Generator fuel use

[Tdog]

What this board needs is another generator thread.

My 15kw generac propane fueled generator has had come to my rescue a couple of times in the last few months. I don't have an hour meter [I do have one ordered], but gestimating, between Gustav & last week's snow, the generator ran 54 hours since my tank was last filled. I had the tank topped off today & it took 106 gallons. Not included is any time it ran for 'practice'. That puts me in the 2 gal./hour range.

Does that seem to be a reasonable usage?

Jack

 

[ragkar]

I was poking around last night and came across the factory specs for a Winco brand 8KW generator. 1.5 propane gallons per hour.

 

[Marc L.]

Good day TDog,

You probably ran a little more than this due to the bi-weekly test. if you ran the generator at close to 80% load, you are pretty much in the ball park (it is a 15 KVA after all, it takes a fair amount of fuel).

My 12 KVA takes about 3.1 litres an hour and it is running almost at 90% all the time.

Remember also, it gave you the comfort you wanted when people around you did not. Just for that, it is worth the expense (think of not having to replace all the stuff in your deep freeze...).

Marc

 

[LBrown59]

What this board needs is another generator thread.
Jack

No a gen fuel thread.

 

[Lasgambler]

Sounds about right for a 15 kw. Terry

 

[Tdog]

Best $310 I've spent in a while on that 106 gallons. However, it does concern me that I begin to bump empty after just over two full days on the generator. The only solution to that is to get a larger tank. Or maybe conserve fuel by running it less than continually. But then, what's the point of a whole-house standby generator?
At least it beats scrounging for gasoline for a portable like I had to do during the weeks after Katrina.

As a post script, after having lost power with the temps in the 30's earlier this month, I really feel for all those who have been hit hard by these last series of deep freezes. It cannot be much fun to go without electricity for days in those conditions.

Jack

 

[Cottonhawk]

2 gal/hr is about right for your 15 kw generator.
My power went out about two days ago and I am running my Onan 20 kw generator right now. While I am very glad that I have this automatic whole house generator, I am also concerned about the availability of propane. For my generator the consumption rate is 72.3 cu ft/hr at half load. One gal. of propane is equivalent to 36 cu ft vapor. At 1/2 load, my generator will use 2 gal/hr. A 500 gal tank should provide sufficient fuel for about eight days and the cost is about $120 per day.

 

[ragkar]

But I 've read that the yearly loss from a tank is about 10% per year. So with a 500 gallon tank you're losing 50 gallons a year ($250).

 

[LBrown59]

What this board needs is another generator thread.

My 15kw generac propane fueled generator has had come to my rescue a couple of times in the last few months. I don't have an hour meter [I do have one ordered], but gestimating, between Gustav & last week's snow, the generator ran 54 hours since my tank was last filled. I had the tank topped off today & it took 106 gallons. Not included is any time it ran for 'practice'. That puts me in the 2 gal./hour range.

Does that seem to be a reasonable usage?

Jack

How many gal. does the tank hold?

 

[LBrown59]

What takes the least fuel to run a Gen.?
Nat Gas
Propane
Gasoline
Diesel / Home heating oil.

 

[RonMar]

Diesel. It has the highest BTU content at around 140,000 BTU/GAL Propane has around 91,000 BTU/GAL, Gasoline around 115,000 BTU?GAL and Natural gas is around 1075 BTU per CU/FT.

A typical small diesel generator set will consume somewhere in the neighborhood of 1/8 gallon per KW per hour, or about 17,500 BTU worth of fuel per KW per hour. Most other gensets should be in the same neighborhood for BTU consumed, with the slight edge going to the liquid cooled engines. The diesel is a little more thermally efficient than a gasoline/propane engine, almost always liquid cooled and uses the highest BTU content fuel, so it will typically use the least ammount of fuel by volume.

 

[Wayne County Hose]

I just had a 500 gallon propane tank installed at my new house. They would only put 400 gallons in it. They told me that this is the norm, I asked around and I guess it is.

 

[ragkar]

I can't answer for all of them, but for my 6.2Kw generator I expect:
propane - 1.25 gal/hr or $7.50 at local current prices
gasoline - .4 gal/hr or $0.65 at current local prices

But there are other considerations such as aging of gas, refilling of tank (7 gal for gasoline and 100 gallon for propane), availability in an emergency etc.

 

[kennyd]

I just had a 500 gallon propane tank installed at my new house. They would only put 400 gallons in it. They told me that this is the norm, I asked around and I guess it is.

Normal. They only fill to 80% capacity to allow for thermal expansion and to allow vapor space in the top of the tank.

 

[kennyd]

What this board needs is another generator thread.

My 15kw generac propane fueled generator has had come to my rescue a couple of times in the last few months. I don't have an hour meter [I do have one ordered], but gestimating, between Gustav & last week's snow, the generator ran 54 hours since my tank was last filled. I had the tank topped off today & it took 106 gallons. Not included is any time it ran for 'practice'. That puts me in the 2 gal./hour range.

Does that seem to be a reasonable usage?

Jack

I have the same genset, I put a hour meter on mine and reads about 72 hours now, I have had it three years now. Not sure on my usage since my 1000gal tank also supplies fuel for my hot water, dryer, stove and backup to the heat pump.

Your usage is also load dependent, my 15kw is only about 60% loaded under normal usage.

 

[Tdog]

How many gal. does the tank hold?

My tank is 200 gallons - - I wanted larger, but that's the largest available when I was set up in February '06. I could probably get a larger one now, except for inertia & $$..

Jack

 

[charlz]

I just had a 500 gallon propane tank installed at my new house. They would only put 400 gallons in it. They told me that this is the norm, I asked around and I guess it is.

Yes, 80% fill rate, leaves room for vapor and expansion.

 

[atgreene]

Just remember you will not be able to get all the fuel out of that tank. Due to freezing of the fuel as the level owers, you generally leave 10-20% in the tank. The larger the tank the less evaporation freezing issues you have. I'm looking at installing an auto gen but going either diesel (but cold weather can be an issue) or putting in 2 500 gallon tanks. 3-4 days w/o power is not unusual for us, and at below zero temps the tank will freeze-up fast.