The use of excess heat could save the EU up to nearly €70 billion a year and cut energy use by 30 million barrels of oil and 650 billion cubic metres of natural gas.
- Using excess heat to replace fuel demand is an easy and efficient approach to improving efficiency and could save €67.4 billion in the EU alone.
- One-third of energy emissions reduction can come from efficiency, yet few policies target increasing it effectively.
- Excess heat in the EU alone amounts to 2,860 TWh per year, corresponding almost to the EU’s total energy demand for heat and hot water in residential and service sector buildings.
A Danfoss whitepaper, The world’s largest untapped energy source: Excess heat, assessed the potential of excess heat as an efficient energy source. According to the International Energy Agency (IEA), a global push for more efficient use of energy can reduce CO2 emissions by an additional 5 gigatons per year by 2030 compared with current policy settings. A third of the reduction needed in energy-related CO2 emissions this decade, according to the IEA net zero scenario, must come from improvements in energy efficiency.
Danfoss president and chief executive Kim Fausing said that it is remarkable that the EU has “close to no initiatives that push for more efficient use of the vast amounts of wasted energy in the form of excess heat.”
The whitepaper from Danfoss, the Danish family-controlled engineering group, highlighted how the more efficient use of such heat would give a productivity boost to the economy, lower energy prices for consumers and businesses and accelerate the green transition.
Using excess heat could transform the energy system
In the EU alone, excess heat amounts to 2,860 TWh per year, corresponding almost to the EU’s total energy demand for heat and hot water in residential and service sector buildings such as schools, hospitals, hotels, restaurants, offices and shopping centres.
Full implementation of technologies that tap into synergies between different sectors and enable utilisation of excess heat has the potential to save €67.4 billion a year once fully implemented in 2050.
Every time an engine runs, it generates heat. Anyone who has felt the warmth behind their fridge can confirm this. The same is true on a larger scale in supermarkets, data centres, factories, wastewater facilities, metro stations and commercial buildings. Excess heat can be reused to supply a factory with heat and warm water or reused by neighbouring homes and industries through a district energy system.
Using this energy that would otherwise go to waste can give a productivity boost to the economy and lower energy prices for consumers.
Excess heat use could help stabilise the grid
Moreover, the use of excess heat can replace significant amounts of fossil fuels that are otherwise needed to produce heat. Used this way, excess heat can help stabilise the future electricity grid by helping to manage demand, and thereby ease the transition to a green energy system.
In some countries, the excess heat can even match the entire heat demand. In the Netherlands, for example, excess heat amounts to 156 TWh per year while the heat demand is only 152 TWh per year. Yet the potential of excess heat is not being explored and is politically ignored.
According to Fausing, recycling heat is not only an overlooked measure in the current energy crisis, but also the next frontier of the green transition.
He said: “The potential for using excess heat in the UK is extraordinary. The UK already has 456 data centres, more than China; if these were put to use to support heating across the country, the cost and emissions savings would be highly significant. For example, in London alone, there are 652 eligible excess heat sources, including data centres, underground stations, supermarkets, wastewater treatment plants, and food production facilities. The excess heat from these sources adds up to 9.5 TWh per year, roughly the amount of heat required to heat 790,000 households.
What makes this particularly challenging is that the technologies for the efficient use of excess heat are widely used and relatively easy to deploy.
Fausing added: “We urgently need policy measures to accelerate the use of excess heat across sectors, both so that citizens and businesses can benefit from lower energy costs and to ensure we step up progress in the green transition. What are we waiting for? This solution would benefit the UK, and many other countries, in relatively quick time.”
Reusing excess heat is energy efficiency in its purest form
In terms of energy security, these energy savings can help avoid almost 30 million barrels of oil per day and 650 billion cubic meters of natural gas per year, which is around four times what the EU imported from Russia in 2021.
“The potential in reusing excess heat is staggering. But we need to change our perspective on it and begin to consider excess heat as an energy resource instead of waste to be disposed of,” adds Kim Fausing.
There are a number of barriers to the efficient use of excess heat that the report identifies. These include a lack of information and regulation. Fausing argued that economic incentives, policy measures and prioritization of partnerships between local authorities, energy suppliers and energy sources are needed, in order to help maximise the full potential of excess heat.
Toby Morgan, senior manager, built environment at Climate Group, added: “The global energy crisis is a wakeup call to stop wasting energy, and Danfoss is right to call for governments and corporates to seize the enormous potential of excess heat. Now more than ever 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.”