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Comments on House-level battery backup now, solar panels later -- what do I need to know?
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House-level battery backup now, solar panels later -- what do I need to know? Question
In the last few years my area has seen increased power outages -- usually a few hours, occasionally longer. I'd like to defend against these better so that a poorly-timed outage doesn't ruin my whole day. I'm thinking, in particular, of whole-house battery backup.
I know that this kind of battery is routinely part of solar systems (else your solar panels wouldn't be much good at night). I do want to upgrade to solar, but my roof is nearing the end of its life and I don't want to have to pay for installing panels, then lifting them for a new roof, and then reinstalling them. I'm willing to wait until it's time to replace the roof anyway and then add solar panels.
What can I do in the meantime to improve my backup-power situation? Ideally I would like to be able to power heat or cooling, the fridge, some lights, and a few computers for up to 24 hours in the event of a power outage. If I buy the battery part of a solar system now, then am I risking expensive incompatibility in a few years when it's time to add the panels? Or is the risk there something that a qualified electrician could handle for me? Is there some other UPS-like system that I could wire into my house?
I don't want to hook up a gas-powered generator. In addition to the extra maintenance hassles there, I live in a city, the neighbors are close, and generators are loud.
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You should consider a whole house standby generator rather than whole house batteries.
From a cost perspective you can get a 20KW generator installed for around $10,000 (USD). A 20KW battery and inverters are likely to cost three to four times as much.
Lifespan for a generator is also much better than for batteries. A standby generator that is used only during occasional outages may last 20 years. Whole house batteries need to be replaced every 5 to 7 years.
Generators can handle much longer power outages than batteries. It is easy to have enough fuel on-hand to last days with a generator. Batteries will usually last only hours and may last much less than that if they aren't fully charged when the power goes out.
The environmental impact of battery production is so great, that buying batteries is worse for the environment than running a standby generator occasionally.
When you get solar, the power grid acts as your energy storage. With net-metering, you send excess energy your panels produce to the grid and you later withdraw it when you need it. Batteries are not typically part of a solar installation unless it is off-grid or net-metering is not available.
When you eventually have a generator, solar panels, and net-metering, your normal usage and production will end up looking something like this where solar is the light orange and usage is the dark orange. During the day the panel produce lots of electricity and ship the extra off to your neighbors. At night you withdraw the extra power that you created during the day. Your solar installer will help you size your solar system so that your overall usage for the year matches what your panels produce.
During a power outage your standby generator provides all the power to your home and your solar panels are not active.
A standby generator will automatically start when the power goes out, so you may have about 15 seconds without electricity. You can solve that problem by using small batteries in uninterruptible power supplies (UPS) for things like computers, routers, telephony, and networking equipment that you don't want to have reboot when the power goes out.
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