A well-designed solar system can meet the majority of the electricity needs for a homeowner, but there are times when power needs to be pulled from the grid. While many energy providers give the option of net metering to cover the cost of electricity used from the local power company, it’s not available to all solar homeowners. Having a backup supply of electricity can provide power during outages and can also provide more electricity cost savings.

Let’s face it, emergencies happen. Many people don’t realize it, but homes powered by PV solar are usually tied to the grid, and they’re shut down along with everyone else during an outage to keep utility workers from getting hurt. Backup power is needed to keep the lights on and your refrigerator running, and the two main ways to achieve that are with a generator or a solar battery for a solar system.

While generators have been a common backup for grid outages for decades, solar batteries are now a more viable option for homeowners to consider. Here are the factors to consider:

Size – The “whole-house” generators needed to power a home over time are bigger than their portable cousins – roughly the size of a typical HVAC unit. But that can vary depending on the size of your house and its electrical needs. Batteries are increasingly getting smaller, e.g. Tesla Powerwall and can be controlled by the owner in terms of energy storage and use.

Noise – Whole-house generators usually make less of a racket than portable ones, but they can still be loud. For the quietest ones, imagine a motorcycle engine running nonstop. Solar batteries are silent.

Fuel – Generators run on natural gas, gasoline or liquid propane, all fossil fuels that pollute the air. Solar batteries run on stored-up solar power and reduce your carbon footprint.

Cost – A generator can cost anywhere from R4,000 to R500,000, though most are at the low end of that range. Once a generator is installed, the owner still has to pay for regular maintenance and fuel. Solar batteries have little or no maintenance costs and the fuel is solar energy from the sun. There’s an unlimited amount of sunlight, so the battery can keep recharging – and powering your home. On top of that, the South African government offers tax incentives for business investment in solar systems. Usually, there are no tax incentives for buying generators.

Advantage: Solar battery
A battery system can save homeowners money in other ways as well. It can be managed easily and its intelligent software maximizes the use of solar power each day to help save money on energy charges. During a blackout, it can be programmed to power select appliances – like a refrigerator full of food – depending on the size of the battery.

(adapted from www.us.sunpower.com)