Solar Energy in Canada
Solar energy can meet three distinct applications: heating water, heating air, and generation of electricity
in any residential or commercial setting. In most cases, solar energy provides the lowest lifecycle cost, and the
lowest environmental impact from the release of greenhouse gases (GHG).
The Cost of Solar Electricity
Solar electric (photovoltaic) modu les are the primary
component in a PV system, but they are not the only
consideration. The balance of system (BOS)
components must also be understood and factored
into the cost, and the following information provides
a breakdo wn of the overall components req uired .
There are two options when considering a PV
system. Someone requiring only lighting, lowdemand
pumping and operation of a cellular phone
could run a 12 volt DC (direct current) system.
Unlike 120 volt AC (alternating current), a DC
system does not require an inverter to convert the
electricity into AC, which can reduce the co st
considerably. A PV system that is designed to run
standard AC appliances, such as a microwave,
coffee maker, toaster, TV or VCR, will require an
inverter that can convert the 12 V generated by the
PV system to 120 V required b y the appliances.
PV modules vary in electrical output, ranging from a
few watts to more than 100 watts DC. When two
modules are connected, it is called a solar array.
The size and number of mo dules require d is
determined by the amount of electricity required. As
a rule, the capacity of your P V modules should
match your consumption demand, although
occasional use systems (such as a weekend
cottage) can use a smaller number of PV m odules if
there is su fficient battery storage. PV m odules in
Canada range in price from $100 to $1,250 each.
The charge controller, also referred to as a
regulator, plays a critical ro le in yo ur PV system . It
regulates the charge from your PV m odule to ensure
that your batteries will never be overch arged. It also
ensures there will be no reverse current flow from
your batteries to the solar module. Some charge
controllers will have built-in meters which allow you
to see the amount of charge (in amps) coming from
your module into your batteries, as well as your
battery state of charge (in volts). The cost of this
component ranges from $50 to $600.
Batteries allow the electricity from the PV m odules to
be store d until it is req uired. Unlike a sh allow-cycle
car battery that is designed for cranking, a deepcycle
battery used with PV systems is designed for
gradual cycles of heavy discharge and recharge
without damage. The batteries can be flooded leadacid
or gelled electrolyte. Lead-a cid batteries give
off hydrogen gas when charging and should,
therefore, be well ventilated. The number, size,
capa city and type of batteries will relate directly to
the electrical load and num ber of autonom ous days
of operation dictated in the system design. The
overall requireme nts will dictate the necessary
capa city (ie: ampere-ho urs) and whether 12 volt, 6
volt or 2 volt batteries will be used. The cost of
batteries ranges from $200 to $4,000.
PV systems should be designed to meet the
electrical code, which requires disconnects for each
power source . In other w ords, a d isconnect shou ld
be in place between your module and your charge
controller, and another between your batteries and
charge controller. When running an AC system,
generally, a larger disconnect is required for
placement between the inverter and batteries.
Disconnects range in price from $50 to $300.
The inverter is necessary to run appliances that
require 120 volt AC current. The size of inverter will
relate to the num ber of A C app liances that will be in
operation simultaneously. For example, if you had a
1/3 HP pump (800 watts) and you were making
coffee (1000 watts) when the pump came on, you
would need an inve rter larger than 1800 watts to
allow operation of both appliances at the same time.
You want to ensure that your inverter has sufficient
surge capacity for appliances with a heavy startup
draw, such as a pump, which can surge at up to 5
times its operating draw.
The inverter will be an expensive component in your
PV system, so yo u shou ld consider sizing this
component at the outset for any future expansion.
Many sizes, make s and models are on the market,
and prices vary widely from $100 to $6,000.
The PV module will require a mounting frame.
Modules are mounted in a location that gives
maximum exposure to the sun and, often, this is on
the roof of the building and requires a roof mount
frame. In some situations, a ground or p ole mo unt is
the appropriate way to go. A roof mou nt frame for a
single PV module will range from $50 to $100 and,
for an eight module array, will rang e from $300 to
$400.
If a groun d mou nt frame is used, more m aterial is
required in the framing, and the cost will range from
$350 (for 3 mo dules) to $850 (for 8 m odules).
Additional materials may include: steel pipe, base
plate, anchor bolts, cement, and more aluminum for
framing. Prices will range from $ 300 to $500 (for 1
module) to $850 to $1,050 (for 8 m odules).
To safeguard your electrical system from lightning
strikes, it is advisable to ensure your system is
properly grounded and has sufficient lightning
arrestors. An AC system typically has two or more
lightning arrestors. A grounding kit, including one
lightning arrestor, would range from $100 to $150.
The wire or cable must be sized properly, and the
correct gauge and type must be determined
according to: (1) the distance of the wire run, (2)
whether it is indoor or outdoor, (3) whether it will be
buried or abo ve ground, and (4) w hat current will it
carry. Prices range from $ 1 per metre for standa rd
indoor AC wiring to $32 per metre for cable that can
carry 10 amps a distance of 500 m etres.
Many PV dealers have prepackaged systems that
will pro vide a savings over buying the com ponents
individually. Some dealers may have incentives for
complete system purchases that can be very
advantageo us to the consume r. Consider product
warranties, product quality, the credentials of the
dealer (length of time in business, number of PV
systems sold/installed), CSA & UL approval ratings
(components not to code will not be passed by the
electrical authority), installation costs and after sales
service.
Referance: Rob Harding www.CanSIA.ca