Rooftop solar PV is is a great way to reduce your electricity bills using renewable energy. There are several components of a rooftop solar installation that are important to know before pursuing one on your building. We have outlined these components below to help you understand how solar works and if your home or commercial building is a good candidate for solar.
The sun is the star at the center of our solar system that provides energy to almost all life on earth. The sun releases waves of energy called photons, which travel 151.95 million km at the speed of light and reach the earth surface in about 8.3 minutes! These photons strike solar panels which generates renewable energy.
A rooftop solar array is a collection of solar panels installed on the roof of a building. Each solar panel consists of photovoltaic (PV) cells which use the photovoltaic effect to convert photons from the sun into direct current (D/C) electricity.
A ground mount solar array is a collection of solar panels installed on the ground near your home or building. These solar arrays are more common on rural and farm properties where land is available and rooftops may be covered by dense trees.
Since homes and businesses cannot use D/C electricity, inverters convert D/C electricity into usable alternating current (A/C) electricity. Inverters also provide ground fault protection, track energy production and carry out maximum power point tracking. There are two types of inverters:
A system that uses a string inverter needs only one inverter for an entire string of solar panels. A string inverter accepts the D/C electricity from the whole solar array and converts it to A/C electricity. This type of inverter is durable, inexpensive and commonly used. Since string inverters connect to multiple solar panels, overall performance is limited to the worst performing panel in the string.
A solar array that uses microinverters has one inverter attached to each solar panel. That way, when some panels are shaded the entire system still performs optimally.
Think of string inverters as the old type of Christmas lights. If one bulb burns out, the whole string goes out. Micro inverters are like the fancy new Christmas lights. If one bulb burns out, it can be replaced without affecting the rest of the lights.
The grid consists of 26,000 km of transmission lines and is responsible for providing electricity to 4 million Albertans 24 hours per day. Since a rooftop solar array produces electricity on site, it reduces your reliance on the grid. However, without an energy storage technology, like a battery, a building with solar will still need to connect to the grid under the micro-generation regulation. Any solar installation must abide by this regulation before it connects to the grid.
Your home or commercial building is perhaps the most important component of a rooftop solar system. The following outlines how your property integrates with solar:
Your roof is the foundation on which the solar panels are mounted so it is important that your roof is in good condition and is relatively unshaded from buildings.
Your electrical panel contains circuit breakers that lead to each electrical load in your building. It is responsible for distributing electricity to electrical loads.
Your electricity meter is bi-directional meaning that it keeps a count of how much electricity you use from the grid and how much electricity you sell to the grid.
Electrical loads use electricity. This could be lights, computers, your oven, your dryer or the fan in your furnace.
How electricity flows
Electricity produced by the solar array converts from D/C to A/C electricity inside the inverter. The electrical panel then distributes it to the electrical loads in your building.
This situation occurs during the day when the solar array is producing electricity and you are using electricity. The electricity produced by the solar array replaces electricity that you would have otherwise imported from the grid, which reduces your electricity bill cost.
You sell electricity to the grid when the amount of electricity produced by the solar array is greater than the amount you are using inside your building. This occurs on sunny days when you aren’t using much electricity in your building.
After converting into A/C electricity inside the inverter, the meter counts how much electricity you are exporting so you can receive a credit on your electricity bill. You won’t ever end up making money on your bill, however if your credit grows large enough, you carry it over into subsequent months.
On cloudy days or at night, the solar array won’t produce enough electricity to feed all your electrical loads. In this situation you import electricity from the grid as you would before getting solar. You are pay for this electricity in the same way as before you had solar. Although your total bill is less due to the two situations above.
Now that you have gained more insight into the anatomy of a rooftop solar installation in Alberta, you will be better equipped to determine if your building is right for solar.
The next step is to get quotes from several qualified solar contractors, which is where Glean can help. We use a qualified network of solar installers to get you multiple quotes so you can make the best decision. Hit the buttons below to learn more about how Glean works or to get competing solar quotes for your home or business.