The difference between on and off grid SOLAR photo voltaic electric systems.

Different TYPES of solar electric energy systems defined.

Here’s a quick look at the various types of solar electric energy systems from the desk of Sun Source Solar Brokers.

Grid-connected solar energy systems allow consumers to use solar energy during the day. When the sun isn’t shining, the system allows them to draw power straight from the grid. Peak loads can also be drawn from grid electricity, which means that solar cells don’t necessarily need to be sized for demand, especially if limited space is an issue, but should be sized for eliminating as much of the base load of electricity bill as possible.  Any surplus power can be exported back to the grid in a form of credit called “net metering”.

Stand-alone grid-connected solar energy systems have an additional battery storage device, which allows users to draw power from battery cells if the grid were to fail. Businesses that require uninterrupted power supplies might want to consider these solar solutions. Residential owners could also look at as a way to avoid power outages.

Potential problems:  Harmonic distortion might also be a problem. Voltage quality has to remain within certain tolerances. Current output waveforms are also expected to remain within certain acceptable levels. The utility company and solar integrator will provide information about the correct way to operate these solar installations.

Off-grid solar energy systems are entirely dependent upon how much sun reaches the solar cells. More intense sunlight produces additional power. Electricity generated by the solar panels has to be used right away. This means that off-grid installations usually focus on direct current, DC. The vast majority of residential wiring is developed for AC circuitry.

On the other hand, some stand-alone off-grid solar installations use battery cells to provide a backup. Unused power charges the battery. Remote homes and telemetry stations often use this sort of installation. Mission critical applications might pair the unit with a diesel generator.  These hybrid installations allow users to provide power during times of the year when the sunlight isn’t sufficient for constant power generation.  Internal combustion generators can also be used to charge the battery.  Fuel costs are supposed to be offset during the sunniest times of the year.


Article written by Jennifer Coleman of Sun Source Solar Energy Brokers, providing solar brokering and solar energy consulting services in Santa Rosa, Marin, Sonoma, Napa, Solano and San Francisco Counties.  For more information, please visit

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Sun Source Solar Brokers
525 East Cotati Avenue, #220
Cotati, California 94931