There is a lot of confusion regarding solar panels & backup power. While it makes sense that if you have your own source of electricity you should have power, the reality is most solar systems do not provide power when the grid is down. Here’s why, and what systems DO provide power at all times.
Also note that ALL solar panel systems can be retrofit with battery-backup capabilities.
Do grid-tied systems provide backup power?
The short answer is no. Normal grid-tied systems are the most affordable type of system, and offer the best return on investment. These systems produce power during the day, and if there is excess, it is pumped onto the utility grid. This earns you a credit with the utility, which you use when the solar is not available, like at night or on stormy days. This credit works on an annual basis, so if your solar array creates more energy in the summer, but you use more electricity in the winter, that credit still allows you to cancel out your annual usage. When the grid goes down, the solar equipment sees this and stops producing energy.
The reason for this is two-fold:
- Safety: The energy you produce could flow back on the power lines and shock line-workers. Line workers are only expecting power to flow from one source, so multiple power sources could be hazardous.
- Solar power fluctuates with the weather. Without a battery to provide a constant stream of power, your solar panels produce varying amounts of energy throughout the day. With clouds or storms, the energy provided jumps up and down, and would not be conducive to reliably powering your home.
How DO you get backup power with solar?
There are a couple of options. For customers looking at grid-tied systems, we can install an inverter that allows you to have a receptacle that can be used when the grid is down. While this does not power your whole house, it does allow you to have a reliable source of electricity when the grid is down and the sun is out. This solution is also available at almost no additional cost to a grid-tied system. Simply request this Secure Power Supply feature, and we’ll install it at the same cost.
The other more elaborate (and more expensive) solution is to install a battery bank with your solar system. Adding a battery-backup system can increase costs by about 40-50%. These costs are significantly more than a comparable generator, but offer very different functionality. With batteries, homeowners can run their critical loads indefinitely, and with no additional fuel. These systems also allow for generator hookup for a truly redundant and reliable source of electricity. This means that if the power is out for days or weeks at a time, your home could have the lights on, running water, and a cold fridge.
What about Tesla batteries?
The Tesla Powerwall and other lithium-ion batteries are now coming available. These batteries are changing the standard for backup power and solar. We currently offer grid-tied packages that are designed to integrate with this new generator of storage technology.