Making Indoor Rinks Sustainable

At RinkWatch, we focus on monitoring how climate conditions affect outdoor skating rinks. At the same time, we’re aware that a lot of people skate, play hockey, and go curling on indoor rinks. As with other buildings, indoor skating rinks have their own environmental challenges, especially through energy use and waste generation. Here are a few ways in which indoor skating rinks can be made more sustainable.

In Canada and the USA, commercial and residential buildings produce an estimated 13% of all greenhouse gas emissions. The biggest part of these emissions result from energy used for winter heating and summer cooling, and from electricity needed to operate the building, such as lighting and elevators. The actual amount of energy consumed by an indoor skating rink – and the amount of greenhouse gases emitted – depend on the size of the facility, its construction, its geographical location, and the nature of the electrical generation system in the jurisdiction. For example, a small, modern rink facility with good insulation, efficient HVAC systems, and LED lighting will typically consume less energy than an older facility that lacks these energy efficient systems. An indoor skating rink in a warm climate may require more energy for air conditioning and dehumidification than a comparable rink in a cooler climate, and in a cold climate energy will be needed to heat the interior of the building. And in any climate, energy will be needed to run the chillers that create the ice surface and power the ice resurfacing equipment.

The extent to which the energy used to operate an indoor ice rink will result in greenhouse gas emissions depends significantly on how electricity is generated in that region. In Quebec, for example, most electricity is produced through hydroelectric generation, which has low greenhouse gas emissions. The electricity used in the operation of indoor rinks there will consequently result in much lower greenhouse gas emissions than in a jurisdiction where electricity is generated by burning coal or natural gas.

There are many opportunities to lower the energy consumption of indoor facilities, especially older ones. These can include installing better insulation of walls and ceiling, upgrading HVAC equipment, and replacing older lighting systems with LED. The large, gently sloping roofs of arenas and indoor ice facilities can also serve as platforms for solar panel installations. There is a 300kW fixed rooftop generation system consisting of 1,147 solar panels on the roof of the arena in the town of Wellesley, Ontario, just a short drive from RinkWatch offices at Wilfrid Laurier University. The NHL’s Seattle Kraken play in an arena with 1,300 solar panels that generate 440,000 kwh annually.

As with all recreational facilities, the users of indoor skating rinks and arenas can generate significant amounts of solid waste. There are many opportunities for reducing the amount of waste produced on site and for diverting waste from landfills through recycling and composting programs. Easy ways of reducing waste include providing clean water bottle refilling stations, and using compostable cups, plates and utensils for food and drinks sold at concessions. Providing clearly labeled receptacles for compostable items and recycling stations for cans, bottles, and other non-compostable materials is also important.

When planning where to build new indoor rinks and other recreational facilities, local governments should look for locations that are easily accessed by public transportation, which helps reduce the amount of greenhouse gas emissions produced by people driving to the facility.

In recent years, ice resurfacing equipment has been electrified, creating opportunities to eliminate the use of internal combustion vehicles for this purpose. This not only reduces fossil fuel use, it also eliminates a source of indoor air pollution that’s not healthy for skaters and spectators.

Indoor ice skating surfaces are typically built on top of a flat and smooth concrete pad that contains pipes through which cold, salty brine is circulated. Brine freezes at a lower temperature than fresh water. Thin layers of water are applied to the surface of the concrete, and this water begins to freeze as the brine circulating below the surface absorbs heat from the concrete and lowers its temperature. The brine that has passed through the concrete travels to a device known as a chiller, where the heat it absorbed from the concrete is exchanged with a compound known as a refrigerant, which in turn is circulated through a compressor unit that removes the excess heat. The process is not unlike the one that operates a household refrigerator, air conditioner, or heat pump.

The chiller and condenser units require energy, and the same factors that determine the energy use of the building itself – age and efficiency of the equipment, the location of the facility and how electricity is generated – influence the greenhouse gas emissions associated with the icemaking equipment. There is one other factor that affects the carbon footprint of the icemaking equipment: the type of compound used as a refrigerant.

Common refrigerants used in making indoor skating rinks include ammonia, carbon dioxide, and synthetic compounds known as hydrofluoroolefins (HFOs). Each of these has its strengths and weaknesses. Ammonia is relatively inexpensive and, unlike many other refrigerants, is not a greenhouse gas (although fossil fuels are often used in producing it). A drawback of ammonia is that if it leaks from the icemaking equipment it can create a significant respiratory health risk. In 2018 three arena workers in a British Columbia town died from exposure to ammonia that leaked from older, poorly maintained icemaking equipment. Using ammonia requires well-kept equipment and facilities for safe handling and storage, which can raise the operating costs of the facility. Carbon dioxide is another naturally occurring substance that poses less of a health risk than ammonia, but it is a greenhouse gas. Carbon dioxide is a very efficient refrigerant but needs to operate under high pressure, which in turn requires more expensive pipes and refrigeration equipment than other systems, which can be an important consideration for older ice rinks and municipal rinks with smaller budgets. Synthetic HFO refrigerants such as those sold under the Opteon brand – a RinkWatch sponsor – are safer to handle than ammonia, relatively inexpensive, and work better than carbon dioxide in older and less expensive refrigeration equipment. HFOs are often used as refrigerants in household appliances and heat pumps. A drawback is that HFOs have a much higher heat trapping capacity (known as ‘global warming potential’) than natural refrigerants should they leak from equipment and escape into the atmosphere. Unlike older generation synthetic refrigerants, HFOs do not have adverse impacts on the ozone layer.

In summary, calculating the overall environmental impacts of an indoor ice skating facility requires assessing the energy use and greenhouse gas emissions of the building, its mechanical and HVAC systems, the icemaking system, waste generation, and indirect greenhouse gas emissions and pollution associated with travel to the facility. In all these areas, operators and users of indoor ice skating facilities have opportunities to help improve environmental sustainability.