A fundamental goal for the Norwegian Ski Federation and the Norwegian Biathlon Association, together with their partners, is to contribute to a future where snow is easily accessible for the next generation of skiers, jumpers and boarders, regardless of if natural snow only exists in the high mountains.
To make this goal possbile, the project “Snow for the future” was started in 2017, and first marketed through the city of Trondheim’s Nordic World Skiing Championship bid. The project is led by SINTEF og NTNU, both World renown research institutions, and with financial backing by the Norwegian Ministry of Sport and Culture. Phase I of the project focused on mapping today’s existing technologies for snow production (especially temperature independent technology), and the potential for improvements.
More detailed information about phase I of “Snow for the future” can be found in it’s final report .
Phase II of the project was financed in 2019, with the goal of researching and developing technologies that can make snow production and snow preservation even more energy efficient, simpler and less expensive. It is also a goal to communicate the project’s knowledge, learnings and new technologies – and with this in mind the “Centre for Snow Competency” was initiated.
The Centre is however just one of the several original “Snow for the future” project goals.
Develop a novel technology for efficient and environmenly friendly temperature independent snow production with solutions for interim storage in various cases
Increase the number of skiing days in local communities and centralized facilities to aid in further development of the skiing tradition and culture in Norway and Europe
Increase the predictability of organizing events, competitions, and activities pertaining to skiing in Norway and Europe
Secure the future value creation for new technology manufacturers to sustain and further develop skiing destinations in Norway and elsewhere in Europe
Establish a research platform and competency centre for snow technology and its practical applications, Center of Snow Competency, that will give lasting effects both nationally and internationally
Generate new jobs and improve public health
For phase II, the main goal is to develop a novel technology for energy-efficient production of artificial snow, including snow production in plus degrees and production independent of the outdoor air temperature. The project focuses on systems and solutions that ensure a sustainable snow production with a limited environmental footprint. Heatpump technology based on environmentally friendly natural freezing elements will be developed, with the focus on utilizing the cold side for snow production and the warm side for the purpose of using or storing heat.
One possibility is to use the surplus heat from the snow production to heat adjacent buildings, swimming pools, etc. Contrary, it is also possible to use surplus heat from industrial processes or district heating during temperate months of the year for snow production. Such an integrated system also includes storage and reuse of snow.
In a combined system for snow production and utilization of surplus heat, the produced snow becomes a by-product with minimal use of extra energy. This enables cost efficient snow production in centrally located areas. An illustration of an integrated system with temperature indepedent snow production, storage and reuse of snow, and utilization and delivery of surplus heat is shown below:
The chapters below cover and summarize the reseach projects implemented through the “Snow for the Future” project.
A fundamental goal for the Norwegian Ski Federation and the Norwegian Biathlon Association, together with their partners, is to contribute to a future where snow is easily accessible for the next generation of skiers, jumpers and boarders, regardless of if natural snow only exists in the high mountains.
To make this goal possbile, the project “Snow for the future” was started in 2017, and first marketed through the city of Trondheim’s Nordic World Skiing Championship bid. The project is led by SINTEF og NTNU, both World renown research institutions, and with financial backing by the Norwegian Ministry of Sport and Culture. Phase I of the project focused on mapping today’s existing technologies for snow production (especially temperature independent technology), and the potential for improvements.
More detailed information about phase I of “Snow for the future” can be found in it’s final report .
Phase II of the project was financed in 2019, with the goal of researching and developing technologies that can make snow production and snow preservation even more energy efficient, simpler and less expensive. It is also a goal to communicate the project’s knowledge, learnings and new technologies – and with this in mind the “Centre for Snow Competency” was initiated.
The Centre is however just one of the several original “Snow for the future” project goals.
Develop a novel technology for efficient and environmenly friendly temperature independent snow production with solutions for interim storage in various cases
Increase the number of skiing days in local communities and centralized facilities to aid in further development of the skiing tradition and culture in Norway and Europe
Increase the predictability of organizing events, competitions, and activities pertaining to skiing in Norway and Europe
Secure the future value creation for new technology manufacturers to sustain and further develop skiing destinations in Norway and elsewhere in Europe
Establish a research platform and competency centre for snow technology and its practical applications, Center of Snow Competency, that will give lasting effects both nationally and internationally
Generate new jobs and improve public health
For phase II, the main goal is to develop a novel technology for energy-efficient production of artificial snow, including snow production in plus degrees and production independent of the outdoor air temperature. The project focuses on systems and solutions that ensure a sustainable snow production with a limited environmental footprint. Heatpump technology based on environmentally friendly natural freezing elements will be developed, with the focus on utilizing the cold side for snow production and the warm side for the purpose of using or storing heat.
One possibility is to use the surplus heat from the snow production to heat adjacent buildings, swimming pools, etc. Contrary, it is also possible to use surplus heat from industrial processes or district heating during temperate months of the year for snow production. Such an integrated system also includes storage and reuse of snow.
In a combined system for snow production and utilization of surplus heat, the produced snow becomes a by-product with minimal use of extra energy. This enables cost efficient snow production in centrally located areas. An illustration of an integrated system with temperature indepedent snow production, storage and reuse of snow, and utilization and delivery of surplus heat is shown below:
The chapters below cover and summarize the reseach projects implemented through the “Snow for the Future” project.
1
Utilization of excess heat for snow production
The text below is a summary of a research project by Ole Marius Moen – ole.moen@sintef.no. The project can be categorized as a mapping task, where the focus has been to find:
Which heat-driven cooling technologies exist and can be used for snowmaking?
How much energy will heat-driven snow production require?
What are the potential sources of heat?
Which winter sport venues can potentially use this type of snow making technology?
Climate changes will lead to warmer temperatures and less natural snow. A likely consequence is that it will become more difficult to provide good conditions for snow sports. The ski season may even disappear in many typical “snow villages”. Since the traditional snow production method using snow lances or fan-guns require temperature below zero degrees Celsius, many locations, especially at low elevation, may not be able to use this method in the future.
Temperature independent snow production
One alternative is to use technologies that can produce snow in warm temperatures, so called temperature independent snow production. Today there are several providers of this technology, and it is used in several places around the World. The systems are costly, and require that the snow is distributed since the production takes places in a central location. Compared with traditional snow production, the technology demands up to 50 times more energy, which leads to high electric bills.
One solution for reducing the operational costs is to replace the electricity with heat as the energy source by using refrigeration technology driven by heat (for example absorption refrigerators). To produce snow using heat requires temperatures of around 90 – 100°C. Compared to using electricity, heat-driven cooling is relatively inefficient, since large parts of the heat can not be utilized. To be economical, such a solution is therefore dependent on being able to use cheap or free excess heat. This will also contribute to reducing the environmental footprint compared to snow making using electricity.
Potential heat sources
In Norway, studies have shown that one can find considerable amount of unused excess heat, especially in industry and waste incineration. In the industry there is potentially up to 10 TWh of available heat at the right temperature range, while for incineration about 1 TWh is not utilized for district heating due to low demand in the summer. Making use of heat from these sources is however not without challenges. The low temperature of the district heating in the summer makes it difficult to use for snow production, and external use of excess heat from the industry is demanding and not common. Both cases will require relatively expensive equipment for heat exchange both for user and provider, and pipes for transportation of the heat between the two.
District heating (also known as heat networks or teleheating) is a system for distributing heat generated in a centralized location through a system of insulated pipes for residential and commercial heating requirements.
Co-location of venues and heat sources
Snow production using heat as the energy source for snow production, it is advantageous that the heat source and the ski location is within a short distance; neither heat nor snow can be transported efficiently over long distances. In Norway, the co-location of winter sport venues for Cross-Country biathlon, ski jumping and alpine, and potential heat sources has been mapped. This shows that 76 out of 168 mapped venues are located in a municipality with district heating or available excess heat from industry. For many of these venues increased snow production would lead to increase skiing since they are located in densely populated areas or are already popular ski destination venues.
Based on calculations with Granåsen, Trondheim as model example, an annual consumption of 1,5 GWh for snow production would contribute to lengthening the ski season with more than 1 month by being able to snow cover the stadium, 3 km of courses and the ski jumps. At the same time, the calculations showed that different factors can significantly alter the energy requirements. The model calculations will therefore be unique for each venue.
Further work
It is suggested that further research focuses on large venues with existing nearby district heating. Techno-economic analyses to concretize each individual venue’s potential may give us answer to if heat-driven snow production is a practical, economical and sustainable solution for future winter sport.
Techno–economic assessment or Techno–economic analysis (abbreviated TEA) is a methodology framework to analyze the technical and economic performance of a process, product or service. TEA normally combines process modeling, engineering design and economic evaluation.
2
Theory – about snow
Physical properties
From the mechanical point of view, snow is a complex material. Its behavior depends on a number of parameters. The various types of snow are characterized by their mechanical properties. For example, the resistance to pressure of newly fallen snow is lower than that of mechanically processed (groomed) snow. Snow deforms under its own weight, depending on its temperature and density. Its viscosity increases at lower temperature and with greater density.
From an optical point of view, the snow absorbs only part of the short-wave radiation received from the sun. For example, up to 95% of the sun’s radiation is reflected by new snow. The albedo (the reflectivity of an object) depends on the condition of the snow surface (grain shape and size, contamination and water content). Dirty snow has low albedo and will melt faster.
The snow’s thermal properties appears clearly when the temperature difference between the various layers of snow strongly influences the properties and the metamorphism (change of form) of the snow layers. Temperature changes are greatest at the surface and smallest close to the ground.
The properties of machine-made snow are distinctly different from those of natural snow. The basic difference is that natural snow freezes from water vapor while machine-made snow freezes from water droplets. In the latter case, water droplets freeze on the outside before the core does. The thermal differences contribute to the fact that compacted natural snow on the surface stays colder than equivalent artificial snow (which melts easier and thereafter freezes)
Compacted natural snow stays ca. – 3 to -5 °C colder than artificial snow during equal condition in the the winter.
Meteorological factors
Solar radiation varies throughout the year. It reaches it’s maximum level in the summer and it’s minimum level in the winter. It depends on the time of the day, the slope of the terrain and the altitude of the location. In December, a 30 degree gradient slope facing south will receive almost two and a half times as much radiation as a horizontal surface.
Wind causes a rapid thermal exchange between the surface of the snow and the surrounding air. The stronger the wind, the faster the exchange. A warm wind accelerates the melting process on the surface rapidly and a cold wind accelerates its cooling.
When the surrounding air is warmer than the snow surface, the temperature of the snow rises. With strong emission or pollution, a stable layer of air can form at the bottom of valleys, since cold air is heavier than warm air. Air exchange progresses at a much slower rate in this case.
When air humidity is high, water vapor condenses on the snow surface. Water then accumulates on the surface. With very low air humidity, air can absorb more water vapor from the snow surface. Snow cools down during evaporation. Low air humidity is therefore beneficial for the freezing of the snow surface. In dry air, ice/snow also sublimates (evaporates without turning to water first) and the snow surface cools down.
Rain or snow transfers energy to the snow surface, depending on the temperature of the precipitation. Due to its higher temperature and thermal exchange effect, free water (wet snow or rain) raises the temperature of the surface of the snow and causes it to partially melt. Rain has however not as much melting effect as wind. If it rains 10 mm and this rain is cooled to 5 °C in the snow, it will only cause 0,6 mm of snow to melt (from Wikipedia).
As energy is absorbed when the snow is at 0℃, the snow crystals/grains start to melt at the edges and corners. They become rounder and a thin layer of water forms around the grains. As melting progresses, pores keep filling with water. When water content is high, the bond between the grains will also dissolve causing the snow to soften. Heat intake and melting may frequently be interrupted by colder night temperatures, and water freezes again. Consequently, the water present between snow grains freezes, forming strong bonds again.
