The US Department of Energy has released a report that examines the energy-saving potential of LED lighting in horticultural applications. The main finding: LED lighting offers a reduction in electricity consumption of 24 to 30 percent per sq ft of grow area for all three main categories of indoor horticulture – 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 maximise grow space, and the lighting is typically mounted within the shelving units.
DOE utilised data from US agriculture and horticulture censuses, as well as catalogue and product specification databases for horticultural lighting products, and interviewed growers, utilities, lighting manufacturers, retailers, and other industry experts.
The principal findings:
- Based on current performance, LED lighting offers 24 to 30 percent reduction in electricity consumption per sq ft of grow area for each of the three categories.
- Non-stacked indoor farms employ the most energy-intensive lighting, with incumbent technology using about 60 watts per sq ft and LED lighting 41.8 watts per sq ft.
- Vertical farms have seen the highest adoption of LED lighting, which comprises 66 percent of all lighting in that application. LED products make up only 2 percent of the lighting in supplemented greenhouses and 4 percent of the lighting in non-stacked indoor farms.
- In 2017, horticultural lighting installations in the USA consumed a total of 5.9 terawatt hours (TWh) of electricity per year, equivalent to 61 trillion Btu (tBtu) of source energy consumption. Of this 5.9 TWh, 89 percent comes from lighting in non-stacked indoor farms, 10 percent from supplemental lighting in greenhouses, and 1 percent 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; that represents energy savings of 40 percent, worth $240 million.
For the complete findings, download the full report here.