SOLAR PHOTOVOLTAICS
VIABILITY ASSESSMENT
for the
City of Medicine Hat
Land and Properties Division
-Saamis Heights Phase 7-
Prepared by
TERRALTA (2006) INC
557 18th Street SW
Medicine Hat, AB
T1A 8C4
403-488-0404
[email protected]
TABLE OF CONTENTS
SECTION
1.0
2.0
3.0
4.0
5.0
6.0
PAGE
Executive Summary....................................................................................................................
Solar Basics 101...........................................................................................................................
Solar Equipment and Components......................................................................................
Exposure and the Solar Market.............................................................................................
System Size, Footprint and Budetary Cost........................................................................
Saamis Heights-Phase 7 Assessment
6.1
Block 23: Lots 61-84....................................................................................................
6.2
Block 33: Lots 52–96...................................................................................................
6.3
Block 34: Lots 19-35....................................................................................................
6.4
Block 35: Lots 1-27.......................................................................................................
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4
5
7
9
11
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1.0 Executive Summary
The City of Medicine Hat, Land and Properties Division has selected Saamis HeightsPhase 7 for a solar viability assessment. Saamis Heights-Phase 7 consists of 111 lots,
separated into four blocks. The purpose of this report is to assess the sites designated by
the City of Medicine Hat for possible residential rooftop solar installations. The following
report will offer unbiased suggestions and make recommendations for these 111 lots,
outlining advantages and disadvantages with respect to solar photovoltaic installations.
Potential system equipment, budgetary cost estimations, system foot print and structural
load data will be provided, as well as suggestions regarding building orientation, roofing
materials, slope and pitch.
Saamis Heights-Phase 7 has great solar potential, with the majority of the lots
requiring very little manipulation. This location could very well become its own solar
community. The block and lots listed below stand out as the best and brightest and they
account for 50% of the total proposed lots (56 of 111 lots). Solar installations on these lots
will have great all day exposure with the systems mounted on the front or back of the
home.
Block 23: all lots
Block 33: lots 52-67, 69-73
Block 34: lots 25-35
The remaining 55 lots will have systems mounted on the front back and side of the
homes. Potentially larger systems may be installed on the homes with “side of home”
footprints as the roof lines may be larger as compared to the front or back roof line.
Aesthetically the systems will most likely be hidden from view.
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2.0
Solar Basics 101
Solar Photovoltaics (PV) are semiconductor devices that convert sunlight directly
into electricity. This is achieved without any moving parts and without generating any
noise or pollution. Ideally, a solar array should be mounted in an unshaded area. Typical
locations or mounting types include rooftop, ground mount or pole mount. Solar PV
systems work very well in Medicine Hat, Alberta where the average annual solar resource
is 3.5-4.5 kWh/m2/day. This number, however, is not the amount of energy that can be
produced by a solar PV panel. The amount of energy produced by a panel depends on
several factors. These factors include the type of collector, the tilt and azimuth of the
collector, the temperature, the level of sunlight and weather conditions. An inverter is
required to convert the direct current (DC) to alternating current (AC) of the desired
voltage compatible with building and utility power systems. The balance of the system
consists of conductors/conduit, switches, disconnects and fuses. Solar systems have been
separated into 3 different categories, the most common and cost effective being grid tied,
pictured below.
Residential and commercial solar systems installed in Medicine Hat follow a
distinctive operating method. When the installed solar system is collecting power, the
home or business will use this energy first. Any needs above what the solar system can
provide are pulled from the utility grid. When the installed solar system is producing
power and the home or business is not using energy, the solar energy is delivered back to
the utility and you are credited against your bill. All electrical providers must install a bidirectional meter to measure incoming and outgoing power. The City of Medicine Hat
provides these meters at no cost to the home owner or business and a separate “MG”
(micro-generation) line is added to your utility bill. The MG line, on your bill accounts for
power pushed back to the utility and you are credited at the going rate for that billing cycle.
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3.0
Solar Equipment and Components
In today’s competitive solar markets there are many different types of technologies
available. Modules vary in wattage size and make up. The two most common modules are
made of polycrystalline or monocrystalline silicone cells.
o
o
Monocrystalline: a silicon wafer made from a single silicone crystal grown in the
form of a cylindrical ingot. Chunks of highly pure polysilicon are melted in a
crucible, along with boron. (1)
Polycrystalline: a silicon wafer made from a cast silicon ingot that is composed of
many silicone crystals. Often distinguished by their square corners. Slightly lower
efficiencies than Monocrystalline modules. (1)
Traditional photovoltaic systems (PV systems) are typically characterized by a
centralized inverter or string inverter. The inverter performs Maximum Power Point Tracking
(MPPT) for large quantities of solar panels as a whole. Since the solar panels are connected in a
series to form strings, the same current must flow through all the modules, the solar inverter
continuously adjusts the electric current in the system to find the average optimal working point
of all the modules. As a result, potential power may be lost whenever a mismatch exists between
modules. Panel mismatch is unavoidable in many cases, due to panel manufacturing tolerance,
partial shading, uneven soiling, or uneven tilt angle.
The introduction of the micro-inverter has significantly changed the solar industry.
Prior to 2005, most residential and commercial solar systems consisted of string inverters
that combined the power of all the solar modules in a specified array into one source.
Residential string inverters are mounted in the mechanical room and a DC wire is brought
into the unit. The string inverter converts the DC power created by the modules to usable
AC for the home or building. The disadvantage associated with string inverters is if one
panel in the array experiences shading, the total power output of the array decreases not
just that panel’s power capabilities.
Micro inverters have made the solar industry safer and more cost effective,
especially from a residential perspective. Micro inverters are mounted right behind the
modules on the roof. They convert the DC current to usable AC power right at the module.
If one module is affected by shading it only decreases that module’s capacity versus a string
inverter that decreases the whole array’s production. A key advantage associated with the
micro inverters is they allow for future expansion. This allows the customer to purchase an
introductory solar system with the possibilities of expanding in the future.
Power optimizers, a recent introduction to the solar industry combine the technology of the
string inverter and the micro inverter. Energy loss due to panel mismatch is prevented by
performing MPPT for each panel individually with a power optimizer. The optimizer is mounted
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behind the panel and makes the most of energy output by performing Maximum Power Point
Tracking (MPPT) individually for each panel and maintains a fixed DC string voltage. String
voltage is kept fixed at all times, so strings can be combined regardless of length, tilt, or type of
panels used. Installer and firefighter safety is enhanced by shutting off the DC voltage whenever
the inverter is disconnected.
A typical solar installation should include the following equipment:
o CSA approved modules
o CSA approved inverters, complete with inter-connection cables or wiring
o Racking and CSA approved mounting hardware. (Note: racking should be
connected to the structures integral truss system with approved hardware)
o Grounding equipment (web clips, grounding lugs)
o A weather proof AC disconnect switch
o Wire run from the roof to the electrical panel complete with a continuous bare
#6 copper grounding wire. (Note: wire gauge should be sized according to the
loads applicable to the array)
Racking systems vary depending on the installation. Residential home installations
are typically flush mounted taking advantage of the homes already accessible tilt/slope.
The roofing material will dictate the attachment method. Asphalt shingles and metal roofs
are the simplest to deal with whereas clay tile and cedar shake roofs can be challenging.
Products are available to overcome these hurdles, however, they can be more costly and
labour intensive. Consulting with a roofing contractor for clay tile application is always
suggested. In some cases additional bracing or strengthening of the trusses is required.
New home construction allows for this additional bracing to be installed during the framing
stage. This additional bracing is most commonly required with less than typical solar
installs. Consulting with the framer and truss manufacture is suggested prior to install.
Flat roof structures require a system that is either ballasted or attached to the
building’s structural trusses. When dealing with a flat roof installation it is extremely
important to ensure that we are not overloading the roofs weight limits and that we
incorporate snow and wind loading data. Acquiring the services of an engineer is
suggested.
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4.0
Exposure and the Solar Market
Early solar adopters paid especially close attention to southern exposure, tilt and
azimuth as the cost to install which was particularly expensive. Since 2010, solar prices
have significantly decreased, we have had improvements in technology and installers have
become more skilled.
Today’s residential solar market is much different and we are starting to see homes
with east/west installations. Ideally, a 12/12 pitched roof, facing directly south is the best
scenario for a residential home owner, however sometimes the house just isn’t situated
properly. The market approach has been one of “let’s use what exposure we have” aside
from North and produce what we can. This attitude is a result of the aforementioned
improvements and cost reductions. Solar modelling software proves that east/west
installation can still harvest significant energy in South Eastern Alberta.
The Canadian solar market has experienced a few hurdles in recent months. The
dipping Canadian dollar and new tariffs implemented May 1st, 2015 on imported Chinese
solar modules have increased costs for the end user. However, the cost to supply and
install is still less than what it was prior to 2010.
With increased uptake on residential and commercial solar installations new
requirements and guidelines have been introduced. Fall protection, electrical codes, and
permitting guidelines are ever changing; just as the systems we install change. Today, to
install a residential or commercial solar system, a micro generation agreement must be
signed and approved by the City of Medicine Hat, a building permit must be pulled with the
City of Medicine Hat planning department and an electrical permit must be submitted as
well. All of the permits and agreements need to have attachments that include things like
spec sheets on the equipment, site plans, single line diagrams, string size, and voltages and
so on. It is suggested that you speak with a trained and certified solar installer to assist
with this process. Improperly submitted permits and applications can significantly delay a
project.
With the new provincial government (NDP), the renewable energy sector is holding
its breath. Potential funding programs have been rumored, while code changes have been
ushered in. The province of Alberta has adopted changes to its building, fire and energy
codes. These changes feature a new building class for housing seniors and people with
disabilities as well as updates to the 2015 national fire code. Radon gas protection and
energy efficiency requirements for housing and small building have also been introduced.
Each new code has a coming into force date as well as a six month transition period.
Specific information can be found online @ municipalaffairs.alberta.ca
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These energy efficiency changes may greatly affect the solar industry and prove to
be beneficial. Installing a solar system will offset your electrical consumption levels, and
push power back to the utility in some cases. It will undoubtedly increase the efficiencies
of your building. A trained and certified energy advisor will determine how much more
efficient you home or building will be, based on the size of the solar system, but it will help
you meet or exceed the new building code requirements.
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5.0
System Size, Footprint and Budgetary Cost
In Medicine Hat, the last two years (2014/2015) have been interesting. The number
of homes with solar has increased, as has the size of the systems. Prior to 2014, a typical
system was 1.5kw - 3kw. Recent installations have been anywhere from 2kw - 5kw. This
increase is directly related to the City of Medicine Hat’s funding (Hatsmart 2015/2016) and
the funding applied from Enmax.
Note: the below costs are strictly budgetary and do not include the interior electrical work
required. When a new home is constructed, the required electrical work is usually included
into the homes overall scope of work.
2.6kw Solar Array (2080watts)
o 260watt solar modules (x10), M215 Enphase micro inverters (x10), HES Fastrack
aluminum racking system, monitoring system, AC disconnect, grounding wire,
mounting hardware and installation labour.
COST: $8060 + GST or $3.10/watt
Physical foot print: 2 rows of 5: 17 x 11’ or 187sq ft. Approx weight: 3lbs per sq ft.
1 row of 10: 34’ x 5.5’ or 187 sq ft. Approx weight: 3lbs per sq ft.
3.12kw solar array (3120watts)
o 260watt solar modules (x12), M215 Enphase micro inverters (x12), HES Fastrack
aluminum racking system, monitoring system, AC disconnect, grounding wire,
mounting hardware and installation labour.
COST: $9672 + GST or $3.10/watt
Physical foot print: 2 rows of 6: 21’ x 12’ or 252 sq ft. Approx weight: 3lbs per sq ft.
3 rows of 4: 14’ x 18’ or 252 sq ft. Approx weight: 3lbs per sq ft.
4.16kw solar array (4160watts)
o 260watt solar modules (x16), M215 Enphase micro inverters (x16), HES Fastrack
aluminum racking system, monitoring system, AC disconnect, grounding wire,
mounting hardware and installation labour.
COST: $12896 + GST or $3.10/watt
Physical foot print: 2 rows of 8: 27 x 12’ or 324 sq ft. Approx weight: 3lbs per sq ft.
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5.2kw solar array (5200watts)
o 260watt solar modules (x20), M215 Enphase micro inverters (x20), HES Fastrack
aluminum racking system, monitoring system, AC disconnect, grounding wire,
mounting hardware and installation labour.
COST: $15872 + GST or $3.10/watt
Physical foot print: 2 rows of 10: 33 x 12’ or 399 sq ft. Approx weight: 3lbs per sq ft.
$3.10/ per installed watt of solar is a safe budgetary cost when inquiring about the
costs associated with solar. Anything above a 5kw system will more than likely drop in
price as we are dealing with larger volumes. Electrical connection cost should be fairly
standard. The advantage we have with new construction is that the wire run from the
mechanical room to the roof will be unobstructed and should be done during the rough in
stage.
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6.0 Saamis Heights – Phase 7 Report
6.1
Block 23 – Lots 61 -84
o Lots 61-73: Will have great Southern exposure. These lots will have all day
exposure and a potential solar system will be mounted on the front of the home
facing the street.
o Lots 74–84: Will have great Southern exposure. Great for all day production. Ideal
lots for solar production. Potential solar installs would be mounted on the back side
of the home, facing the proposed park area.
6.2
Block 33 – Lots 52-67, 69-90, 92-96
o Lots 52-67, 69-73: These lots are perfect for solar installations and will have all day
exposure. Potential solar system will be mounted on the back side of the home
facing the green space.
o Lots 74-90: These lots also have great potential with respect to solar installations.
A properly designed home that incorporates a large roof line on the south side of the
home could harvest large amounts of solar energy. Exposure would be SW which
allows for great afternoon production which is when the sun is at its most powerful.
Note: Lot 74 and lot 75 could have either SW or SE exposure depending on the
design of the home.
o Lots 92-96: These lots have potential; however the system will most likely be
mounted on the front of the home, facing the street. Lots 95 and 96 will have SW
exposure, where 93 and 92 may be more west than south. Still great lots, just less
morning sun and more afternoon sun.
6.3
Block 34 - Lots 19-35
o Lots 19-24: Great potential on these lots. South West exposure with the potential
system installation taking place on the south side of the home. Long flat roof lines
along the SW side of the home with limited peaks and valleys would be an asset for
potential solar.
o Lots 25-35: Excellent lots for solar installations. Great all day exposure. Potential
installations will be mounted on the front of the homes facing Sunwood Cres.
Architecturally, a front of house design will be very important and the roofs
mounting surface needs to be large enough to accommodate a solar install.
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6.4
Block 35 - Lots 1 - 27
o Lots 1-5: Another great set of lots with SW exposure. System installations would
take place on the back side of the home facing the back lane. SW exposure offers
great afternoon production.
o Lots 6- 27: Good lots with most of them having SW exposure and a few with S (lots
13-18). These lots will have potential systems installed on the south side of the
home. Overall great lots.
Architectual design will be a major contributor to the viability of these lots. If solar
is the focus for these lots many additional things need to be accounted for other than the
orientation of the lot. Roofing materials, asphalt shingles vs clay tile or metal; these minor
changes may make it more difficult for an installation to happen. Slope and roof design also
contribute to ease of installation as well as production. Fortunately, we live in a region
with great solar potential so slope is not a major factor, however roof design and the
amount of workable space is. Having enough square footage of workable roof is the biggest
challange we face in today’s solar market.
Another thing to be considered in the planning and development stage is the
structual height of the proposed builidngs. This consideration will only affect Block 33 –
lots 75 to 90, Block 35 – lots 6 to 27, and Block 34 – lots 19 to 24. Allowing a two story
construction south of a single level dwelling will certainly affect the solar potential. Idealy
it would be great if all of the homes were designed to the same heights.
.
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7.0 Conclusion
An additional option for Saamis Heights – Phase 7 would be the installation of a
solar shade structure in the park area. Installations of this type are becoming more and
more common and the power produced could be used to power some street lights or
lighting for the parks concept areas
The condition of todays solar market, paired with Medicine Hat’s great solar
potential make most homes adequte for PV installations. The 111 lots in Saamis HeightsPhase 7 are above avergae lots and stand to generate signifcant power for potential home
owners.
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