1 · Solar Theory
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How solar works and the parts of a system.
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Module 1 · Solar Theory & General Knowledge
Welcome — let’s talk solar
This course is about building solar energy systems in (and with) First Nation communities. It’s four short modules — here’s the path.
Finish this module and you’ll be able to read a solar panel’s spec label and explain how a solar system turns sunlight into usable power — and you’ll earn your Solar Theory badge.
The four modules:
2 · Project Management
Planning, procurement, financing and scheduling.
3 · Solar Build
Site design and overseeing construction.
4 · Post-Build
Commissioning, warranties and monitoring.
Module 1 · Solar Theory & General Knowledge
How a solar panel makes electricity
It starts with light. Sunlight hits the panel and knocks electrons loose — that flow is electricity.
This is the photovoltaic effect — “photo” (light) + “voltaic” (voltage).
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Where does the term “photovoltaic” come from?
Module 1 · Solar Theory & General Knowledge
What is electricity?
Electricity is the flow of electrons through a closed circuit.
A closed circuit is a complete, unbroken loop — electricity only flows when the path connects all the way around. Open the loop (flip a switch, cut a wire) and the flow stops.
DC flows steadily in one direction. AC flips back and forth 60 times per second (60 Hz).
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AC voltage…
Module 1 · Solar Theory & General Knowledge
The three things that make electricity work
Electricity behaves a lot like water moving through a pipe. Once you picture it that way, three words do all the heavy lifting — volts, amps and watts.
Volts
The push
The pressure that pushes electricity through a wire.
In the pipe: water pressure.
Amps
The flow
How much electricity is actually moving. A wider wire carries more.
In the pipe: the rate of water flow.
Watts
The power
The actual work done — lighting a bulb or running a motor.
The formula: Watts = Volts × Amps.
Watts = Volts × Amps
A panel pushing 29.5 V at 7.8 A → 230 W
Real label from a solar panel Quick check
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What is voltage?
Module 1 · Solar Theory & General Knowledge
Ohm's Law
Ohm's Law links voltage, current, and resistance in a circuit.
V = I × R
Voltage (volts) = Current (amps) × Resistance (ohms)
V is voltage, I is current, R is resistance. Module 1 · Solar Theory & General Knowledge
Finding power
Know any two values and you can find the third.
Watts = Volts × Amps
120 V × 4 A = 480 W
An appliance rated 120 V drawing 4 amps uses 480 watts. Quick check
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If a circuit is 120 volts and 480 watts, what is the current (amps)?
Module 1 · Solar Theory & General Knowledge
Inside a solar panel
A panel is built like a sandwich — layers that protect the cells while letting the light through.
Module 1 · Solar Theory & General Knowledge
Inside a solar panel
Cells are wired in series, so their voltages add up.
Each cell makes about 0.5 V, so a 60-cell panel produces roughly 30 V.
Module 1 · Solar Theory & General Knowledge
Why we need inverters
Panels make DC power, but homes and buildings run on AC.
AC is more dangerous than DC. The AC side is wired by an electrician and needs Electrical Safety Authority approval.
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Solar panels produce…
Module 1 · Solar Theory & General Knowledge
Types of solar panels
Solar cells are made of silicon, which creates the photovoltaic effect.
Choose a panel type by weighing your budget against the efficiency you need.
Module 1 · Solar Theory & General Knowledge
Bifacial panels
Bifacial panels capture sunlight on both the front and back surfaces. They are about 22-23% efficient and are now common across Ontario and North America.
Module 1 · Solar Theory & General Knowledge
Monocrystalline panels
Grown from a single silicon crystal, mono panels are about 18-23% efficient and great for rooftops.
Module 1 · Solar Theory & General Knowledge
Polycrystalline panels
Poly panels have square cells with straight corners. They run about 17-21% efficient, a bit lower than mono, but they cost less.
Poly is melted, cut into crystals, and sliced thin, making it more cost effective than mono.
Module 1 · Solar Theory & General Knowledge
Thin film panels
Thin film is a flexible, delicate sheet that can be rolled up like a spool, handy for deploying solar quickly. It is the least efficient at 8-14% and is rarely used in Canada.
It damages easily from hail or wind, and hidden micro cracks can quietly drop its output.
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Which statement is true?
Module 1 · Solar Theory & General Knowledge
Panels keep getting more efficient
Solar panels make more power from the same size every year.
More efficient panels mean more power from the same area.
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How are solar panels sized?
Module 1 · Solar Theory & General Knowledge
Peak sun hours
Panels make the most power when the sun is high, around noon.
Peak sun hours also depend on location and time of year.
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Peak sun hours…
Module 1 · Solar Theory & General Knowledge
Peak sun hours by month
Software estimates the sun each site gets every month.
This data helps plan how much a system will produce before you build it.
Module 1 · Solar Theory & General Knowledge
Why higher efficiency matters
Two panels make the same power, but one is smaller.
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Which statement is true?
Module 1 · Solar Theory & General Knowledge
Wiring panels: series and parallel
The positive and negative wires, called whips, connect panels together.
Panels wired in series are called a string.
Module 1 · Solar Theory & General Knowledge
Bypass diodes: a shaded cell
A panel is only as strong as its weakest cell.
Without help, current gets stuck at the shaded cell.
Module 1 · Solar Theory & General Knowledge
How bypass diodes help
Bypass diodes route current around the shaded section.
You lose about one-third of power, but still keep two-thirds instead of none.
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The junction box on a solar panel contains…
Module 1 · Solar Theory & General Knowledge
Solar module warranties
Panels come with two kinds of warranty.
Two warranties: a workmanship warranty (20-25 yrs) and a performance warranty for output.
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Solar panels degrade from…
Module 1 · Solar Theory & General Knowledge
Reading the warranty
Most makers guarantee about 80% output in year 25.
Panels are one of the most expensive parts, so make sure the warranty covers you.
Module 1 · Solar Theory & General Knowledge
Will the maker still be there?
A warranty only helps if the company is still in business.
A performance warranty can run 25 years, so check the maker's bankability: is their technology durable and reliable, do they follow regulations, and are they well regarded in the industry? If the company is gone in year 15, you cannot claim it.
Pick makers likely to last, so the warranty is still worth something later.
Module 1 · Solar Theory & General Knowledge
The Spec Label
Every panel has a spec label that tells you what it can do.
The big ones to read first: Maximum power (peak watts), open circuit voltage, short circuit current, efficiency, and tolerance.
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The maximum power on a solar panel is measured in…
Module 1 · Solar Theory & General Knowledge
Where Max Power Comes From
The top line, maximum power, is just volts times amps.
Watts = Volts × Amps
29.49 V × 7.8 A = 230 W (the max power on this label)
Comparing labels this way helps you pick the right panel for a project. Module 1 · Solar Theory & General Knowledge
Reading the Whole Label
Each line on the label tells you something useful about the panel.
Tolerance means the real output sits within +/- 3% (about 223-237 W). Operating temperature limits (-40 to +90 C) matter when claiming a warranty.
Module 1 · Solar Theory & General Knowledge
Grid-Tied Systems
A grid-tied system connects your panels to the utility grid.
The inverter turns panel DC into household AC. That AC feeds the main panel and is used by the building first.
Module 1 · Solar Theory & General Knowledge
Sending Power Back
Extra solar power flows back to the grid and earns you credits.
A meter tracks the extra power you export. You get Hydro credits for it, which lowers your bill.
Module 1 · Solar Theory & General Knowledge
Four Inverter Options
Inverters change panel DC into the AC homes use, in four main types.
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A grid-tied inverter…
Module 1 · Solar Theory & General Knowledge
Central Inverters
Central inverters are huge units built only for very large projects.
One central inverter means one single point of failure - if it breaks, the whole system stops. Too large for small JAZZ projects.
Module 1 · Solar Theory & General Knowledge
String Inverters
String inverters are the most common choice and fit projects our size.
Only one inverter to maintain, so it is easy to troubleshoot. But it lasts 5-10 years, so plan to replace it around Year 10 - well before the panels.
Module 1 · Solar Theory & General Knowledge
Micro Inverters
Micro inverters put one small inverter on every single panel.
Each panel gets its own inverter, so conversion happens at the panel level. You need one micro inverter per panel.
Module 1 · Solar Theory & General Knowledge
Micro Inverter Trade-offs
Micro inverters avoid one big failure point but cost more.
Plus: no single point of failure and shade on one panel won't drag down the rest. Minus: many units to maintain and about 30% more expensive.
Module 1 · Solar Theory & General Knowledge
Hybrid inverters
Hybrid inverters can work with or without batteries.
Hybrids can store extra energy for use during a blackout. They are not common on most projects.
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Which of these is not an inverter?
Module 1 · Solar Theory & General Knowledge
Mapping micro-inverters
Each inverter has its own barcode, so you can find it fast.
Mapping each unit means a broken inverter is easy to locate and replace.
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Which of these inverters allows for system monitoring?
Module 1 · Solar Theory & General Knowledge
Example monitoring system
Module 1 · Solar Theory & General Knowledge
Maximum Power Point Tracking
The inverter tunes volts and amps to squeeze out the most power.
MPPT aims for the most power, not the most voltage or the most current.
Module 1 · Solar Theory & General Knowledge
Anti-islanding feature
When the grid goes down, the inverter shuts itself off.
Anti-islanding is built into all grid-tied inverters. It is a critical safety feature.
Module 1 · Solar Theory & General Knowledge
Why it matters
During an outage, a solar building could keep feeding the grid and create a live 'island' of power. That is deadly for line workers fixing the lines, so the inverter must shut down.
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What is anti-islanding?
Module 1 · Solar Theory & General Knowledge
Power optimizers
Optimizers are like micro-inverters, but they keep the power as DC.
Optimizers reach 99.5% peak efficiency and cost up to 30% less than micro-inverters.
Module 1 · Solar Theory & General Knowledge
Scenario 1: panels face different ways
When panels point in different directions, they make different volts and amps as the sun moves. An optimizer tunes each panel on its own so each one gives its best.
Module 1 · Solar Theory & General Knowledge
Scenario 2: heavy shading
If a tree shades one panel, that panel acts like a resistor and blocks power. If you cannot remove the shade, an optimizer can bypass the whole panel so the rest keep producing.
Under heavy shade, even the panel's own bypass diodes are not enough on their own.
Module 1 · Solar Theory & General Knowledge
Optimizer system monitoring
Map every panel and watch how each one performs.
If an optimizer fails, you can see where it is and replace it. Monitoring is free for 25 years.
Module 1 · Solar Theory & General Knowledge
Net metering systems
Use your own solar power, and stay connected to the grid.
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Net metering is…
Module 1 · Solar Theory & General Knowledge
The bi-directional meter
One meter tracks power going both ways.
Sending extra power earns Hydro credits. The utility installs this meter as the last project step.
Module 1 · Solar Theory & General Knowledge
Does net metering pay off?
Payback tells you how many years to earn back the cost.
Payback years = System cost ÷ Yearly utility bill
$28,479 ÷ $3,754 = 7.58 years
A payback of 10 years or less is generally a good investment. Quick check
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How do you calculate ROI (return on investment)?
Module 1 · Solar Theory & General Knowledge
Module summary
Nice work — here’s the quick recap of what this module covered.
You can now explain how a panel makes power, read the three core terms (volts, amps, watts), tell the panel types apart, and follow power from the panel through the inverter to net metering.
Next up: the post-test — then you’ll see your score and anything worth a second look.
Post-test · what stuck?
Post-test
Answer these to see what landed. We’ll point you back to anything worth a second look.
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