How solar panels supply electricity to a home

Panels, inverter and household circuits

The photovoltaic cells inside a solar panel convert light into direct-current electricity, often shortened to DC. Several panels work together as an array. The panels generate electricity while light reaches them; they do not store it for later.

An inverter converts DC into alternating current, or AC, used by household electrical circuits. Depending on the design, the equipment may use one central inverter or smaller inverters at individual panels. The proposal should identify which arrangement is being supplied and how you will monitor it.

The home’s electrical distribution equipment connects the supply to circuits serving lights, appliances and other loads. This is a description of the system’s roles, not an installation plan. Leave electrical connections, equipment inspection and design to the professionals responsible for the project.

The grid fills gaps in solar generation

While the grid is operating, a connected home can draw electricity when its demand exceeds the solar supply. If generation exceeds what the home is using, surplus electricity may go to the grid or to a battery, depending on the installed equipment and connection arrangements.

Exporting electricity and being paid for it are separate questions. Ask your provider to explain the proposed utility connection, metering and applicable agreement. This guide does not estimate a bill reduction or assume an export payment.

Production changes throughout the day

Clouds do not always stop generation: panels can use diffuse light as well as direct sunlight. The amount of light reaching the panels changes with weather, time of day, season, shading and snow cover. A panel’s rated power is measured under test conditions; it is not a promise of continuous household supply.

After sunset, the panels do not generate electricity from sunlight. The home then needs another supply, such as the operating grid or energy previously stored in a suitable battery system. Ask for a property-specific assessment before relying on any production estimate for a Calgary home.

Ask separately about outage backup

Solar panels on a roof do not establish that a home will have power during an outage. Operation without the grid depends on equipment and a system designed for that purpose. A battery stores energy, but its presence alone does not establish which circuits can run or for how long.

If backup matters to you, ask the proposed system designer to answer these questions in writing:

• Will this exact system supply any household circuits during a grid outage?
• Which circuits are included, and which appliances must remain off?
• What inverter, battery and isolation equipment does that operation require?
• Can the panels recharge the battery during an outage, and under what conditions?
• What limits depend on stored energy, sunlight and the equipment running at the time?
• Where are the operating instructions and the contact for equipment questions?

Keep these answers with the equipment proposal. They describe the system you are considering; a general solar brochure cannot confirm them.