Diesel more cost effective than Natural gas? Sure about that? I see fuel stability and gelling in cold weather an issue as well.

Natural gas costs about $1.25 per therm. You et 100,000 BTU"s for that. Diesel runs around $4/gallon and delivery 147k BTU's per gallon. Even if the diesel engine is 30% more efficient thermally (not likely that much)... natural gas is still around 1/2 the cost. Less if you factor in the higher up front costs.

Natural gas is supplied continuously and it the delivery is extremely reliable and in unaffected by most natural disasters... and even after severe tornadoes that may have levelled houses, is restored well before electricity.