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The solar-and-battery system at the home of Patrick Altier’s client is a model for resilient energy planning.
At the home north of Ocala, Florida, Solar Trek installed enough solar photovoltaic panels and battery energy storage to power the whole home, including multiple air conditioners and a charging station for two Teslas. But while the batteries are enough to power the home for about three days, Altier’s client wanted an extra insurance policy: a propane standby generator.
“The generator is that safety net” for when the sun isn’t shining, says Altier, owner and president of the central Florida company that installs solar electric systems and generators. “Let’s say there’s a storm and it hangs around longer than we anticipated. I can use that generator to charge the batteries or run the house. We’ve got several customers that fall into that group where they are concerned about long-term power.”
With battery energy storage systems becoming more popular as a way to convert clean solar power to protection against grid outages, Altier and Solar Trek have become adept at discussing the pros and cons of batteries and standby generators fueled by propane or natural gas. And in recent years, new inverter technology has enabled systems that combine the best features of both.
For this project in southeast Ocala, Florida, Solar Trek installed a solar array and a propane-fueled standby generator to keep the home powered when the solar panels are unable to operate.
Advantages of generators and batteries
When Altier’s sales teams sit down with customers to talk about emergency power, the first question they ask is whether they want to be prepared for a short-term storm or a long-term grid event. To make it through a storm, a standby generator is a great choice, Altier says. For the same power output, a generator is about a quarter of the cost of an equivalent battery system.
If the customer wants to be able to operate for long periods off the grid, a solar-and-battery system might be a better choice. Solar Trek can install a system that islands the home from the grid, and the solar panels can recharge the battery when the sun is shining.
Installing a system that combines both batteries and a generator used to be rare, but it became more realistic about four years ago, when Altier started working with Chilicon Power. Chilicon’s solar inverter and communications gateway allow power from the solar panels to feed through the generator to reduce the generator’s fuel consumption by up to 50 percent. A generator could also be used to recharge the battery system when weather doesn’t allow the solar to operate.
That’s the setup at Altier’s own home, which has a solar photovoltaic system with Chilicon inverters and a Generac propane standby generator. “If there’s a hurricane, I can make it in my house for about 11 or 12 days on the generator,” he says — or longer if the propane tank is refilled.
Maximizing the benefits of propane
Altier’s use of propane for standby power is fairly common in the region, says James Marchese, a Generac sales representative and system designer with Canter Power Systems who also sells some solar projects through Solar Trek.
“Here in Central Florida, you’ve got some communities that have natural gas. But most don’t,” Marchese says. “A lot are rural. And we’re going to put a propane tank in the ground or next to the house to run the generators.” About 70 percent of his generator projects use propane, he says.
To help get his clients comfortable with bringing in propane, Marchese frequently has a larger conversation about the benefits of converting other parts of the home to propane. “Usually with the [propane] tankless water heater, if we’re replacing an electric tank water heater, your power bill is going to be a lot less also,” he says. “If you add on that gas range, you can get to a lower price with the propane contractor on your fill-ups. I can say, ‘Well, your investment in the propane just by itself would raise the value of the house by 5 to 7 percent.’”
Transitioning large electric loads such as water heating to propane also makes it easier to install a smaller, more affordable generator or battery system, Marchese says.
Marchese sees growing interest in generators from clients worried about man-made threats to the power grid, such as computer hackers. And with Florida’s large retiree population, it’s not easy to evacuate quickly when they get notice of an approaching hurricane. In Central Florida, the power outage is more of a threat than the storm damage itself. “If you’re 70 or 80 years old and you want to stay in your house and not run away from a storm, this is a great option to keep your lights on,” he says.
Like Altier, Marchese sees growing interest from clients in making their solar-and-battery systems more resilient or more affordable by adding propane generators. One client in Texas was upset with her solar contractor, who installed a battery system and told her she wouldn’t have anything to worry about. She was OK during an outage after the first two cloudy days but then experienced a third and a fourth cloudy day, Marchese says. “And she said, ‘For the third and fourth day, my panels can’t recharge my battery. I’ve got nothing but a bunch of glass and the battery in my car.’”
“The generator at that point would kick on and keep those batteries topped off,” he says. “It might save you from having to have six batteries where you could have four batteries. You can optimize it so you’ve got the power you need at the price you can see as reasonable.”
