Is LED more sustainable than HPS? Recent trials in European stadiums gave the answer.
The latest and most scientifically sophisticated test SGL were involved in has just been finished in one of Europe’s most popular stadiums. The results were educational and eye opening and confirming the recent insights of SGL.
For the last 10 years SGL have done extensive research with various light & heat sources and given an objective and thorough view on the technology and developments. This test has once more confirmed that the influence of warmth has often been underestimated as a growth factor. Although light is creating Photosynthesis, the temperature is crucial for the process and should always be in balance with the light. That is the most important 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.
Due to the fact that HPS lamps produce both PAR light and radiation heat, it cannot be controlled separately. The beauty of LED Systems, in combination with IR heaters, is that they have the ability to control light & temperature independent of each other. So in theory, you only apply heat when needed, and light as much as necessary. If you would assume that the lighting systems are used all year round, in many circumstances this could mean LED is more efficient. However, in practise in Europe the main “lighting season” is between September to March. These are the months that the amount of light is not sufficient for (quality) grass growth, but also the outside temperatures are often also not sufficient, so additional heating would be required at all times during these months.
Light intensity & distribution
Besides temperature there are a lot of other factors that determine the quality of growth, such as light intensity, light distribution and light spectrum. The winter trials show that the same light intensity and light distribution of the HPS system can also be obtained with LED. 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. The latest comparative tests show that SGL have the most efficient LED system in the market, with not only the most optimal light intensity and light distribution, but also the most efficient light spectrum.
Despite those facts, it was not possible for SGL, nor for participating competitors, to create the same quality of growth during winter as an HPS system with less total energy input than the 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.
While SGL has been doing extensive research around LED, it has not been the only point of attention on the subject of efficiency. Possibilities for improving the efficiency of the HPS systems are also continuously being researched. In the past years some customers have already shown that HPS systems can be used up to 30% more efficiently by monitoring and analysing using the SGL Smart system.
That is why 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 solution that is best for their specific circumstances. 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.
Conclusions in short
- LED technology is still in an infancy stage but is 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