Generators

[john37]

Can someone please tell me the advantages and disadvantages of Natural Gas generators vs. Diesel Gas generators? I always see Diesel gas generators around but someone was asking me about the advantages and disadvantages of both types. One reason I can think of diesel being better than natural gas is because in case of a natural disaster the gas probably would be shut off. Is there a generator that has a combination of primary running off gas but has a back up diesel tank? My knowledge is very limited on generators so any help would be appreciated. Thanks...

 

[iwire]

In general propane or natural gas generators are limited in size.

As you noted the natural gas supply may not be considered reliable.

However you could just as easily store propane as diesel.

I do not know of any Gasoline / Diesel combination fuel units but you can get gasoline / propane, natural gas units.

 

[frenchelectrican]

Let me step in for a min with the Natrual gas / LP generator size.,,

Yes there is larger units that can run on Natrual gas and Propane fuel they are larger spark ingited engine majorty of the generator manufacters do have them on their listing.

Pretty good percentage of Natrual gas units do have option to switch over to LP gas if the sisuation called for.

The switching over is done by have one set of fuel regualtors for natual gas and second set for Propane it is done by either electric soilonid or manually by valves [ most use electric verison for faster respond ]

As Iwire [Bob] mention there is pretty good size of LP storage tank.

As far for Natual gas/ Diesel fuel dual fuel set up IIRC i think there is one manufacter done that but how well it work that part i can't comment because it hard to say.

Now let me pass a head up if you run on Biodiesel fuel you will run a issue is shelf life they are somehow shorter than convental diesel fuel due they will pick up tons of moisture and very easy to get fungus in the tank and clogged up the line.

{ few generator manufacters spec'ed stated that no biodiesel can be used with stand by units but prime units seems ok }

Merci,Marc

 

[john37]

Thanks guys....In our situation we are very limited on space and that they are proposing to put a 150KW generator on the roof of the 12 story condo bldg. The condo bldg is right on the beach.
The intenet was to put the generator on the roof and diesel fuel tank on the ground floor and pump the fuel to the roof. (A small tank would also be up on the roof for testing, etc).
I guess my questions comes down to if a diesel generator is "better" than a propane or natural gas generator? Are there any physical size differences between the two? (I'm currently trying to search on the internet on the Caterpillar website). Would a natural gas generator require to be larger in KW vs. a diesel generator? Or would that not make any difference?
Thanks...

 

[iwire]

Having a diesel set on the roof with a day tank up there and a ground level storage tank is certainly an option.

I will say this, I know of two separate incidences of day tanks on roofs being overfilled and causing many thousands of dollars in clean up costs.

In both cases malfunctions with the fuel pump control forced the pump to run continuously. All I am saying having some redundant, independent fuel level monitors on the day tank would not be a bad idea.

As for KW as far as I know KW is KW. Diesels are typically heaver, but also have longer lives.

 

[iwire]

One other thing, in my experience CATs are much quieter then Cummings.

 

[frenchelectrican]

For the 150 KW generator engine both are roughly the same size anyway

But check with the local code for latest info related to the geneator system senice you are mounting on the roof you may want a building engnieer to check out the structure to handle additonal weight.

Typically 150 Kw diesel unit weight in about 8~12K pounds depending on setup.

Merci,Marc

 

[mdshunk]

I try to stay out of the fuel choice decisions, but it seems like it often comes down to what's on site already. If they already heat with fuel oil, they'll often go with a diesel. If they have a sufficient natural gas supply on site or in the street, they seem to go with natural gas.

 

[frenchelectrican]

That true Marc S. that is pretty much seal the deal there is the fuel supply at the location unless that place have both Natual gas and Fuel Oil [ Diesel fuel ] then the choice will be latter one useally diesel unless a Co-generation then natual gas will be wise choice due the fuel price somehow cheaper than diesel fuel. { i am not say super cheap but dont be suprised it will catch up one way or other }

Merci,Marc