Greener Lights for Green Growers

Some 11 million acres of US farmland have given way to development and other non-farm uses over the past 15 years, according to American Farmland Trust, and the nation continues to shed cropland at the rate of 1.5 million acres annually. At the same time, consumer interest in locally grown produce, farmer’s markets, farm-to-table restaurants, and plant-based options is surging.

Against this backdrop, a sea change is happening in U.S. agriculture, as a new type of farming is quickly gaining ground. The American Council for an Energy-Efficient Economy (ACEEE) reported the market value of controlled environment agriculture (CEA – crop production within an enclosed structure) was $47 billion in 2017, and estimated to expand at a compound annual growth rate of 3.4 percent across North America between 2018 and 2023. In the U.S., the market for just one type of CEA – vertical farming, which utilizes stacked layers for crop growing – is projected to reach $3 billion by 2024, according to a 2019 report, exhibiting a compound annual growth rate of 24 percent.

From a “green” perspective, CEA wins points for requiring fewer chemicals like pesticides and herbicides, needing a smaller growing area, and using less water than traditional farming. When it comes to energy use, however, it hits a sustainability ceiling – particularly in terms of lighting.

The annual electricity consumption of all indoor U.S. horticultural installations is about 5.9 terawatt hours, according to the U.S. Department of Energy (DOE). That’s approximately equal to the annual usage of more than half a million U.S. households and estimated to grow between 15 and 25 percent between 2017 and 2025 as indoor farming increases.

In the burgeoning legal marijuana industry alone, New Frontier Data’s latest Cannabis Energy Report pegs legal cannabis cultivation electricity consumption in the U.S. at approximately 1.1 million megawatt hours annually. That’s enough to power 92,500 homes or a community the size of Newark, NJ, and accounts for carbon emissions equivalent to that of 92,600 cars. has reported that indoor cultivation requires ten times as much energy per square foot as a typical office building and four times as much as a hospital. With 33 states and the District of Columbia having passed laws legalizing marijuana cultivation in some form, New Frontier Data forecasted that the sector’s electricity usage will increase 162 percent from 2017 to 2022, and recommended the industry “evaluate energy-efficient and renewable energy technologies”.

Acknowledging that biggest culprit in this equation is the intense lighting needed for effective indoor horticulture, the DOE report referenced above stated that switching to all light-emitting diode (LED) technology could reduce electricity usage in the vertical farming sector alone by 40 percent, saving approximately $240 million. In addition to potentially saving energy costs for growers, switching to super-efficient, long-lasting LEDs can be an effective tactic to reduce electricity consumption in states working toward energy and greenhouse gas emission reduction targets.

Regulations governing cannabis cultivation in the states of Massachusetts and Illinois, for example, emphasize the need to manage energy consumption. Both states include reference to a policy developed by the DesignLights Consortium (DLC), a non-profit organization that helps utilities define and incentivize high performance, efficient lighting for the commercial and industrial sector. Unveiled in late 2018, the DLC policy sets a first-of-its-kind performance standard for horticultural light fixtures.  One US utility, Efficiency Vermont, began offering the nation’s first rebates for grow lights complying with the DLC standard last spring and dozens of other utilities have since followed suit.

The DLC’s policy established a qualified products list (QPL) for horticultural lighting products. As a starting point, products bearing the DLC’s QPL logo must be at least 10 percent more energy efficient than the most efficient non-LED grow light alternatives (high pressure sodium fixtures). The DLC’s Horticultural QPL now contains over 70 products from 23 different manufacturers and is expected to grow to several hundred qualified products. The first major round of requirements for horticultural lighting are in effect through December 2020, at which time they will be updated and efficiency levels raised following a stakeholder input process.

Uncertainty is a hurdle to widespread acceptance that any new technology must clear. Acknowledging that broad adoption of commercial LED grow lights will hinge on positive customer experiences with the technology, the DLC has set product requirements for the lifetime of critical components such as fans and drivers as well as a threshold for energy efficiency.

Horticultural lighting represents one of fastest growing electric load categories for many US utilities. By the same token, it offers an opportunity to mitigate a significant energy load and the environmental impacts while supporting a dynamic young industry.  We’re eager to continue down this path, refining product requirements in response to both new research and the real-world experiences of today’s indoor farmers.

Christina Halfpenny is Executive Director and CEO or the DesignLights Consortium.