Generator fuel use

[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.