Standby Generator - Diesel or NG?

[hwp]

I am thinking about installing a 40kw packaged standby generator but can't decide between diesel and NG. I don't expect it to run a lot - we haven't had a power outage in the 10 years we have lived here. But if we did it would be a disaster. If I thought it would get a lot of use I would definitely go diesel. My guess is that almost all of the run time will be in the weekly automatically scheduled test. The fuel oil tank for the furnace for my garage is very close to where it will be installed so I could use it to run a diesel. But NG is a cheaper and cleaner fuel and should be easier starting. It will take some piping changes to run extend a NG line to the generator but not a big item. It looks like a NG unit is a couple thousand dollars less than a diesel unit. Any suggestions?

 

[MikePA]

I'd go NG. You don't have to worry about filling a tank. How long would a tank of diesel last if you had to run the generator and heat your house?

 

[kennyd]

I would use NG without hesitation if it's available. Why do you need such a large unit?

 

[ToadHill]

NG no doubt, oil stays cleaner, fuel does not spoil as it ages or get contaminated with moisture. Most of the NG units I'm familiar with also have a program that starts them every so often to keep everything from setting up. I'm not sure if diesel units do.

 

[Skyco]

Where do you get the NG? From a local gas utility? Are you positive they'll be in operation during an outage/disaster? Diesel you can haul yourself, NG you can't.
Just food for thought.

 

[hudr]

Have you thought about Propane? Like NG you dont' have the fuel storage issue or the oil getting dirty but you are not tied to the NG infrastructure. We used to have several propane powered tractors and such (still have one old 2 cyl JD) and they just don't wear out. I wish I had been patient enough to wait on a propane powered welder when I bought. Propane would have only added about $200 to the purchase price but it added several weeks to the delivery date. Now they want nearly $800 to do the conversion.
Anyway, a 500 gallon propane tank would run a generator for quite a while. Plus you could get a wet line on it and fill your gas grill tanks or whatever else you had that ran on propane. Also, propane you can also haul yourself if need be.

 

[kenmac]

I don't know what your running but, a 40 kw is a fairly big generator.I would go N.G. myself. A 40 KW is about 680 C.F.H. of N.G.

 

[chh]

If its a short run to your fuel storage tank so you can keep fresh fuel to it diesel wouldn't leave you reliant on the natural gas system. I guess it would be how much confidence you have in it staying in service in a disaster. Any particular reason with going with a 40 kw? That is what I have but it is a leftover from when we had a confinement hog operation. A 40 kw would run that setup and it took a lot of juice. A rule of thumb on generators is to use whatever the number is on your electric transformer. Most houses here are on a 10 kw transformer. But sure and have the transfer switches installed by a qualified electrician. A generator can backfeed down power lines and be fatal to anyone who contacts the "dead" line.
Good luck!

 

[hwp]

Thanks for the various opinions. My inclination is to go with NG.

I have a 400 amp 220 Volt single phase service. By my calculations that 88kVA or 88KW so a 40KW generator would provide less than half maximum possible load, although I doubt I ever get close to that.

My main concern is an electrical outage from ice and wind damage to the overhead wires. As I said before, we haven't had a major power outage in the 10 years we have been here, but we are in a rural area with a lot of trees along the power lines and we do get bad ice storms.

The NG mains are buried so I am not concerned about a gas disruption. If the gas goes out we are in trouble - with or without a power disruption. There is a NG line to a roof top furnace/AC that ends about 60 feet from where the generator would be installed. I would need to increase the size of the line going to the rooftop unit and then extend it to the generator.

Any other comments appreciated.

 

[bearhawk]

Natural Gas...

I think most people put a transfer switch that powers all the essential stuff.

Furnace
Well Pump
Refrigerator
And a few essential outlets / lights

You figure out what the current draw is for the essentials, and size your generator to that. No need to have everything powered up in an emergency.

I think a 10 or 12KW would be plenty.

I have run the above on a 4500 watt portable.

Jim