15kw diesel generator recommendations

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  #1  
Old 08-27-05, 03:13 PM
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15kw diesel generator recommendations

Hi everyone,

We live in the British Virgin Islands and we are experiencing ongoing power supply problems, we have decided to purchase a generator. I am pretty convinced we want diesel (1800 rpm), but are also considering propane. Natural gas is not an option.

We need a 15kw standby generator which can run an entire house/small business for up to 10 days (or longer) at a time. Ten days is the longest period of time we have been without power after a hurricane.

Money is certainly a consideration, but more important is that the unit be very reliable and relatively maintenence free. I don't mean changing oil or standard sort of maintenance such as running it at least once a month, I mean any kind of maintenence requiring a mechanic. I can manage basic stuff provided there are directions on what to do and how to do it.

So, what I am asking is which makes and models would you recommend. We are in the islands. Parts and (good) mechanics are hard to come by. Any suggestions?
 
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  #2  
Old 08-27-05, 06:52 PM
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We loose power rather often (but not as bad as hurricane alley) and use a tractor driven generator. It was a less expensive option since I already have the tractos and I did not want another engine to maintain. You can get about one kw for two horsepower at the tractors pto.

You may be able to find a used tractor for a reasonable price. Around here (North Carolina) tractors over 40hp are extremely cheap. A 13kw pto generator is about $1'100 USD and a 27kw unit is around $2'000.

As for reliability I think almost any basic diesel tractor or generator is going to be reliable enough for your needs. Generally I think a slower turning engine is going to be more relaible over the very long haul but will not make much difference for most people. If you lived on a private island where the generator would get thousands of hours use every year it would be very important. A few hundred hours is not much use for any diesel, even a faster turning (2'600 or 2'800 rpm) will most likely last forever for your needs.

I am a bit torn choosing between a diesel or propane powered generator in BVI, but I tend towards a propane powered one. I think fuel storage will be your biggest problem and engine reliability will be secondary. If planning to run a 15kw generator for ten days you are going to need to keep a lot of fuel on hand. I am totally guessing, but I am thinking (average) about 1gal/hr diesel and 2gal/hr propane.

Diesel is readily available and easily transported but it spoils if stored for too long and can be contaminated by water, dirt & bacteria. You can add preservatives and stirr the fuel to increase the storage life, but in the tropics it won't keep forever. Propane is probably more expensive, harder to acquire & transport during an emergency; but it does store well for long periods (forever) and it is very hard to contaminate.
 
  #3  
Old 08-27-05, 08:41 PM
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We're in Florida and just put in a 40KW propane generator, made by Generac. It's enough to run a 3,500 sq ft house including all of the lighting, refrigerator, microwave, stove, two air conditioners, and well, about anything else in the house. Also installed is a 500 gal propane tank. This should last about 2 weeks in a power outtage situation, assuming you're not wasting electricity needlessly.

What I've found with lp/natural gas generators is that the pricing varries the most when you jump from an air cooled to liquid cooled engine. So 10KW, 15KW, and 20KW air cooled generators are all very similar in price. But a 20KW liquid cooled could be several thousand more than a 20KW air cooled.

We went with LP instead of gas/diesel mainly because of fuel storage. We may go a year and not use a significant amount of fuel. With LP, that's not a problem. It sits there and waits for you to use it. With diesel, you can have water and degredation problems which can render your whole tank of fuel about worthless.

My only experience with installed 'whole house' generators is with Generac (made by Guardian; also the same as Centurion). But everything so far has been positive. The generator itself is quiet; appears to be well built; and works just like advertised.

As for pricing, a 40KW Generac can be had for under $10,000 with a 200A transfer switch, if you shop around. This doesn't include the electrical work, or the propane.
 
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Old 08-28-05, 07:01 AM
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Talking

Thanks fellas,

Your mention of fuel contamination is a big cause for concern. I hadn't thought of that at all! Natural gas is not an option here because there isn't any to be had, but there is plenty of propane (its what everyone uses for cooking) and they have trucks that deliver too ... which I wouldn't get with diesel unless I take large quantities! I can get 100, 300 and 500 pound propane tanks without any trouble.

Hmmm, maybe propane is the best way to go afterall? So what should I look for in propane. All my investigations so far have been into diesel. Are there any drawbacks to propane. Are they noisier? Cost more? Anything?

I forgot to mention, we don't have a lot of tractors here. I live on Tortola (the main island) but there isn't a lot of agriculture here. The terrain isn't exactly suited to crop growing.
 
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Old 08-28-05, 07:34 AM
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We live out in the country and have a 1'000 gallon propane tank, which actually holds about 800 gallons. Propane tanks are never filled full. They must leave about 20% empty at the top of the tank so the liquid propane has room to expand on hot days.

Propane has about 91'000 btu's per gallon where diesel has about 130'000 btu's per gallon. In other words a gallon of diesel contains more power than a gallon of propane, so you will need 30-40% more propane (than diesel) to generate the same amount of electricity.

Propane is very easy on an engine, so it will tend to live longer than the same engine run on gasoline. A propane generator will likely have a gasoline engine that has been converted to burn propane, so most auto mechanics will be able to work on it. The only thing I would recommend is to keep some of the propane specific parts on hand since you probably will not find them in the islands. There are regulators that control the propanes pressure and there is a valve, usually electrically controlled, that turns the propane supply on/off. All of those propane regulators and valves are inexpensive so a couple hundred dollars can buy a lot of spares. Since many forklits are powered by propane a forklift repair shop can work on your engine and it's propane fuel system.
 
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Old 08-28-05, 09:16 AM
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The suggestion to keep spare parts on hand is a good one and I will do that! What do you think of the Generac 15kw propane units? Are they a good quality?
 
  #7  
Old 08-28-05, 09:49 AM
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I don't know what kind of building codes you have down there. Up here, it is not unusual to have propane storage on property, but in residential (non-farm) areas, it would be very unlikely we could get a permit to store any amount of gasoline or diesel ( anything more than about 5 gallons.)
 
  #8  
Old 08-28-05, 04:12 PM
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Fuel storage isn't a problem at all.
 
  #9  
Old 08-28-05, 07:11 PM
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We don't have any regulations about fuel storage for residential uses.

If would buy the largest tank you can afford. They don't get much bigger looking when you go to the next larger size. Keep in mind that a 375 gallon tank will only hold 300 gallons. A large tank gives you the option of buying fuel when it is cheap and riding out the expensive times.

I did a quick internet search and found that the Generac 15kw air cooled propane generator consumes 2.4 gallons an hour at full load (13kw) and 1.6 gallons at half load. So a 375 gallon tank will let you make about 6.5kw for 7.8 days or the full 13kw for about 5.2 days. You may want to go to a 500 or 1'000 gallon tank.


I think my 1'000 gallon above ground propane tank was about $1'100 US Dollars, but that was before steel prices skyrocketed last year.
 
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