Energy makes up all we do, it is transferred from place to place, gradually losing its ability to do useful work. However, there are many people researching how to increase energy efficiency and reclaim it.
This article looks to explore that and add a little something different into the world of reclaimed heat.
I am a huge Shania Twain fan, which is where this article started. The thought occurred to me when watching Shania Twain at the O2 Arena. It was very warm inside the arena, due to the number of people, the lighting, and the sound equipment. The aircon was blasting away to cool the venue, and I couldn’t help wondering why AC had been chosen instead of using reclaimed heat technology and ambient loops?
What are ambient loops?
An ambient loop can be defined as a ‘heat sharing network’. It is a low-temperature network that connects multiple buildings or properties. By operating close to ambient temperature, it reduces heat losses, lowers insulation requirements, and can enable smaller pipework compared with conventional heat networks.
How much heat could Taylor Swift generate?
Although to me Shania Twain is the ultimate megastar, I am aware that some concerts are much larger, and this brings us to Taylor Swift…
The Eras tour is the highest-grossing tour of all time, beating records previously held by Elton John; and it is the second most attended tour in history. Taylor Swift’s Eras tour spanned 5 continents in two years with 149 shows undertaken
Taylor Swift’s concert in London took place in the Wembley Arena (for the following calculations we assume a roof has been built).
- Wembley Arena Capacity: 90,000
- Concert Length: 3 hours 15 minutes
How much heat does a person generate when dancing?
For energetic dancing, a metabolic rate of around 3–4 MET may be assumed (ISO 7730), corresponding to approximately 300–400 W of heat per person. Taking a mid-range value of 350 W per person, a crowd of 90,000 people over a 3.25-hour event would generate around 100 MWh of heat.
This represents a theoretical estimate and, in reality, the figure is best interpreted as an indication of the magnitude of occupant heat gains rather than a recoverable energy source.
In addition to metabolic heat, a concert has significant electrical energy consumption associated with lighting, sound equipment and general site operations. Portland Fuel[1] estimates that approximately 10 MWh of electricity is used per Eras Tour show. In accordance with the principle of energy conservation, this electrical input ultimately appears as internal heat gains within or around the venue.
Where could this heat go?
The population of London is 8.945 million (GLA, 2025). Taylor Swift’s London shows could meet 77,000/71,560,000 = 0.11% of London’s DHW demand for one day.
What about Ambient Loops?
Although it is interesting to calculate the number of people the concerts could supply with DHW, the bigger picture is ambient loops.
This low-grade energy could be fed into a heat network which would minimise the uplift required for a heat pump to meet the high-grade heat needed in homes and commercial properties. Ambient heat networks are designed to accept intermittent, low-grade heat.
The key part here being that intermittent, ambient loops are well-suited for utilising heat from sporadic events such as concerts. Reducing the lift required for a heat pump significantly improves efficiency, reduces losses, and lowers electrical demand5.
It is also important to note that ambient loops are not the whole solution to waste heat, but they are part of the solution. Ambient loops can reduce building carbon emissions by 13% and energy demand by 40% 5.
So Long, London…
For now, Taylor Swift won’t be back any time soon. It was estimated that Taylor Swift’s UK shows generated £1bn for the country’s economy.
However, it’s not just Taylor Swift’s concerts that generate heat; they all do. Next time you dance, wonder how many homes that boogying could power…
About the author:
Sophie Sibley is principal engineer at Synergie Environ
References:
- Portland Fuel. (2024). Oil Market Report – 08/24 – Portland Fuel. [online] Available at: https://portland-fuel.com/en/market-reports/oil-market-report-08-24/ (Accessed: 29th October 2025)
- ASHRAE (2020). Chapter 26, Air-to-Air Energy Recovery. Available at: https://www.ashrae.org/file%20library/technical%20resources/covid-19/si_s20_ch26.pdf (Accessed: 29th October 2025)
- DESNZ – Department for Energy Security and Net Zero (2024) Domestic hot-water use: observations on hot-water use from connected devices. London: Crown Copyright. Available at: https://assets.publishing.service.gov.uk/media/65f43b919d99de001d03df8a/domestic-hot-water-use-insights.pdf (Accessed: 29th October 2025).
- Brent Council (2025). History of Wembley and Tokyngton. [online] Available at: https://www.brent.gov.uk/libraries-arts-and-heritage/brent-museum-and-archives/your-local-area/history-of-wembley-and-tokyngton (Accessed: 29th October 2025)
- Gillich, A., Godefroy, J., Ford, A., Hewitt, M. and L’Hostis, J. (2022). Performance analysis for the UK’s first 5th generation heat network – The BEN case study at LSBU. Energy, 243, p.122843. doi:https://doi.org/10.1016/j.energy.2021.122843.