Why solar backup is better for the planet and your health

Instead, she and other experts recommend investing in more planet-friendly sources of backup energy, namely solar technology and batteries. These units can range from portable solar batteries to larger home installations that include rooftop solar panels connected to battery storage systems. Depending on the technology and the amount of energy you’re using, some of these systems can power an entire house for days during power outages. They can also offer year-round benefits, including lower utility costs.

“A back-up gas generator for your home is like an insurance policy where it doesn’t pay any value until you have a really bad day,” said Mark Dyson, managing director of carbon-free electricity at energy think tank RMI. “Other solutions we’re interested in exploring – like solar plus storage, for example – save money every day and then also provide backup in case of an emergency.”

We looked at how solar batteries stack up against traditional fossil fuel generators. Here’s what you need to know.

The size of a generator or battery backup depends on how much power you need, said Noah Kittner, a power systems expert and assistant professor at the University of North Carolina at Chapel Hill.

These are the oldest and most common type of generators. They run on a variety of fuels, including diesel, propane, and natural gas, and can be portable or permanently installed.

You can use them to provide electricity for various electronic devices, larger appliances and entire houses. The number of devices a fuel generator can power depends on its size, output power and how much fuel you have.

Batteries also come in different sizes and can be removable or installed. Smaller batteries can be enough to power a small electric fan, charge cell phones, or power a radio.

For a refrigerator, you might want at least eight to 12 hours of backup power, Kittner said. Common household-sized lithium-ion rechargeable batteries can generally provide this amount of power.

Self-contained batteries are limited in time, Dyson said. Even the biggest ones can run out of juice pretty quickly if you use them to power devices that draw a lot of power, such as stoves or air conditioners. This means if you use these batteries during an outage, after they run out you’ll have to wait for the power to come back on or find another way to charge them.

Portable batteries, which also differ in their output power, can be equipped with small solar panels so that they can be charged without being plugged in. If the battery is completely drained, it may take several hours to recharge using solar energy.

You can also have larger rooftop solar panel systems connected to battery storage systems. These residential structures can benefit homeowners even when the power is not out, said Mr. Smith, principal and director of building sustainability and performance at EskewDumezRipple, an architecture firm with offices in New Orleans and Washington, DC.

“The economics of a battery and solar system, you benefit all the time, whereas the generator is a dead loss and its benefit is only during a power outage,” Smith said.

Rooftop solar and storage systems are connected directly to home electricity systems, Dyson said. Most portable batteries connect directly to individual devices or with extension cables. Similar to a fossil fuel-based backup generator, some larger batteries can be connected using transfer switches, which connect them to your electrical panel, he said. When the power goes out, the switch allows your home to draw power from your backup source instead of the power grid.

Emergency power sources can be more effective if your home is well-insulated and weather-sealed to prevent air leaks, Dyson said.

Regardless of the type of backup power you have, be aware of your energy usage during outages, Burke said.

“It’s usually necessary to … be judicious with how you’re using your energy in your home,” she said. “You’re not going to run your dishwasher, washer and dryer, everything in the house all at the same time. These are emergency circumstances.”

Avoiding harmful fumes and pollutants is one of the main advantages of not using fossil fuel generators.

These generators produce emissions that contain hazardous pollutants, including sulfur dioxide, nitrogen oxide, particulate matter and carbon dioxide. Their use can also release carbon monoxide, an odorless, colorless gas that can kill people in minutes if it accumulates indoors. Generators also tend to be noisy.

“One of the main concerns is local air quality,” Burke said. “Imagine a neighborhood loses power and every house or every other house has some kind of fossil-burning generation going on all the time, it’s incredibly hot and humid—that all the compounds in the very bad ground-level ozone, the which causes serious respiratory distress.”

You should never run fossil fuel burning generators inside your home or garage, even if the windows are open. Place portable generators at least 20 feet away from any residences, open windows or garages with discharge directed away from homes, according to the Centers for Disease Control and Prevention.

“It’s essential that people understand that if they do this kind of informal thing of taking a gasoline generator and keeping it powered and putting it on their porch or something like that, you’re essentially bringing what could be a source of danger in or adjacent to your home,” Smith said.

The cost of each type of generator will depend in part on its size and technology, but prices can also vary between similar models.

For example, a 5,000-watt portable diesel generator, a common size that can be used for small homes, apartments, and RVs, can cost anywhere from about $500 to more than $5,000. A solar battery model that can generate 5,000 watts continuously costs around $4,700.

If you want a heavier and more permanent form of power reserve, it will cost. The initial price of installing a residential solar panel and battery storage system will be significantly higher than a similarly sized gasoline or diesel generator, Dyson said. But these systems can generate savings for homeowners in the longer term, and there are federal tax incentives, and in some cases, no-down financing options, to help lower the cost of technology and installation.

“If you look at solar alone value, in most places in the country it comes back very quickly,” Dyson said. Storage batteries, he added, are also becoming more cost-effective.

Meanwhile, the cost to maintain and fuel standard generators can add up over time. Without regular maintenance, your generator may not be running when you need it.

“The difference is that the diesel generator sits there breaking down, whereas the solar plus battery system is giving you value all the time, and adding a battery can give you resilience,” Smith said.