I am currently building a house, and read your article on generators used with a battery/inverter system to provide off grid power. This intrigued me.
My question is whether or not it is better to get an LP powered generator, versus a diesel because of the price of fuel. The price difference in my area is almost $2.00 per G. I realize that diesel motors usually have greater longevity than other types, but Guardian has introduced an 1800 rpm liquid cooled 18KW generator, and I’m wondering if that might not be more cost effective.
I would also appreciate any info you could provide that would allow my builder to do the install correctly for a future battery /inverter system.
My selection of generator type has to do with how often it will be running each week, month, or year. For example, if I want a generator for backup power for a home on the grid that only suffers a power outage for a few hours or days each year, I would select a propane generator as the fuel (propane) does not go stale or get old, so it can sit in the tank for years until needed. Of course you should run the generator every few weeks to keep everything lubricated and operational.
If I was designing an off-grid solar home and the solar system was large enough that the generator would only be needed to run a few hours each week, I would also select the propane fueled generator for the same reason.
If I was designing an off-grid system that needed a generator to run many hours each week I would select the diesel generator as the fuel costs will be lower and would also allow making my own bio-diesel if needed. Since this generator would go through a fuel tank much faster than an occasional use generator, there is less chance that the diesel fuel would go old. Of course you can add additives to the diesel to make it store better, but most of these additives are expensive and another thing to take care of.
If the home’s location is not accessible for filling the propane tank with a propane delivery service truck, you may have to select the diesel, as it will be easier to deliver the diesel fuel in 5 gallon hand-carried fuel cans.
As you see, all designs are have trade-offs and there is not always a perfect answer.
Hope this helps,