Which genset for home power?

[bimota]

Propane is good, diesel is a sloppy mess. If you have propane - then go propane. Diesel backup typically is a problem unless you have regular source of diesel, refresh the fuel regularly and run any genset fully loaded - bottom line for a home that is not going to happen unless you need to run AC all summer all day and night which would break the bank. The small Honda's are hard to beat for short term mobile applications. Propane makes more sense if you are going to have 1-7 day outages. At half the price of gas, propane is best for long outages.

 

[Isaac-1]

The problem with propane is resupply, you are dependant on a delivery truck, and in a major outage they will all be busy resupplying critical services.

My inlaws use propane for heat, hot water and cooking, they were unlucky with their fuel level when hurricane Rita came through (also lost part of their roof, etc.) as they had just ordered a refill on their tank 4 or 5 days before the storm hit, but were too far down the list to get delivery, of course the propane supplier was shut down for the next week or so as their delivery drivers had all evacuated the area, etc. To make a long story short even though they had an order for propane in before the storm hit they were not resupplied until 22 days after the storm (the delivery was on a Sunday afternoon), note they lived less than 5 miles from the propane supplier. With diesel you can load it into a 55 gallon drum and carry it (legal for up to 2 drums) in the back of a pick up truck.

 

[edgephoto]

Propane is good, diesel is a sloppy mess. If you have propane - then go propane. Diesel backup typically is a problem unless you have regular source of diesel, refresh the fuel regularly and run any genset fully loaded - bottom line for a home that is not going to happen unless you need to run AC all summer all day and night which would break the bank. The small Honda's are hard to beat for short term mobile applications. Propane makes more sense if you are going to have 1-7 day outages. At half the price of gas, propane is best for long outages.

Propane is a good choice. The negatives are you need a tank to store it and you can't refill it yourself. Propane has roughly 10% less power per gallon than gasoline. If you already have a propane tank then I would go with propane to power a generator. I would just go with a larger tank.

In my case I have no propane appliances other than a grill. I already have 275 gallons of diesel in my cellar. So for my purpose diesel is a better choice.

The original poster has to decide what is the best fuel.

 

[quickfarms]

Edge photo your last sentence said it all. My MEP903B has a day tank on it and us plumbed directly to a larger tank. When the day tank gets low a level switch turns on a pump and refills it. You would probably have to place the pump in your basement but it would eliminate the need to manually haul the fuel.

 

[edgephoto]

Edge photo your last sentence said it all. My MEP903B has a day tank on it and us plumbed directly to a larger tank. When the day tank gets low a level switch turns on a pump and refills it. You would probably have to place the pump in your basement but it would eliminate the need to manually haul the fuel.

My oil tank is about 125 feet from where the generator will live. So for my purposes I will probably haul the fuel manually. That is why I have thought about either a 15 or 30 gallon drum. I could move that on a hand truck, refill it and wheel it back. Just make a hose that will reach outside so I don't have to haul it up a set of stairs full. I have not worked this part out yet. I also thought of maybe a pickup truck tank on a slab near the generator. Leaning toward the drum.

 

[bimota]

long resupply times are typical with propane - only luck would leave you out

The problem with propane is resupply, you are dependant on a delivery truck, and in a major outage they will all be busy resupplying critical services.

My inlaws use propane for heat, hot water and cooking, they were unlucky with their fuel level when hurricane Rita came through (also lost part of their roof, etc.) as they had just ordered a refill on their tank 4 or 5 days before the storm hit, but were too far down the list to get delivery, of course the propane supplier was shut down for the next week or so as their delivery drivers had all evacuated the area, etc. To make a long story short even though they had an order for propane in before the storm hit they were not resupplied until 22 days after the storm (the delivery was on a Sunday afternoon), note they lived less than 5 miles from the propane supplier. With diesel you can load it into a 55 gallon drum and carry it (legal for up to 2 drums) in the back of a pick up truck.

Typical home resupply with propane is 3-6 months per resupply (tanks run from 150-500gals) - so going 22 days is not an issue unless you happen to be very low and then had the low probability of no resupply. Trying to move diesel in 55s in a 4x4 is simply messy and possibly hazardous and not suited to typical family situations. The wife, 3 kids and 55 at 500lbs with poor strapping and rough road is going to be rough on the marriage. Sure, it can be done but having 250 gals of propane that runs for 3 months will make the situation much safer and the wife happier.

 

[storeman]

* 1 cubic foot propane = 0.0278 gallons propane
* 100 cubic feet propane = 2.78 gallons propane
* 1 gallon propane = 35.97 cubic feet propane
* 100 gallons propane = 3597 cubic feet propane

GE 7 and 10 kw propane generator consumption:

Fuel consumption* (at ½ Load )

33 ft3/hr (LP) 80 ft3/hr (NG)

35 ft3/hr (LP) 84 ft3/hr (NG)

At 1/2 load, your 250 gallon tank (which the propane company will only -by law- fill to 80% to allow for expansion) will last you about 200 hours, if "full" when the emergency occurs. Resupply becomes an issue very quickly.

Jerry

 

[wreckerman893]

I have a MEP003A 10K diesel mounted on a trailer.

It sucks fuel even when just loafing along......if needed it would run the whole house (all electric with wood heat for emergencies) but we have a small gas burner we use for projects around the farm that need power.

At some point in time I'm going to intergrate it with a solar power system I have (still in the crate), a battery bank and a grid tied backup system.

You definatly need to do an energy audit to determine exactly what your maximum load will be.

When I was in the Alternative Energy business the average home we audited could be run by a 10,000 watt system if the loads were managed properly.

 

[Isaac-1]

Bimota, maybe hauling a 55 gallon drum is a problem for you, but proper loading, securing and balancing in the back of even a half ton pickup truck is not rocket science. Unloading can be a little tricky if your on your own without a hoist, etc., however at least around here empty 55 gallon steel drums sell for under $20 (often can be found for free), and a siphon pump goes for about the same or a bit less if you buy the cheap junk. Simply park the truck next to your empty drum, transfer the fuel out of it, and repeat as needed. As to diesel being messy, that is true only if you spill it, otherwise it is reasonably clean fuel option, particularly modern ultra low sulphur diesel. Maybe it is the fact that I grew up on a farm and deal with 55 gallon drums where I work, so the ability to load heavy stuff onto trucks and trailers is something I take for granted. In fact I don't even really consider a 400 pound 55 gallon drum as all that heavy (diesel weighs in at about 7.1 pounds per gallon), sure I would not want to carry it in the back of a family car, but the same can be said for gasoline.

 

[edgephoto]

Bimota, maybe hauling a 55 gallon drum is a problem for you, but proper loading, securing and balancing in the back of even a half ton pickup truck is not rocket science. Unloading can be a little tricky if your on your own without a hoist, etc., however at least around here empty 55 gallon steel drums sell for under $20 (often can be found for free), and a siphon pump goes for about the same or a bit less if you buy the cheap junk. Simply park the truck next to your empty drum, transfer the fuel out of it, and repeat as needed. As to diesel being messy, that is true only if you spill it, otherwise it is reasonably clean fuel option, particularly modern ultra low sulphur diesel. Maybe it is the fact that I grew up on a farm and deal with 55 gallon drums where I work, so the ability to load heavy stuff onto trucks and trailers is something I take for granted. In fact I don't even really consider a 400 pound 55 gallon drum as all that heavy (diesel weighs in at about 7.1 pounds per gallon), sure I would not want to carry it in the back of a family car, but the same can be said for gasoline.

Not everyone has a pickup. I have 2 company cars. If I had a pickup truck I would have to pay for car insurance, taxes and the truck. So for me hauling a drum of fuel is not possible. I will use Jerry cans and my home heating oil tank to fill my diesel storage drum. I have considered another tank near the generator but I am not sure my oil company will fill it.

 

[bimota]

oh yeah, the cost is important as well

* 1 cubic foot propane = 0.0278 gallons propane
* 100 cubic feet propane = 2.78 gallons propane
* 1 gallon propane = 35.97 cubic feet propane
* 100 gallons propane = 3597 cubic feet propane

GE 7 and 10 kw propane generator consumption:

Fuel consumption* (at ½ Load )

33 ft3/hr (LP) 80 ft3/hr (NG)

35 ft3/hr (LP) 84 ft3/hr (NG)

At 1/2 load, your 250 gallon tank (which the propane company will only -by law- fill to 80% to allow for expansion) will last you about 200 hours, if "full" when the emergency occurs. Resupply becomes an issue very quickly.

Jerry

You did not mention that 200 gallons of propane would be roughly $400 delivered and the same amount of diesel would be roughly $800 plus delivery (so if you made four trips with the pickup and a 55 gallon drum) your cost for 200 gallons of diesel would be in the $1,000 range depending on how far you had to drive to get it. So resupply is a cost issue as well.

 

[Triple Jim]

It varies a little, but propane has an energy content of about 91,000 BTU per gallon, and diesel fuel has about 139,200 BTU per gallon, so you really can't compare cost per gallon directly.

 

[bimota]

for heating yes, but for genset run it works ok

It varies a little, but propane has an energy content of about 91,000 BTU per gallon, and diesel fuel has about 139,200 BTU per gallon, so you really can't compare cost per gallon directly.

yes, and when using for heating fuel the energy content matters more but when running a genset it is gallons per hours and generators are 30%-35% or so efficient - a 5-10kw unit of either type run about .75-1.5 gallons per hour - so run time equals gallons - with a slight efficiency boost for diesel. 200 hours will take 200 gallons more or less. generators are like cars - you can get many options, flavors and load capacities - The toughest piece is load management but the most costly is the fuel if the genset is used and depreciation if it is standby. depreciation is the highest cost for backup units. Fuel the highest cost for used unit. Hope that helps!

 

[Isaac-1]

Diesel generators do tend to get better fuel economy than gasoline units in gallons per hour for the same rated load, but also tend to have a much more linear output load than spark ignited engine powered generators, so if running at a fraction of full output diesel has advantages, particularly in air cooled models that are less prone to wet stacking. I will give you that there is some cost advantage to Propane if bought in quantity, the exact amount depends on a number of factors including location, however none of that makes up for the fact that after a major storm of other event you are unlikely to be able to get resupplied for considerable amount of time. So what if you have to drive a hundred miles every couple of days to resupply your diesel, at least that means you have power, the food in the freezer stays cold, or the house does not freeze, yes it will cost money, but so would alternatives like evacuating the area and staying in a hotel...

Ike

p.s. as a side note this resupply issue when using a popular and perhaps most generally suggested generator for home back up on this section, the 5KW MEP-002a, you will consume about .57 gallons of diesel per hour at full load (or about .3 gallons per hour at half load), a 55 gallon drum will last you about 100 - 180 hour if ran 24 hours per day depending on load, that can be up to 360 hours at about half load on a pair of 55 gallon drums or in other words about 15 days of continuous power, so a fuel run would be required about every 2 weeks.

p.p.s. to back this up with some relevant numbers, using the commercial cousins to the popular MEP-002a and MEP-003a generator, Onan built the J series generators and engines in both diesel and spark ignited (gasoline) forms, although they shared the same basic generator ends, output ratings did not exactly match, the closest were the 12.5KW rated gasoline powered JC and the 12KW diesel powered DJC.

The 12.5KW gasoline powered JC is rated at 2.1 GPH on gasoline, 200 cu ft per hour on natural gas or 92 cu ft per hour on propane

The 12 KW diesel powered DJC is rated at 1.05 GPH

(these are full load consumption numbers)

sure these are older engine designs, and newer ones may improve economy some, but that is still a big difference (numbers are taken from scans of the original sales lit posted on the smokstak Onan generator board)

 

[bimota]

Great input on MEP-002 fuel consumption

Diesel generators do tend to get better fuel economy than gasoline units in gallons per hour for the same rated load, but also tend to have a much more linear output load than spark ignited engine powered generators, so if running at a fraction of full output diesel has advantages, particularly in air cooled models that are less prone to wet stacking. I will give you that there is some cost advantage to Propane if bought in quantity, the exact amount depends on a number of factors including location, however none of that makes up for the fact that after a major storm of other event you are unlikely to be able to get resupplied for considerable amount of time. So what if you have to drive a hundred miles every couple of days to resupply your diesel, at least that means you have power, the food in the freezer stays cold, or the house does not freeze, yes it will cost money, but so would alternatives like evacuating the area and staying in a hotel...

Ike

p.s. as a side note this resupply issue when using a popular and perhaps most generally suggested generator for home back up on this section, the 5KW MEP-002a, you will consume about .57 gallons of diesel per hour at full load (or about .3 gallons per hour at half load), a 55 gallon drum will last you about 100 - 180 hour if ran 24 hours per day depending on load, that can be up to 360 hours at about half load on a pair of 55 gallon drums or in other words about 15 days of continuous power, so a fuel run would be required about every 2 weeks.

p.p.s. to back this up with some relevant numbers, using the commercial cousins to the popular MEP-002a and MEP-003a generator, Onan built the J series generators and engines in both diesel and spark ignited (gasoline) forms, although they shared the same basic generator ends, output ratings did not exactly match, the closest were the 12.5KW rated gasoline powered JC and the 12KW diesel powered DJC.

The 12.5KW gasoline powered JC is rated at 2.1 GPH on gasoline, 200 cu ft per hour on natural gas or 92 cu ft per hour on propane

The 12 KW diesel powered DJC is rated at 1.05 GPH

(these are full load consumption numbers)

sure these are older engine designs, and newer ones may improve economy some, but that is still a big difference (numbers are taken from scans of the original sales lit posted on the smokstak Onan generator board)

Thanks for the great input on the MEP-002 fuel consumption - I have three of these units and plan to build them for diesel customers. My business is helping off-grid customers run their homes and I use mil-tech when possible due to the quality. So my typical implementation is a hybrid model with solar PV, generator, inverters, batteries etc. Actually, if anyone needs input on that I can help. The downside of the military units is the noise and complexity - the design assumption is there is plenty of labor and training - in the civi world that is not the case. Backup generators are always an interesting debate - it is all a matter of fear, geography, real loads vs perceived loads. Generac makes good money selling crappy generators - but hey that is business! I'm just glad we turned this thread into some meaningful content and gave people some food for thought - thanks again!

 

[epitts]

I have a MEP-002 on a trailer. I went to the local Big truck junk yard and picked up a 100 gal alum fuel tank for 75.00 + tax. This I will mount on the front of the trailier. I can then refill from a 55 gal drum or pull the trailier to the gas station.