LED for growing grass: sustainability and costs vs quality
It’s the talk of the town: using LED lighting for growing grass sports playing surfaces. The increasing global awareness for a clean environment and a sustainable climate in the past decades generated the demand for lower energy consumption in lighting and also in pitch management. SGL is well known in the world of sports for its wide variety of pitch management tools. Grass grow lighting installations form a key element in the company’s product portfolio and have been developed and delivered by the company to customers all over the world. SGL have been conducting research and tests with LED in the SGL Research and Development Centre in the Netherlands for a number of years already. The development is now in the stage of field-operational tests and an advanced LED system is currently being trialled in European stadiums and there are more trials planned in stadiums in different climates across the world.
Why the interest in LED?
For the last 15 years there has been a revolution in pitch management and we are proud to have been contributing to this revolution. Because of the ever increasing knowledge of groundsmen, helped by technologies like the SGL system, the grass quality and usage hours have been greatly improved. Now the industry takes a next step into looking at the most sustainable way of having a high quality pitch. For many years HPS (High Pressure Sodium) has proven to be a very successful light source for growing grass in every climate and environment. It is a light source that finds its origin in greenhouses and consists of approximately 50% PAR light (the part of the light spectrum that is used by a plant for photosynthesis) and 50% Infrared light (warmth that radiates to the surface and increases surface temperature). For the past few years LED is being considered as an alternative by some stadiums because of its sustainable potential. LED has a lower power consumption and has the possibility to create a light recipe: to choose and combine the most efficient colours from the light spectrum for plant growth.
Our view on LED
It is an evolving light source and in essence it has good potential for grass growth. Results show that we can achieve the same light level with LED as with HPS, but for consistent, reliable and high quality growth, light alone is not enough. At this point LED has the disadvantage that it does not radiate heat to the surface, while many stadiums that need the extra light in winter also need the temperature increase to maintain their pitch quality. It is possible to add heat by means of Infrared armatures, but this immediately almost entirely takes away the economical/environmental advantage of the LED lighting. Together with the relatively high investment costs for LED, this is the main reason that there has not been any real evidence of realized cost savings in stadiums by LED systems, based on equal quality to our HPS systems. Therefore there has not yet been a full pitch successfully treated by LED systems.
For who is LED the right choice?
We often come across the misconception that choosing the light source is the first step. Our view is that you should always start with determining your desired quality and that the light source is a tool to reach that goal. In the end it is a matter of quality vs sustainability and costs. When it comes to quality, there are a number of aspects that determine whether a light source will be able to deliver a high quality grass surface or not. Think about light spectrum, light level, light distribution, radiation or convection heat and weight of the system. Following, different aspects for costs should be taken into account. Think about investment costs, power consumption and electricity price. At SGL we have created a model that calculates which light source can deliver the highest quality at the lowest possible costs, based on the specific circumstances of your stadium or playing surface. We base our advice for lighting systems on that calculation. When the calculation is in favour of LED, we will advise you an LED system and we are able to supply you with the most efficient, advanced and user friendly LED system out there. If the outcome shows HPS or maybe a hybrid system is more efficient, this will be our recommendation. Our only goal is to offer the right customized solution for each individual customer.
Goals of current stadium tests
We have designed an LED lighting system that contains all requirements for delivering high quality grass growth. Together with Philips we have designed the most efficient light recipe, the light levels are sufficient, the light distribution is very even across the entire footprint and the Infrared is automatically added based on ground temperature and light level. We will measure the efficiency of our LED system. We measure the turf quality in every aspect and we do 24/7 measurements and analysis of the growing conditions with the SGL Analyser. The results will be used by our agronomists and product developers to determine what alterations need to be made to improve and perfect the LED system and in what situations the system could be used to maintain a high quality pitch.
Our next steps
We will do more trials with the LED system in different climates, to obtain a great amount of data which we can use to see in which circumstances the system could be efficient and more sustainable. However, we do not prefer one type of light source over the other, because our 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 we believe that the right system and light source will be different for every stadium. We 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 we offer a solution, our customers can be assured that the results in terms of grass quality and the required power consumption are guaranteed. For the last 15 years we have delivered on our promises and we will continue to do so.