The high-pressure sodium lamps (HPS) are the most common choice for having a high additional light intensity in the production of crops in greenhouses. The traditional HPS lamps works with magnetic power supplies, but the new electronic power supplies which are typically smaller, quieter and between 10 and 15% more efficient. In addition, electronic power supplies are much lighter and the light emitted from the bulb degrades at a slower speed compared to the use with a magnetic power supply.