Indoor > Of High Times and Red Herrings

Energy up in Smoke:
The Carbon Footprint of Indoor Cannabis Production

A Low Point for High Times


You know you’re in trouble when the marijuana industry’s leading trade journal cites long-debunked claims by coal-industry hacks that the (unrelated) IT sector uses such-and-such amounts of energy as a reason why we somehow shouldn’t worry about the carbon footprint of indoor pot.  Who would have thunk it...?

As a case in point, after five years of no comment, High Times decided to review the study in the context of a cover story on “Indoor vs Outdoor”.   We offered the following set of corrections to the non-fact-checked review, excerpts of which they published on-line (see below).  Their response to that -- cast as a sort of pseudo debate -- repeated several misstatements, ignored a number of the corrections altogether, and misconstrued yet additional points about the original study. 


From: Evan Mills <>

Date: Mon, Apr 4, 2016 at 6:36 PM

Subject: Comments on Sirius J's two articles in the May Issue of High Times


To the Editor,

I thought it may be constructive to be in touch regarding the appraisal included in your May issue of the peer-reviewed research I published in 2012 on the energy use associated with indoor grows.  The two notes by your science editor, Sirius J, contain several of errors of fact and misinterpretations of the referenced study.  Details aside, it would be constructive for High Times to meet the energy question with proactive curiosity and a desire to pinpoint best practices regarding energy and environment. Clearly much more needs to be done and whether more research validated my exact findings or found the numbers too low or two high by a factor of two or whatever, the qualitative implications would be the same ... this is an under-attended issue that now deserves more attention.  Meanwhile, nothing provided in the High Times articles supports the statement that the original analysis is "wildly inflated". 

First the factual items:

  1. The 19 kWh/GB sound bite quoted in the first blurb is a completely fabricated number from coal-industry-funded crackpots, of all things, and was debunked more than two years ago (see, for example This is only the latest in a series of “analyses” by a group that has been repeatedly discredited repeatedly for a decade and a half.  It would have been best if High Times fact-checkers had caught this.

  2. The quoted 1500 TWh/year for the “tech industry” is way off. The entire national electricity use for all sectors is only twice that number.  Data centers (which is perhaps what they are trying to describe) are about 1/20th of that number.  

  3. The published greenhouse-gas emissions number is 4600 lbs/lb (source here), not 3000, as quoted by Sirius J, which is from a preliminary working paper.  While my analysis includes many contributing factors, it certainly does not include "nearly everything required to grow, process and transport" indoor cannabis.  In particular, it does not even capture the full picture, e.g., embodied energy in fertilizers, insecticides, energy associated with water production and handling, interstate transportation, creating extracts, downstream process energy for making extracts or edibles, building materials, etc.  

  4. The study states that indoor cannabis represents about 1% of US electricity consumption, not energy consumption (as stated by Sirius J) which would include direct uses of oil, gas, etc.  Big difference.

  5. The factoring in “all the different electricity sources” is not a problem, as implied in Sirius’ first missive. My analysis properly estimates the median situation (blend of the various ways electricity is generated around the US).  This is the only responsible way of calculating a representative weighted-average electric carbon footprint for the country.  Anything else would bias the result up (e.g. 100% diesel) or down (e.g. 100% renewable), and would defeat the purpose of the analysis.  For example, if you look at the fully off-grid diesel-powered producers, the footprint is 50% higher than US average (300% higher than using California’s relatively clean electric grid).  That said, subsequent analyses do point the way to particularly low-hanging fruit in terms of carbon emissions reduction potential.

  6. Vehicle use represents only 12% of the total carbon footprint shown in my analysis (this is not a “very significant” part of the total, as Sirius states).  More importantly, irrespective of how the product may be shipped, one must count all vehicle miles associated with production and delivery to point of shipment, as well as consumer travel at the retail end of the value chain.  Numbers will of course vary widely, but handicapping the analysis to include only the shipping stage is misleading and overlooks a lot of associated transportation energy.  

  7. The assumptions about fans are solidly representative of Mendocino county.  While other places or methodologies may differ, this is clearly a red herring in Sirius J’s missive.  In the analysis, oscillating fans are only about 8% of the total footprint – even if the real number was zero (hypothetically), this would be neither a “gross overestimate” nor a “significant” part of the overall energy use.  Sirius J's questionable “correction” reduces the electricity estimate by well over 50%, which is wrong on the face of it.  (I can’t reproduce his logic/analysis.  Sirius J may be working with the 27% in my chart, but that clearly includes fans, dehumidification, and fans in line with the lighting fixtures and even if completely eliminated wouldn’t yield the adjustment he’s claiming.)

Some broader perspective is important.  Without debating what portion of production goes to medical vs recreational use, the sad fact is that the US uses twice as much electricity and spends 6-times more money on it for indoor Cannabis than for all other pharmaceuticals combined. In any case, as noted above, both need to be addressed (not just the relatively large one).  

Aside from what the numbers do or don’t say, it’s not constructive to deflect attention away from one legitimate problem to an ostensibly bigger one. There is no one cause of climate change, and thus no one solution.  We need to find emissions reductions anywhere and everywhere we can. It is not a zero sum situation.  Cannabis is a rare “sector” where energy efficiency has sadly never been a serious focus – it is arguably four decades behind the rest of the economy when it comes to getting smart about energy using technology.


Many are waiting to see an industry more forthcoming about its carbon footprint and one that signals more interest in managing it and raising consumer awareness.  High Times has an opportunity to become part of that process.  To imply that the problem sits solely with the energy companies (and the fuels they choose to make electricity) surely addresses only half the problem.  Incumbent on media in particular is careful reading of their source documents and fact-checking that readers expect.


Evan Mills

Post-script:  High Times wrote the following response (last entry on this page).

Quickly, the following two mistakes that I pointed out originally were somehow repeated in HT’s response:

  1. HT repeats the error of stating that the study found indoor marijuana to use “1% of US energy”.  It is 1% of electricity, which makes a world of difference.

  2. You continue to cite the working paper, rather than the much more extensive final peer-reviewed journal article.

HT repeats their skepticism about numbers of fans assumed.  As pointed out before, this is a red herring, as the assumption has little meaningful impact on the results or the conclusions.

Some new points are raised, and confusion injected.

HT seems to say that dehumidification is only required in a closed-loop room.  That is certainly not the case in large swaths of the country (including California’s North Coast) where the outdoor humidity is higher than allowable indoors, not to mention the huge amounts of moisture introduced through irrigation.

Saying that running the lights at night eliminates the need for heating is quite odd.  At indoor set-points of 75-80F, there is clearly a need in most parts of the country to condition outside air when the lights are off (6h/day in veg and 12h/day in flower).  The converse is true for cooling.  Cooling loads will materialize whenever the outdoor air rises above the indoor set-point.  Of course, scheduling lighting to minimize HVAC needs is a fine thing to do.

The study does not assume that combustion is the sole way of introducing CO2; it also looks at compressed tanks.  They have embodied energy as well, for which citation is provided.  In any case, the humidity associated with this is another red herring (trivial compared to other sources).

Sorry, but the share of indoor versus outdoor production is not computed using relative potencies.  That would, as you say, be silly.  That said, assuming that a value from 2006 holds today would not be accurate; there has of course been a huge shift from indoor to outdoor since then.  The assumption used in the study comes from people working in the industry. In 5 years of quite high visibility no one has quibbled with the assumption.  Also, the study actually did not apply a growth rate to the c.2006 production level, and so that assumption is actually a conservatism in that regard.  In any case, whether the national energy cost is $6 billion per year (as estimated in the study) or $2 billion or $10 billion, the policy implications are effectively the same.  The problem cannot be waived away.

The question was raised about whether US pharmaceutical energy expenditures of $1 billion per year should be compared to that of Cannabis’ $6 billion per hear, given that 40% of the legal drugs americans take are manufactured overseas.  Another red herring.  The “adjusted comparison would be $1.7b vs $6b, which is still a factor of more than three higher.  There is no qualitative difference in the underlying point being made.

I actually have no “bias against the cannabis industry” or legitimate medical uses of its products, but, do have one against excessive avoidable energy use and associated greenhouse gases wherever they can be found.  Marijuana is hardly being singled out here.  On the contrary, it has had a free ride for decades while all other energy uses have had to come into the 21st century.

We are left where we started: an emergent environmental problem about which little is being done. Rather than waiting for unsympathetic regulators to step in, the industry would do well to be less defensive and more proactive about owning its history and moving forward into a greener future along with the rest of us.