Across both the Olympic and Paralympic Games, the events produced 4.5m tonnes of emissions – roughly equivalent to one-and-a-half-times Fiji’s total emissions in 2022. About 10% was attributed to operations, 16% to venue construction, 19% to infrastructure construction, and 55% to spectators.
The figures, highlighted today (23 October) by a new IMechE report, illustrate the scale of the sports sector’s contribution to climate change. The industry is responsible for approximately 350m tonnes of carbon equivalent emissions each year – about 1% of global emissions.
“Engineering better sports venues: Designing for athletes, spectators and the environment” explores the role of engineers in developing sustainable and inclusive sports venues, with a particular focus on the large stadiums used for elite sport.
“Sports venues are often thought of as being the preserve of the civil engineer,” said report author Ruth Shilston to Professional Engineering, “but there is a huge amount of mechanical engineering that goes into any building, and in particular sports venues – and more so now that we have so much focus on sustainability and low energy.”
Solar cells and recycled urine
Emissions reductions should be considered “from day one” when building or refurbishing stadiums, said the technical director from engineering consultancy Mott MacDonald, where she works on the design of sports venues.
Considerations include being as efficient as possible with materials such as concrete and steel, introduction of low-energy and passive cooling, and inclusion of renewable energy technology, said the IMechE trustee.
This could include installation of solar cells, as announced today for West Ham’s London Stadium, originally built for the 2012 Games. Cleantech firm Ameresco will install ultra-thin panels, light enough for the stadium’s ‘membrane’ roof, with projected annual generation of 0.85m kWh.
Other sustainable features for venues could include green roofs and rainwater harvesting, said Shilston, which can help provide some of the huge daily water requirement – equivalent to 625 bath tubs – of professional football pitches.
National League club Forest Green Rovers went one further with a space-mission inspired urine recycling system, which reuses treated fan urine to maintain the pitch by converting it into clean water and fertiliser. “It reduces their water use, it’s certainly innovative,” said Shilston.
Known as the world’s first carbon-neutral football club, Forest Green also plans to build the world's first timber stadium, designed by Zaha Hadid Architects. The project will include on-site solar generation. Other innovations include an all-vegan food menu and kits made of recycled coffee and plastic.
Flexible design
Venue operators can also reduce their overall impact on the environment by hosting more frequent, diversified events, said Shilston – including other sports, concerts, or conferences – thereby maximising the use of the embodied carbon and preventing the need for more venues.
Mechanical engineers have a key role to play in this aspect, installing systems that allow partial use of venues without wasting energy. “We should never dismiss the role of the architect in any design. But it's also the role of the engineer to ensure that we're designing the building with all that flexibility in mind,” she said.
“When you want to turn on the heating for the building, for example, you have separate controls for separate parts of the building, the same with the lighting design. It's making sure that you're really designing in the ability to switch things on and off depending on what you want to use.”
There are major stadiums in the UK where the entire building needs to be turned on for a meeting in one room, she added – hardly an efficient use of energy.
The report, which was also authored by Dr Anna Coppel, associate director at Arup, and IMechE's Kahu Te Kani and Dr Laura Kent, calls for more consideration of hybrid, temporary and portable venues. Stadiums built for large events such as the Olympics and the football World Cup are not always fully utilised after the events, due to a lack of regular demand. Temporary venues can instead be built and dismantled – and even transported, said Shilston. “You can almost imagine in the future we could have an Olympic venue that follows the Olympics around.”
Temporary venues are also well-suited to growing clubs and sports, she added, facilitating an increase in crowd size before being replaced with permanent structures after several years.
Turning down the heat
Cutting emissions and boosting sustainability is only becoming more important as the world gets warmer. “Climate change is now something that we have to design into everything we're doing, be that heat or be that flooding,” said Shilston. “As engineers, we have a real responsibility to help the client understand – ‘This is a flood risk, this is the mitigation you can put in place, here is a heat risk.’”
Events such as the Qatar World Cup have shown the reality of holding elite sports events in extreme conditions. Although the tournament took place in winter, stadiums were built with summer temperatures of over 50ºC in mind, placing strict requirements on player and spectator comfort.
Stadium cooling and ventilation was provided by passive and active shading, insulation, mechanical cooling, and contouring the stadium to control air flow. Water mist cooled spectators as they entered the arena, while cool air from chillers and air handling systems controlled temperatures in the terraces. Players on the pitch also benefitted from the chilled air from the grandstands and air jets positioned at ground level.
“You can't play elite sport in a hot and humid environment, the human body can't do it. And we're asking players to push themselves the limit,” said Shilston.
Such intensive efforts also have a significant climate impact, however. “I don't want to air condition the outside world as an engineer, because it's not responsible. But I can advise a client on that risk, I can do the climate change modelling, I can do the thermal comfort modelling.”
Thermal comfort could even become a major issue in the UK, where many of the big sports events happen in summer. Distributed sensors around venues should play an important role in monitoring temperature, humidity, carbon dioxide levels and more, Shilston said, as well as player-worn sensors.
Level playing field
The positive impact of sports on society is plain to see. Participants benefit from exercise and social contact, and millions of fans enjoy the spectacle of seeing their teams compete each week. But could the venues themselves ever have a net positive impact on the environment – or is it always going to be a case of mitigation?
“I think it is a possibility, but it's going to be a challenge,” said Shilston. “Most of my clients will say: ‘What's the innovative solution to fix this? What's the new material? What's the new product?’
“The best sustainability is really boring. It is about having reusable cups, it's about reducing solar gain into the building, it's about how we use the design before we throw tonnes of technology at trying to solve the problem.
“So the best and most sustainable buildings are really simple. They have their on site renewables, they have higher biodiversity, which is something actually the government's starting to push a lot more… they're designed simply and flexibly.”
The report also calls for greater transparency of net-zero efforts, new funding schemes for sustainability and accessibility, and more inclusive stadium design, using a systems engineering approach to improve accessibility and navigation.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.