14 kW 11 kW 44 solar PV modules near Consort Solar Electricity 7 … · 67 solar PV modules near...

#1

Gordon Howell, P.Eng.

©2006-2014Edmonton

14 kW67 solar PV

modulesnear Okotoks

6 kW27 solar PV modulesnear Lamont

7 kW30 solar PV

modulesnear Spruce Grove

6 kW24 solar PV modulesnear Lacombe

Millet2014 March 06

Solar ElectricitySolar Electricity……coming to a farm or acreage coming to a farm or acreage

near younear you

4.5 kW21 solar PV modules

near Devon

11 kW44 solar PV modulesnear Consort

#2

Intro: Me

my house: 2.3 kW PV systemmy house: 2.3 kW PV system44thth gridgrid--connected PV house in Canada in 1995connected PV house in Canada in 1995

~100% solar electricity~100% solar electricity

I am a professional engineerI am a professional engineer

I am a solarI am a solar--electric system project developerelectric system project developerworking with solar energy since 1977 and working with solar energy since 1977 and with solar electricity since 1983with solar electricity since 1983

I develop, design, supply and commission solarI develop, design, supply and commission solar--electric systemselectric systems

I have no vested interests in any one solarI have no vested interests in any one solar--electric technologyelectric technology

I want you to make your decisions I want you to make your decisions with your eyes wide open with your eyes wide open

so that you can decide so that you can decide what may be right for youwhat may be right for you……

#3

Information… energy, power, solar

A lot of information to be aware ofA lot of information to be aware of

A lot of A lot of mismis--information and information and disdis--informationinformation

You need to understandYou need to understand……

basics about solar energybasics about solar energy

basics about energy basics about energy vsvs powerpower

your electricity bill and its pricesyour electricity bill and its prices

#4

Intro: Solar Electricity

OverviewOverview

What are the components?What are the components?

How does it work?How does it work?

What angles are best?What angles are best?

How much can it reduce your electricity bill? How much can it reduce your electricity bill?

What would it cost for your house or farm?What would it cost for your house or farm?

Photo credit: Great Canadian Solar, Edmonton

#5

To start:The basics about solar electricity…

Every great movement must experience three stages: John Stuart Mill…ridicule, discussion, adoption.

#6

Uses of Solar Energy in a House…

Part of a solar ventilation air pre-heating system

Part of a solar

domestic hot water heatingsystem

Part of a solar electricity-generating system

Direct gain passive

solar space heating windows

Solar illumination windows

#7

Solar Heating and Solar Electricity

are NOT the same…

Solar electricity– Much like a computer chip– Photons of light bump

electrons out of an atom– Wires carry electrons away

Solar heatingA dark surface sitting in the sun lightWater or air flows past solar-heatedsurface and carries heat away

#8

Solar heating Solar heating thermal thermal collectorscollectors

Solar electricity Solar electricity photovoltaic photovoltaic modulesmodules

Solar panel Solar panel mechanical configuration mechanical configuration several solar PV modules attached several solar PV modules attached on a mounting rackon a mounting rack

What words do we use?

#9

Solar ElectricityThe technology is called "The technology is called "photovoltaicsphotovoltaics", but we only call it "PV".", but we only call it "PV".

solar PV cell

solar PV module

solar PV panel (because the modules are all

fastened together on one contiguous rack)

array of solar PV modules

#10

PV Terms

Solar PV

Solar PV Solar PV ArrayArray

PV can generate any amount of electricity.Large PV systems = more PV modules.

Solar PV Solar PV ModuleModuleSolar PV Solar PV CellCell

30,000 modules, 6000 kW

5,000 modules1000 kW

170,000 modules34,000 kW

#11

Solar PV System – Major Components…

Solar PV module…to generate

DC electricity

Inverter…to convert to

AC electricity

Battery…to store

DC electricity

maybe… but not usually

#12

Solar Photovoltaic (PV) System

1. Array of solar PV modules

2. DC disconnect switch

3. DC to AC Inverter

4. Customer service box and panelboard

1

2

3 4

7. Electrical utility wires

8. Distribution transformer(dedicated or shared with other customers)

© 2011 Jim Dunlop Solar (modified)

7

8

DC

AC

Notes:DC = direct currentAC = alternating currentComponents #2, 3, 4 are usually inside a house

6. Electrical utility revenue meter

6

5

5. House loads

#13

PV Module Technologies

multimulti--crystalline crystalline

siliconsilicon

single single crystal crystal siliconsiliconTechnologies:Technologies:

singlesingle--crystal silicon (Si)crystal silicon (Si)multimulti--crystalline silicon (Si)crystalline silicon (Si)amorphous silicon (Si)amorphous silicon (Si)(no crystalline structure)(no crystalline structure)thinthin--film (film (CdTe/CdSCdTe/CdS, CIGS, CIS, , CIGS, CIS, GaAsGaAs..)..)

thinthin--filmfilm

CdTe/CdSCdTe/CdS

Myth Myth ---- RareRare--earth metals ???earth metals ???NONO, PV does not contain , PV does not contain rarerare--earth metals.earth metals.RareRare--earth metals do not have the earth metals do not have the correct atomic characteristics for correct atomic characteristics for the the ““photovoltaicphotovoltaic”” effect to work.effect to work.

#14

Continuous silicone seal

Tempered glassEVA embedding

Solar cellsTough polymer back sheet

High strength frame

Typical PV Module Construction

SolarWorld USA

#15

PV Module Manufacturers

Module manufacturers and countries:Module manufacturers and countries:America: America:

First Solar, Evergreen, First Solar, Evergreen, UniUni--Solar, Solar, SunPowerSunPower ++++Canada:Canada:

Day4EnergyDay4Energy, Canadian Solar, , Canadian Solar, EclipsallEclipsall, , SilfabSilfab ++++China:China:

SolarfunSolarfun, Suntech, Trina, , Suntech, Trina, YingliYingli, , AstronergyAstronergy, LDK ++++, LDK ++++France:France:

PhotowattPhotowattGermany:Germany:

ConergyConergyJapan:Japan:

Kyocera, Sharp, Sanyo, Mitsubishi ++Kyocera, Sharp, Sanyo, Mitsubishi ++Korea:Korea:

LG, Samsung, HyundaiLG, Samsung, HyundaiSpain:Spain:

IsofotonIsofoton, , HelieneHeliene++ many ++ many manymany more countries andmore countries and

manufacturersmanufacturers……

50,000 solar PV modules available from50,000 solar PV modules available from

1164 module manufacturers1164 module manufacturers……! **! **** http://www.photon.info/photon_site_db_solarmodule_en.photon

#16

PV Module Standards

18 tests including:Hail test – 25 mm at 83 km/hTemperature cycling test, -40°C to +85°CDamp-heat testUV testWind, snow, ice loading testRated performancePerformance at low irradianceOutdoor exposureHot-spot endurance testHumidity-freeze testWet insulation resistance test

Design, certified and tested to international standard IEC 61215do not buy a PV module that does not have this testing designation shown on the brochure…

#17

Inverters convert DC electricity (produced by the solar array)to AC electricity (used by any AC loads)

Xantrex GT Canada

grid-dependentstring inverter

3.8 kW

Fronius IGAustriagrid-dependentstring inverter2 kW to 5.1 kW

SMA Sunny Boy Germanygrid-dependentstring inverter3 to 11 kW

Xantrex XWCanada

grid-connectedinverter/charger

4 kW to 6 kW

EnphaseAmericagrid-dependentmodule inverter0.2 kW

DC to AC Inverters

#18

DC to AC Inverter Banks…

Each: 0.2 kW to 11 kW, 1 phaseEach: 0.2 kW to 11 kW, 1 phase

Each: 1Each: 10 kW to 1000 kW, 3 phase0 kW to 1000 kW, 3 phase

8200 solar inverters available from8200 solar inverters available from

364 inverter manufacturers364 inverter manufacturers……! **! **** http://www.photon.info/photon_site_db_wechselrichter_en.photon?ActiveID=1241

#19

4 major components:PV arrayDC switchSolar inverterAC switch (maybe)

No energy storage

Typically simpleto design, install, operate

Most commongrid-connected configuration (99.9%)

Solar PVarray1

23

4

Grid-dependent Solar PV System

#20

Importregister

kWh

kWh

Export register

kWh

kWh DC

Electric Wires Company’s electrical distribution grid

AC

All electrical circuits in a building

1

2

3

4

Inverter

Exports to the grid when there is a site surplus.Imports from the grid when there is a site shortage.Typically 50% to 90% is exported over the year from a house.

Generating solar electricity into a building

and also back into the grid…

©1995-2014

Solar electric array

DC to ACInverter

Solar PVarray

Panelboard

Breakers

#21

PV Array

Inverter

DC

AC

All electrical circuits in a house

1

2

3

4

The inverter senses that there is a electrical outage and turns itself off.

When electric power returns, the inverter turns itself on automatically.

What happens during an electrical outage?

Electric Wires Company’s electrical distribution grid

kWh

kWhImportregister

Export register

kWh

kWh

©1995-2014

Panelboard

Breakers

DC to ACInverter

Solar electricarray

#22

Grid-Connected System – with batteries

7 major components

Includes energy storage

Not common at all25 in Canada?

#23

PV Array

DC

Electric Wires Company’s electrical distribution grid

AC

1

2

3

4

This configuration has a battery bank but it is not common.

How about energy security?

AC

5

Battery BankDC

6

7

kWh

kWhImportregister

Export register

Inverter/charger

ChargeController

©1995-2014Main electrical circuits in a house

Main Panelboard

Breakers Essential circuit panelboard

Breakers

kWh

kWh

#24

PV Array

kWh

kWhImportregister

Export register

1

The inverter senses that there is a electrical outage. It disconnects itself from the main breaker panel but continues to run the essential circuits.

During an electrical outage…

Essential circuit panelboard

AC

Battery BankDC

3

DC 2

4

5

6

7

ChargeController

Inverter/charger

Electric Wires Company’s electrical distribution grid

©1995-2014

AC

Main electrical circuits in a house

Main Panelboard

Breakers

Breakers

kWh

kWh

#25

Planning Decisions…

Fit within dimensions and area of available space

#26

Planning Decisions…

Minimise obstructions from other equipment, buildings

#27

Planning Decisions…

Minimise shading from buildings and trees

#28

Technical Decisions…Engineering

Energy● Goal: maximise annual energy generation

Electrical ● Match modules to inverter (voltage, current, power)

at max. and min. module temperatures

Angles● Maximise energy production and generation● Minimise snow cover

Structural fastening ● Minimise extra structural loading on building● Maximise passive cooling and minimise module

temperature to increase module efficiency

#29

What tilt angle to use?

0

2

4

6

8

1 2 3 4 5 6 7 8 9 10 11 12

Annual

0°, horizontal

Month #s

Edmonton

Daily incoming solar radiation

sun-hours= kWh/m2/day

Solar radiation – horizontal surface

#30

What tilt angle to use?

0

2

4

6

8

1 2 3 4 5 6 7 8 9 10 11 12 Annual

Month #s

27°, 6/12 roof pitch

0°, horizontal

Edmonton

In many ways our future is passing us by, Gary Lamphier… and our energy riches may one day look like fool's gold. Edmonton Journal

Daily incoming solar radiation

sun-hours= kWh/m2/day

#31

What tilt angle to use?

1 2 3 4 5 6 7 8 9 10 11 12 Annual

Month #s

0

2

4

6

8

27°, 6/12 roof pitch

0°, horizontal

53°, = latitude

Edmonton

Daily incoming solar radiation

sun-hours= kWh/m2/day

#32

What tilt angle to use?

1 2 3 4 5 6 7 8 9 10 11 12 Annual

Month #s

0

2

4

6

8

27°, 6/12 roof pitch

0°, horizontal

53°, = latitude

90°, = vertical

Edmonton

Daily incoming solar radiation

sun-hours= kWh/m2/day

#33

Optimal Annual Solar Tilt Angle(to use when you’re connected to the grid)

maximum annual solar energy production occurs at around a 50° tilt.tilt angle can be from 18° to 80° and still be within 10% of maximum energy

precise optimum tilt and orientation to collect maximum amount of solar energywide degree of flexibility to orient and tilt solar equipment and still not be too far off the optimum

% of energy

reduced from

optimal annual

tilt angle (and

facing due

south)-30%

-25%

-20%

-15%

-10%

-5%

0%0 13 23 33 43 53 63 73 83 90

Horizontal Vertical

4.8sun-hours/day= kWh/m2/day

3.6

4.0Edmonton

data from simulation software

#34

Optimal Winter Solar Tilt Angle (to use when you’re off grid)

Edmonton

% of energy

reduced from

optimal winter tilt

angle (and

facing due

south) -80%

-70%

-60%

-50%

-40%

-30%

-20%

-10%

0%0 13 23 33 43 53 63 73 83 90

Horizontal Vertical

3.8sun-hours/day

1.0

3.4 3.75

maximum winter solar energy production occurs at around a 83° tilt.tilt angle can be from 50° to 90° and still be within 10% of maximum winter energy

Reduction from snow cover?Enhancement from reflection off snow fields?

data from simulation software

#35

-12%

-10%

-8%

-6%

-4%

-2%

0%230 220 210 200 190 180 170 160 150 140 130

SW SESouth

Orient PV array up to 45° either side of south and still be within 10% of maximum energy

SW South SESSESSW

% of energy

reduced from

optimal annual

orientation angle

(at tilt angle = latitude)

Edmonton

Optimum Annual Solar Orientation Angle

data from simulation software

#36

Solar Window

Sunpath ChartThe solar window:Where most of the sun's energy comes from…

Path of the sun Path of the sun across the skyacross the sky

Sun's pathDecember 21 Sun's path

June 21

NorthSouth

East

West

3pm

10am

#37

Get a sun path chart for your area Site your PV array where there is little or no shading between 10am and 3pm

Sun Path

Make a sun path chart fromhttp://solardat. uoregon.edu/SunChartProgram.html

solar window

#38

Shading Analysis

from the PV system at the Kerry Wood Nature Centre, Red Deer

Huge tree

Solmetric SunEyeshading analysis instrument solar window

#39

SunEye – Monthly Solar Access

from the PV system at the Kerry Wood Nature Centre, Red Deer

100%

93%

76%

67%65%

82%

71%

64%69%

Annual solar access prorated across the

energy availability per month= 88%

#40

What about snow?

What about snow cover?

Do I have to push the snow off my PV array?

What difference does it make?

#41

PV covered with snow works PV covered with snow works just as well as it does at nightjust as well as it does at night

Of course, when the big light in the sky turns off, Of course, when the big light in the sky turns off, solar PV systems donsolar PV systems don’’t work t work so instead we draw electricity from the electricity grid.so instead we draw electricity from the electricity grid.

Riverdale NetRiverdale Net--Zero Energy houseZero Energy house2008 November 20, 19:262008 November 20, 19:26

#42

Snow can stick at lots of angles…

53° tilt angle

Riverdale Net-Zero-Energy House2008 December 30, noon, -20°C

#43

PV Compromises – Snow Cover

Belgravia Green near NZE Belgravia Green NZE Belgravia Green NZE-ready

60°

23°

50° tilt angle

Snow can easily stick and stay… depending on air temperature Over-size the PV system to accommodate unclearedsnow cover

focus on amount of energy generated over the whole year, not generated only in the winter

#44

Reduction in Generation due to Snow Cover – typical year

tilt angle from horizon

Huge variation in depth and duration of snow cover from year to year

data from my observations and guesses

… this data is an informal approximation… it is way better than ignoring snow…

Reduction in annual generated amount

#45

PV Array Mounting Systems

Can be mounted in many ways

Ground-mounted arraysRacks, poles and sun-tracking mounts

Roof-mounted arraysRacks for flat roofsStandoffs for sloped roofsDirect or flush

Orientation typeFixed-tilt, adjustable and sun-tracking arrays

#46

PV Array Mounting – Ground

Need protection from physical harm, module theft, and safetyby fencing or elevating the array

#47

PV Array Mounting – Rack

Can be installed on the ground using concrete footingson roofs, or on the sides of buildings

#48

PV Array Mounting – Pole

Pole-mounted arrays are used for many applications. Larger arrays require substantial foundations to resist winds

#49

Need space for thisLikely will never be used in a cityWould work well on a farm

PV Array Mounting – Pole

#50

PV Array Mounting – Roof Standoff

Standoff mounts are the most common way PV arrays are attached to sloped rooftops.

Many many products available for stand offs.

Sharp Solar

#51

PV Array Mounting – Fixed-Tilt

fixed orientation toward the sunmost common PV array mounting

#52

Tracking the Sun

Single axis trackingpitch function = E-W axis, facing due south, tracking up-down13% more annual energy than array at optimum fixed-tilt angle

Single axis trackingyaw function = vertical axis, optimum array tilt, tracking E-W33% more annual energy than array at optimum fixed-tilt angle

Usuallythe cost of the PV array tracker and a system's increase in energy production is comparable to a fixed tilt system with a bigger PV array!

#53

Single axis trackingroll function = N-S axis, horizontal axis tilt, tracking E-W9% more annual energy than array at optimum fixed-tilt angle

Roll-Axis – Axis Not Tilted

340 kW, California

#54

Single axis – angled axisroll function = N-S axis, axis tilt = 64°, tracking E-W21% more annual energy than array at optimum fixed-tilt angle

Roll-Axis – Tilted Axis

#55

Feeds a house west of Edmonton16.8 kW totalOperational since August2-axis tracking38% more annual energy than array at optimum fixed-tilt angle

Two-Axis Tracking

#56

Economics

Let’s look at costs and economics

#57

Benefits of Solar PV…

Savings on utility bills

Energy price securityalmost all the costs are paid upfrontonly maintenance cost is inverter replacement in 20 years

Energy supply security and independenceonly if you have a battery bank

No noise

No operating emissions (air, water, soil)

Does not incur any new real estate or site development costs (if you mount it on a building)

#58

Exported electricity diagram

SellBuy kWh

1 kWh 1 kWh 1 kWh

PV system owner

Bi-directional kWh meter

Ordinary kWh meter

Electricity is delivered to your neighboursby your Electricity Delivery Company for their normal delivery fee.

Imported electricity

paid in full

Energy Retailer sells your exported energy to your neighbour for full retail price.

1

3

4

1 kWh supplied, 1 kWh paid for

kWh

©1995-2014

Where does exported electricity go?Energy Retailer, Electricity Delivery

Company

Electricity delivery wires

Neighbour

Exported electrical energy credit

Imported electricity paid in full

2

no PV system (yet)

#59

Understanding Electricity Bills:Energy vs. Power

0.3 0.4 0.3 0.4 0.40.5

1.1

1.4

0.70.5 0.5

1.0

0.5 0.5 0.5 0.5

1.5

3.0

1.2

0.8 0.8 0.70.5

0.3

0.75

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Avg

Time of Day [hour]

Pow

er [k

W] BUT they only get paid

for delivering this much electrical energy

Electric companies need to design and build their electricity generating, transmitting and delivery systems to generate and deliver this much electrical power… (plus a safety margin)

Area of brown bars = total energy= 18 kWh/day= 6600 kWh/year

#60

DERS + ATCO Electric Pricesfor an Acreage or House

Prices: charge for energy + charge for gridDERS E1 purchase: 7.78 ¢/kWh $109 /year (March 01)

ATCO D11 delivery: 10.52 ¢/kWh $517 /year (April 01)

Total charges: 18.30 ¢/kWh $627 /year

Bill for 7200 kWh/year: ¢/kWh x kWh/year = $ for energy + $ for grid

DERS E1 purchase: 7.78 x 7200 = $ 560 + $109 /yearATCO D11 delivery: 10.52 x 7200 = $ 757 + $517 /yearTotal charges: 18.30 x 7200 = $1318 + $627 /year

68% 32%--------------------------------------------------------------------------------------

Total bill = $1944 /year(appearance: $1944 / 7200 = 27 ¢/kWh, which is not correct)

GST included in all prices

#61

Time-based connection fee + energy-based feeEnergy fee = amount of electricity purchased and delivered + GSTFor a typical house, the potential savings are $1318 (68% of your bill).

}Amount of electricity used (kWh)

Electricity bill ($)

Annual connection fee ($627 per year, 32% of bill)

Actual price of electricity including purchase, delivery, taxes & GST (18.30 ¢/kWh)

Average household consumption

Average household electricity billAverage

household bill: $1944 per year

7200 kWh/year0$0

Energy fee $1318

Electricity bill = Grid-connection fee

} Connection fee $627

+ (Electricity consumption x electricity price)

Electricity Bill – House

#62

DERS + ATCO Electric Pricesfor a Farmhouse

Prices with 10 kVA transformer: charge for energy + charge for gridDERS E5 purchase (incl GST): 7.88 ¢/kWh $116 /year (March 01)

ATCO D56 delivery (all included): 1.52 ¢/kWh $1216 /year (April 01)

Total charges: 9.40 ¢/kWh $1332 /year

Bill for 7200 kWh/year: ¢/kWh x kWh/year = $ for energy + $ for grid

DERS E5 purchase: 7.88 x 7200 = $567 + $ 116 /yearATCO D56 delivery: 1.52 x 7200 = $110 + $1216 /yearTotal charges: 9.40 x 7200 = $677 + $1332 /year

34% 66%--------------------------------------------------------------------------------------

Total bill = $2009 /year(appearance: $2009 / 7200 = 28 ¢/kWh, which is not correct)

GST included in all prices

#63

Time-based connection fee + energy-based feeEnergy fee = amount of electricity purchased and delivered + GSTFor a typical farm, the potential savings are $677 (34% of your bill).

}

Amount of electricity used (kWh)

Electricity bill ($)

Annual connection fee ($1332 per year, 66% of bill)

Actual price of electricity including purchase, delivery, taxes & GST (9.4 ¢/kWh)

Average household consumption

Average household electricity billAverage

household bill: $2009 per year

7200 kWh/year0$0

Energy fee $677

Electricity bill = Grid-connection fee

Connection fee $1332

+ (Electricity consumption x electricity price)

Electricity Bill – Farm Rate

(D56)

#64

DERS + ATCO Electric Pricesfor a Farm (and its operations)

Prices with 7.5 kVA transformer: charge for energy + charge for gridDERS E5 purchase (incl GST): 7.88 ¢/kWh $116 /year (March 01)

ATCO D56 delivery (all included): 1.52 ¢/kWh $977 /year (April 01)

Total charges: 9.40 ¢/kWh $1093 /year

Bill for 25,000 kWh/year: ¢/kWh x kWh/year = $ for energy + $ for grid

DERS E5 purchase: 7.88 x 25,000 = $1970 + $ 116 /yearATCO D56 delivery: 1.52 x 25,000 = $ 380 + $ 977 /yearTotal charges: 9.40 x 25,000 = $2350 + $1093 /year

68% 32%--------------------------------------------------------------------------------------

Total bill = $3444 /year(appearance: $3444 / 25,000 = 13.8 ¢/kWh, which is not correct)

GST included in all prices

#65

Comparison: a house and farmusing 25,000 kWh/year

A house using 25,000 kWh per yearDERS E1 purchase: 7.78 x 25,000 = $1945 + $109 /yearATCO D11 delivery: 10.52 x 25,000 = $2630 + $517 /yearTotal charges: 18.30 x 25,000 = $4575 + $627 /year

88% 12%--------------------------------------------------------------------------------------

Total bill = $5202 /year

A farm using 25,000 kWh per yearDERS E5 purchase: 7.88 x 25,000 = $1970 + $ 116 /yearATCO D56 delivery: 1.52 x 25,000 = $ 380 + $ 977 /yearTotal charges: 9.40 x 25,000 = $2350 + $1093 /year

68% 32%--------------------------------------------------------------------------------------

Total bill = $3444 /year

#66

0.00.20.40.60.81.01.21.41.61.82.02.22.42.6

0 3 6 9 12 15 18 21 24Time of day

[hours]

Act

ive

Pow

er [k

W]

PV system generation

House electricity consumption

Avg

Avg

Exported energyValue: 7.9 ¢/kWh

PV energy used on siteValue: 7.9 + 1.5 = 9.4 ¢/kWh

Imported energyValue: 7.9 + 1.5 = 9.4 ¢/kWh

Imported energy Value: 7.9 + 1.5 = 9.4 ¢/kWh

Time of day [hours]

Consumption without PV: 18.6 kWh = $1.75Deficit electricity imported: 72% 13.3 kWh = $1.25PV used on site: 5.3 kWh = $0.50PV electricity exported: 30% 2.2 kWh = $0.17Total PV generation: 7.5 kWh = $0.67Savings (energy) ($): 40% 38%

Farm Export and Import Prices (¢/kWh)Actual measured PV and house

performance, 1997 February

#67

0.00.20.40.60.81.01.21.41.61.82.02.22.42.6

0 3 6 9 12 15 18 21 24Time of day

[hours]

Act

ive

Pow

er [k

W]

PV system generation

House electricity consumption

Avg

Avg

Exported energyValue: 7.8 ¢/kWh

PV energy used on siteValue: 7.8 + 10.5 = 18.3 ¢/kWh

Imported energyValue: 7.8 + 10.5 = 18.3 ¢/kWh

Imported energy Value: 7.8 + 10.5 = 18.3 ¢/kWh

Time of day [hours]

Consumption without PV: 18.6 kWh = $3.40Deficit electricity imported: 72% 13.3 kWh = $2.43PV used on site: 5.3 kWh = $0.97PV electricity exported: 30% 2.2 kWh = $0.17Total PV generation: 7.5 kWh = $1.14Savings (energy) ($): 40% 34%

Acreage Export and Import Prices (¢/kWh)Actual measured PV and house

performance, 1997 February

#68

What to look for with PV prices…

Modules (~30% of total system cost)Price divided by rated power: $/ WExample: 250 W PV module for $250 is $1 / WTypical range: $0.85 to $1.10 / W wholesale,

$1.00+ / W retailInverter

Example: 3000 W inverter for $1350 is $0.45 / WTypical range: $0.55 to $1.00 / W

Installation labourTypical range: $0.50 to $0.70 / W

Other costs: design, development, permits and approvals, racking, wiring, disconnects

Total grid-connected system, range: $2.80 to $4 /W

#69

How much solar PV do you need?(house)

1. Add up your electric energy consumption (kWh) in a year from your monthly bills

● e.g. 7200 kWh/year● cost is likely $1944 /year = 7200 x 18.3 ¢/kWh / 100 + $627

2. Divide by the PV system annual yield● e.g. 7200 kWh/year / 1200 kWh/year / kW

3. Gives you PV array capacity (kW)● e.g. 6 kW to generate the same amount of electric energy as

you use over the year

#70

4. Multiply by typical price of installed PV system● e.g. 6 kW x 1000 x $3 /W● $3 /W for typical installations (some installers can do it for a bit less)

5. Gives you the cost of your PV system to generate 100% of your annual electric energy

● e.g. = $18,000

6. Value of annual PV electrical energy = $790 (= 10.94 ¢/kWh x 7200 kWh)● (10.94 ¢/kWh is based on 70% energy exported,

7.78 ¢/kWh energy purchase price,10.52 ¢/kWh ATCO Electric delivery price)

● (you don’t have to generate 100%, you can easily generate any amount less than 100%)

How much solar PV do you need? (house)

#71

What are the economics of PV? (house)

7. Divide initial cost by 1st-year savings● e.g. $18,000 / $790 /year = 23 years

This is only a simple way to do an economic analysis. This is not the correct way to do an economic analyses…● Economic analyses need to include:

20-year analysis periodfinancing costsincrease in electricity pricesdiscount rate, consumer inflation ratesmall performance decrease from PV system (0.5% /year)replacement of inverter after 20+ years

#72

Price of solar PV electricity (house)

8. Divide initial cost by 23-year amount of electricity generated● For example:

$18,000 initial cost7200 kWh /year x 23 years = 165,600 kWhminus 5% for module aging = 157,000 kWh$18,000 / 157,000 = 11.4 ¢/kWh

fixed price for 23 years, then free electricity after that…

● Comparison: today’s price for grid electricity:Edmonton ~13 ¢/kWh (energy purchase + delivery)Fortis ~14 ¢/kWhATCO ~18 ¢/kWh

is rising at 4% to 10% per year

#73

Full economics analysis(house)

analysis period: 20 years for bank loanfinancing costs: 3% per yeardiscount rate: not considered because you are using

the bank’s money not your ownincrease in electricity prices: 4% per year (can range up to 10%)consumer inflation rate: 2% per yearPV performance decrease: 0.5% per yearinverter replacement life: 20 yearssystem insurance cost: $50 per year (0.3% of system cost)maintenance cost: $0 per yearportion of energy exported: 70% per year (reasonable estimate)price of PV electricity: 21 ¢/kWh over 20 yearsprice of grid electricity: 27 ¢/kWh over 20 years

#74

How much solar PV do you need?(farm)

1. Add up your electric energy consumption (kWh) in a year from your monthly bills

● e.g. 25,000 kWh/year● cost is likely $3444 /year = 25,000 x 9.40 ¢/kWh / 100 + $1093

2. Divide by the PV system annual yield● e.g. 25,000 kWh/year / 1200 kWh/year / kW

3. Gives you PV array capacity (kW)● e.g. 21 kW to generate the same amount of electric energy as

you use over the year● What is the size of your transformer’s breaker?

This is a limiting factor…

#75

4. Multiply by typical price of installed PV system● e.g. 21 kW x 1000 x $3 /W● $3 /W for typical installations (some installers can do it for a bit less)● could be down to $2.20 /W if you install it yourself

5. Gives you the cost of your PV system to generate 100% of your annual electric energy if you install it yourself

● e.g. = $46,000

6. Value of annual PV electrical energy = $2160 (= 8.65 ¢/kWh x 7200 kWh)● (8.65 ¢/kWh is based on 50% energy exported (???),

7.9 ¢/kWh energy purchase price,1.5 ¢/kWh ATCO Electric delivery price)

● (you don’t have to generate 100%, you can easily generate any amount less than 100%)

How much solar PV do you need? (farm)

#76

What are the economics of PV? (farm)

7. Divide initial cost by 1st-year savings● e.g. $46,000 / $2160 /year = 21 years

This is only a simple way to do an economic analysis. This is not the correct way to do an economic analyses…● Economic analyses need to include:

20-year analysis periodfinancing costsincrease in electricity pricesdiscount rate, consumer inflation ratesmall performance decrease from PV system (0.5% /year)replacement of inverter after 20+ yearsAccelerated Capital Cost Allowance (50% per year)

#77

Price of solar PV electricity (farm)

8. Divide initial cost by 21-year amount of electricity generated● For example:

$46,000 initial cost25,000 kWh /year x 21 years = 525,000 kWhminus 5% for module aging = 500,000 kWh$46,000 / 500,000 = 9.2 ¢/kWh

fixed price for 21 years, then free electricity after that…

● In comparison: today’s price for grid electricity:Fortis (not calculated yet)ATCO ~9.4 ¢/kWh

is rising at 4% to 10% per year

#78

Full economics analysis(farm)

analysis period: 20 yearsfinancing costs: 3% per yeardiscount rate: not considered because you are using

the bank’s money not your ownAccelerated CCA: 50% per year capital cost allowancemarginal tax rate: 18% (wild guess)increase in electricity prices: 4% per year (can range up to 10%)consumer inflation rate: 2% per yearPV performance decrease: 0.5% per yearinverter replacement life: 20 yearssystem insurance cost: $130 per year (0.3% of system cost)maintenance cost: $0 per yearportion of energy exported: 50% per year (wild guess)price of PV electricity: 11.8 ¢/kWh over 20 yearsprice of grid electricity: 14.0 ¢/kWh over 20 years

#79

Farm near Villeneuve

46 PV modules, 240 W each11 kW$4 /W = $44,000

Solar project designed and installed by: Great Canadian Solar, Edmonton

#80

Farm near Lacombe

24 PV modules5.8 kW$4 /W = $23,000

Solar project designed and installed by: Great Canadian Solar, Edmonton

#81

Farm near Consort

44 PV modules of 240 W each10.6 kW$3.80 /W = $40,000

Solar project designed and installed by: Great Canadian Solar, Edmonton

#82

Farm near Lamont

27 PV modules of 240 W6.5 kW$4 /W = $26,000

Solar project designed and installed by: Great Canadian Solar, Edmonton

#83

Acreage near Okotoks

67 PV modules of 200 W each13.4 kW

Solar PV system installed by homeowner

#84

How many PV systems are there?

Off-grid:Thousands of tiny 2- to 4-module off-grid systems throughout oil and gas fields

Grid-connected:177 in Edmonton (2013 October), increase by ~115 over the last 2 years

780+ in Alberta (2013 October)

30,000 (equivalent) in Canada (???)

11 million (equivalent) around the world… (???)

1000 kW5000 solar PV

modulesNapa Valley

California

#85

Geiseltalsee SolarparkGermany 4000 kW. 25,000 PV modules

Solar PV Farms

Solar prospectors look for rentable farm land

Typically: 6 acres / MW

#86

Caveat…

Solar PV is technical subject and a high-voltage electrical system. Safety and proper design are critical.

There are many factors to be considered in its design, grid-connection approvals and economic calculations.

Be aware of hearsay, products that are not used widely, and wild performance claims.

Do your research well.

Hire someone who knows what they are doing, with qualifications, references, and proven experience.

#87

The dawn of a new era…

……we allwe allcan be part of it

Anyone who thinks they are too small to make a difference… Africanhas never spent the night with a mosquito. Proverb

Solar Electricity

#88

Solar PV ElectricitySolar PV ElectricitySimple Simple –– Clean Clean –– Reliable Reliable –– AffordableAffordable

Local Local …… UnsubsidisedUnsubsidised ... Democratic ... Democratic …… NowNow

Gordon Howell, P.Eng.Howell-Mayhew Engineering

EdmontonPhone: +1 780 484 0476

E-mail: ghowell@hme.ca©1995-2014Photo credits: Gordon Howell and several others

Other PV presentations are

available atwww.hme.ca

/presentations

We welcome any feedback, questions, suggestions, comments and challenges to anything we present.