Recovering wasted heat in EU could cover bloc’s hot water & heating needs, report says

The wasted heat from buildings in the European Union would be nearly enough to meet the bloc’s whole energy demands for central heating and hot water, according to a new report by Danish engineering giant Danfoss.

At a time when the continent is experiencing a severe energy crisis – in part sparked by Russia’s invasion of Ukraine – the paper calculates that excess heat in the bloc amounts to 2,860 TWh per year. If harnessed, it could help avoid the use of almost 30 million barrels of oil per day (corresponding to three times Russia’s average production during 2021) and 650 billion cubic metres of natural gas per year (four times what the EU imported from Russia in 2021).

It also says that heat recovery technology that can capture excess heat already exists, including from some of the biggest emitters, like industrial factories, wastewater facilities, data centres, supermarkets, underground stations and commercial buildings.

The effectiveness of this heat capturing can vary depending on distance though, according to Adrian Joyce, Secretary General of the European Alliance of Companies for Energy Efficiency in Buildings (EuroACE).

“One of the key factors about what’s actually recoverable is the geographical location of that excess heat, if you like, production unit, and where it can then be used for secondary use, like in a district heating system [a heating network covering a specific area],” he told Euronews.

“So, when the proximity, geographical proximity is short and I think in district heating terms that’s a couple of kilometres, then the technologies are not, to my understanding, overly expensive and can be quite readily put into place.

“The question, of course is, is the market there for the secondary use or can that recovered heat displace, for example, fossil burning in a district heating system, which would be a really good thing because you’re getting a double win then?”

Potential €67 billion in savings

The report comes as the EU rolls out measures, through its European Green Deal legislation, to become the first carbon-neutral continent by 2050.

Part of this includes the renovation of buildings to make them more energy-efficient.

Danfoss argues that capturing all of the EU’s wasted heat would help achieve this goal more easily, saving €67 billion in the process.

Currently, Brussels requires member states to prepare national heat maps, which identify where there are concentrations of excess heat, which can then be recovered.

However, there is no EU-wide legislation in place mandating companies or building owners to recapture the heat that is lost in these areas.

Joyce told Euronews that even if the idea of mandatory heat capturing is not yet being considered, it may not be such a bad plan.

“Mandatory capture of excess heat is not something I’ve considered…but my policy person’s hat says, yes, it’s a good idea to have regulations in place, so that when there is recoverable heat, it is readily recoverable and there are not any obstacles, regulatory or bureaucratic obstacles to that and it would be recovered for beneficial use elsewhere,” he said.

The report by Danfoss found that the amount of London’s heat waste came to 9.5 TWh per year, which would heat 790,000 homes in the city. Its top three top heat-generating sites alone produce 4.8 TWh per year.

For Brussels, the excess heat calculated came to 1.5 TWh per year, with its main three sites wasting 1.3 TWh per year.