DOE has just released a report that examines the energy-saving potential of LED lighting in horticultural applications. All three main categories of indoor horticulture were investigated: supplemented greenhouses, which use electric lighting to extend the hours of daylight, supplement low levels of sunlight on cloudy days, or disrupt periods of darkness to alter plant growth; non-stacked indoor farms, where plants are grown in a single layer on the floor under ceiling-mounted lighting; and vertical farms, where plants are stacked along vertical shelving to maximize grow space, and the lighting is typically mounted within the shelving units.

DOE utilized data from U.S. agriculture and horticulture censuses, as well as catalog and product specification databases for horticultural lighting products, and interviewed growers, utilities, lighting manufacturers, retailers, and other industry experts.

Among the findings:

-Based on current performance, LED lighting offers 24% to 30% reduction in electricity consumption per ft² of grow area for each of the three categories.

-Non-stacked indoor farms employ the most energy-intensive lighting, with incumbent technology using about 60W/ft² and LED lighting 41.8 W/ft².  

-Of the three categories of indoor horticulture, vertical farms have seen the highest adoption of LED lighting, which comprises 66% of all lighting in that application, while LED products make up only 2% of the lighting in supplemented greenhouses and 4% of the lighting in non-stacked indoor farms.

-In 2017, horticultural lighting installations in the U.S. consume a total of 5.9 terawatt hours (TWh) of electricity per year, which is equivalent to 61 trillion Btu (tBtu) of source energy consumption. Of this 5.9 TWh, 89% comes from lighting in non-stacked indoor farms, 10% from supplemental lighting in greenhouses, and 1% from lighting in vertical farms.

-If all horticultural lighting today was converted to LED technology, annual horticultural lighting consumption would be reduced to 3.6 TWh, or 37 tBtu, which represents energy savings of 40%, or $240 million.

For the complete findings, download the full report.