Preventing heat waste has largely been ignored as a solution. A new report by the global engineering company Danfoss highlights the potential of excess heat recovery.
“The global energy crisis is a wakeup call to stop wasting energy,” said Toby Morgan, senior manager of built environment at the Climate Group, an environmental not-for-profit. He adds that “we need to make better use of the energy we already produce, we simply can’t afford to let it literally escape out the window. Energy efficiency improvements, like capturing and recycling excess heat, are absolutely critical to lower fossil fuel demand and lower bills.”
Various sources, including supermarkets, transportation networks, data centres and commercial buildings, emit excess heat. Much of this can be harnessed and utilised through existing heat recovery technologies like heat pumps, as well as more efficient air conditioning systems and manufacturing machinery. Further opportunities lie in improved urban planning and district energy systems that rely on networks of renewable energy sources.
The research is led by Brian Vad Mathiesen, a professor in energy planning and renewable energy systems at Aalborg University. According to Vad Mathiesen: “The amount of cities, regions and countries in Europe which waste heat while spending billions on natural gas or electric heating is mind-blowing,” and he warns that Europe’s energy security is at stake.
“Take the Netherlands – there is virtually no district heating even though there is almost twice the amount of waste heat compared to the heat demand. Denmark is the same size but has towards 60% per cent district heating with only one third of the population. The use of waste heat is certainly not connected to technical differences. While the physical laws are the same, the political will and traditions are very different.”
The report highlights the excess heat potential of cities in the EU. On average, 78.8% of the excess heat from these cities could be recovered from their top three sites alone. In Brussels, the top three sites provide 1.3 TWh out of a possible 1.5 TWh. Kim Fausing, CEO of Danfoss stated that the emissions savings and revenue from selling this heat would be significant and that “in Greater London, we have identified at least 648 eligible excess heat sources, including data centres, underground stations, supermarkets, wastewater treatment plants and food production facilities. Why aren’t businesses and local government organisations using these?” Fausing adds that London’s excess heat equated to 9.5 TWh a year, roughly enough to heat 790,000 households.
Reusing excess heat offers incredible opportunities for businesses to reduce their emissions, save money and make money. To rapidly tackle the energy crisis, Vad Mathiesen proposes a heat planning directive that enables local authorities to base their plans on local conditions. This would involve mapping existing waste heat sources in greater detail, then proposing thermal networks that distribute heat more effectively and initiatives that improve energy efficiency in buildings. Energy efficiency improvements are climate-critical and the time for action is now.
Emilia Samuelsson
based on
Report by Danfoss. (2023). The world’s largest untapped energy source: Excess heat. https://www.whyenergyefficiency.com/solutions/allsolutions
and Recapturing excess heat could power most of Europe, say experts, Anna Turns, The Guardian, https://www.theguardian.com/environment/2023/feb/23/recapturing-excess-h... 3924=3424
