I. On grid (Grid-tied) Solar Power System without Battery backup
These solar power systems are the simplest and least expensive to set up. This is also the easiest and most popular way to get started in PV power. You can install grid-tied solar power systems wherever access to utility-generated power is available. All that is included is an PV array, an inverter, and a utility meter. The inverter converts the electricity from your solar panels to power that your electric devices and the grid can use.
These systems simply tie into your existing power system and the utility grid. If your array generates more energy than you use, the energy is sold back to the power grid and creates a credit for you. Of course grid-tied systems do not need to offset all your power. They can also be used for “peak load shaving”. That is, you can offset your usage during the highest rate tiers, where the payback is best.
The maintenance cost of grid-tied systems is very low. Solar panels routinely have 20-25 year warranties and some of the panels created in the 1950’s as part of NASA’s space program are still operational.
Because the system is connected to the grid without battery back-up, the obvious drawback is that when power goes out in your area, your solar power system will also shut down. That disadvantage is offset when you consider that these systems are much more efficient and less expensive than those that include backup batteries. Unless you live in an area subject to frequent outages, it will generally be to your benefit not to be concerned about the occasional outage.
II. On grid (Grid-tied) Solar power system with Battery backup
Solar-powered battery backups provide an extremely reliable source for your electric demand – even when the utility company’s power fails. And unlike other backup systems that burn propane or natural gas, these batteries are powered entirely with energy from the sun, meaning no fuel, no pollution and no noise from gas-powered generators.
Standard systems include a PV array, batteries, a charge controller, an inverter, and a utility meter. During the day, your solar panels will continue converting sunlight into electricity as usual, but will also top off the batteries each day. Batteries can store excess energy generated by the solar panels, and even send the surplus electricity out to the grid. Of course, the system is connected to the electricity grid which is why it is called “on-grid.”
When the electricity goes out, a backup power system provides a seamless, clean, silent and ecologically friendly way to maintain energy for your electric devices – for a matter of hours or indefinitely. During the day, your batteries are recharged to power your critical loads or a whole home or office as long as the outage continues. When utility power is restored, the inverter switches automatically back to battery-charge and on-grid mode. Because batteries are used just as a backup, their lifespan increase significantly and this system also requires minimal maintenance.
Solar power systems with backup are particularly well-suited to small businesses with important loads that must stay powered up, even during an outage. If you have a business, when the grid’s down, there’s no reason why your clients can’t continue to count on your services. Solar-powered battery backups are also used in homes, allowing families to stay tuned to the outside world during disasters or even routine outages.