A recent study by the Resource Innovation Institute (RII) found that indoor cannabis cultivation facilities that utilize LED lighting systems were, on average, more energy-efficient and more productive than facilities using non-LED lights.
The non-profit organization analyzed data from 84 indoor cultivators who submitted energy use and production data to the group’s Cannabis PowerScore tool, a benchmarking platform that gathers confidential facility information about energy use, production output and cultivation methods, and provides operators with ranking relative to other respondents. (RII uses the aggregate PowerScore data to inform governments, utilities and the supply chain on how to support cultivators in achieving greater efficiency.)
RII looked at the average of all the operator’s electric facility efficiency and electric production efficiency. Average electric facility efficiency is a metric RII uses to calculate energy efficiency by measuring energy use relative to an operation’s flowering canopy size. Kilowatt-hour per square foot (kWh/sq. ft.) and electric kiloBtu per square foot (kBtu/sq. ft.) are both used to determine electric facility efficiency. A lower figure indicates better average electric facility efficiency.
Average electric production efficiency is the metric that measures energy use against yield in grams (g/kWh and g/electric kBtu). A higher average electric production efficiency figure indicates better energy productivity.
In its analysis, RII found that indoor operations using LED lighting for flowering growth stages achieve 34% better average electric facility efficiencies and 80% better average electric production efficiencies than indoor facilities using double-ended (DE) HPS lighting for the flowering growth stage. Facilities using LED lighting systems averaged 606 kBtu/sq. ft. compared to an average of 882 kBtu/sq. ft. for non-LED systems. Additionally, LED facilities’ average productivity was 0.44g/kBtu compared to an average of 0.24g/kBtu for non-LED facilities.
“These findings demonstrate the ability of LED technology to drive energy and production efficiency in horticultural operations,” said Derek Smith, RII’s executive director, in a press release. “It should be noted that the range of performance across the facilities we studied is broad, meaning there is a large variability among users.” He added to Cannabis Business Times, “We know cultivator education and training is essential to [the] achievement of energy savings, and we also know that cultivators have different objectives as it relates to quality and therefore different patterns of energy use.”
“More research is critical to establishing standards that result in greater energy efficiency and productivity, improved product quality and lower environmental impact,” Smith said in the release.
Another interesting finding, according to RII, was that “some of the indoor [respondents] … using HPS lighting are dimming the wattage of the fixture at the ballast.” While dimming ballast intensity improved electric facility efficiency, “average electric production efficiency of facilities using HPS did not keep up with those using LED, despite some facilities dimming fixtures at the ballast,” Gretchen Schimelpfenig, RII’s technical director wrote to CBT.
The quarterly report also analyzed the efficiency and productivity of lighting systems in greenhouse settings, but “greenhouses may be increasing light output to prolong growing seasons, induce higher cannabinoid levels, or achieve greater yields, so more investigation into other contributing factors is needed”, according to Schimelpfenig. In future reports, facility location, daily light integral (DLI) target ranges, total canopy size and the number of light fixtures per square foot will be looked at to further understand how greenhouse operators are using supplemental lighting.
Schimelpfenig also noted more responses from different geographical locations are needed for proper analysis. “The value of the PowerScore is only going to get better the more people participate,” she told Cannabis Business Times.
The study’s results were published in RII’s “Quarterly Resource Benchmarking Report” for Q3 2020, which is available to RII’s registered members.