While industrial hemp generally doesn’t require a lot of inputs, indoor-grown medical cannabis can be a real energy hog.
Industrial hemp is grown outdoors, much like any other crop – in fact, it uses less inputs such as herbicides and isn’t as thirsty as some crops.
On the other hand, medicinal marijuana is often grown indoors under tightly controlled conditions. This is in order to maximise the production of cannabinoids such as tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN).
Indoor operations require power for grow-lights, as well as air-conditioning, dehumidifiers, pumps, chillers, fans, heaters and water purifiers..
Earlier this year it was reported electricity use in Denver, Colorado has been increasing at the rate of 1.2 percent a year, and 45 percent of that jump comes from marijuana-growing facilities.
Back in 2011, Evan Mills, Ph.D.* estimated legal and illegal cannabis production in the USA used as much as one percent of the nation’s electricity – $5 billion a year in power at that time and enough to supply the electricity needs of 2 million US homes.
Following the legalization of cultivation of medical marijuana in California in 1996, Humboldt County experienced a 50% rise in per-capita residential electricity use compared to other areas. However, much of this production wasn’t/isn’t legal.
Power densities in intensive operations were around 200 watts per square foot using what were conventional methods – around the same as modern data centers.
Since Dr. Mills’ report; much has changed – while the number of states permitting the cultivation has increased; as have the number of growers, market forces are compelling cultivators to become more energy efficient. After all, electricity isn’t free.
In addition to switching to LED lights and more efficient air-conditioning systems, solar power holds some answers as growing operations are usually located in largish buildings with substantial roof space. The energy storage revolution will also play a role; enabling growers to store surplus energy during the day in batteries for use during night and in unfavourable conditions.
There may also be a shift to growing more outdoors as cultivation and extraction techniques improve. Also improving is selective breeding techniques that result in increased production of desired cannabinoids.
By embracing solar and various other sustainability measures, the medicinal marijuana industry will no doubt make itself substantially more environmentally friendly, while improving its bottom line.
*Dr. Mills’ 2011 study is often incorrectly attributed to Lawrence Berkeley National Laboratory. While Dr. Mills does have some association with Lawrence Berkeley, his study was carried out independently. Dr. Mills is a scientist specializing in energy analysis and the role of energy in climate change.