How Do Solar Panels (PV Systems) Work?

The solar industry is full of technical terms, but the basic idea is simple: panels turn sunlight into electricity you can use at home. If you are considering rooftop solar in Ontario, understanding how a photovoltaic (PV) system works makes it easier to compare quotes and ask the right questions.

A Short History of Solar Energy

People have used the sun's energy for a very long time. Some historians believe that as early as the 7th century BC, magnifying materials were being used to concentrate sunlight and start fires. Photovoltaic technology itself is much younger. In 1839, French physicist Edmond Becquerel observed the photovoltaic effect: light striking certain materials in a conducting solution could generate an electric current. That discovery laid the groundwork for how the cells in a modern solar panel convert sunlight into electricity.

Later research led to silicon-based solar cells in the 1950s, and the technology has been improving ever since. Today, PV panels are a mainstream way to power homes and businesses across Canada.

How Do Solar Cells Make Electricity?

The key component in a solar panel is the photovoltaic cell. Each cell is made from semiconductor material, usually silicon, and produces electricity through the photovoltaic effect in three steps:

1. Light is absorbed by the cell and knocks electrons loose from their atoms.
2. The loose electrons are pushed in one direction, creating a direct current (DC) of electricity.
3. That current is collected by thin metal contacts and carried away through wiring.

A single cell produces only a small amount of power, a few watts at most. A solar panel connects dozens of cells together, and an array connects many panels, so a residential rooftop system can produce enough electricity to cover a large share of a household's annual use.

What Happens After the Panels?

Panels produce DC electricity, but homes run on alternating current (AC). An inverter converts the DC power into AC power, which then feeds your home's electrical panel. Any extra electricity can flow back to the grid, and in Ontario, net metering lets you earn credits for that energy. You can read how it works in our guide to net metering in Ontario. For a deeper look at the equipment, see our guide to solar inverters and their pros and cons.

What Types of Solar Cells Are There?

Two types of silicon solar cells are common for homes and businesses: monocrystalline and polycrystalline.

Monocrystalline Cells

These are cut from a single silicon crystal. Because electrons move through the material more freely, they are generally more efficient and perform well in limited roof space. They typically cost more to produce.

Polycrystalline Cells

These are made by melting many silicon fragments together. The manufacturing process is simpler and cheaper, which keeps the price lower, but efficiency is generally a little lower as well, so more roof area is needed for the same output.

Efficiency is only one factor. Warranty, real-world performance in Ontario weather and how the panels pair with your inverter matter just as much, and your installer should explain the tradeoffs for your specific roof.

Generating Power From the Sun

Capturing the sun's energy is one of the cleanest ways to produce electricity, and it relies on a resource that is available every day. Demand for solar has grown year after year as costs have fallen and technology has improved. Homeowners who go solar generate part of their own power, which can reduce exposure to rising electricity rates.

Getting Started With Solar in Ontario

Terawatt Solar offers a free solar system assessment for homeowners across the GTA and Ontario. Our in-house, ESA-licensed crews handle design and installation with no subcontractors, so you deal with one accountable team from start to finish. Learn more about residential solar, try the solar calculator for a quick estimate, or contact us to book your assessment.

Frequently Asked Questions

How much power does a solar panel produce?

Output depends on panel size, cell efficiency, sun exposure, roof angle and shading. A modern residential panel is rated in hundreds of watts, and a full rooftop array is sized around your household electricity use.

Do solar panels work in cloudy weather?

Yes. Panels still produce electricity under cloud cover, just at a reduced rate. Ontario homes with well-designed systems generate power year-round.

What is the difference between DC and AC power?

Solar panels produce direct current (DC). Your home uses alternating current (AC), so an inverter converts one into the other before the power reaches your outlets.