Two weeks ago, my hubby and I went on a hot date (for geeks!) -- a Solar Energy Society of Alberta evening on electric vehicles. We came away convinced that, for the sake of our planet (not to mention our wallets), we should probably sell our present vehicle and go electric. The panel of presenters were very convincing. Now we just need a car company to come up with an electric vehicle high enough to get down our back alley in the winter without getting high-centred (we actually cracked our present crossover vehicle's under-grill trying to get down our alley last winter). Our solar panels produce enough energy that we can easily power our home and an electric vehicle, so we'll get there eventually, and cut our greenhouse gas emissions by half yet again.
Lee recently wrote an update regarding our solar installation and how it's performing, along with suggestions for others who are considering their own solar power. So if you have yet to make it to an SESA event, here's our experience, as told by Lee:
Going Solar in Edmonton
Two
Years of Residential Solar Electric Generation
I am writing this post to assist others who
may be thinking about a solar electric system installation in Alberta or Canada. It contains information about our system and
actual performance over a two-year period. I suspect others may have questions about what
to consider and hence might learn from our experience.
System
Design Parameters:
Physical
Configuration:
-
Total panels = 24:
o
20 panels on the garage, 4
panels on the house
-
Total installed estimated maximum
capacity - ~6.24 kW
-
1 microinverter for each two
panels
-
Panel Manufacturer: Canadian
Solar, 260P, 260W
-
Microinverter Manufacturer:
APSystems
Orientation – south
facing
Inclination of
panels -- ~20 degrees on the garage and house
Considerations
for Installation and Design:
·
Roofing: For asphalt shingled roof
installations like ours, the support stands for the panels have mounts that fit
under the existing shingles. This keeps
things sealed on your roof envelop.
Before you install such a system, it is highly recommended to
re-shingle your roof with long life shingles.
We chose ones with a 25 to 30 year lifespan. Our solar electric system should last at least
that long. Replacing shingles around a
solar panel installation is a major undertaking. It is best to think ahead and delay this issue
as long as you can.
·
Snow: The steeper the panels are
inclined on the roof, the more likely that snow will fall off by itself during
the winter. During a sunny day, light
penetrates the snow cover on the panels and warms the snow so it falls off
naturally. For Edmonton, the optimal
angle to maximize solar energy collection is about 50 degrees. To minimize wind sheer issues, panels are
typically installed parallel to the roof surface for residential applications,
so ideally panels should be installed on steeper roof sections. Something to watch out for when you select
the location of your panels, is don’t place them near sidewalks or other areas
you typically walk under. You may have a
sudden icy surprise on your head as the panels shed snow or find a slippery
section on your sidewalk that is difficult to keep ice free.
·
Electrical: These systems use direct
current near the panels which is converted to alternating current that can be
used in your house. Engaging a qualified
electrician is highly recommended due to inherent dangers (shock and fire) during
and after improper installation. Another
consideration is to check your electrical panel before installation. We had enough spare capacity to connect the
system, but some houses may not. An
electrical panel upgrade can be expensive.
·
Protection from Rodents and Leaves: Our
system’s panels are raised slightly above our roof to allow for airflow. To protect against gnawing rodents (they
apparently enjoy chewing through cables) and leaves and other build up, a
protective mesh was installed around the bottom of our panels along the roof
line.
·
Rebates: Check if rebates for solar
installations are available in your community or province. They can make a significant difference for
your installation costs (saving you thousands) and reduce the payback period
for your system.
·
Electrical Maintenance: Photovoltaic
(PV) systems are relatively low maintenance and worry-free – almost. One of the microinverters was defective and failed
in October 2016 and this was not noticed by us and repaired until April
2017. As a result, the electrical generation
performance for part of 2016 and early 2017 is slightly lower than would have
been expected (~1/12th loss).
From a practical perspective:
o
I recommend that you check system
performance from month-to-month. Our microinverter manufacturer has a website that
shows individual panel performance. It
is fascinating to watch as your panels produce electricity throughout the day
and it also makes detecting issues very easy provided you check for them
periodically. An email alert for
system failures would be a nice feature… in case any manufacturers are reading
this post.
o
As electronics for these
systems can fail earlier than expected, it is a good idea to get a
warranty. It is worth the peace of mind.
o
When you pick an installation
company, remember that ongoing service should be a consideration. When the occasional malfunction occurs, it is
nice to know you can rely on the installing company to perform the needed
service. The one we chose came and fixed
things quickly once we noticed the outage.
·
Other Maintenance:
o
Washing: Keep an eye out for dust and
other build up on the panels. Dust, bird
droppings and other build up can reduce system capacity. Washing them gently with water from time to
time should be considered.
o
Trees and other shadowing: When we
installed our system, I trimmed the top of a tree next to the system to reduce
the amount of shadowing during later afternoon.
It is time to do this again.
·
Thinking Ahead:
o
Electric Cars: When we installed our
system, we purposefully built it so we could add extra capacity for an electric
vehicle in the future. Our installation
company recommended at least 8kW for a combined home/car system. Cable sizing and placement, physical space
for additional panels and electrical panel capacity are key considerations.
o
Battery Backup: Our system is a
grid-connected configuration. This is
apparently the most common type of system installed today. When it does not detect an energized
electrical grid, the inverters do not produce electricity. This avoids feeding electricity into a
de-energized electrical grid during an outage and potentially putting your
local utility workers in harms way. This
has two implications: 1) the system will not provide backup electricity during
an electrical outage, and 2) if a battery backup system is installed for such a
scenario, it needs to be disconnected from the electrical grid during an outage
and / or allow for solar recharging of batteries in a disconnected situation. A local Alberta company, Eguana Technologies,
seems to have a system that will work for this situation. This is an area I am still investigating and
would be interested in the experience of others.
Observations
of Actual System Performance:
 |
On warm days, our panels produce up to 40 kilowatt hours in a day.
We had a several cm of snow on the 13th, and not much sun since... |
·
Time of year and snow does make a
difference for electrical generation.
Don’t expect too much electricity generation in the months of December
and January. The sun is just too low in
the sky to generate very much. I tried
to remove snow from the panels in December but saw limited electrical
generation. Even 6 inches (15 cm) of
snow pretty much stopped the panels from working. In the shoulder months of November and
February, the amount of electrical generation increased appreciably when
temperatures rose sufficiently for the panels to shed their snow load by
themselves.
·
Total Yearly Solar Electric Generation:
o
Year one (June 2016 to May
2017): 5824 kWh (see note above about failed inverter)
o
Year two (June 2017 to June
2018): 6023 kWh
·
Generation Pattern - The following chart
shows how much electricity was generated by our system at various times of the
year from June 2016 to May 2018.
(Maria's note: We don't have to think too much about our solar panels. They do their work, we do ours, and it's all good, especially because we're not contributing more than we have to when it comes to greenhouse gases. We think solar is a great way to go!)
