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The yearly greenhouse-gas pollution of the $40 billion per year marijuana industry is responsible for about 3% of all electricity use or 8% of household use. Indoor growers use high-intensity lights that are 500 times more powerful that a standard reading lamp. They also use several other high energy industrial practices. The closest comparison for these massive, industrial-style grow facilities are data centers, which consume about two percent of the nation’s electric power.
by Tracey de Morsella, Green Economy Post
It turns out that grass (Marijuana) is not all that green, particularly if it is grown indoors. Evan Mills, Ph. D, a longtime energy analyst at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, last week released his independent study that examined the carbon footprint of the indoor marijuana industry.
In his report, Energy Up in Smoke: The Carbon Footprint of Indoor Cannabis, Mills reports that indoor Marijuana production, considered the largest cash crop in the U.S., with an annual production value estimated at about $40 billion, uses 1% of the nation’s entire electricity consumption. This comes to energy expenditures of $5 billion per year. This is due to the fact that Cannabis production has for the most part shifted indoors, were it is out-of-sight of law enforcement. This is particularly the case in California, which is the top producer among the 17 states to allow cultivation for medical purposes, where medical marijuana growers use high-intensity lights. These lights are usually reserved for operating rooms that are 500 times more powerful that a standard reading lamp.
Also driving the large energy requirements are 30 hourly air changes (6 times the rate in high-tech laboratories, and 60 times the rate in a modern home). The closest comparison for these massive, industrial-style grow facilities are data centers, which consume about two percent of the nation’s electric power.
“The yearly greenhouse-gas pollution”, Mills wrote. “the practice is responsible for about 3% of all electricity use or 8% of household use.
Marijuana production has raised other environmental concerns. Each Marijuana plant said to need between 3 and 5 gallons of water per day to grow to fruition, which significantly raises its carbon footprint. The Bay Citizen, a San Francisco publication, reported last year on the risk of pot being tainted with pesticides used by growers. Even though 17 states allow growing Marijuana for medical purposes, it is a controlled substance under federal law and U.S. regulatory agencies do not supervise how it is grown or monitor the pesticides used in its cultivation. Mills also notes that marijuana growers often raise indoor carbon dioxide levels to four-times natural levels to boost plant growth.
Broken down to the individual level, one Cannabis cigarette represents 2 pounds of CO2 emissions, an amount equal to running a 100-watt light bulb for 17 hours with average U.S. electricity. It has the greenhouse gas impact of driving 15 miles in a 44-mile-per-gallon car.
Mills, a member of the U.N. Intergovernmental Panel on Climate Change, compiled his data from open literature and interviews with horticultural equipment retailers. He conducted the study quantify a previously undocumented component of energy demand in the United States, to understand the underlying technical drivers, and to establish baseline impacts in terms of energy use, costs, and greenhouse-gas emissions.
Mills writes in his report that criminalization contributes to inefficient energy practices. Compared to electric grids, off-grid power production often produced more greenhouse-gas emissions, requiring 70 gallons of diesel fuel to produce one indoor Cannabis plant, or 140 gallons with smaller, less-efficient gasoline generators. He also describes how long driving distances and odor suppression measures take away from ventilation efficiencies. Mills also points out that the huge carbon footprint is caused by the lights, fans, and air filters need for indoor cultivation. Outdoor weed plantations do not have these types of energy use issues, and when managed correctly, do not have a significant environmental impact, but also suggests that there are solutions for indoor growers.
Mills observed that there are many reversible inefficiencies are embedded in current practices. “If improved practices applicable to commercial agricultural greenhouses are any indication, the energy use for indoor cannabis production can be reduced dramatically,” he said. “Cost-effective efficiency improvements of 75 percent are conceivable, which would yield energy savings of about $25,000/year for a generic 10-module growing room,” he wrote.
Eric Wesoff, at GreentechEnterprise suggests pot cultivation’s carbon footprint could be reduced by replacing metal halide and high-pressure sodium lights with more energy-efficient solid-state LED lighting. “This LED grow light site claims reductions in electricity usage of 40 percent to 75 percent compared MH or HPS lights. However, other sites in the indoor grow community have some reservations over the effectiveness of LEDs,” he wrote.
Mills provided the following recommendations for growers, communities, suppliers, utilities, regulators, and medical dispensaries:
Visit Mills’ web site to to read his study.
© 2011, Tracey de Morsella. All rights reserved. Do not republish.
Author: Tracey de Morsella (323 Articles)
Tracey de Morsella started her career working as an editor for US Technology Magazine. She used that experience to launch Delaware Valley Network, a publication for professionals in the Greater Philadelphia area. Years later, she used the contacts and resources she acquired to work in executive search specializing in technical and diversity recruitment. She has conducted recruitment training seminars for Wachovia Bank, the Department of Interior and the US Postal Service. During this time, she also created a diversity portal called The Multicultural Advantage and published the Diversity Recruitment Advertising Toolkit, a directory of recruiting resources for human resources professionals. Her career and recruitment articles have appeared in numerous publications and web portals including Woman Engineer Magazine, Monster.com, About.com Job Search Channel, Workplace Diversity Magazine, Society for Human Resource Management web site, NSBE Engineering Magazine, HR.com, and Human Resource Consultants Association Newsletter. Her work with technology professionals drew her to pursuing training and work in web development, which led to a stint at Merrill Lynch as an Intranet Manager. In March, she decided to combine her technical and career management expertise with her passion for the environment, and with her husband, launched The Green Economy Post, a blog providing green career information and covering the impact of the environment, sustainable building, cleantech and renewable energy on the US economy. Her sustainability articles have appeared on Industrial Maintenance & Plant Operation, Chem.Info,FastCompany and CleanTechies.