A “Grid-Tied” solar power system is the most common type of solar installation. Starting with an existing grid power connection, a solar power system is “tied” in (to a breaker panel) to power the building and reduce grid power use.
Grid-tie systems serve one essential function: to offset use of power from the grid during the daytime. They can be used with a home battery (see Backup Power Systems), but solar panels on their own are a lower-cost introduction to becoming self-powered.
Since this type of system is interconnected with the grid, it is also dependent on grid power (or a battery) to operate. When the grid has a power outage, the solar power system turns off automatically. If back-up power is desirable, the solar power can be combined with a battery
How it works
As solar power is generated it flows directly through the breaker panel and to any concurrent electrical loads on the property, reducing grid power use. Excess solar power flows to the grid, and insufficient power is compensated by the grid. The percentage of solar power used compared to solar power exported to the grid is known as your solar “self-consumption”. Higher self-consumption of solar results in greater bill reduction.
Power use and sunshine fluctuate constantly, varying by the season, the home, and the occupants. But to fully optimize self-consumption, align power use with sunshine as much as possible.
In most cases, a solar power system will be sized to generate as much electricity as is used during the daytime on average, or around half of total use.