> external combustion tends to be very fuel inefficient compared to internal combustion. This is true in general
No, that's not true at all. Big power plants stayed with steam for efficiency reasons, and they are pretty close to theoretical limits.
Cars and aeroplanes, and later ships and trains, went to internal combustion because size and weight are very real concerns for them, and this trade-off against pure efficiency (heat-to-torque) was worth making. In the name of overall efficiency, if you like -- smaller engines meant more cargo room, so in oil-to-cargo terms you could come out ahead.
More electrical now is gas-turbine, but again this is about trading efficiency for other things -- peak-hour electricity is worth much more than 3am electricity, etc.
No, that's not true at all. Big power plants stayed with steam for efficiency reasons, and they are pretty close to theoretical limits.
Cars and aeroplanes, and later ships and trains, went to internal combustion because size and weight are very real concerns for them, and this trade-off against pure efficiency (heat-to-torque) was worth making. In the name of overall efficiency, if you like -- smaller engines meant more cargo room, so in oil-to-cargo terms you could come out ahead.
More electrical now is gas-turbine, but again this is about trading efficiency for other things -- peak-hour electricity is worth much more than 3am electricity, etc.