Solar Power 101 : How it Works

There are three basic types of photovoltaic systems:

An off-grid system is designed around the estimated electrical load consumption both with production (solar array) and storage (batteries). It involves solar modules (array), solar charge controllers, batteries, and inverters (DC-AC power conversion). Most off-grid systems incorporate a generator for backup. The generator can be configured to automatically start when needed.


A grid-tie system does not use batteries and does not provide utility backup. It involves a solar array which generates DC power during the day which is converted to AC by an inverter and sent into the house side of the electrical meter. If the home is using less power than the system is generating the electricity flows out the meter (spinning it backwards) to the grid. A grid-tie system will reduce your power bill by the amount of kWhs produced and is the least expensive pv system choice.


Grid-Tie with Backup
A grid-tie/backup system is essentially a combination of a grid-tie and an off-grid system. It uses a similar inverter to the off-grid systems and incorporates a battery bank. It back feeds power either to the house loads or to the grid like a grid-tie system but in the event of a grid power outage it can provide backup power to designated critical loads.

NABCEP Certified

PV Installation Professional
Henry Dykema
Cert # 041704-11