Cost, maintenance, consumables, emissions for starters - assuming internal combustion, dinosaur technologies with band aid improvements. No doubt the cheapest mass produced solution to date -...
ADVANTAGES: Efficiency: They burn less fuel to generate a given amount of horsepower. They are 20 - 30% more efficient than a gas engine. Engine Durability: Because a diesel engine must be built...
They are noisy and they require a lot of fuel (Water and something to burn).
This means they must constantly be monitored so they don't blow up, due to loack of water.