Heat Waste: ‘World’s Largest Untapped Energy Source’
Capturing and reusing waste heat could be the next “breakthrough” in Europe’s energy security and competitiveness - helping sever its reliance on gas - and saving a fortune.
A new report from Danish engineering firm Danfoss found that two-thirds of global energy was wasted as heat in 2024. This means that "we are throwing away energy that we have already paid for." They say that waste heat from facilities such as supermarkets, factories, wastewater treatment plants and data centres are the world’s “largest untapped” energy source. However, governments are lagging when it comes to unlocking its potential.
Waste heat is the excess warmth given off by everyday processes, such as a supermarket running its refrigerators. Instead of letting this escape into the air, it can be captured and re-used by existing tried and tested technology.
Natural gas provides roughly 17 percent of the EU's total electricity generation, but gas is the dominant source of energy for EU households, powering around one third of residential consumption, with roughly 40 percent of homes connected directly to a gas network. As of 2026, Russia accounts for about 18 percent of the European Union's total natural gas supply (including both pipeline gas and liquefied natural gas), down sharply from about 45 percent before Putin's "special military operation" in Ukraine. So, like oil, there are energy security issues at play here, as well as cutting emissions.
The analysis by Danfoss states that reusing waste heat could save Europe a staggering €140 billion a year, based on the vast amount that was dumped in 2024. To put that into perspective, the researchers estimate that Europe’s waste heat alone could power the entire city of Paris for 48 years.
The report argues that to make the most out of waste heat, industry must make heat recovery “standard practice”. Energy operators also need to make connections easier while governments need to remove the barriers that make electricity more expensive than gas for these investments. “Get those pieces in place and waste heat stops being waste. It becomes a source of cheaper energy, greater resilience and stronger competitiveness.”
