Are they permanently wired into the house wiring? Or do you somehow connect them if needed? And do they run on gasoline? batteries?
Would welcome any information, thanks.
The portable ones run on gasoline. The ones I’ve seen don’t plug directly into the house’s electrical system; you simply run extension cords from whatever you want powered (e.g., your refrigerator) to it.
There are permanent ones, that can be wired into your house’s electrical system, which run on natural gas, and which will automatically kick in if your power goes out for more than a few seconds. Those are much more expensive (several thousand dollars).
They can’t be permanently connected: You have to disconnect the house from the mains before connecting the generator. Some high-end models do this automatically, but most, you have to do it yourself. Sometimes, the generator is set up to only run a couple of your house’s circuits: You want your refrigerator to keep running, but you can probably do without your TV and most of your lights in an emergency.
If a product is called a “generator”, then it probably runs on gasoline (or maybe some other fossil fuel). But there are also battery-based devices that serve the same purpose. Usually, a batter backup is just for a single device (like a computer), though, because even with recent advances, batteries have nowhere near as much energy density as gasoline.
Or propane.
Try $4,000 to $5,000 for the generator, then another $4-5 K for installation.
If it does not automatically kick in (and function as intended), it is not much of an emergency generator.
Note that (for instance) Diesel fuel typically has such-and-such a maximum shelf life, so there is some maintenance involved; propane should be more stable, but these systems need to be tested periodically in any case.
You can go from a little portable generator that will handle your refrigerator and a few lights with an extension cord, all the way to a monster that’s hardwired into your home and will turn on as soon as it detects a power failure and will power everything in your house.
Small portable generators usually run on gasoline, but lots can be found that use both gasoline or propane (like the barbecue grill tanks).
The large generators (Kohler, Generac) run on natural gas or propane only, and can power your entire house, or select circuits. They are pretty pricey when installation is figured in, though.
There are ways to power almost your entire house without breaking the bank, but the subject is complicated.
Some larger generators run on diesel fuel.
There are also generators that are permanently wired into your house’s electrical system but don’t automatically kick in when the power goes out.
Larger generators like this are connected through what is called a “transfer switch”. Basically, this switch selects whether your house gets its power from the utility company or if it gets its power from your own generator. Some transfer switches are automatic, and switch over when the backup generator kicks on automatically. Others require you to physically throw the switch over to the generator position (more common with generators that don’t kick on automatically).
The switch is necessary so that you don’t accidentally backfeed your generator’s electricity onto the local power grid, as this could injure or kill workers who are trying to restore power.
Sometimes you can have two different breaker boxes. The idea here is that the second breaker box contains only the important stuff in your home, like your furnace and refrigerator. This second breaker box has the transfer switch on it, so it gets its power either from the main breaker box or from the generator. The first breaker box contains all of the less important stuff in your house. The idea is that when the power comes from the utility company, you have plenty of power to power both breaker boxes and everything in your house gets power. But if the utility company fails, you can switch over to the generator, which only powers the second box, and therefore only the most important things in your house have power. This means that you can get by with a smaller generator or you can get longer life or use less fuel with a larger generator.
NB by “some” we mean “nearly all”, at least 20 years ago in the U.K.:
E.g (2000 government report):
The total capacity of reliably operable standby generation in the UK is estimated to be around 20GW, nearly all of which is driven by diesel engines. This is equivalent to nearly 40% of the England and Wales system peak, although of course only a very small fraction will ever be generating at the same time. Most plant is for large offices blocks, hospitals, supermarkets, and various installations where continuous power is important such as airports. Therefore most is in urban areas, particularly city and commercial centres. It is estimated that around 10% of plant exceeds 1MW, about 50% is in the 200kW-1MW range, and the remaining 40% is sub-200kW. Although it is growing, only a very small proportion is believed to be used regularly for peak lopping, the vast majority just being only for standby generation.
If you need some sort of generator, the best way to start is determine how much you can spend, then determine what needs to be powered during a power failure.
Diesel actually has a pretty long shelf life. However, I used to work at a place where we had several dozen commercial sizes generators, and maintenance was a pretty big deal. The most common issue was the batteries and battery chargers used to start the diesel engines. Critical buildings had more than one generator, and were tested weekly, non-critical buildings were tested monthly. Even then, it wasn’t unheard of to have them fail to start right away when there was a power outage. I would think residential generators running on gasoline, natural gas, or propane would be easier to start than a diesel, but if I had one I would run it monthly.
A portable 2000 or 3000 watt inverter generator is handy to have for keeping a refrigerator running, which is all I really need during a long outage. And it doesn’t have to come on right away, I lug it out and use it if the outage lasts longer than an hour.
A Tesla Powerwall advertises 13.5 kW⋅h. You can also imagine sticking a dozen of them in a building if necessary. The new ones include a solar inverter.
We had a whole house generator for our previous home that cranked on as soon as the power went out (via an built-in automatic transfer switch), with no need for us to manually shut off/switch from the regular power supply.
We investigated installing a similar system with our current house, but felt it was too expensive for a model that wouldn’t even have powered everything in the house. So we bought a powerful portable gas generator (it will also run on propane) and had an electrician install an interlock device, which fits onto the existing breaker panel and in order to power the circuits you want, must be shifted into a position that prevents the main circuit breaker from being active. Interlocks are cheaper than separately installed transfer switches for portable generators, which require a separate breaker box and (at least as it was explained to us) mandate that you to set up a limited number of dedicated breakers for whatever you want to power in an emergency. The interlock device allows us to power whatever circuits we want at any given time, within the capacity of the generator. For us, the essentials during a blackout are the circuits for firing up the gas furnace, the fridge, freezer, microwave, a few lights, one TV and plugs to recharge laptops and cellphones.
Of course, with a portable generator you can run extension cords to whatever you want to power, but that’s an unwieldy pain in the ass.
Note that a number of solar generators have come onto the market, with capacity and duration of effective use that so far is considerably less than that of most gas or propane generators. They might be OK for small apartments or if you only need emergency power for laptops, cellphones and so on.
This is what I have:
1,000 gallon buried propane tank
8,000 watt portable gasoline generator converted to burn propane
16 circuit manual transfer switch
My setup powers the well pump and most circuits in my house, but NOT HVAC, oven or dryer. The water heater is whole house tankless.
Nothing automatic here. During a power failure, I have to manually start the generator, then flip the transfer switches.
This setup saved me a ton of money though, and I have my home theater, all communications, hot water, all lights and refrigerator for a week or two.
Total cost = about $2,500 not including the propane tank.
After posting, I realized that I had not run my generator in about 6 months. So I just hauled it out of the garage and after about a dozen or so pulls it fired up. Plugged in my electric leaf blower and cleaned up my patio. The wind will undo my work in a day or so, but it looks good now.
I live in a rural subdivision and installed a Generac 15KW propane unit with an automatic transfer switch. I can run my A/C and heat as well as my freezer refrigerator. Runs lights etc as well. I have geothermal heat/AC so there’s not that much of a load for those systems. If I had resistance heat as initially installed it might not handle it.
Modem & wifi, plus various chargers.
Disagree. The best way is to FIRST determine what you need to power, then determine what you can spend.
Looking at price first means you’ll start looking at off-brand generators, like I did. They’re fine as long as they work, but sooner or later they’ll need service, and you’ll run into the problem that no one services that brand, or all the parts have to be special ordered from somewhere in Asia.
Come to think of it, maybe the best place to start is to look around and see who services what brands, and then start looking for the right size and an affordable price.
“Need” is a sliding scale. I mean, if you absolutely didn’t need a particular appliance at all, you wouldn’t have it in the first place. At some point, you have to say “Well, this device is nice to have, but it’s not worth the extra $2000 it would cost for a system that would keep it running an extra couple of days”.
My point was that both need to be considered.
Of course they can be permanently connected. We have one that came with our house. I don’t know the specs off the top of the head, but it runs off the house propane tank and just comes on automatically if the power goes out. It’s not like I have to throw some big switch or anything.
Every Friday morning it automatically comes on for a few minutes to run a test.