Thoughts on home backup generators

I just made this response on another (non-camping) forum and thought I would repost it here, if anyone is thinking about getting a home power backup system. Our power grid will get less reliable in the upcoming years since it is aging and is mostly still built around 1950's technology - and many parts were installed back then, too - but little of the equipment gets upgraded. There are now modern threats from hackers, terrorists, EMPs, and massive solar flares. We just missed a massive solar flare last year that would have wiped out our power system for months or years if it had hit Earth. NASA predicts in any given decade there is a 12% chance of this hitting us directly!   Article from NASA here. We were lucky it pointed in a different direction. I recently read about a study on ice cores from Antarctica (I believe it was there) where they found evidence of several large direct hits that were multiple times larger that occurred back in the Middle Ages.

On a related note, please consider stocking up on additional food and supplies. You don't need to label yourself a "prepper". You are just adding some extra protection for you and your family, and really nobody needs (or really should) know about it. We could have a viral epidemic, massive hurricane, or many other "everyday" emergency at any time.

My original post to someone that asked about getting a large Generac generator:

What you need to know depends if you will be installing it yourself, or not. Based on your question I assume you’ll hire someone so I won’t get into many details other than you need a large propane tank, an electrician to install the generator and make the electric connections, and a plumber rated to do gas to hook up the gas line.

Personally I don’t recommend large Generac generators anymore. My first backup installed 10 years ago is a 12 kw Generac, and during long outages I still use it to run my electric water heater and well pump, for 1-2 hours a day. But what they don’t like to tell you is how expensive they are to run. Mine uses a minimum 1.5 gallons per hour (it goes over 2 at full load), and since I don’t own my tank I’m at the supplier’s mercy on the price – often $4-5-6 a gallon at its peak. So at $4 if I ran it for a full day it would cost me at least $144. My entire utility electric bill averages $200 per month, for comparison. Propane has its advantages, since it doesn’t go bad and you can easily store a large amount with little hassle. But in a big emergency nobody is coming to refill that tank once it is gone – and you can’t hook up the generator to small 20-pound tanks to run it (usually you need a 250 gallon tank, minimum, to provide enough surface area in the tank to provide enough gaseous propane). They also provide “dirty” power – the frequency and voltage wavers slightly and you’ll notice it in your lights. So big Generacs are expensive to run, I forgot to mention very loud, have dirty output,and really only good for your “average” emergencies like ice storms and hurricanes. Fine for short periods running your well pump while you take a shower but you don’t want to run them for days on end.

Next I added a very large battery bank with an inverter. Lots of maintenance, and I couldn’t afford a solar array big enough to charge it properly. It was there to load shift. Generators run most efficiently near full load so it made sense to run it hard in spurts to recharge the batteries, then leave it off for 6-12-18 hours. It is also nice having the silence. Batteries are very expensive and they need lots of maintenance.

Next I modified my Prius so it would run the inverter I used with the battery bank. Now we hit the efficiency sweet spot – about 0.13 gallons/hour of gasoline to run pretty much everything in my house w/o conserving. When my big battery bank died I didn’t replace it because this worked much better – but this is also a highly technical solution that 99% of people shouldn’t even try. It was mostly for my enjoyment.

However, there is a solution that is just as efficient as the Prius – modern inverter-generators. The big name brands with proven reliability are Honda and Yamaha although there are cheaper alternatives now. Still too new to trust for long-term reliability, IMO. They sell them cheaper because they make them cheaper. Stick with the blue or red. Unlike the Generacs or the old-style contractor screamer generators, this new technology allows the engine to idle most of the time which saves gas and makes them very quiet. Usually even at full power they run slower than old generators so they are still quieter. They output perfectly clean power, sometimes cleaner than your utility. In your average emergency when you don’t need to conserve your house only needs a few hundred watts 2/3 of the time – to run the fridge, etc while you sleep or are at work. There are a few hours where it will need 1000-2000 watts, running everything while you are awake, and then spurts where it will need 5000-10000 watts to run the big stuff. So most of the time you only need a small generator. And, if you run out of fuel you can bring more home yourself (if you can find it – but at least the option is there). You do need to rotate out your gas stock every 6-12 months, so there is more hassle, but depending on your local codes you can store enough of it (20-30-40 gallons) to last as long as a big 250 or 500 gallon propane tank would have lasted running the big Generac. Also you can buy or convert yourself many small generators to run on a 20 pound propane tank.

Which brings me to my current recommendation based on my own experience. Buy a 2000-3000 Honda or Yamaha inverter-generator to run your baseline loads 24/7. After converting all lights to LEDs/CFLs, upgrading appliances like TVs to LED and fridges to modern efficient models, that is more than enough power to run just about all 120 volt loads in your house. I can turn on just about everything in my house while running my Honda EU3000is, and it only burns about 0.2 gallons/hour on average (about the same as the Prius). Let it run 24/7 (if you aren’t conserving in a big emergency). I only have to refill every 24 hours. Then also buy a large cheap contractor grade generator big enough to run your big loads, if you have big loads. It only needs to run for short periods of time when needed. It will act as a backup to the smaller generator, too. Pay an electrician $500 to install a hookup and transfer switch. Both generators will still cost far less than the Generac once you get a tank installed, etc. Figure $6000+ for the Generac vs. $3000 for the two portables. If I had to do it all over again this is what I would do.

Keep in mind you don’t need to run any generator 24/7 if you need to conserve fuel. A fridge/freezer will hold its cold, and in the winter a house won’t cool off to a dangerous level that fast. You can get away with running a fridge or furnace 1-2 hours, then off for 4-6 hours or even a full 8 hours sleep period once a day. Doing that will extend your fuel supply 3-4-5 times.

To give you an example of how a big propane generator compares with the double gasoline generator system I recommend, here is fuel use if you aren’t conserving (running 24/7). A 12 kw LP generator will use 36 gallons of propane per day, costing $144. If you have a 250 gallon tank it only holds 200 gallons when full (suppliers can only fill to 80% to leave room for expansion when it warms up), so at first you might think that would last you 5.5 days (200/36), but really as propane tanks get low under a high load the last 20-30-40 gallons may not be enough to produce enough gas to run the generator. So figure it might only last 5 days at a cost of around $700. Some fuel will be left in the tank. Over those same 5 days the Honda I have will burn 24 gallons (0.2 x 24 x 5). Knowing gas prices will go up again, at $3/gallon that is $72. Assuming the larger contractor generator runs 2 hours a day and burns 1 gallon per hour, over the same 5 days it will burn 10 gallons at a cost of $30. So a total of 34 gallons at a cost of $102. During a big emergency you can stretch those 34 gallons to last a month, easily.