Dr. David Connolly:

The old city is perfect. The old city is where we would be bringing the biggest benefit. One of the biggest benefits which I should have flagged earlier is that when a building is connected to district heating, heat can typically be supplied at 70°C or 80°C which means we do not need building fabric upgrades to get a 70% or 80% upgrade in the carbon emissions footprint. That does not stop anybody who will be connecting to district heating in, say, 2027 from upgrading their windows. That would mean they would buy less heat, in the same way that using LED instead of incandescent light bulbs reduces consumption. It means we would not have to have all the building retrofits done before doing anything, which is often a major hindrance, especially in city centre locations. City centre locations are incredibly difficult projects, but many people in the industry are interested and willing to do them. They are ideal places for district heating to start because heat density is highest there.

Going back to the Deputy's point about waste heat, with district heating we have to apply a time horizon to every answer. For some projects, getting access to waste heat will happen on day one but for others it may be in year ten. I would be astonished if most of our major cities were not connected to some kind of waste heat stream at some point in that time horizon. I would not expect all of them to have it on day one. I would expect most of them to get there in ten or 15 years, after a network is developed. The flip thing then happens. When industries see there is a district heating network, they start to locate nearby. I was in a sulphuric acid plant once and the manager said that if it was not for the district heating network in that city, they would be in China. That is the benefit they had by being there.