ArticlePDF Available

The Carbon Footprint of Indoor Cannabis Production

Authors:
  • Lawrence Berkeley National Laboratory (Retiree Affiliate)

Abstract and Figures

The emergent industry of indoor Cannabis production -- legal in some jurisdictions and illicit in others -- utilizes highly energy intensive processes to control environmental conditions during cultivation. This article estimates the energy consumption for this practice in the United States at 1% of national electricity use, or $6 billion each year. One average kilogram of final product is associated with 4600kg of carbon dioxide emissions to the atmosphere, or that of 3 million average U.S. cars when aggregated across all national production. The practice of indoor cultivation is driven by criminalization, pursuit of security, pest and disease management, and the desire for greater process control and yields. Energy analysts and policymakers have not previously addressed this use of energy. The unchecked growth of electricity demand in this sector confounds energy forecasts and obscures savings from energy efficiency programs and policies. While criminalization has contributed to the substantial energy intensity, legalization would not change the situation materially without ancillary efforts to manage energy use, provide consumer information via labeling, and other measures. Were product prices to fall as a result of legalization, indoor production using current practices could rapidly become non-viable.
Content may be subject to copyright.
The carbon footprint of indoor Cannabis production
Evan Mills
Energy Associates, Box 1688, Mendocino, CA 95460, United States
article info
Article history:
Received 7 September 2011
Accepted 10 March 2012
Available online 17 April 2012
Keywords:
Energy
Buildings
Horticulture
abstract
The emergent industry of indoor Cannabis production – legal in some jurisdictions and illicit in others
utilizes highly energy intensive processes to control environmental conditions during cultivation. This
article estimates the energy consumption for this practice in the United States at 1% of national
electricity use, or $6 billion each year. One average kilogram of final product is associated with 4600 kg
of carbon dioxide emissions to the atmosphere, or that of 3 million average U.S. cars when aggregated
across all national production. The practice of indoor cultivation is driven by criminalization, pursuit of
security, pest and disease management, and the desire for greater process control and yields. Energy
analysts and policymakers have not previously addressed this use of energy. The unchecked growth of
electricity demand in this sector confounds energy forecasts and obscures savings from energy
efficiency programs and policies. While criminalization has contributed to the substantial energy
intensity, legalization would not change the situation materially without ancillary efforts to manage
energy use, provide consumer information via labeling, and other measures. Were product prices to fall
as a result of legalization, indoor production using current practices could rapidly become non-viable.
&2012 Elsevier Ltd. All rights reserved.
1. Introduction
On occasion, previously unrecognized spheres of energy use
come to light. Important historical examples include the perva-
sive air leakage from ductwork in homes, the bourgeoning energy
intensity of computer datacenters, and the electricity ‘‘leaking’’
from billions of small power supplies and other equipment.
Intensive periods of investigation, technology R&D, and policy
development gradually ensue in the wake of these discoveries.
The emergent industry of indoor Cannabis production appears to
have joined this list.
1
This article presents a model of the modern-day production
process – based on public-domain sources – and provides first-
order national scoping estimates of the energy use, costs, and
greenhouse-gas emissions associated with this activity in the
United States. The practice is common in other countries but a
global assessment is beyond the scope of this report.
2. Scale of activity
The large-scale industrialized and highly energy-intensive
indoor cultivation of Cannabis is a relatively new phenomenon,
driven by criminalization, pursuit of security, pest and disease
management, and the desire for greater process control and yields
(U.S. Department of Justice, 2011a; World Drug Report, 2009). The
practice occurs across the United States (Hudson, 2003;Gettman,
2006). The 415,000 indoor plants eradicated by authorities in
2009 (and 10.3 million including outdoor plantations) (U.S.
Department of Justice, 2011a, b) presumably represent only a
small fraction of total production.
Cannabis cultivation is today legal in 15 states plus the District
of Columbia, although it is not federally sanctioned (Peplow,
2005). It is estimated that 24.8 million Americans are eligible to
receive a doctor’s recommendation to purchase or cultivate
Cannabis under existing state laws, and approximately 730,000
currently do so (See Change Strategy, 2011). In California alone,
400,000 individuals are currently authorized to cultivate Cannabis
for personal medical use, or sale for the same purpose to 2100
dispensaries (Harvey, 2009). Approximately 28.5 million people
in the United States are repeat consumers, representing 11%
of the population over the age of 12 (U.S. Office of National
Drug Control Policy, 2011).
Cultivation is also substantial in Canada. An estimated 17,500
‘‘grow’’ operations in British Columbia (typically located in residen-
tial buildings) are equivalent to 1% of all dwelling units Province-
wide, with an annual market value of $7 billion (Easton, 2004).
Official estimates of total U.S. Cannabis production varied from
10,000 to 24,000 metric ton per year as of 2001, making it the
nation’s largest crop by value at that time (Hudson, 2003;
Gettman, 2006). A recent study estimated national production
at far higher levels (69,000 metric ton) (HIDTA, 2010). Even at the
Contents lists available at SciVerse ScienceDirect
journal homepage: www.elsevier.com/locate/enpol
Energy Policy
0301-4215/$ - see front matter &2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.enpol.2012.03.023
E-mail address: evanmills1@gmail.com
1
This article substantively updates and extends the analysis described in
Mills (2011).
Energy Policy 46 (2012) 58–67
lower end of this range (chosen as the basis of this analysis), the
level of activity is formidable and increasing with the demand for
Cannabis.
No systematic efforts have previously been made to estimate
the aggregate energy use of these activities.
3. Methods and uncertainties
This analysis is based on a model of typical Cannabis produc-
tion, and the associated energy use for cultivation and transporta-
tion based on market data and first-principals buildings energy
end-use modeling techniques. Data sources include equipment
manufacturer data, trade media, the open literature, and inter-
views with horticultural equipment vendors. All assumptions
used in the analysis are presented in Appendix A. The resulting
normalized (per-kilogram) energy intensity is driven by the
effects of indoor-environmental conditions, production processes,
and equipment efficiencies.
Considerable energy use is also associated with transportation,
both for workers and for large numbers of small-quantities trans-
ported and then redistributed over long distances before final sale.
This analysis reflects typical practices, and is thus intended as
a ‘‘central estimate’’. While processes that use less energy on a
per-unit-yield basis are possible, much more energy-intensive
scenarios also occur. Certain strategies for lowering energy inputs
(e.g., reduced illumination levels) can result in lower yields, and
thus not necessarily reduce the ultimate energy-intensity per unit
weight. Only those strategies that improve equipment and pro-
cess energy efficiency, while not correspondingly attenuating
yields would reduce energy intensity.
Due to the proprietary and often illicit nature of Cannabis
cultivation, data are intrinsically uncertain. Key uncertainties are
total production and the indoor fraction thereof, and the corre-
sponding scaling up of relatively well-understood intensities of
energy use per unit of production to state or national levels could
result in 50% higher or lower aggregate results. Greenhouse-gas
emissions estimates are in turn sensitive to the assumed mix of
on- and off-grid power production technologies and fuels, as off-
grid production (almost universally done with diesel generators)
can – depending on the prevailing fuel mix in the grid – have
substantially higher emissions per kilowatt-hour than grid power.
Final energy costs are a direct function of the aforementioned
factors, combined with electricity tariffs, which vary widely
geographically and among customer classes. The assumptions
about vehicle energy use are likely conservative, given the longer-
range transportation associated with interstate distribution.
Some localities (very cold and very hot climates) will see much
larger shares of production indoors, and have higher space-
conditioning energy demands than the typical conditions
assumed here. More in-depth analyses could explore the varia-
tions introduced by geography and climate, alternate technology
configurations, and production techniques.
4. Energy implications
Accelerated electricity demand growth has been observed in
areas reputed to have extensive indoor Cannabis cultivation. For
example, following the legalization of cultivation for medical
purposes (Phillips, 1998;Roth, 2005;Clapper et al., 2010)in
California in 1996, Humboldt County experienced a 50% rise in
per-capita residential electricity use compared to other parts of
the state (Lehman and Johnstone, 2010).
Aside from sporadic news reports (Anderson, 2010;Quinones,
2010), policymakers and consumers possess little information on
the energy implications of this practice. A few prior studies
tangentially mentioning energy use associated with Cannabis
production used cursory methods and under-estimate energy
use significantly (Plecas et al., 2010 and Caulkins, 2010).
Driving the large energy requirements of indoor production
facilities are lighting levels matching those found in hospital
operating rooms (500-times greater than recommended for read-
ing) and 30 hourly air changes (6-times the rate in high-tech
laboratories, and 60-times the rate in a modern home). Resulting
power densities are on the order of 2000 W/m
2
, which is on a par
with that of modern datacenters. Indoor carbon dioxide (CO
2
)
levels are often raised to 4-times natural levels in order to boost
plant growth. However, by shortening the growth cycle, this
practice may reduce final energy intensity.
Specific energy uses include high-intensity lighting, dehumi-
dification to remove water vapor and avoid mold formation, space
heating or cooling during non-illuminated periods and drying,
pre-heating of irrigation water, generation of carbon dioxide by
burning fossil fuel, and ventilation and air-conditioning to remove
waste heat. Substantial energy inefficiencies arise from air clean-
ing, noise and odor suppression, and inefficient electric generators
used to avoid conspicuous utility bills. So-called ‘‘grow houses’’ –
residential buildings converted for Cannabis production – can
contain 50,000 to 100,000 W of installed lighting power (Brady,
2004). Much larger facilities are also used.
Based on the model developed in this article, approximately
13,000 kW/h/year of electricity is required to operate a standard
production module (a 1.2 1.2 2.4 m (4 48 ft) chamber). Each
module yields approximately 0.5 kg (1 pound) of final product
per cycle, with four or five production cycles conducted per year.
A single grow house can contain 10 to 100 such modules.
To estimate national electricity use, these normalized values
are applied to the lower end of the range of the aforementioned
estimated production (10,000 t per year), with one-third of the
activity takes place under indoor conditions. This indicates
electricity use of about 20 TW/h/year nationally (including off-
grid production). This is equivalent to that of 2 million average
U.S. homes, corresponding to approximately 1% of national
electricity consumption or the output of 7 large electric power
plants (Koomey et al., 2010). This energy, plus associated fuel uses
(discussed below), is valued at $6 billion annually, with asso-
ciated emissions of 15 million metric ton of CO
2
equivalent to
that of 3 million average American cars (Fig. 1 and Tables 1–3.)
Fuel is used for several purposes, in addition to electricity. The
carbon dioxide injected into grow rooms to increase yields is
produced industrially (Overcash et al., 2007) or by burning propane
or natural gas within the grow room contributes about 1–2% to the
carbon footprint and represents a yearly U.S. expenditure of $0.1
billion. Vehicle use associated with production and distribution
contributes about 15% of total emissions, and represents a yearly
expenditure of $1 billion. Off-grid diesel- and gasoline-fueled
electric generators have per-kilowatt-hour emissions burdens that
are 3- and 4-times those of average grid electricity in California. It
requires 70 gallon of diesel fuel to produce one indoor Cannabis
plant (or the equivalent yield per unit area), or 140 gallon with
smaller, less-efficient gasoline generators.
In California, the top-producing state, indoor cultivation is
responsible for about 3% of all electricity use, or 9% of household
use.
2
This corresponds to the electricity use of 1 million average
California homes, greenhouse-gas emissions equal to those from
1 million average cars, and energy expenditures of $3 billion per
2
This is somewhat higher than estimates previously made for British
Columbia, specifically, 2% of total Provincial electricity use or 6% of residential
use (Garis, 2008;Bellett, 2010).
E. Mills / Energy Policy 46 (2012) 58–67 59
year. Due to higher electricity prices and cleaner fuels used to
make electricity, California incurs 50% of national energy costs but
contributes only 25% of national CO
2
emissions from indoor
Cannabis cultivation.
From the perspective of individual consumers, a single Cannabis
cigarette represents 1.5 kg (3 pounds) of CO
2
emissions, an amount
equal to driving a 44 mpg hybrid car 22 mile or running a 100-watt
light bulb for 25 h, assuming average U.S. electricity emissions. The
electricity requirement for one single production module equals that
of an average U.S. home and twice that of an average California
home. The added electricity use is equivalent to running about 30
refrigerators.
From the perspective of a producer, the national-average
annual energy costs are approximately $5500 per module or
$2500 per kilogram of finished product. This can represent half
the wholesale value of the finished product (and a substantially
lower portion at retail), depending on local conditions. For
average U.S. conditions, producing one kilogram of processed
Cannabis results in 4600 kg of CO
2
emissions to the atmosphere
(and 50% more when off-grid diesel power generation is used), a
very significant carbon footprint. The emissions associated with
one kilogram of processed Cannabis are equivalent to those of
driving across country 11 times in a 44-mpg car.
These results reflect typical production methods. Much more
energy-intensive methods occur, e.g., rooms using 100% recircu-
lated air with simultaneous heating and cooling, hydroponics,
or energy end uses not counted here such as well-water pumps
and water purification systems. Minimal information and con-
sideration of energy use, coupled with adaptations for security
and privacy (off-grid generation, no daylighting, odor and noise
control) lead to particularly inefficient configurations and corre-
spondingly elevated energy use and greenhouse-gas emissions.
The embodied energy of inputs such as soil, fertilizer, water,
equipment, building materials, refinement, and retailing is not
estimated here and should be considered in future assessments.
The energy use for producing outdoor-grown Cannabis (approxi-
mately two-thirds of all production) is also not estimated here.
Mechanically
ventilated light fixture
Ballast
High-intensity lamps
Motorized lamp
rails
Heater Water purifier
CO2
generator Pump
Submersible
water heater
Vehicles
Dehumidifier
In-line duct fan,
coupled to lights
Oscillating fan Room fan
Chiller
Controllers
Powered
carbon filter
Ozone
generator
Fig. 1. Carbon footprint of indoor Cannabis production.
Table 1
Carbon footprint of indoor Cannabis production, by end use (average U.S
conditions).
Energy intensity
(kW/h/kg yield)
Emissions factor (kgCO
2
emissions/kg yield)
Lighting 2283 1520 33%
Ventilation &
dehumid.
1848 1231 27%
Air conditioning 1284 855 19%
Space heat 304 202 4%
CO
2
injected to
increase foliage
93 82 2%
Water handling 173 115 2%
Drying 90 60 1%
Vehicles 546 12%
Total 6074 4612 100%
Note: The calculations are based on U.S.-average carbon burdens of 0.666 kg/kW/h.
‘‘CO
2
injected to increase foliage’’ represents combustion fuel to make on-site CO
2
.
Assumes 15% of electricity is produced in off-grid generators.
E. Mills / Energy Policy 46 (2012) 58–6760
If improved practices applicable to commercial agricultural
greenhouses are any indication, such large amounts of energy are
not required for indoor Cannabis production.
3
The application of
cost-effective, commercially-available efficiency improvements to
the prototypical facility modeled in this article could reduce
energy intensities by at least 75% compared to the typical-
efficiency baseline. Such savings would be valued at approxi-
mately $40,000/year for a generic 10-module operation (at
California energy prices and $10,000/year at U.S. average prices)
(Fig. 2(a)–(b). These estimated energy use reductions reflect
practices that are commonplace in other contexts such as more
efficient components and controls (lights, fans, space-condition-
ing), use of daylight, optimized air-handling systems, and reloca-
tion of heat-producing equipment out of the cultivation room.
Moreover, strain choice alone results in a factor-of-two difference
in yields per unit of energy input (Arnold, 2011).
5. Energy intensities in context
Policymakers and other interested parties will rightfully seek
to put these energy indicators in context with other activities in
the economy.
One can readily identify other energy end-use activities with
far greater impacts than that of Cannabis production. For example,
automobiles are responsible for about 33% of U.S. greenhouse-gas
emissions (USDOE, 2009), which is100-times as much as those
produced by indoor Cannabis production (0.3%). The approxi-
mately 20 TW/h/year estimated for indoor Cannabis production
is about one/third that of U.S. data centers (US EPA, 2007a,
2007b), or one-seventh that of U.S. household refrigerators
(USDOE, 2008). These shares would be much higher in states
where Cannabis cultivation is concentrated (e.g., one half that of
refrigerators in California (Brown and Koomey, 2002)).
On the other hand, this level of energy use is high in compari-
sion to that used for other indoor cultivation practices, primarily
owing to the lack of daylighting. For comparison, the energy
intensity of Belgian greenhouses is estimated at approximately
1000 MJ/m
2
(De Cock and Van Lierde, No date), or about 1% that
estimated here for indoor Cannabis production.
Table 2
Equivalencies.
Indoor Cannabis production consumesy3% of California’s total
electricity, and
9% of California’s
household electricity
1% of total U.S.
electricity,
and
2% of U.S.
household
electricity
U.S. Cannabis production & distribution
energy costsy
$6 Billion, and results in the
emissions of
15 Million tonnes per
year of greenhouse
gas emissions (CO
2
)
Equal to the
emissions of
3million
average cars
U.S. electricity use for Cannabis
production is equivalent to that ofy
1.7 Million average U.S.
homes
or 7 Average U.S. power
plants
California Cannabis production and
distribution energy costs...
$3 Billion, and results in the
emissions of
4Million tonnes per
year of greenhouse
gas emissions (CO
2
)
Equal to the
emissions of
1Million
average cars
California electricity use for Cannabis
production is equivalent to that ofy
1Million average California
homes
A typical 4 48-ft production module,
accomodating four plants at a time,
consumes as much electricity asy
1Average U.S. homes, or 2Average California
homes
or 29 Average new
refrigerators
Every 1 kilogram of Cannabis produced
using national-average grid power
results in the emissions ofy
4.3 Tonnes of CO
2
Equiva-
lent to
7Cross-country trips
in a 5.3 l/100 km
(44 mp g) car
Every 1 kg of Cannabis produced using a
prorated mix of grid and off-grid
generators results in the emissions
ofy
4.6 Tonnes of CO
2
Equiva-
lent to
8Cross-country trips
in a 5.3 l/100 km
(44 mp g) car
Every 1 kg of Cannabis produced using
off-grid generators results in the
emissions ofy
6.6 Tonnes of CO
2
Equiva-
lent to
11 Cross-country trips
in a 5.3 l/100 km
(44 mp g) car
Transportation (wholesaleþretail)
consumesy
226 Liters of gasoline per kg or $1 Billion dollars
annually, and
546 Kilograms of
CO
2
per
kilogram of
final product
One Cannabis cigarette is like drivingy37 km in a 5.3 l/100 km
(44 mpg) car
Emitting
about
2kg of CO
2
, which is
equivalent to
operating a 100-watt
light bulb for
25 Hours
Of the total wholesale pricey49% Is for energy (at average
U.S. prices)
3
See, e.g., this University of Michigan resource: http://www.hrt.msu.edu/
energy/Default.htm
E. Mills / Energy Policy 46 (2012) 58–67 61
Energy intensities can also be compared to those of other
sectors and activities.
Pharmaceuticals Energy represents 1% of the value of
U.S. pharmaceutical shipments (Galitsky et al., 2008) versus
50% of the value of Cannabis wholesale prices. The U.S.
‘‘Pharma’’ sector uses $1 billion/year of energy; Indoor Canna-
bis uses $6 billion.
Other industries Defining ‘‘efficiency’’ as how much energy is
required to generate economic value, Cannabis comes out the
highest of all 21 industries (measured at the three-digit SIC
level). At 20 MJ per thousand dollars of shipment value
(wholesale price), Cannabis is followed next by paper (14),
nonmetallic mineral products (10), primary metals (8),
petroleum and coal products (6), and then chemicals (5)
(Fig. 3). However, energy intensities are on a par with Cannabis
in various subsectors (e.g., grain milling, wood products, rubber)
and exceed those of Cannabis in others (e.g., pulp mills).
Alcohol The energy used to produce one marijuana cigarette
would also produce 18 pints of beer (Galitsky et al., 2003).
Other building types Cannabis production requires 8-times
as much energy per square foot as a typical U.S. commercial
building (4x that of a hospital and 20x that of a building for
religious worship), and 18-times that of an average U.S. home
(Fig. 4).
6. Outdoor cultivation
Shifting cultivation outdoors can nearly eliminate energy use
for the cultivation process. Many such operations, however, require
water pumping as well as energy-assisted drying techniques.
Moreover, vehicle transport during production and distribution
remains part of the process, more so than for indoor operations.
A common perception is that the potency of Cannabis pro-
duced indoors exceeds that of that produced outdoors, leading
Table 3
Energy indicators (average U.S. conditions).
per cycle, per
production
module
per year, per
production
module
Energy use
Connected load 3,225 (watts/module)
Power density 2,169 (watts/m
2
)
Elect 2756 12,898 (kW/h/module)
Fuel to make CO
2
0.3 1.6 (GJ)
Transportation fuel 27 127 (Gallons
On-grid results
Energy cost 846 3,961 $/module
Energy cost 1,866 $/kg
Fraction of wholesale price 47%
CO
2
emissions 1936 9,058 kg
CO
2
emissions 4,267 kg/kg
Off-grid results (diesel)
Energy cost 1183 5,536 $/module
Energy cost 2,608 $/kg
Fraction of wholesale price 65%
CO
2
emissions 2982 13,953 kg
CO
2
emissions 6,574 kgCO
2
/kg
Blended on/off grid results
Energy cost 897 4,197 $/module
Energy cost 1,977 $/kg
Fraction of wholesale price 49%
CO
2
emissions 2093 9,792 kg
CO
2
emissions 4,613 kgCO
2
/kg
Of which, indoor CO
2
production
9 42 kgCO
2
Of which, vehicle use
Fuel use
During production 79 Liters/kg
Distribution 147 Liters/kg
Cost
During production 77 $/kg
Distribution 143 $/kg
Emissions
During production 191 kgCO
2
/kg
Distribution 355 kgCO
2
/kg
0
1000
2000
3000
4000
5000
6000
7000
8000
Worst Average Improved
Carbon Footprint (kgCO2/kg finished Cannabis)
Vehicles
Drying
Water handling
CO2 injected to increase foliage
Space heat
Air conditioning
Ventilation & Dehumid.
Lighting
54%
12%
41%
34%
8%
0
500
1000
1500
2000
2500
3000
Worst Average Improved
Electricity Cost ($/kg finsihed Cannabis)
California residential
65% (energy cost as % of wholesale value)
electricity price
US residential
electricity price
Fig. 2. Carbon footprint and energy cost for three levels of efficiency. (a) Indoor
cannabis: carbon footprint. (b) Indoor cannabis: electricity cost. Assumes a
wholesale price of $4400/kg. Wholesale prices are highly variable and poorly
documented.
Fig. 3. Comparative energy intensities, by sector (2006).
E. Mills / Energy Policy 46 (2012) 58–6762
consumers to demand Cannabis produced indoors. Federal sources
(National Drug Intelligence Center, 2005) as well as independent
testing laboratories (Kovner, 2011) actually find similar potencies
when best practices are used.
Illegal clearing of land is common for multi-acre plantations, and,
depending on the vegetation type, can accordingly mobilize green-
house-gas emissions. Standing forests (a worst-case scenario) hold
from 125 to 1500 t of CO
2
per hectare, depending on tree species,
age, and location (National Council for Air and Soil Improvement,
2010). For biomass carbon inventories of 750 t/ha and typical yields
(5000 kg/ha) (UNODC, 2009), associated biomass-related CO
2
emis-
sions would be on the order of 150 kg CO
2
/kg Cannabis (for only one
harvest per location), or 3% of that associated with indoor produc-
tion. These sites typically host on the order of 10,000 plants,
although the number can go much higher (Mallery, 2011). When
mismanaged, the practice of outdoor cultivation imposes multiple
environmental impacts aside from energy use. These include defor-
estation; destruction of wetlands, runoff of soil, pesticides, insecti-
cides, rodenticides, and human waste; abandoned solid waste; and
unpermitted impounding and withdrawals of surface water
(Mallery, 2011;Revelle, 2009). These practices can compromise
water quality, fisheries, and other ecosystem services.
7. Policy considerations
Current indoor Cannabis production and distribution practices
result in prodigious energy use, costs, and unchecked greenhouse-
gas pollution. While various uncertainties exist in the analysis,
the overarching qualitative conclusions are robust. More in-depth
analysis and greater transparency of the energy impacts of this
practice could improve decision-making by policymakers and
consumers alike.
There is little, if any, indication that public policymakers have
incorporated energy and environmental considerations into their
deliberations on Cannabis production and use. There are addi-
tional adverse impacts of the practice that merit attention,
including elevated moisture levels associated with indoor cultiva-
tion that can cause extensive damage to buildings,
4
as well as
electrical fires caused by wiring out of compliance with safety
codes (Garis, 2008). Power theft is common, transferring those
energy costs to the general public (Plecas et al., 2010). As noted
above, simply shifting production outdoors can invoke new
environmental impacts if not done properly.
Energy analysts have also not previously addressed the issue.
Aside from the attention that any energy use of this magnitude
normally receives, the hidden growth of electricity demand
in this sector confounds energy forecasts and obscures
savings from energy efficiency programs and policies. For exam-
ple, Auffhammer and Aroonruengsawat (2010) identified a
Fig. 4. Comparative energy intensities, by U.S. building type (2003).
Table A1
Configuration, environmental conditions, set-points.
Production parameters
Growing module 1.5 m
2
(excl.
walking area)
Number of modules in a room 10
Area of room 22 m
2
Cycle duration 78 days
Production continuous throughout
the year
4.7 cycles
Illumination Leaf phase Flowering
phase
Illuminance 25 klux 100 klux
Lamp type Metal halide High-pressure
sodium
Watts/lamp 600 1000
Ballast losses (mix of magnetic &
digital)
13% 0.13
Lamps per growing module 1 1
Hours/day 18 12
Days/cycle 18 60
Daylighting None none
Ventilation
Ducted luminaires with ‘‘sealed’’
lighting compartment
150 CFM/1000 W
of light (free
flow)
Room ventilation (supply and
exhaust fans)
30 ACH
Filtration Charcoal filters on
exhaust; HEPA on
supply
Oscilating fans: per module, while
lights on
1
Water
Application 151 liters/room-
day
Heating Electric submersible
heaters
Space conditioning
Indoor setpoint day 28 C
Indoor setpoint night 20 C
AC efficiency 10 SEER
Dehumidification 7x24 hours
CO
2
production target
concentration (mostly natural gas
combustion in space)
1500 ppm
Electric space heating When lights off to
maintain indoor
setpoint
Target indoor humidity conditions 40–50%
Fraction of lighting system heat
production removed by
luminaire ventilation
30%
Ballast location Inside conditioned
space
Drying
Space conditioning, oscillating fans,
maintaining 50% RH, 70–80F
7 Days
Electricity supply
grid 85%
grid-independent generation (mix
of diesel, propane, and gasoline)
15%
4
For observations from the building inspectors community, see http://www.
nachi.org/marijuana-grow-operations.htm
E. Mills / Energy Policy 46 (2012) 58–67 63
statistically significant, but unexplained, increase in the growth
rate for residential electricity in California during the years when
indoor Cannabis production grew as an industry (since the mid-
1990s).
Table A2
Assumptions and conversion factors.
Service levels
Illuminance
n
25–100 1000 lux
Airchange rates
n
30 Changes per hour
Operations
Cycle duration
nn
78 Days
Cycles/year
nn
4.7 Continuous
production
Airflow
nn
96 Cubic feet per
minute, per module
Lighting
Leafing phase
Lighting on-time
n
18 hrs/day
Duration
n
18 days/cycle
Flowering phase
Lighting on-time
n
12 hrs/day
Duration
n
60 days/cycle
Drying
Hours/day
n
24 hrs
Duration
n
7 days/cycle
Equipment
Average air-conditioning age 5 Years
Air conditioner efficiency [Standards
increased to SEER 13 on 1/23/2006]
10 SEER
Fraction of lighting system heat production
removed by luminaire ventilation
0.3
Diesel generator efficiency
n
27% 55 kW
Propane generator efficiency
n
25% 27 kW
Gasoline generator efficiency
n
15% 5.5 kW
Fraction of total prod’n with generators
n
15%
Transportation: Production phase (10
modules)
25 Miles roundtrip
Daily service (1 vehicle) 78 Trips/cycle. Assume
20% live on site
Biweekly service (2 vehicles) 11.1 Trips/cycle
Harvest (2 vehicles) 10 Trips/cycle
Total vehicle miles
nn
2089 Vehicle miles/cycle
Transportation: Distribution
Amount transported wholesale 5 kg per trip
Mileage (roundtrip) 1208 km/cycle
Retail (0.25oz 5 miles roundtrip) 5668 Vehicle-km/cycle
Total
nn
6876 Vehicle-km/cycle
Fuel economy, typical car [a] 10.7 l/100 km
Annual emissions, typical car [a] 5195 kgCO
2
0 kgCO
2
/mile
Annual emissions, 44-mpg car
nn
2,598 kgCO
2
0.208 kgCO
2
/mile
Cross-country U.S. mileage 4493 km
Fuels
Propane [b] 25 MJ/liter
Diesel [b] 38 MJ/liter
Gasoline [b] 34 MJ/liter
Electric generation mix
n
Grid 85% share
Diesel generators 8% share
Propane generators 5% share
Gasoline generators 2% share
Emissions factors
Grid electricity U.S. [c] 0.609 kgCO
2
/kW/h
Grid electricity CA [c] 0.384 kgCO
2
/kW/h
Grid electricity non-CA U.S. [c] 0.648 kgCO
2
/kW/h
Diesel generator
nn
0.922 kgCO
2
/kW/h
Propane generator
nn
0.877 kgCO
2
/kW/h
Gasoline generator
nn
1.533 kgCO
2
/kW/h
Blended generator mix
nn
0.989 kgCO
2
/kW/h
Blended on/off-grid generation CA
nn
0.475 kgCO
2
/kW/h
Blended on/off-grid generation U.S.
nn
0.666 kgCO
2
/kW/h
Propane combustion 63.1 kgCO
2
/MBTU
Prices
Electricity price grid
(California PG&E) [d]
0.390 per kW/h (Tier 5)
Electricity price grid (U.S.) [e] 0.247 per kW/h
Electricity price off-grid
nn
0.390 per kW/h
Electricity price blended on/off CA
nn
0.390 per kW/h
Electricity price blended on/off U.S.
nn
0.268 per kW/h
Propane price [f] 0.58 $/liter
Gasoline price U.S. average [f] 0.97 $/liter
Diesel price U.S. average [f] 1.05 $/liter
Table A2 (continued )
Wholesale price of Cannabis [g] 4,000 $/kg
Production
Plants per production module
n
4
Net production per production module [h] 0.5 kg/cycle
U.S. production (2011) [i] 10,000 metric tonnes/y
California production (2011) [i] 3,902 metric tonnes/y
Fraction produced indoors [i] 33%
U.S. indoor production modules
nn
1,570,399
Calif indoor production modules
nn
612,741
Cigarettes per kg
nn
3,000
Other
Average new U.S. refrigerator 450 kW/h/year
173 kgCO
2
/year (U.S.
average)
Electricity use of a typical U.S. home 2009
[j]
11,646 kW/h/year
Electricity use of a typical California home
2009 [k]
6,961 kW/h/year
Notes:
n
Trade and product literature; interviews with equipment vendors.
nn
Calculated from other values.
Notes for Table A2.
[a]. U.S. Environmental Protection Agency., 2011.
[b]. Energy conversion factors, U.S. Department of Energy, http://www.eia.doe.gov/
energyexplained/index.cfm?page=about_energy_units, [Accessed February 5, 2011].
[c]. United States: (USDOE 2011); California (Marnay et al., 2002).
[d]. Average prices paid in California and other states with inverted-block tariffs are
very high because virtually all consumption is in the most expensive tiers. Here the
PG&E residential tariff as of 1/1/11, Tier 5 is used as a proxy for California http://
www.pge.com/tariffs/ResElecCurrent.xls, (Accessed February 5, 2011). In practice a
wide mix of tariffs apply, and in some states no tier structure is in place, or the
proportionality of price to volume is nominal.
[e]. State-level residential prices, weighted by Cannabis production (from Gettman.
2006) with actual tariffs and U.S. Energy Information Administration, ‘‘Average
Retail Price of Electricity to Ultimate Customers by End-Use Sector, by State’’, http://
www.eia.doe.gov/electricity/epm/table5_6_a.html, (Accessed February 7, 2011)
[f]. U.S. Energy Information Administration, Gasoline and Diesel Fuel Update (as of
2/14/2011) – see http://www.eia.gov/oog/info/gdu/gasdiesel.asp Propane prices –
http://www.eia.gov/dnav/pet/pet_pri_prop_a_EPLLPA_PTA_dpgal_m.htm, (Accessed
April 3, 2011).
[g]. Montgomery, 2010.
[h]. Toonen et al., 2006); Plecas et al., 2010.
[i]. Total Production: The lower value of 10,000 t per year is conservatively retained.
Were this base adjusted to 2011 values using 10.9%/year net increase in number of
consumers between 2007 and 2009 per U.S. Department of Health and Human
Services (2010), the result would be approximately 17 million tonnes of total
production annually (indoor and outdoor). Indoor Share of Total Production:The
three-fold changes in potency over the past two decades, reported by federal
sources, are attributed at least in part to the shift towards indoor cultivation See
http://www.justice.gov/ndic/pubs37/37035/national.htm and (Hudson, 2003). A
weighted-average potency of 10% THC (U.S. Office of Drug Control Policy, 2010)
reconciled with assumed 7.5% potency for outdoor production and 15% for indoor
production implies 33.3%::67.7% indoor::outdoor production shares. For reference,
as of 2008, 6% of eradicated plants were from indoor operations, which are more
difficult to detect than outdoor operations. A 33% indoor share, combined with per-
plant yields from Table 2, would correspond to a 4% eradication success rate for the
levels reported (415,000 indoor plants eradicated in 2009) by the U.S. Drug
Enforcement Agency (http://www.justice.gov/dea/programs/marijuana.htm).
Assuming 400,000 members of medical Cannabis dispensaries in California (each
of which is permitted to cultivate), and 50% of these producing in the generic 10-
module room assumed in this analysis, output would slightly exceed this study’s
estimate of total statewide production. In practice, the vast majority of indoor
production is no doubt conducted outside of the medical marijuana system.
[j]. Total U.S. electricity sales: U.S. energyinformation administration, ‘‘retail sales of
electricity to ultimate customers: Total by end-use sector’’ http://www.eia.gov/
cneaf/electricity/epm/table5_1.html, (Accessed March 5, 201 1)
[k]. California Energy Commission, 2009;2011.
E. Mills / Energy Policy 46 (2012) 58–6764
Table A3
Energy model.
ELECTRICITY Energy
type
Penetration Rating
(Watts or %)
Number of
448-ft
production
modules served
Input energy per
module
Units Hours/day
(leaf phase)
Hours/day
(flower
phase)
Days/cycle (leaf
phase)
Days/cycle
(flower phase)
kW/h/cycle kW/h/year per
production
module
Light
Lamps (HPS) elect 100% 1,000 1 1,000 W 12 60 720 3,369
Ballasts (losses) elect 100% 13% 1 130 W 12 60 94 438
Lamps (MH) elect 100% 600 1 600 W 18 18 194 910
Ballast (losses) elect 100% 0 1 78 W 18 18 25 118
Motorized rail motion elect 5% 6 1 0.3 W 18 12 18 60 0 1
Controllers elect 50% 10 10 1 W 24 24 18 60 2 9
Ventilation and moisture control
Luminare fans (sealed from conditioned
space)
elect 100% 454 10 45 W 18 12 18 60 47 222
Main room fans supply elect 100% 242 8 30 W 18 12 18 60 31 145
Main room fans exhaust elect 100% 242 8 30 W 18 12 18 60 31 145
Circulating fans (18’’) elect 100% 130 1 130 W 24 24 18 60 242 1,134
Dehumidification elect 100% 1,035 4 259 W 24 24 18 60 484 2,267
Controllers elect 50% 10 10 1 W 24 24 18 60 2 9
Spaceheat or cooling
Resistance heat or AC [when lights off] 90% 1,850 10 167 W 6 12 18 60 138 645
Carbon dioxide Injected to Increase foliage
Parasitic electricity elect 50% 100 10 5 W 18 12 18 60 5 24
AC (see below) elect 100%
In-line heater elect 5% 115 10 0.6 W 18 12 18 60 1 3
Dehumidification (10% adder) elect 100% 104 0 26 W 18 12 18 60 27 126
Monitor/control elect 100% 50 10 5 W 24 24 18 60 9 44
Other
Irrigation water temperature control elect 50% 300 10 15 W 18 12 18 60 19 89
Recirculating carbon filter [sealed room] elect 20% 1,438 10 29 W 24 24 18 60 54 252
UV sterilization Elect 90% 23 10 2.1 W 24 24 18 60 4 18
Irrigation pumping elect 100% 100 10 10 W 2 2 18 60 2 7
Fumigation elect 25% 20 10 1 W 24 24 18 60 1 4
Drying
Dehumidification elect 75% 1,035 10 78 W 24 7 13 61
Circulating fans elect 100% 130 5 26 W 24 7 4 20
Heating elect 75% 1,850 10 139 W 24 7 23 109
Electricity subtotal elect 2,174 10,171
Air-conditioning 10 420 W 583 2,726
Lighting loads 10 W 259 1,212
Loads that can be remoted elect 100% 1,277 10 W 239 1,119
Loads that can’t be remoted elect 100% 452 10 W 85 396
CO2-production heat removal elect 45% 1,118 17 W 18 12 18 60 ——
Electricity Total elect 3,225 W 2,756 12,898
FUEL Units Technology
Mix
Rating
(BTU/h)
Number of
448-ft
production
modules served
Input energy per
module
Hours/day
(leaf phase)
Hours/day
(flower
phase)
Days/cycle (leaf
phase)
Days/cycle
(flower phase)
GJ or
kgCO
2
/cycle
GJ or kgCO
2
/
year
On-site CO
2
production
Energy use propane 45% 11,176 17 707 kJ/h 18 12 18 60 0.3 1.5
CO2 production –4emissions kg/CO
2
20 93
Externally produced Industrial CO
2
5% 1 0.003 liters
CO
2
/hr
18 12 18 60 0.6 2.7
Weighted-average on-site/purchased kgCO
2
210
E. Mills / Energy Policy 46 (2012) 58–67 65
For Cannabis producers, energy-related production costs have
historically been acceptable given low energy prices and high
product value. As energy prices have risen and wholesale com-
modity prices fallen, high energy costs (now 50% on average of
wholesale value) are becoming untenable. Were product prices to
fall as a result of legalization, indoor production could rapidly
become unviable.
For legally sanctioned operations, the application of energy
performance standards, efficiency incentives and education,
coupled with the enforcement of appropriate construction codes
could lay a foundation for public-private partnerships to reduce
undesirable impacts of indoor Cannabis cultivation.
5
There are
early indications of efforts to address this.
6
Were such operations
to receive some form of independent certification and product
labeling, environmental impacts could be made visible to other-
wise unaware consumers.
Acknowledgment
Two anonymous reviewers provided useful comments
that improved the paper. Scott Zeramby offered particularly
valuable insights into technology characteristics, equipment con-
figurations, and market factors that influence energy utilization in
this context and reviewed earlier drafts of the report.
Appendix A
See Tables A1–A3.
References
Auffhammer, M., Aroonruengsawat A., 2010. Uncertainty over Population, Prices,
or Climate? Identifying the Drivers of California’s Future Residential Electricity
Demand. Energy Institute at Haas (UC Berkeley) Working Paper, August.
Anderson, G., 2010. Grow Houses Gobble Energy. Press Democrat, July 25.See
/http://www.pressdemocrat.com/article/20100725/ARTICLES/100729664S.
Arnold, J., 2011. Investigation of Relationship between Cannabis Plant Strain and
Mass Yield of Flower Buds. Humboldt State University Proposal.
Barnes, B., 2010. Boulder Requires Medical Pot Growers to Go Green. NewsFirst5.com,
Colorado Springs and Pueblo. May 19 /www.newsfirst5.com/y/boulder-requires-
medical-pot-growers-to-go-green1/S, (accessed June 4, 2011).
Bellett, G., 2010. Pot growers stealing $100 million in electricity: B.C. Hydro
studies found 500 Gigawatt hours stolen each year. Alberni Valley Times.
October 8.
Brady, P., 2004. BC’s million dollar grow shows. Cannabis Culture. /http://www.
cannabisculture.com/articles/3268.htmlS, (accessed June 4, 2011).
Brown, R.E., Koomey, J.G., 2002. Electricity use in California: past trends and
present usage patterns. Lawrence Berkeley National Laboratory Report No
47992. /http://enduse.lbl.gov/info/LBNL-47992.pdfS.
California Energy Commission, 2009. California energy demand: 2010–2020
adopted forecast. Report CEC-200-2009-012-CMF), December 2009 (includes
self-generation).
California Energy Commission, 2011. Energy almanac. /http://energyalmanac.ca.
gov/electricity/us_per_capita_electricity.htmlS, (accessed February 19, 2011).
Caulkins, P., 2010. Estimated cost of production for Legalized Cannabis. RAND
Working Paper, WR-764-RC. July. Although the study over-estimates the hours
of lighting required, it under-estimates the electrical demand and applies
energy prices that fall far short of the inclining marginal-cost tariff structures
applicable in many states, particularly California.
Central Valley High Intensity Drug Trafficking Area (HIDTA), 2010. Marijuana
Production in California. 8 pp.
Clapper, J.R., et al., 2010. Anandamide suppresses pain initiation through a
peripheral endocannabinoid mechanism, Nature Neuroscience, 13, 1265–
1270, doi:10.1038/nn.2632 /http://www.nature.com/neuro/journal/v13/n10/
full/nn.2632.htmlS.
De Cock, L., Van Lierde, D. No Date. Monitoring Energy Consumption in Belgian
Glasshouse Horticulture. Ministry of Small Enterprises, Trades and Agriculture.
Center of Agricultural Economics, Brussels.
Easton, S.T., 2004. Marijuana Growth in British Columbia. Simon Frasier University,
78 pp.
Galitsky, C.S.-C. Chang, E. Worrell, Masanet, E., 2008. Energy efficiency improvement
and cost saving opportunities for the pharmaceutical industry: an ENERGY STAR
guide for energy and plant managers, Lawrence Berkeley National Laboratory
Report 62806. /http://ies.lbl.gov/iespubs/62806.pdfS.
Galitsky, C.N. Martin, E. Worrell, Lehman, B., 2003. Energy efficiency improvement
and cost saving opportunities for breweries: an ENERGY STAR guide for energy
and plant managers, Lawrence Berkeley National Laboratory Report No. 50934.
/www.energystar.gov/ia/business/industry/LBNL-50934.pdfS.
Garis, L., 2008. Eliminating Residential Hazards Associated with Marijuana Grow
Operations and The Regulation of Hydroponics Equipment, British Columbia’s
Public Safety Electrical Fire and Safety Initiative, Fire Chiefs Association of
British Columbia, 108pp.
Gettman, J., 2006. Marijuana Production in the United States, 29pp. /http://www.
drugscience.org/Archive/bcr2/app2.htmlS.
Harvey, M., 2009. California dreaming of full marijuana legalisation. The Sunday
Times, (September). /http://business.timesonline.co.uk/tol/business/indus
try_sectors/health/article6851523.eceS.
Hudson, R., 2003. Marijuana Availability in The United States and its Associated
Territories. Federal Research Division, Library of Congress. Washington, D.C.
(December). 129pp.
Koomey, J., et al. 2010. Defining a standard metric for electricity savings.
Environmental Research Letters, 5, http://dx.doi.org/10.1088/1748-9326/5/1/
014017.
Kovner, G., 2011. North coast: pot growing power grab. Press Democrat. /http://
www.pressdemocrat.com/article/20110428/ARTICLES/110429371?Title=Report-
Growing-pot-indoors-leaves-big-carbon-footprint&tc=arS.
Lehman, P., Johnstone, P., 2010. The climate-killers inside. North Coast Journal,
March 11.
Mallery, M., 2011. Marijuana national forest: encroachment on California public
lands for Cannabis cultivation. Berkeley Undergraduate Journal 23 (2), 1–49
/http://escholarship.org/uc/our_buj?volume=23;issue=2S.
Marnay, C., Fisher, D., Murtishaw, S., Phadke, A., Price, L., Sathaye, J., 2002.
Estimating carbon dioxide emissions factors for the California electric power
sector. Lawrence Berkeley National Laboratory Report No. 49945. /http://
industrial-energy.lbl.gov/node/148S(accessed February 5, 2011).
Mills, E., 2011. Energy up in smoke: the carbon footprint of indoor Cannabis
production. Energy Associates Report. April 5, 14 pp.
Montgomery, M., 2010. Plummeting marijuana prices create a panic in Calif.
/http://www.npr.org/templates/story/story.php?storyId=126806429S.
National Drug Intelligence Center, 2005. Illegal and Unauthorized Activities on
Public Lands.
Overcash, Y., Li, E.Griffing, Rice, G., 2007. A life cycle inventory of carbon dioxide as
a solvent and additive for industry and in products. Journal of Chemical
Technology and Biotechnology 82, 1023–1038.
Peplow, M., 2005. Marijuana: the dope. Nature doi:10.1038/news050606-6,
/http://www.nature.com/news/2005/050607/full/news050606-6.htmlS.
Phillips, H., 1998. Of pain and pot plants. Nature. http://dx.doi.org/10.1038/
news981001-2.
Plecas, D.J., Diplock, L., Garis, B., Carlisle, P., Neal, Landry, S., 2010. Journal of
Criminal Justice Research 1 (2), 1–12.
Quinones, S., 2010. Indoor pot makes cash, but isn’t green. SFGate, /http://www.
sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/10/21/BAPO1FU9MS.DTLS.
Revelle, T., 2009. Environmental impacts of pot growth. 2009. Ukiah Daily Journal.
(posted at /http://www.cannabisnews.org/united-states-cannabis-news/
environmental-impacts-of-pot-growth/).
Roth, M.D., 2005. Pharmacology: marijuana and your heart. Nature http://dx.doi.
org/10.1038/434708a /http://www.nature.com/nature/journal/v434/n7034/
full/434708a.htmlS.
See Change Strategy, 2011. The State of the Medical Marijuana Markets 2011.
http://medicalmarijuanamarkets.com/S.
National Council for Air and Soil Improvement, 2010. GCOLE: Carbon On Line
Estimator. /http://www.ncasi2.org/GCOLE/gcole.shtmlS, (accessed Sepember 9,
2010).
Toonen, M., Ribot, S., Thissen, J., 2006. Yield of illicit indoor Cannabis cultivation in
the Netherlands. Journal of Forensic Science 15 (5), 1050–1054 /http://www.
ncbi.nlm.nih.gov/pubmed/17018080S.
U.S. Department of Energy, Buildings Energy Data Book, 2008. Residential Energy
End-Use Splits, by Fuel Type, Table 2.1.5 /http://buildingsdatabook.eren.doe.
gov/docs/xls_pdf/2.1.5.xlsxS.
U.S. Department of Energy, 2009. ‘‘Report DOE/EIA-0573(2009), Table 3.
U.S. Department of Energy, 2011. Voluntary Reporting of Greenhouse Gases
Program /http://www.eia.doe.gov/oiaf/1605/ee-factors.htmlS, (accessed Feb-
ruary 7, 2011).
U.S. Department of Health and Human Services, 2010. 2009 National Survey on
Drug Use and Health. /http://oas.samhsa.gov/nsduhLatest.htmS.
U.S. Department of Justice, 2011a. Domestic Cannabis Eradication and Suppression
Program. /http://www.justice.gov/dea/programs/marijuana.htmS, (accessed
June 5, 2011).
U.S. Department of Justice, 2011b. National Drug Threat Assessment: 2010
/http://www.justice.gov/ndic/pubs38/38661/marijuana.htm#MarijuanaS,
(accessed June 5, 2011).
5
The City of Fort Bragg, CA, has implemented elements of this in TITLE 9 –
Public Peace, Safety, & Morals, Chapter 9.34. http://city.fortbragg.com/pages/searchRe
sults.lasso?-token.editChoice=9.0.0&SearchType=MCsuperSearch&CurrentAction=
viewResult#9.32.0
6
For example, the City of Boulder, Colorado, requires medical Cannabis
producers to offset their greenhouse-gas emissions (Barnes, 2010).
E. Mills / Energy Policy 46 (2012) 58–6766
US EPA, 2007a. Report to Congress on Server and Data Center Energy Efficiency:
Public Law 109-431. Washington, DC: U.S. Environmental Protection Agency,
ENERGY STAR Program. August 2.
U.S. Environmental Protection Agency, 2007b. Report to Congress on Server and
Data Center Energy Efficiency Public Law 109-431 133 pp.
U.S. Environmental Protection Agency, 2011. Emission Facts: Average Annual
Emissions and Fuel Consumption for Passenger Cars and Light Trucks. /http://
www.epa.gov/oms/consumer/f00013.htmS. (accessed February 5, 2011).
U.S. Office of National Drug Control Policy, 2011. Marijuana Facts and Figures.
/http://www.whitehousedrugpolicy.gov/drugfact/marijuana/marijuana_ff.
html#extentofuseS, (accessed June 5, 2011).
UNODC, 2009. World Drug Report: 2009. United Nations Office on Drugs and
Crime, p. 97. /http://www.unodc.org/unodc/en/data-and-analysis/WDR-2009.
htmlSFor U.S. conditions, indoor yields per unit area are estimated as up to
15-times greater than outdoor yields.
E. Mills / Energy Policy 46 (2012) 58–67 67
... Apart from BVOC emissions, carbon dioxide (CO 2 ) is a greenhouse gas and known driver of climate change, which is mainly emitted due to energy use from the cannabis production. Life cycle assessment 96,97 shows that for every dry kilogram of cannabis grown indoors, 2200 kg CO 2 -eq to 6600 kg CO 2 -eq is emitted to the atmosphere, a number that is strongly dependent on the source of the grid power. These emissions come mainly from lighting (33%), ventilation and dehumidification systems (27%), and air conditioning systems (19%) needed in indoor cultivation facilities. ...
... These emissions come mainly from lighting (33%), ventilation and dehumidification systems (27%), and air conditioning systems (19%) needed in indoor cultivation facilities. 97,98 Moving cannabis cultivation outdoors may greatly reduce carbon emissions from energy use, but it would increase water pumping, energy for the drying process, and vehicle use. 97 Mehboob et al. 99 developed complex models to simulate the energy consumption of CCFs. ...
... 97,98 Moving cannabis cultivation outdoors may greatly reduce carbon emissions from energy use, but it would increase water pumping, energy for the drying process, and vehicle use. 97 Mehboob et al. 99 developed complex models to simulate the energy consumption of CCFs. They identified lighting during the flowering stage as the most energy intensive activity. ...
Article
This review addresses knowledge gaps in cannabis cultivation facility (CCF) air emissions by synthesizing the peer-reviewed and gray literature. Focus areas include compounds emitted, air quality indoors and outdoors, odor assessment, and the potential health effects of emitted compounds. Studies suggest that β-myrcene is a tracer candidate for CCF biogenic volatile organic compounds (BVOCs). Furthermore, β-myrcene, d-limonene, terpinolene, and α-pinene are often reported in air samples collected in and around CCF facilities. The BVOC emission strength per dry weight of plant is higher than most conventional agriculture crops. Nevertheless, reported total CCF BVOC emissions are lower compared with VOCs from other industries. Common descriptors of odors coming from CCFs include "skunky", "herbal", and "pungent". However, there are few peer-reviewed studies addressing the odor impacts of CCFs outdoors. Atmospheric modeling has been limited to back trajectory models of tracers and ozone impact assessment. Health effects of CCFs are mostly related to odor annoyance or occupational hazards. We identify 16 opportunities for future studies, including an emissions database by strain and stage of life (growing cycle) and odor-related setback guidelines. Exploration and implementation of key suggestions presented in this work may help regulators and the industry reduce the environmental footprint of CCF facilities.
... Several African countries exploited taxes from the cannabis trade for a long time (Duvall 2019 Wartenberg et al. 202). Indoor cannabis cultivation requires considerable energy inputs proportional to greenhouse gas emissions (Mills 2012) depending on the power source. For example, the use of generators by illicit cannabis growers produced a triple amount of CO 2 compared to facilities powered by the grid (Mills 2012). ...
... Indoor cannabis cultivation requires considerable energy inputs proportional to greenhouse gas emissions (Mills 2012) depending on the power source. For example, the use of generators by illicit cannabis growers produced a triple amount of CO 2 compared to facilities powered by the grid (Mills 2012). Production of 1 kg of consumable cannabis resulted in 4600 kg of CO 2 emissions in an indoor facility (Mills 2012). ...
... For example, the use of generators by illicit cannabis growers produced a triple amount of CO 2 compared to facilities powered by the grid (Mills 2012). Production of 1 kg of consumable cannabis resulted in 4600 kg of CO 2 emissions in an indoor facility (Mills 2012). Therefore, cannabis growing conditions, equipment used, and power sources are important when deciding to reduce the carbon footprint. ...
... To maximize agricultural productivity, growers can manipulate, and optimize environmental conditions, and thus the timing of development, to shift allocation patterns toward desired yield outputs (Loomis et al., 1971;Stearns, 1992;Weiner, 2003Weiner, , 2004. Crops grown indoors are unique in that their environmental conditions, like light quality and quantity and temperature, can be strictly controlled, compared to traditional outdoor farms where productivity is often limited by climatic conditions (Mills, 2012;Arnold, 2013;Banerjee and Adenaeuer, 2014;Barbosa et al., 2015). Photoperiodic crops, plants that align their development with the amount and timing of light they receive (Thomas and Vince-Prue, 1996;Jackson, 2009), require a specific lighting schedule to flower and thus produce harvestable materials. ...
... In Canada alone, ∼2 million square meters of space is licensed for indoor C. sativa cultivation (Government of Canada, 2021) that helps fuel this $2.2 billion industry (Statistics Canada, 2019). In the United States, the amount of electricity used to cultivate C. sativa is an estimated $6 billion dollars with lighting being the primary source of that cost (Mills, 2012;Arnold, 2013). Thus, optimizing the timing of development is key to minimizing costs in this burgeoning industry. ...
Article
Full-text available
Cannabis sativa L. is an annual, short-day plant, such that long-day lighting promotes vegetative growth while short-day lighting induces flowering. To date, there has been no substantial investigation on how the switch between these photoperiods influences yield of C. sativa despite the tight correlation that plant size and floral biomass have with the timing of photoperiod switches in indoor growing facilities worldwide. Moreover, there are only casual predictions around how the timing of the photoperiodic switch may affect the production of secondary metabolites, like cannabinoids. Here we use a meta-analytic approach to determine when growers should switch photoperiods to optimize C. sativa floral biomass and cannabinoid content. To this end, we searched through ISI Web of Science for peer-reviewed publications of C. sativa that reported experimental photoperiod durations and results containing cannabinoid concentrations and/or floral biomass, then from 26 studies, we estimated the relationship between photoperiod and yield using quantile regression. Floral biomass was maximized when the long daylength photoperiod was minimized (i.e., 14 days), while THC and CBD potency was maximized under long day length photoperiod for ~42 and 49–50 days, respectively. Our work reveals a yield trade-off in C. sativa between cannabinoid concentration and floral biomass where more time spent under long-day lighting maximizes cannabinoid content and less time spent under long-day lighting maximizes floral biomass. Growers should carefully consider the length of long-day lighting exposure as it can be used as a tool to maximize desired yield outcomes.
... Many (interrelated) environmental parameters can be optimized in order to maximize yields, including temperature, humidity, CO 2 concentration, and fertility. However, in indoor cultivation environments, LI is one of the most prominent and expensive input parameters under the complete control of the cultivator (Mills, 2012). The optimum LI in a given production scenario will depend on many economic factors, but the responses of modern cannabis genotypes' yield and secondary metabolite composition to LI are key input factors that can only be elucidated experimentally. ...
Article
Full-text available
Cannabis (Cannabis sativa) flourishes under high light intensities (LI); making it an expensive commodity to grow in controlled environments, despite its high market value. It is commonly believed that cannabis secondary metabolite levels may be enhanced both by increasing LI and exposure to ultraviolet radiation (UV). However, the sparse scientific evidence is insufficient to guide cultivators for optimizing their lighting protocols. We explored the effects of LI and UV exposure on yield and secondary metabolite composition of a high Δ9-tetrahydrocannabinol (THC) cannabis cultivar ‘Meridian’. Plants were grown under short day conditions for 45 days under average canopy photosynthetic photon flux densities (PPFD, 400–700 nm) of 600, 800, and 1,000 μmol m–2 s–1, provided by light emitting diodes (LEDs). Plants exposed to UV had PPFD of 600 μmol m–2 s–1 plus either (1) UVA; 50 μmol m–2 s–1 of UVA (315–400 nm) from 385 nm peak LEDs from 06:30 to 18:30 HR for 45 days or (2) UVA + UVB; a photon flux ratio of ≈1:1 of UVA and UVB (280–315 nm) from a fluorescent source at a photon flux density of 3.0 μmol m–2 s–1, provided daily from 13:30 to 18:30 HR during the last 20 days of the trial. All aboveground biomass metrics were 1.3–1.5 times higher in the highest vs. lowest PPFD treatments, except inflorescence dry weight – the most economically relevant parameter – which was 1.6 times higher. Plants in the highest vs. lowest PPFD treatment also allocated relatively more biomass to inflorescence tissues with a 7% higher harvest index. There were no UV treatment effects on aboveground biomass metrics. There were also no intensity or UV treatment effects on inflorescence cannabinoid concentrations. Sugar leaves (i.e., small leaves associated with inflorescences) of plants in the UVA + UVB treatment had ≈30% higher THC concentrations; however, UV did not have any effect on the total THC in thesefoliar tissues. Overall, high PPFD levels can substantially increase cannabis yield, but we found no commercially relevant benefits of adding UV to indoor cannabis production.
... A study published in 2012 aimed to assess the carbon footprint, using Life Cycle Assessment (LCA), of indoor cannabis production in California and the impacts of energy consumption both on the environment and economically. They concluded that the energy needs for indoor production produced about 4 600Kg of carbon dioxide per kilo of plant (considering its entire lifetime) and also generated other problems such as the increase in the probability of electrical fires and economic constraints with the increase that has been observed in the price of energy [8]. ...
Article
Full-text available
Introduction: Cannabis has recently gained a medical status in several countries in the world. Its production for medical purposes should be analysed based on the three pillars of sustainability, taking into account the country in which it is located. Methods: literary research was conducted through scientific databases and grey literature, such as institutional websites. Results: Studies from the United States of America and Australia on the socioeconomic and environmental impacts of medical cannabis production were consulted, showing that this crop can be socially and economically beneficial in the place where it is executed but, in environmental terms, there is still a long way to go to understand the impacts on the consumption of energy, water, pesticides, fertilizers and waste waters compliance. Conclusions: The introduction of new non-autochthonous species should be accompanied by studies assessing their impact on the production site. The production of medical cannabis has been increasing and it is imperative to study its impacts in order to be able to implement measures to mitigate potential negative effects.
... The carbon footprint and sustainable development can be related. That is, Mills (2012) estimates that producing 1 kg of Cannabis indoors results in approximately 4,600 kilograms of carbon dioxide. This production is due to the need to use artificial lighting, irrigation systems, and environmental controls, among other energyconsuming activities. ...
Article
Full-text available
The medical Cannabis industry has experienced significant growth in recent years thanks to changes in the legislation of many countries. Latin America has been no stranger to these dynamics. Therefore, it is interesting to study the progress made in this industry, and investigation of the impact may have on the competitiveness in the production and processing of this plant. This article aims to identify and analyze the salient aspects of the use and development of technologies for the medical cannabis industry. There is a particular emphasis on the horticulture of the plant. To this end, the authors carried out a technological surveillance exercise. Technological surveillance is a systematic analysis of scientific and technical information to identify research and technological development trends. As a result, it was possible to focus on three areas: improving growing conditions, products related to cultivation, and improving genetics. These results contribute to describing the global technological panorama of medicinal Cannabis cultivation. Additionally, they are the basis for decision making in orienting the use of technologies of interest internationally and in considering the possibilities of diversification in this emerging industry in countries such as Colombia.
... Later, it became the primary cause of global warming, as burning onsite and/or offsite of this waste can result in pollution. It has been reported previously that 1 kg of cannabis waste results in the release of 3000 kg of carbon dioxide adding substantially to the leading cause of global warming [6]. To expand the vision of circular bioeconomy, it is necessary to trace the yearly consumption and production statistics of cannabis after legalization and the steps taken by the government for effective waste management. ...
Article
Full-text available
The global cannabis (Cannabis sativa) market was 17.7 billion in 2019 and is expected to reach up to 40.6 billion by 2024. Canada is the 2nd nation to legalize cannabis with a massive sale of $246.9 million in the year 2021. Waste cannabis biomass is managed using disposal strategies (i.e., incineration, aerobic/anaerobic digestion, composting, and shredding) that are not good enough for long-term environmental sustainability. On the other hand, greenhouse gas emissions and the rising demand for petroleum-based fuels pose a severe threat to the environment and the circular economy. Cannabis biomass can be used as a feedstock to produce various biofuels and biochemicals. Various research groups have reported production of ethanol 9.2–20.2 g/L, hydrogen 13.5 mmol/L, lipids 53.3%, biogas 12%, and biochar 34.6% from cannabis biomass. This review summarizes its legal and market status (production and consumption), the recent advancements in the lignocellulosic biomass (LCB) pre-treatment (deep eutectic solvents (DES), and ionic liquids (ILs) known as “green solvents”) followed by enzymatic hydrolysis using glycosyl hydrolases (GHs) for the efficient conversion efficiency of pre-treated biomass. Recent advances in the bioconversion of hemp into oleochemicals, their challenges, and future perspectives are outlined. A comprehensive insight is provided on the trends and developments of metabolic engineering strategies to improve product yield. The thermochemical processing of disposed-off hemp lignin into bio-oil, bio-char, synthesis gas, and phenol is also discussed. Despite some progress, barricades still need to be met to commercialize advanced biofuels and compete with traditional fuels.
Article
Although the vegetative stage of indoor cannabis (Cannabis sativa) production can be relatively short in duration, there is a high energy demand due to higher light intensities (LI) than the clonal propagation stage and longer photoperiods than the flowering stage (i.e., ≥ 16 vs. 12 h). While electric lighting is a major component of both energy consumption and overall production costs, there is a lack of scientific information to guide cultivators in selecting a LI that corresponds to their vegetative stage production strategies. To determine the vegetative plant responses to LI, clonal plants of ‘Gelato’ (indica-dominant hybrid genotype) were grown for 21 days with canopy-level photosynthetic photon flux densities (PPFD) ranging between 135 and 1430 µmol·m⁻²·s⁻¹ with a 16-h photoperiod (i.e., daily light integrals of 7.8–82.4 mol·m⁻²·d⁻¹). Plant height and growth index (i.e., a canopy volume metric) responded quadratically; the number of nodes, stem thickness, and aboveground dry weight increased asymptotically; and internode length and water content of aboveground tissues decreased linearly with increasing LI. Foliar attributes had varying responses to LI. Chlorophyll content index (i.e., SPAD value) increased asymptotically, leaf size decreased linearly and specific leaf weight increased linearly with increasing LI. Generally, PPFD levels of ≈ 900 µmol·m⁻²·s⁻¹ produced compact, robust plants while PPFD levels of ≈ 600 µmol·m⁻²·s⁻¹ promoted more open plant architecture (i.e., taller plants with longer internodes), which can increase intra-canopy airflow and may reduce development of potential foliar pests in compact (e.g., indica-dominant) genotypes.
Article
Full-text available
The full text of this article is available in the PDF provided and as HTML.
Article
Full-text available
The motor vehicle industry in the U.S. spends about $3.6 billion on energy annually. In this report, we focus on auto assembly plants. In the U.S., over 70 assembly plants currently produce 13 million cars and trucks each year. In assembly plants, energy expenditures is a relatively small cost factor in the total production process. Still, as manufacturers face an increasingly competitive environment, energy efficiency improvements can provide a means to reduce costs without negatively affecting the yield or the quality of the product. In addition, reducing energy costs reduces the unpredictability associated with variable energy prices in today?s marketplace, which could negatively affect predictable earnings, an important element for publicly-traded companies such as those in the motor vehicle industry. In this report, we first present a summary of the motor vehicle assembly process and energy use. This is followed by a discussion of energy efficiency opportunities available for assembly plants. Where available, we provide specific primary energy savings for each energy efficiency measure based on case studies, as well as references to technical literature. If available, we have listed costs and typical payback periods. We include experiences of assembly plants worldwide with energy efficiency measures reviewed in the report. Our findings suggest that although most motor vehicle companies in the U.S. have energy management teams or programs, there are still opportunities available at individual plants to reduce energy consumption cost effectively. Further research on the economics of the measures for individual assembly plants, as part of an energy management program, is needed to assess the potential impact of selected technologies at these plants.
Article
Full-text available
The U.S. pharmaceutical industry consumes almost $1 billion in energy annually. Energy efficiency improvement is an important way to reduce these costs and to increase predictable earnings, especially in times of high energy price volatility. There are a variety of opportunities available at individual plants in the U.S. pharmaceutical industry to reduce energy consumption in a cost-effective manner. This Energy Guide discusses energy efficiency practices and energy efficient technologies that can be implemented at the component, process, system, and organizational levels. A discussion of the trends, structure, and energy consumption characteristics of the U.S. pharmaceutical industry is provided along with a description of the major process steps in the pharmaceutical manufacturing process. Expected savings in energy and energy-related costs are given for many energy efficiency measures, based on case study data from real-world applications in pharmaceutical and related facilities worldwide. Typical measure payback periods and references to further information in the technical literature are also provided, when available. The information in this Energy Guide is intended to help energy and plant managers reduce energy consumption in a cost-effective manner while meeting regulatory requirements and maintaining the quality of products manufactured. At individual plants, further research on the economics of the measures?as well as their applicability to different production practices?is needed to assess potential implementation of selected technologies.
Article
Full-text available
This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor The Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or The Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof, or The Regents of the University of California.
Article
Full-text available
Annually, breweries in the United States spend over $200 million on energy. Energy consumption is equal to 38 percent of the production costs of beer, making energy efficiency improvement an important way to reduce costs, especially in times of high energy price volatility. After a summary of the beer making process and energy use, we examine energy efficiency opportunities available for breweries. We provide specific primary energy savings for each energy efficiency measure based on case studies that have implemented the measures, as well as references to technical literature. If available, we have also listed typical payback periods. Our findings suggest that given available technology, there are still opportunities to reduce energy consumption cost-effectively in the brewing industry. Brewers value highly the quality, taste and drinkability of their beer. Brewing companies have and are expected to continue to spend capital on cost-effective energy conservation measures that meet these quality, taste and drinkability requirements. For individual plants, further research on the economics of the measures, as well as their applicability to different brewing practices, is needed to assess implementation of selected technologies.
Article
Energy consumption and energy efficiency are topical matters in the Belgian glasshouse horticulture. In Belgium only a few data on energy consumption in the agricultural and horticultural sector are available. To fill this gap of information, the Centre of Agricultural Economics developed an extrapolation model that uses data from the Farm Accountancy Data Network of the Centre and data of the Agricultural Census of the National Institute of Statistics to monitor the energy consumption in the glasshouse horticultural sector from 1980 till now. The model is developed in such way that for each holding of the population the energy consumption is estimated. This allows us to estimate the energy consumption for different aggregates. The estimation of the share of the different energy sources in the total energy consumption makes it possible to estimate emissions due to the heating of the glasshouses. On the other hand the model creates an instrument for researchers and policy makers to evaluate the impact of energy saving actions on the energy consumption of the glasshouse horticultural sector.
Article
Life cycle inventories of four industrial carbon dioxide production processes are reported. The inventory data were calculated using design-based methodology. Energy consumptions and critical emissions of the four processes are compared. Quasi-microscopic allocation was applied to processes with multiple products. The inventory data of this study are transparent and can be used in other life cycle studies. Copyright © 2007 Society of Chemical Industry
Article
This paper provides a general overview of electricity consumption and peak load in California, by both sector and end use. We examine the growth in electricity demand between 1980 and 2000, as well as the composition of electricity end uses in 1999. One of the main conclusions from this analysis is that electricity use in California in the 1990s did not grow explosively, nor was the amount of growth unanticipated. In both absolute and relative terms, growth in electricity use was greater in the 1980s than the 1990s. During the 1990s, most of the growth in electricity use has been in the buildings sector, particularly commercial buildings. In 2000, the building sector accounted for 2/3 of annual electricity consumption and 3/4 of the summer peak load.