Dynamic control of supplemental lighting intensity in a greenhouse environment

The global increase in energy prices, the urgent need to reduce CO2 emissions to the atmosphere and the high energy usage are currently the major threats to the greenhouse industry. Optimised control of the lighting quality, quantity and periodicity can contribute to improvements in the productivity and energy efficiency of greenhouses. In this paper, the effects of dynamic control of supplemental lighting intensity on electricity consumption and fresh weight accumulation of lettuce plants are investigated. The use of the dynamic lighting control resulted in a 20% reduction in the electricity consumption in comparison to a similar lighting system operated under a discontinuous on-off regime. However, there was no statistically significant difference between both regimes in terms of plants' average fresh weight accumulated per electrical energy unit consumed.