MJBiz - July/August 2024 - 34

SUSTAINABLE IS ATTAINABLE
important to cannabis cultivation as
plant genetics, Anderson said.
It's no secret, however, that
indoor grows rely on a massive
amount of energy: Each kilogram of
final cannabis product contributes
4,600 kilograms (10,141.3 pounds) of
carbon dioxide emissions.
That's far higher than emissions
for most agricultural and food
products, ranking among beef
products such as hamburger
and steak, according to research
published in 2021 in Nature
Sustainability. One pound of
cannabis grown indoors produces
more carbon emissions than a flight
between Tokyo and San Francisco,
the study said.
While the environmental
imperative for energy efficiency
and sustainability in facility design
is clear, the economic benefits and
necessities driving these design
changes often are overlooked.
Concurrently, some states have
enacted stringent-and sometimes
expensive-environmental
regulations, such as California's
Environmental Quality Act (CEQA).
On the bright side, many energyefficiency
requirements come
with rebates, although accessing
them often requires a lot of
administrative work.
MODERNIZING INDOOR
CANNABIS CULTIVATION
There are three categories of
common upgrades that improve
efficiency in cannabis cultivation
facilities, but they all are linked and
affect one another, according to
Anderson.
It's well-established that lightemitting
diode (LED) lights are far
more efficient but more expensive
than high-pressure sodium (HPS)
lights, which historically have
been preferred by many growers,
particularly for the flowering
stage.
Cultivators are finding new ways to
keep electrcity costs down.
Photo by stock.adobe.com/luzkovyvagon.cz
LEDs convert electrons to
photons, using roughly 90%
less energy than incandescent
bulbs and about 50% less than
compact fluorescent bulbs. That's
a significant savings, with lighting
accounting for 38%-75% of the total
energy used in indoor cannabis
cultivation, according to a 2021
report by electric utility company
Southern California Edison.
For example, Michigan-based
cannabis technology company
Agrify Corp. says its lights deliver up
to 60% more photosynthetic photon
flux density (or light intensity) to
plants than HPS lights.
Another critical difference: HPS
lights produce much more heat
than LED lights. That means that
HPS require more work-and more
cost-from HVAC systems than LED
lights.
Depending on the grow, the
mechanical system (or HVAC/
HVAC-D system) might require
tweaking or a full replacement.
For cooling, Southern California
Edison recommends chilled water
systems over direct expansion, air
conditioning systems. Chilled-water
systems cool the air and return heat
from the building using water, while
air conditioners use large amounts
of refrigerant chemicals, Anderson
explained.
34 July-August 2024 | MJBizMagazine
Chilled-water systems also offer
lower operating costs and more
flexible air-handling capabilities.
For smaller to midsize grows
seeking better energy efficiency,
mini-split systems, which are also
ductless, are good choices.
Edison recommends having
a dedicated dehumidification
system that's separate from
air conditioning. Having
dehumidification and air
conditioning independent of each
other is more energy efficient.
Plus, if one fails, the other one
will continue functioning. The
architecture of an indoor grow
will also impact energy efficiency,
according to Anderson.
Vertical grows are less of a burden
on HVAC systems, but they also
can benefit from energy-efficient
upgrades, such as reducing or
eliminating any wood in the
structure, which can house mold
and require more dehumidifying.
Also, many first-generation
cannabis facilities lack ceilings,
leaving the grow exposed to a steel
truss in the roof that's vulnerable
to the elements outside. When
temperatures change, the steel
conducts the heat and cold and can
create problematic moisture and
even dripping on the plants indoors.
But there are solutions, Anderson
said.
" You either want to insulate the
outside of your building, which is
expensive, or you want to insulate
the truss itself, which is difficult and
fussy. Or you want to separate your
plant entirely with a ceiling in the
room. "
The costs of these renovations can
vary widely depending on the size
and scale of the grow, but LED and
HVAC typically will compromise
approximately half of the total cost
of building a new facility.
" The heaviest, biggest, most
costly things that you can spend
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MJBiz - July/August 2024

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