California: A cannabis-climate train wreck in progress

Evan Mills, Ph.D.
9 min readDec 7, 2021

An analysis I performed ten long years ago found that the carbon footprint of electricity use in cannabis production in California (for legal and illegal activities combined), amounted to that of 1 million average homes or 1 million cars. With the rapid industrialization of cannabis cultivation over the intervening years (facilities well over 100,000 square feet are now being constructed — and sometimes grouped together in compounds with millions of square feet), energy use may be higher … or lower … no one knows. California policymakers are flying blind regarding the current carbon footprint of this burgeoning industry. Surely, they would not want this fledgling industry to negate the hard-won greenhouse-gas reductions earned through decades of effort. Alas, read on.

California is not only a symbol of progressive environmental thought, it has long been an engine for innovative environmental technologies and policies. Many of the nation’s leading energy research and policy centers are located in the state, the utilities have been in the vanguard as developers of energy efficiency programs and policies for many decades, and California is one of the top states in the nation in terms of renewable energy production. State legislators have passed some of the most far-reaching climate change policies and targets in the world, notably State Bill 32 (SB 32), the California Global Warming Solutions Act of 2006 which aims to reduce statewide greenhouse-gas emissions to a level 40% below 1990 levels by the year 2030.

Yet, a quiet but potent countervailing challenge to the attainment of these goals is ticking deep within in the regulatory structure established for the cannabis industry, which is codified in the Medicinal and Adult-Use Cannabis Regulation and Safety Act (MAUCRSA). Seemingly prior to any rigorous analysis of energy impacts, MAUCRSA dictated that indoor cultivation was integral to the broader goal of legalization, creating a preordained “purpose” that cannot be trumped by subsequent environmental considerations.

At a higher level, the state’s flagship California Environmental Quality Act (CEQA) guidelines for development set a high bar for industries such as cannabis by stipulating that “[i]f analysis of the project’s energy use reveals that the project may result in significant environmental effects due to wasteful, inefficient, or unnecessary use of energy, or wasteful use of energy resources, the EIR [Environmental Impact Report] shall mitigate that energy use. This analysis should include the project’s energy use for all project phases and components, including transportation-related energy, during construction and operation.” Project owners are also required to make good-faith estimates of long-term greenhouse-gas impacts and give more consideration to water issues [CEQA Guideline §§15064.4, 15155].

These safeguards are well-founded in the case of cannabis. I recently completed a couple of calculations that are truly shocking.

The first one involves a thought experiment to see how much “rooftop solar” it would take to “zero-out” all the energy needed by indoor grow facility. Even in areas with excellent solar availability, less than 5% of a facility’s electricity needs could be generated on the roof (and none in the case of greenhouses). One noted large-scale facility aiming to be as sustainable as possible achieved a solar contribution of about 30% (Daniels 2019), which presumably required using a very large area of land beyond the building footprint. A ‘state-of-the-art’ facility in Canada is projecting to offset only 8% to 10% of its electricity use by covering its entire roof (CBC 2019b), emitting approximately 9,000 tons of CO2 per year instead of 10,000 tons without the solar. Among the nation’s largest proposed facilities, with 2.4 million square feet of enclosed “cannabis industrial park”, would only provide 4% of the needed electricity from its rooftops, despite being in an optimal solar resource area on the California-Arizona border. Meeting the full electricity demand would require approximately 1,400 acres of photovoltaic panel area. An 80-megawatt dedicated natural-gas power plant is instead proposed to provide energy (Kidder Mathews 2019). Such a generator would need to produce 1.23 TWh-year. That’s enough to power 90,000 average U.S. all-electric homes.

Hypothetical solar PV area requirements for proposed cannabis industrial park in Blythe, California. Array area range represents the annual electricity intensity (kWh/square foot) estimated by Mills (2012), similar to that measured in nearby Nevada (NFD 2018). Solar output per unit area estimated by Sage Energy using Helioscope software.

Alternatively, it might be argued that cannabis industry could be powered with centralized renewable energy, the amounts required are prodigious and for practical purposes (e.g., land-use constraints) rarely achievable. Although California’s Coachella Valley is one of the largest wind-energy production areas in that state, cannabis production there (assuming business-as-usual energy efficiencies) will soon eclipse the entire output of all 40 wind-power projects located in the area (Figure). Full build-out of existing cannabis facility entitlements in the Coachella Valley would consume far more: 11-times as much power as can be produced by all existing wind systems in the area, and more than all the wind power generated across all of California. It has taken decades and the dedication of vast land areas to build up this level of wind-generation capacity. From a broader public-policy vantage point, there is an acute shortage of investment in renewable energy infrastructure to offset even existing carbon emissions, let alone emissions growth from new energy-intensive development. This comparison serves as a poignant illustration of the broader problematic tension between advances in renewable energy supply and unbridled growth in energy demand.

California’s Coachella Valley is the site of 10% of the State’s wind energy production. Cannabis cultivation facilities already in operation in five cities within the Coachella Valley require 13% of the entire electricity production of the 40 wind energy projects (2,229 turbines) located throughout the valley. This will grow to more than 70% as the area’s total wind energy output upon completion of cannabis-facility projects proposed or under development. Full build-out per existing entitlements will consume eleven-times as much power, significantly exceeding the 14 TWh/year generated by wind power in all of California. Sources: photo of turbines from ecoflight.com, with permission; satellite view from USGS (2019); interior of cultivation facility from systemsnspace.com, with permission; Rendering of Venlo type glasshouse by Sunniva (under construction), with permission.

Estimated cultivated area development status in five Coachella Valley cities, based on data gathered by Simmons in 2019, with 350,000 square feet of “canopy” as of April 2019, 19.4 million square feet proposed or under development, and 30 million square feet entitled. Energy intensity is that calculated by Mills (2012). Note that while NFD (2018) cites lower average electricity intensity for some states, their value for the one desert state (Nevada) in their sample is virtually identical to that used here for a California desert location. Wind energy generating capacity values are from USGS (2019) and associated energy production from CEC (2019). Average production rates for 26 projects (475 MW) in the area (2.23 GWh/MW) are applied to the total installed 663 MW for the area to estimate total electricity production.

Here’s another illustration of the emerging madness. Even in areas with excellent solar availability, only about 5% of a facility’s electricity needs could be generated on the roof (Mills 2018). One noted large-scale facility aiming to be as sustainable as possible achieved a solar contribution of about 30% (Daniels 2019), which presumably required using a very large area of land beyond the building footprint. A ‘state-of-the-art’ facility in Canada is projecting to offset only 8% to 10% of its electricity use by covering its entire roof (CBC 2019b), emitting approximately 9,000 tons of CO2 per year instead of 10,000 tons without the solar. Among the nation’s largest proposed facilities, with 2.4 million square feet of enclosed “cannabis industrial park”, would only provide 4% of the needed electricity from its rooftops, despite being in an optimal solar resource area on the California-Arizona border. Meeting the full electricity demand would require approximately 1,400 acres of photovoltaic panel area.[1] An 80-megawatt dedicated natural-gas powerplant is instead proposed to provide energy (Kidder Mathews 2019). Such a generator would need to produce 1.23 TWh-y, enough to power 90,000 average U.S. all-electric homes (Figure 3).

[1] Array area range represents the annual electricity intensity (kWh/square foot) estimated by Mills (2012), similar to that measured in nearby Nevada (NFD 2018). Solar output per unit area estimated by Sage Energy using Helioscope software.

Remarkably, despite available evidence, the state’s Department of Consumer Affairs initial CEQA analysis of proposed regulations for licensing of cannabis businesses (applicable to cultivation operations up to 10,000 square feet) in California arrived at a “Negative Declaration”, indicating a perception of negligible environmental impacts (Bureau of Cannabis Control 2017). The report deemed the energy-related impacts as “Less Than Significant”. A parallel Environmental Impact Report (EIR), prepared by the California Department of Food and Agriculture (CDFA), examined the larger-scale cultivation and “track-and-trace” system for product distribution. The CDFA report concedes that “[d]ue to the proprietary and often illicit nature of past and current cannabis cultivation activities, limited accurate and reliable data are available … sufficient detail is not available to determine whether this [legalization] could result in a meaningful change in energy use and GHG emissions compared to baseline conditions” (California Department of Food and Agriculture 2017). They thus undertake a “qualitative” rather than “quantitative” analysis.

Despite their enormous caveat, the EIR takes several leaps of faith to conclude that the legalization program will be “beneficial” to attaining the State’s greenhouse-gas emission reduction goals. They achieve this feat by assuming that overall cannabis production levels will not rise materially following legalization, while the legal fraction of total statewide production will increase from approximately 5% to 10% of the state totals (the rest being black market) and that this increment will automagically conform with the state’s SB emissions-reduction target. Thus, thanks to quick arithmetic, the overall average emissions would be (slightly) lower than without legalization. Additional (seemingly irrelevant) benefits are claimed via improvements in non-greenhouse-gas emissions by diesel generators (with perhaps some assumed efficiency gains therein). Moreover, in practice, diesel generators are rarely if ever used by legal operators, so this is a largely irrelevant claim of benefits. The document predicts a “small increase” in indoor cultivation, but does not document or quantify this heroic assumption or anticipate the fact that localities are forcing large numbers of legal projects indoors. In an additional oversight, no serious consideration seems to be given to potential increases (due to regulatory requirements) in transportation energy use and thus emissions given the large number of times that the product must be transported among intermediaries before reaching the point of sale.

To their credit, the EIR finds that: “a ‘No High-Intensity Grow Light’ alternative is considered environmentally superior [to other alternatives]. This alternative would focus cultivation activities on outdoor and mixed-light techniques using natural lighting and would prohibit indoor cultivation and some mixed-light cultivation techniques that rely solely or partially on high-intensity grow lights.” However, this option is ultimately rejected because of the requirement under MAUCRSA that indoor cultivation be allowed. The even more environmentally superior alternative of restricting cultivation to outdoor farming (as is most of the other agriculture in the state), was dismissed as well.

The net effect of these machinations is that California has thus far failed to grasp a rapidly-closing window of opportunity to manage energy use and greenhouse-gas emissions from the cannabis industry. California is:

  • Allowing a degree of statewide development that cannot be met by renewable energy
  • Establishing an onerous post-prohibition regulatory regime that is compelling producers to return to the black market and its covert, energy-intensive practices
  • Fostering cannabis development in some of the harshest climates in the state, leading to higher energy use
  • Forcing cannabis cultivation to be done only indoors in many localities, per decisions made at the city/county level
  • Providing financial incentives to indoor producers (via utility rebates), without corresponding incentives to outdoor producers who save even more energy
  • Not investing in R&D on how to manage energy and greenhouse-gas emissions in this sector

To their credit, a few localities have made preliminary efforts to manage energy use and emissions. Yet, only 3 of 58 counties have implemented regulations calling for renewable energy and/or limits on energy use (California Department of Food and Agriculture 2017). Unfortunately, the very low stipulated energy budgets (e.g., 6 to 10 kWh/square foot per year) called for are not achievable in practice in indoor facilities and thus presumably are being disregarded by cultivators.

What’s wrong with this picture?

References

Bureau of Cannabis Control. 2017. “Commercial Cannabis Business Licensing Program Regulations: Initial Study/Negative Declaration.” 491pp.

California Department of Food and Agriculture. 2017. “CalCannabis Cultivation Licensing: Final Program Environmental Impact Report.” 534pp.

California Energy Commission. 2019. “Electricity from Wind Energy: Statistics and Data.”

CBC. 2019b. “Solar Pot: Alberta Cannabis Producer Unveils Rooftop Solar System.” Canadian Broadcasting Corporation, CBC News, November 12.

Daniels, Melissa. 2019. “A Model of Sustainable Commerce: Carbon Footprint, Grid Concerns Push SoCal Weed Industry to Be More Green.” Desert Sun. October 10.

Kidder Mathews. 2019. “Prospectus for Palo Verde Center Cannabis Industrial Park, Blythe, California.” 15pp.

U.S. Geologic Survey. 2019. “The U.S. Wind Turbine Database.”

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Evan Mills, Ph.D.

Energy & environment scientist, with 40 years experience developing and advancing climate change solutions. http://evanmills.lbl.gov