a catastrophic power failure, Mr. Gallagher and other engineering experts said.

But it could cost as much as $100 million and would likely take years to put in place. So far, most airports have chosen not to make the investment.

“It comes down to a cost-benefit analysis,” Mr. Gallagher said. “At the minute, there seems to be an assumption that it would cost too much.”