Thinking About Generators

by jefftkjefftk1 min read16th May 20217 comments


Personal Blog

Every so often I think about what we would do in an extended power outage. Generally this comes up when a crisis is in the news, so not a good time to buy things. During the February Texas Storm I set myself a reminder for three months later to think about generators. So: here I am.

We currently have two sources of standard 120V power in a blackout:

(2 kW is the capacity of the SPS; the panels themselves are rated for a total of 5 kW.)

They do have downsides, though. The battery has a limited capacity, and the solar requires the sun to be shining, the panels to be clear, and the sun to be in the right part of the sky. They complement each other somewhat, using the battery to time-shift, but there are many blackout situations (ex: winter storm) where once the battery is depleted the solar wouldn't give us anything.

A fossil fuel generator is potentially a good fit here. While it doesn't have the long-term properties of solar, fuel is cheap enough that you can have a capacity far larger than you would want to spend on batteries.

For example, a generator can turn a five gallon can of gas into ~15 kWh. That's already much more than my battery, and each additional can of gas is far cheaper than a large battery.

On the other hand, gas is a pain. It turns to varnish in a few months and (especially if it has some ethanol) it pulls in water from the air, so even if you're using fuel stabilizer you want to rotate it. It's not safe or legal to store in your basement, and the temperature fluctuations of storing it outdoors aren't great for it either. Storing gas in your car's gas tank could be good, since it will get automatically rotated, but most cars now have anti-siphon filters.

Propane seems more attractive: it doesn't go bad, you can store it outdoors if you keep it out of direct sun, and while it's less efficient than gasoline a 20lb propane tank still gets you ~10 kWh.

You can get inverter generators that can take both gasoline and propane (ex: $535), which seems like a good combination? Thoughts?

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Question is: Do you really need one? How often does a blackout occur annually that you can not cover with the existing backup systems?

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...aaand you already wrote an article about that.

I've used a gas/propane generator for years.  We also have a manual transfer switch to plug the generator into our house.  

The best thing I can say about it is that there's not much to say about it.  When we have a power outage I can plug it in, flip the transfer switch, start it up and continue living my life. No fussing around.  

The biggest downside is that capacity is limited so you can't run everything that you'd normally run.  I live in the Midwest so if we have a power outage when it's cold enough I have to shut off our water main (can turn it back on for short amounts of time to flush toilets and get drinking water otherwise it can freeze and burst pipes) and confine ourselves to a small section of the house I can heat with space heaters. A generator that would power our central electric heat is prohibitively expensive.  We're considering re-locating to another Midwest location and a key priority for the new place is a gas/propane furnace which will continue to run during a power outage if you have a generator capable of running the blower on the unit. (The blower takes very little power to run)

Apparently, it's important to get an inverter-type of generator if you're wanting to run computers and stuff off of it so that's what I've always used.

If you have natural gas to your house that might also be an option -- nothing to store and it's always on as it were. This would be nice for any extended use of the generator where the gas or propane tank might run out and need to be refilled requiring the generator motor to be shut off. 

Also, if you want to use your car as the fuel container, check to see if the fuel rail on the manifold has a fuel outlet port -- many do for things like attaching a pressure gauge or just releasing the pressure in the line and draining. You can also splice something into the lines if not. Then you can just use the fuel pump in the tank to fill the generator (or fill the fuel jug that will fill the generator).

Any options for folks who live in an apartment or condo? 

Battery backups work well for electronics and small appliances for up to  30-60 min outages, but are likely prohibitively bulky and expensive to run everything.  Presumably on a condo it's possible to convince other owners to pitch in in on a generator for the community, probably through the HOA.

Another option, which may only work if you own a hybrid vehicle, is to use the vehicle's engine as a generator. Connect the vehicle's battery to an inverter, and plug your house stuff into that. Only requires an inverter of however many watts you expect to use, and an extension cord.