Off Grid or Prime Power generator essentially means there is NO utility available. Manufacturers look at this segment the same way even if you have solar, wind, batteries and the generator is only to support the loss of these sources. Your application is still "Prime Power".
These units are built to a different standard than a residential gen and come with a warranty that will clearly identify your coverage for intended use.
A 12kw residential generator will have zero warranty if used for off grid/prime power. Kohler builds a 12kw off grid generator complete with supporting warranty.
Don't get caught comparing kw to kw, this would be like comparing a 300hp pick up to a 300hp dump truck.
For the off grid home, cabin and business with solar, wind and batteries the good news is you have more options than ever. If propane is already in use for heat, hot water and cooking a propane generator is a clean easy solution in both high and low speed generators.
If propane delivery is an issue look to low speed diesel options you fuel yourself.
We stock from 12kw propane and up.All our generators come standard with two wire start so any auto start control on your solar system will seamlessly interact for hands free operation. Independence from grid has never been easier.
(Geco only provides generators and support for generators, we are not a supplier nor do we support anything solar, wind, batteries or inverter. We will provides the names of great companies that do solar power)