Every stadium needs its own growth recipe

We are heavily investing in future technology. Already for the last 10 years we have done research with various light & heat sources and given an objective and thorough view on the technology and developments. LED is one of the main focus areas where weL are working in. In direct cooperation with Philips and other industry experts we are doing tests in different stadiums across the world. The latest and most scientifically sophisticated test we were involved in, was just finished in one of Europe’s most popular stadiums. The results were educational and eye opening and confirming our recent insights. 

Latest research

Recent LED trials (winter 2017/2018) in European stadiums show advantages and disadvantages of traditional and new lighting systems. 

What the research shows the most, up to now, is that the influence of warmth has been often underestimated as a growing factor. Although the light is creating Photosynthesis, the temperature is crucial for the process and should always be in balance with the light. In most climate regions the minimum temperature is not achieved naturally during the winter season; it requires an additional heat-source to allow growth. That shows the interesting difference between LED and HPS lamps, as with HPS up to 50% of the energy reaches the plant as radiation heat, where with LED also 50% of the energy is heat (convection) but it does not reach the plant. HPS stadium light systems can be split into treatment with light and temperature. Due to the fact that HPS lamps produce both with the help of the bulb (and the reflector), it cannot be controlled separately. The beauty of LED Systems (in combination with IR heaters) is that they give the ability to control light and temperature independent of each other. So in theory, you only apply heat when needed, and light as much as necessary. 

This brings us to the practical usage of the grass lighting systems. In Europe the main “lighting season” is between September and March. Depending on the average outside temperatures it can be calculated how much additional heat is needed to produce the optimum growing environment. SGL created a “LED-Configurator” which allows to theoretically calculate, based on historical weather data and stadium characteristics, if an LED system can be more energy efficient than an HPS system, or if the additionally required temperature, undo the LED savings.

Test results

With the tests in Ireland, Germany and France, it was not possible for SGL nor for participating competitors, to create the same quality of growth during winter with less total energy input than with an HPS system. In individual situations it even occurred that the LED systems with infrared requested more energy input to create the same amount of light output (mmol) and heat (°C) as HPS Systems. 

The most important findings summarized:

  • LED technology is still in an infancy stage but progressing
  • Price/Performance ratio of LED is still higher than HPS
  • Plant temperature is crucial for grass growth
  • Stadium tests show that SGL have the most efficient LED system on the market
  • Modelling and research by SGL creates efficiency and quality
  • SGL Analyser and advanced measuring tools allow for objective research
  • Every stadium needs a tailormade calculation to choose LED or HPS

SGL's views on LED

SGL founder and Managing Director Nico van Vuuren has been personally involved with SGL’s LED research in the last 10 years and he knows all the ins and out when it comes to using light to create growth. “In essence, we do not really care what light sources we use. In roses, we are looking for the best quality rose that keeps its beauty for as long as possible” says Nico, who is also co-owner of one of the most technologically advanced rose greenhouses in the world. “With SGL we help our customers to create the best quality pitch. That is the main focus, because that is the stage which is viewed by millions every week and where top athletes need to perform at their very best. You simply cannot take any risk with that. All that matters is creating that top quality in the most cost efficient way, whether that is with LED or HPS is actually irrelevant, SGL can offer both.”

LED as light for plant growth is still in the state of infancy, but it is worthwhile to have a look at the progress in this respect at SGL, the company that is well-known for its grass grow light installations in over 250 leading sport stadiums in the world. SGL are an authority in the care of grass for sports and their portfolio encompasses (lighting) installations and equipment for grass growth, plant fungus elimination and soil improvement, besides management and control systems to monitor and advise on 24/7 basis on pitch improvement. Many stadiums worldwide, with the assistance of SGL, have been able to substantially increase their pitch quality and pitch utilization efficiency.

The SGL Research and Development Centre in Waddinxveen, the Netherlands, together with Philips Lighting, have been focussing on LED light for grass growth and pitch improvement for a number of years. The research target initially was to develop LED grow light installations that can match or even improve the existing and well established HPS (High Pressure Sodium) installations in performance, and subsequently obtain lower energy consumption. The developments at SGL are now in the stage of field-operational tests and an advanced LED system is currently being trialled in several European stadiums while more trials are planned in stadiums in different climates across the world.

Tests show that the required HPS light intensity and light distribution on a pitch can also be obtained with LED, but the choice of the right light spectrum with LED forms a key element to obtain the right results. The specific light spectrum for grass growth differentiates from the spectrum for other plants, even for the development stage of the plant (young vs mature) as well as the circumstances of additional daylight. Besides the light spectrum and light intensity, the ground and plant temperature is an important aspect for growth. LED radiates no heat and depending of the climate circumstances, heat forms an imperative stimulus for plant growth as well. The well-proven HPS lamps have all these elements inherent available: optimal light spectrum and radiation of heat. For that purpose and depending on the climate conditions, infrared light (IR) has been included in the LED test installations of SGL to obtain the best results.

Is LED more sustainable than HPS?

The main motivation for the application of LED as the light source for growth is sustainability, saving energy, but also in some circumstances the ability to alter the light spectrum. Since climate conditions count and often heat as a source for growth has to be added, depending on the prevailing climate conditions, the energy and investment costs will rise. SGL therefore have developed a model for the assessment of sustainability for each potential location of LED installations. So far this model has been proven and justified every time in real life situations. Elements in the model are prevailing temperatures, light necessity (expected hours of additional light on the pitch), electricity costs and installation depreciation costs. LED light installations for stadium pitches have higher investment costs than HPS installations. Nowadays, due to substantial research by SGL, in most climates grass growth results as obtained with HPS, can now also be obtained with LED. However, despite their lower energy consumption and costs, in most places around the globe LED installations do not yet match HPS installations in operational costs.

The solution is custom made

SGL do not prefer one type of light source over the other, because their goal will always be to achieve the highest possible quality at the lowest possible costs and environmental footprint. Each light source has its own characteristics that might be beneficial for one, but not for the other. Therefore SGL believe that the right system and light source will be different for every stadium and will continue to research every possible option and will provide every customer with a lighting solution that is best for their specific circumstances; whatever light source needs to be used. What matters is that when SGL offer a solution, their customers can be assured that the results in terms of grass quality and the required power consumption are guaranteed. For the last 15 years SGL have delivered on their promises and will continue to do so.

When deciding on the best possible solution, we always put quality at the top. There are a lot of factors that we take into account:

  • Grass growth
  • Grass quality
  • Durability of growth
  • Root growth
  • Operational efficiency, ease of use
  • Maintenance
  • Weight of the system, pressure on the pitch
  • Investment costs
  • Running costs

For more information or detailed data and results, please contact us.