Supplemental Sunlight + LEDs = Maximum Energy Savings
The billion-dollar cannabis industry and the constant energy consumption it requires is pushing the U.S. electric grid to the limit. One scientist has created a solution to reduce energy usage by a whopping 80 percent; using sunlit solar-tubes supplemented with adjustable LED lighting.
For decades, cannabis enthusiasts have suffered from a sort of ideological dissonance. Many well-meaning: earth-conscious, sustainability-promoting and low carbon impact-maintaining bud lovers have looked the other way when it comes to the environmental harms caused by cannabis cultivation — like a kid blissfully enjoying a Happy Meal, it’s easy to forget about the roughly 600 hundred gallons of water it took to make that burger.
Traditionally, indoor and greenhouse cannabis has been a glutton for energy input. Operating costs were high and required relentless climate control systems and intense sodium lighting to produce mind-blowing flowers. That was seen as tolerable collateral damage during an enforcement peak of the Drug War, when the environmental shortcomings of covert indoor grows were a necessary evil to safeguard against criminal prosecution.
But now that the industry is riding a steady wave of cannabis acceptance across the nation, the massive energy drain from indoor cultivation is becoming evident and demanding sustainable solutions.
Neuroscientist and President/CEO of CCV Research, Dr. Jonathan Cachat, rose to the challenge of developing a solution. He began compiling large amounts of data on cannabis while working as a researcher at U.C. Davis in California. Feeling stymied by academia’s penchant for runaway bureaucracy and hamstrung by the looming behemoth of federal prohibition, Cachat leapt into the medical cannabis space to make quicker headway on his research.
“[I was” intrigued by a data-driven approach,” he said. “Studying the relationship of the light spectrum coming into a cannabis growing space and the real-time energy use to reach commercial-level production yields,” typically 1.5-2 pounds per tray under one 1,000-watt high-pressure sodium (HPS) bulb.
Cachat’s data quickly showed that operating costs were far too high using HPS lights — not a huge surprise — but more importantly, that those lights did not provide the ideal light spectrum for plant growth. He turned to LEDs to decrease power consumption, selecting Swedish-based LED company Heliospectra as his lighting supplier.
“They were energy efficient and also the first to offer connectivity and spectral control,” he said. “We selected Heliospectra’s LX60 lights for our systems because they are intelligent, network-connected LED solutions.”
Adjustable LED lights provide an array of spectrums, which cultivators can dial in to produce laser-sharp spectral light strategies, which can mean more diversified cannabinoids and terpenes, higher THC/CBD percentages and larger yields.
Cachat then contacted Solatube Home Daylight in San Diego, which collaborated with chemists at 3M, to produce solar tubes called “tubular daylighting devices” — a souped-up version of a skylight you might find at a home improvement store.
This combination of Heliospectra’s adjustable LEDs and Solatube devices quickly became the basis for Cachat’s brainchild: the dynamic supplemental sunlight (DSS) system, capable of growing the equivalent of outdoor plants within an indoor space — with up to an 80 percent decrease in cost.
The DSS method is basically turns an indoor grow space into a super-efficient greenhouse; an environment that’s insulated, controlled and regulated, but with one very key feature: spaces are devoid of infrared radiation (IR).
Indoor cannabis growers continually wrestle with creating ambient temperatures to provide comfort zones for thriving plants. That generally means large amounts of energy usage. Whether under artificial lights or using greenhouse structures, growers constantly battle fluctuating heat and humidity. And since LED grow spaces run a little hotter than HPS spaces (often by as much as 10-degrees Fahrenheit), the need to maintain ambient temp requires great attention.
But the combination of Solatubes and LED lights effectively eliminate all heat-producing IR (which naturally occurs in greenhouses), translating to greatly decreased need for climate control systems, as well as elimination of excess water usage by overheated plants.
The DSS system also allows growers to use artificial light exclusively when “waking up” plants or “putting them to sleep,” or on cloudy days when photosynthetically active radiation (PAR; the light that feeds plants), is too low. That translates to a significant energy savings during the 12-hour light cycle.
And Cachat said the plants love all that natural light.
“What knocked us off our feet was looking at time-lapse footage of fan leaves throughout the day moving toward that natural [solar tube] light,” he said.
He added that the addition of Heliospectra’s LX60 lights into the DSS system creates a perfect pairing for a variety of reasons.
“The ability to stepwise increase or decrease the overall light output in response to fluctuating exterior sunlight levels, in addition to having granular control over specific light spectrums made Heliospectra LEDs an easy choice,” he said.
Beyond that control and operating cost efficiencies, plants can also be influenced to meld into certain physical characteristics.
“We are able to take advantage of these energy efficient LEDs also to drive or direct plant performance and optimal growth,” he said. “For instance, we can trip or trigger the plant from stretching tall to a more compact [size] with larger bud production using the far-red spectrum of light, which initiates a hormone cascade.”
The “far-red push,” as it’s known, induces flowering and expression of a gene that participates in flowering. This flowering response to red light explains why many growers use warm-colored high-pressure sodium (HPS) lamps for the flowering stage and cooler-hued metal halide (MH) lamps for vegetative growth.
And the lab tests speak for themselves: the DSS system delivers the best aspects of outdoor, but Cachat says the final product is slightly more refined.
“[It has] crisper flavor profiles and slightly higher cannabinoid and terpene levels compared to indoor grown,” he said. “We can now bring the benefits of sun grown to interior environments.”
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