How it works

The exact number of modules or panels required for a home solar power system depends on a household’s annual energy consumption, the amount of sunlight a home receives, available roof space, and the size or power of each solar module (in watts), among other considerations.

Solar power systems are sold as a measure of the capacity of energy they can generate in kilowatts, for example, a 5-kW system. This means that all the solar modules or panels together add up to 5 kW. This could look like a system of 20 solar modules, each with 250-watts of power: 250 W x 20 modules = 5,000 W or 5 kW.

The size of the solar power system needed depends on how many kWh of electricity a home uses in a year and by how much a homeowner is looking to offset their usage from the grid. Th​e greater the energy requirements, the larger the solar power system needed to offset this usage.

In Alberta, the Micro-generation Regulation stipulates that customers can generate enough power to meet some or all of their annual electricity consumption, but not more. When a customer generates more power than they need at any given moment, they’ll receive a credit on their bill from their retailer—at their electricity rate—for every (kWh) sent back to the grid.​​​​​

Power is measured in watts. A kilowatt (kW) is 1,000 watts of power. A megawatt (MW) is 1 million watts of power. Watts measure the rate of power at a moment in time.

Kilowatt⁠-⁠hours (kWh) measure the amount of energy used over a specific time period, in kilowatts per hour. Electricity used for powering home electronics and small or large appliances, whether for just a few seconds or for most of the day, is measured in kilowatt-hours.

Total electricity consumption for a home appears as kilowatt-hours on a monthly utility bill, for example, 600 kWh. A homeowner is responsible to pay for this usage at their current electricity rate, usually shown as cents/kWh.

Likewise, micro-generation from a home solar power system appears on a monthly utility bill as kilowatt-hours. When it occurs, micro-generation shows as a credit on a utility bill as cents/kWh.

It typically takes 6 to 12 weeks from customer approval to final energization of the system.

Solar power system installation includes:

• Preliminary assessment
• Detailed design and quotation
• Customer approval
• Permitting and procurement (2 to 6 weeks)
• Installation (typically 1 to 2 days)
• Inspections
• Bi-directional meter replacement (typically 1 to 4 weeks post inspections)
• System walkthrough and energization

Different communities may have guidelines or specific permits related to solar installations

Qualified solar installers will typically manage the permitting process

A roof should be in good condition prior to a solar power system installation. Properly installed, solar modules typically last 30 to 40 years when checked periodically. All installations come with a digital monitoring application to watch for system status and energy production levels over time. 

Qualified solar installers will typically offer a warranty on labour and installation for new equipment. Manufacturer warranties are included with the modules and other equipment.

Hail and snow

Solar modules are extremely durable and hail damage is uncommon. Most modules are installed in a way that reduces the likelihood of a direct perpendicular hit from hail.

A light snow will quickly melt off the modules as they generate a small amount of heat. The angle of the modules also helps to clear snow due to gravity. In case of a large snowfall, modules may be obstructed for a period, but this usually occurs during the months with the least direct sunlight, so impact to the overall power generation of the modules is generally low.