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What generator fuel do you like, and why?


T-W-X's Avatar
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11-10-12, 09:16 AM   #1  
What generator fuel do you like, and why?

I know that this is another of many, many generator threads, but I hadn't noticed any dedicated to fuel.

So, obviously if one has municipal natural gas service then one would probably want natural gas for one's generator fuel. How about when one doesn't have any piped-in fuel service? Obviously a fuel for a generator needs to be either capable of being stored in large quantities on hand, or user refillable, or some combination therein.

I see the following options:
  • Natural Gas in a large, fixed cylinder
  • Propane in a large, fixed cylinder
  • Propane in small modular cylinders
  • Diesel in a large, fixed tank
  • Diesel in a small, fixed tank with small jerry cans for resupply
  • Gasoline in a small, fixed tank with small jerry cans for resupply
I do not see gasoline in a large, fixed tank as an option where I live because we have oxygenated fuel that will go skunky and varnishy after awhile.

I look at the small tank options for propane, diesel, and gasoline as being the most end-user serviceable as one can potentially drive to where one can buy fuel, fuel up, and return home to keep the generator running. On the other hand, if problems are far and wide then it might not be practical to drive far, and since gasoline doesn't store well for long term that poses a headache. I gather diesel does store well long-term, and I know that Propane does.

For the big fixed tank options, propane and natural gas tanks undoubtedly require a professional to refill from a delivery truck. Granted, one could probably go a long time on a fill, but it's unlikely that installing such tanks will be something one can do one's self, and will probably require extensive permitting in a suburban environment, plus tank positioning that allows a delivery truck access. A large diesel tank, however, might be integral to the generator itself, or if nothing else isn't a pressurized vessel. Plus, between jerry cans and pickup truck transfer tanks, can be refilled by the user if delivery isn't available, though can also be fueled by delivery.

I guess that for the moment, I see propane as the most practical fuel if one doesn't want a large fuel tank, and diesel the most practical if one does.

Storing several 5 gallon cylinders of propane isn't unheard of if people have barbecue grilles or outdoor heaters, and one can simply rotate through tanks and refill after each use to keep the tanks in good repair. And refill could possibly happen if a service station has propane available by driving one's empty tanks over.

And for large tanks, since diesel is fairly shelf-stable and can be purchased and refilled by the user, one doesn't have to keep extra fuel stored in jerry cans but can keep some empty cans ready to be used for transfer from the fuel station to the tank if the tank ever gets low and delivery isn't available.

 
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11-10-12, 09:40 AM   #2  
Barring natural gas availability, I like propane due to its longer shelf life than gasoline. Diesel is kind of in between these two for me.

 
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11-10-12, 09:57 AM   #3  
I am unaware of any tanks that would be suitable for storing natural gas in a residential setting. So if you do not have natural gas piped to your home you can forget that fuel.

Propane, from a large tank is a good idea IF you are also using propane for other purposes such as cooking or space heating. Having a large fixed tank for just a generator means either paying an exorbitant rental fee or else purchasing your own tank. For several reasons I do not advise purchasing a tank. Nor do I advocate using several 20 or 30 pound (5 and 7-1/2 gallon) readily portable tanks. For running a generator I suggest 100 pound tanks which sell for about $120 each if I remember correctly. The worst thing about the 100 pound tanks is that you almost need a pick-up truck to move them around. This is not because they weigh so much (maybe 150-175 pounds when full) but because by law you have to transport them upright.

While not as bad as gasoline, diesel fuel definitely can "go bad" as it is subject to biological growth. You can treat for this but I still would not want to use old diesel fuel for a generator. Fuel injectors are machined to extremely close tolerances and the slightest bit of dirt, water or "muck" (a technical term ) can screw them up badly. Large tanks WILL accumulate water although in the Arizona desert probably not as fast as in more humid climates.

For me, gasoline is simply not an option. For one thing, it has a relatively short "shelf life" and the other is that I simply do not want to store even five gallons of the stuff in or near my home. It is a pain to keep a gasoline engine in a state of ready standby as well.

So that pretty much leaves the option of propane for the fuel and whatever size tanks/cylinders that make the most sense to you in your particular situation.

 
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11-10-12, 05:01 PM   #4  
I prefer diesel for several reasons. One, you get more BTUs per volume which means longer run time per gallon (just like cars getting more mileage when they are diesel). Another reason is that diesel pretty much doesn't go bad. Twenty year old diesel will still run fine as long as you don't let it grow bacteria. I have a diesel engine that doesn't get used often and it is still running on the tank I filled probably 3 years ago. Another thing is that diesels don't get carburetor trouble. Small engines made to run diesel have pretty tough injectors that just don't give problems and the engines are built very tough and last longer (again, refer to cars... diesel vehicles commonly accumulate 500,000 miles and are still running when the rest of the car is driven into the ground). Another reason I prefer diesel is because diesel engines will run on a variety of things. If you run out of propane and your generator takes it, you are done. If you run out of diesel, you can pour in some mineral spirits, transmission fluid, clean motor oil, kerosene, even vegetable oil or melted fat. You don't want to use these things all the time, and they may not give perfect performance, but in a pinch they can work.

Drawbacks of diesel: Noisy and vibrations, and initial purchase and replacement parts cost.


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11-10-12, 05:38 PM   #5  
In this recent power outage here in NJ, I lost power for eight days. I used approx 6 gallons of gas a day to run my Honda 5.0kw genny. Gasoline is a pain to get when in short supply. I had considered getting a natural gas genny and permanently mounting it but since I rent generators and always have portables on hand I'm going to convert one of my Honda 6.5kw to multifuel and install a natural gas disconnect near garage. Since I have an all natural gas house I don't require a larger genny. I never considered a conversion before until I read a thread where furd was talking about it. Apparently it will cost around 200.00 for the kit. Perfect solution.

Natural/propane is definitely the way to go. Diesel does yield higher output but the smell in a residential neighborhood and the issues in it's long term storage are two big negatives.

 
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11-10-12, 06:42 PM   #6  
Propane in a big, submarine sized tank, would be my first choice.

I have a three tier approach to power generation at our house. Half the day there is nothing. No generators running and no fuel consumption. Then for about 6 hours depending on the season I run a small gas generator to provide enough for running a few lights and the tv. Then for an hour or two as needed I run the big diesel that can run most everything. The small gas generator uses about a gallon per day (running about 6 hours). The diesel burns 2-4 gallons per hour depending on load.

This tiered approach allows us to tailor power generation to usage and minimize fuel consumption. It is inconvenient since showers and laundry must be done when the big generator is running but it means that a few jugs of fuel can be made to last for days.

I think natural gas is the best option for many though I am still concerned that you still rely on it being supplied by someone else after the storm. If a pipeline gets damaged or their is a control failure you may be out of gas so I'm a fan of fuels you can keep on site. This is easier done in rural areas and a judgement call that has to be made.

Storing liquid fuel is a PITA. It stinks and it has a shelf life. I'm on a schedule where I put a fuel jug into one of the vehicles every week or two to insure that the fuel on hand remains fresh. It means regularly getting jugs filled, even when the weather is nice but it is nice having fuel at home for those times you don't have time to buy gas before a road trip.

 
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11-11-12, 03:13 AM   #7  
but because by law you have to transport them upright.
Furd, I did not know that, but thanks. I did as you described....got rid of the large tank due to rental costs, bought a 100# tank and all is happy. I had my guys build a cradle to go in my truck when it needs filling. Easy to upload, and gravity helps to unload it . The guys at the propane place have never questioned my transporting it laying flat, and I do take care not to allow it to be damaged. Propane is my fuel of choice for the generator. Runs smoother, smells less "fuely", and seems to run longer per fill up than liquid fuels, but that may be the nature of the fuel.

 
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11-11-12, 04:26 PM   #8  
I have never been questioned by the people at the propane filling station either and I have regularly set 20 pound tanks inside my car or put 30 pound tanks in my trunk on their sides. Nonetheless, Department of Transportation regulations DO require that the tanks be transported in an upright position because the safety valve or safety blow-out plug is not tested to operate in any other tank position. It is one of those little known regulations that covers scenarios that are highly unlikely to ever happen, but also one that could trip you up if a savvy cop wanted to push the issue.

 
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11-11-12, 05:04 PM   #9  
That's OK, our cops can't even spell "savvy", so I guess I'm OK Thanks for the updated information.

 
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11-12-12, 04:25 PM   #10  
My opinion is different from the rest, and I know Iíll get some disagreement.

I made my generator decision a year ago when I set up a gasoline-powered portable generator (6700 watts), connected via an interlock kit.

Propane or natural gas would have been my preference if I was using either in my house for heat (or cooking, I guess), but Iím not. I decided I wouldnít install a large propane tank simply for a standby or portable generator. It could sit unused for years, other than for generator tests. If I wasnít cheap, and thought I would need the generator often (who knows?), I would have had a propane tank installed and filled. If I had someone living with me with a medical condition that required power, I would have installed an automatic standby unit and a propane tank. Weíre all healthy, and can live with the down time during an emergency that is required to refill a generator.

A 20-pound propane tank (barbecue grill size) will run a generator my size for about 6 or 8 hours. That means that I would have to have a lot of them if I was going to run my generator for any length of time. They can be refilled during an emergency, but in far fewer places, and these places are far less likely to be open (and have propane available) during an emergency. 120-pound propane tanks would be monstrous to handle, and I would still have the same supply problem in an emergency.

Diesel: you can put it in a tank, but once again, unless you have a diesel vehicle or something else that is using it, it may sit unused for years. Diesel is less volatile than gasoline, has a longer shelf life, and it is usually going to be available when gasoline is available. It is safer than having gasoline on your property. You can fill 6-gallon cans of it most of the time that gasoline is available. It is a little less likely to be available than gasoline, but not much less likely.

Gasoline. A pain in the butt. It has a short shelf life, unless you stabilize it. It is the most volatile. However, stabilizer doesnít cost much, and stabilizing is a simple process. My small engine repair man recommends a mix of Seafoam and fuel stabilizer for best results.

So, hereís what I do. I keep 40 or 50 gallons of stabilized gasoline (stabilized with two years of stabilizer) in my detached barn/garage (75 feet from my house), with each can dated with the date I filled the can. I use the gas in my lawn mower and snow blower. If it gets over six months old, I pour it into my car, five gallons at a time, so Iím not wasting any gas, and donít have to worry about disposing of anything.

I will always have gasoline on my property for power equipment, and although the risk is slightly higher of a fire with 40 gallons on hand than the 5 or 10 gallons I would have on hand otherwise, if 5 or 10 gallons catches on fire, my barn is gone. Iíve been fine storing gas in my barn for 20 years, and no one else where I live has had gasoline burn anything down, although I know of two propane tank fires that cost homes around here. Gasoline certainly does have risks.

Having seen two major emergencies/outages firsthand recently and heard reports from friends on another, I can tell you that there is no perfect way to make sure you have fuel on hand for a long-term outage. During Hurricane Irene, which tore up my town, those with propane or natural gas tanks couldnít get them refilled, because the roads and bridges were either gone or impassable. Their generators had fuel for two or three days, and would have lasted less than that had it been a winter outage when they needed the fuel for heat as well. Gasoline was available, although some had to use ATVís to go the last mile to their home. Gasoline was also available during an ice storm outage here four years ago that kept some people out of power for ten days.

During Snowtober in Connecticut (I brought a generator to a friend there), the nearest gas stations that were open were an hour away. I think that propane delivery trucks were able to make it through to most areas after the roads were cleared of trees, which were literally everywhere.

With Sandy, gasoline was tough to come by. Iím not sure if the propane trucks were able to get filled and make deliveries (perhaps someone else can give us that answer).

If youíre wondering why I went with an interlock kit, it was an expense issue. A 6- or 10-circuit transfer switch would have required (very costly) wiring to my main panel and to two remote panels, one 50-feet away, and one 50 feet away and two floors up. I could have installed a 200-amp whole-house transfer switch at my main, but the cost for that would have been $1800 for the complete installation, and offered me no significant advantage over the interlock kit. The interlock kit makes all my breakers available and could theoretically overload my generator, but I can monitor my power usage well enough even with all my breakers available.

If you go with a portable generator, run it with an electric load once a month (weekly is better), and perform all the scheduled maintenance. Of course, never refuel it while it is running, and remember, the cheaper the generator, the more likely it is that it wonít work if you have let it sit for two years and then try to use it. Get the most reliable engine you can afford.

 
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11-12-12, 04:34 PM   #11  
I went to Generator school at Winco in Minnesota

70% of generator failures are fuel related

interesting...


so natural is my choice

LP is great, but you need a 1000 gallon tank when you're -20 below 0 to get the gas vaporized

 
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11-12-12, 04:58 PM   #12  
I'm glad that it rarely even freezes at night here...

Boilernut, there's a 30kW Winco generator on Phoenix Craigslist circa 1982, powered by a Chrysler slant six. They state 120/206 volts, would that be a misprint on their part with the ad?

 
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11-12-12, 05:01 PM   #13  
I never really though about the boiling/vaporization temperature of propane until my brother in law moved to central Alaska. One year we called to wish them a happy holiday and they were not able to cook. He sent a video of him opening the 20lb tank from their grill and pouring it (propane) out into a cup. It just sat there like water until he took his glove off and picked the cup up.

 
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11-12-12, 06:09 PM   #14  
T W X Not to get off track here, but if there's enough leads on that generator end, it can be connected to be 240V residential. Sounds like a 3PH unit...talk to the owner to verify and if it can be reconnected.

 
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11-12-12, 06:14 PM   #15  
Where you live will dictate the type of fuel you burn too. If you live in the Northland, natural is great. LP is okay too, but remember if you're over 12KW you must consider the size of your LP tank for those cold nights. Starting and running a diesel on demand in the Northland is a lot more work. Where I live here in the heartland, natural is everywhere except out in the country.

 
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11-13-12, 04:21 AM   #16  
While on the boiling point, would an underground propane tank quell the problem somewhat?? We have many buried tanks in our area, mainly for aesthetics, but would it work in the colder climes???

 
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11-13-12, 04:57 AM   #17  
Yes, I would think even in permafrost the ground would not get as cold as the air.

 
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11-13-12, 05:33 AM   #18  
Being outside the Natural gas service area, I would opt for diesel or standard gas.
Being on oil heat (with an indoor tank), diesel would be a good option, but could cause issues with two demands on the oil supply if caught close to fill up.
standard gas storage wouldn't be too big of a deal as I keep the generator full and both vehicles with at least half a tank each.
To compensate for the poor shelf life of standard gas, I'm currently keeping the genny topped up, and siphon from it into my gas powered yard equipment (lawn mower, snow blower, quad someday).
I do need to come up with a bit better siphon method.

 
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11-13-12, 07:10 AM   #19  
I do need to come up with a bit better siphon method.
Yeah, dry-retching for half an hour sucks...

 
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11-13-12, 07:25 AM   #20  
I try to avoid drinking the stuff. That is what beer is for.

Once I build my generator dog house (small shed beside the house specifically for the generator), I might opt to go with a seporate fuel cell of some sort mounted a bit higher up, with a fuel line going to the generator, and a fuel line (on a valve) available so I can drop it in a small can to full the other equipment. The idea is simple, just need to see if it'll have issues with any sort of building of fuel handling code.

 
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11-13-12, 10:18 AM   #21  
A transfer pump might be a safer idea, since it wouldn't be gravity fed and therefore couldn't just drain out if the valve failed...

 
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11-13-12, 10:30 AM   #22  
A transfer pump might be a safer idea, since it wouldn't be gravity fed and therefore couldn't just drain out if the valve failed...
That could be a valid solution. I'll keep it in mind.
I haven't really put too much thought into the setup as of yet as I have other more urgent things to fix and/or get ready for winter.

 
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11-24-12, 08:26 PM   #23  
Hello folks;

Just jumping late in to the pool here. Before I started to narrow down my fuel choices for my gennie purchase I started with the permitting regulations of the area I live in. Real eye opener and narrowed down the possibilities.
-Propane, my municipality FORBIDS anything over the twenty pound tank (barbacue size). So to be able to run for awhile I would need alot of them and at anywhere from $29 - 37 bucks apiece that is not possible.
-Natural gas. A good bet but since I have NO NG in my house that would require putting in some gas lines or resurveying some real old disconnected ones. Either way I found that the gas company years ago would cap the gas in the street to prevent problems. The cost of permitting, digging, reattaxhing was way more than I could contemplate.
-Diesel, very good possibility as I heat with oil but as stated what if starting to get low when needed. In Sandy my scheduled resupply happened to be during the storm. 10 days later the truck got here and I was really starting to sweat (no pun) having any oil at all. Possible solution another large tank but my basement is limited and underground tanks are a No-No!!!
Another problem here was Big Brother, in the way of noise restrictions and proximity to other house. The fact that some others would be doing tha same thing never went into their thought process.
- Leaves gasoline. I have gradually purchased gas, added stabilizers, keep in a shed I vent with some recycled large computer fans powered by a small solar panel. Keeps the shed air circulating and fumes from accumulating. Each can is numbered and a listing is kept on the door with each can listed, refill date and whether stabilized. As a can gets old it goes into the cars and power equip.
During Sandy I lost power for eight days and really didn't much sweat gas. As I used it a empty can went into the car and if I saw some gas I got a refill, other wise I had enough for about 12 days. Even shared some the gennie load to my neighbor to help keep some food for their kids fresh.

 
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11-24-12, 10:18 PM   #24  
If you are storing gas in jerry cans, you can also store diesel in jerry cans. Also, the noise of a diesel is usually not as bad as the noise from a standard duty gas engine from the distance of the typical neighbor's house. With you having the oil tank as well, it sounds like diesel would be the best choice by far in your position, but whatever works.


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Last edited by cheese; 11-24-12 at 10:33 PM.
 
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11-29-12, 06:56 AM   #25  
I'm surprised that a city can limit the size of a portable fuel cylinder, mainly since those cylinders are commonly mounted on RVs in size much larger than the 5 gallon units. Maybe the limit is just for fixed-installation use, but even then, it would be difficult for them to find one in noncompliance if it just happens that the hose will reach the taller tanks in addition to the 5 gallon one...

Even though I don't have natural gas service at my home, I'm curious as to how often people with a municipal natural gas powered generator have lost their natural gas service during a natural disaster.

 
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11-29-12, 11:23 AM   #26  
Even though I don't have natural gas service at my home, I'm curious as to how often people with a municipal natural gas powered generator have lost their natural gas service during a natural disaster.
I would suspect 99% of the time a genny would be needed, the supply will be there. That one time however... Will probably be the most critical time of all.

 
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