Maximum Yield Cannabis Canada 2017 November/December | Page 43

Going Off-Grid
Once you have created an energy-efficient greenhouse
and equipped it with proper heating and cooling
systems, the final step of net-zero energy greenhouse
is supplying, or offsetting, electricity usage.
Not all greenhouses require electricity. Some
growers forgo it and use thermal mass and passive
systems for climate control. Instead of ventilation
fans, solar vent openers provide air circulation and
cooling without electricity. Going this route is an
excellent option for growers in milder climates or
those who may only want to grow cold and hardy
crops through the winter. The major downside is
limited control and hands-on operation as electric
fans, back-up heaters, lights, and automated irriga-
tion systems are not possible.
Most growers who plan to grow year-round,
however, rely on the helpful automation of
fans and other electric appliances to facilitate.
Exhaust fans are usually the most useful electric
equipment, as overheating the greenhouse is very
easy. (On a related side note, try at all costs to
avoid electric heaters, which are extremely energy-
intensive to run and make it difficult to create a
net-zero energy structure.) To supply these power
loads, one can integrate a solar panel system into
the greenhouse. The specifics of installing a solar
photovoltaic (PV) system depend on your goals and
the power requirements of the greenhouse. Like
a home PV system, there are options: connecting
the panels to the grid (grid-tied), adding battery
backup (grid-tied with battery backup), or creating
an off-grid system with battery storage.
Most growers who want to be completely
disconnected from the grid opt for an off-grid system
with batteries. With the proliferation of small solar
panel kit systems, owners of small greenhouses
with limited electric demand can quite easily
generate and store enough energy to operate an
exhaust fan and low-power equipment. For larger
systems, this is usually much more expensive than
grid-tied, given the added cost of an extensive
battery bank. An important consideration early on
is whether your home is a better location for the
panels. Houses usually have more space for panels,
allowing for a larger and more cost-effective system,
and can be eligible for tax cr