Originally Posted by
paperwastage
good/high-heat dryers need to be vented, so you cant just stick it anywhere
I assume all parts of the airport need to be ventilated, but sure it would add to the requirements.
usually they would be gas-powered too (quicker than electric)
That's only true if electricity service is limited in some way such as having old household wiring. An airport presumably has much higher current service available -- if they have enough to start a 777 jet engine they can probably run a clothes dryer. Whether that's cost effective depends on the relative cost of power in the area so... probably not happening in Heathrow any time soon. Though as long as people are willing to pay enough to cover the cost of electricity it could still work, and there are plenty of places where electricity prices are not significantly higher than gas.
(incidentally the automated machines I linked to before are fully electric and require 16kW of power for two washers and industrial size dryer. In the case of Heathrow I imagine the bigger problem is the wonky plumbing in T5 rather than the power or ventilation)