Wanna math? OK, I have some. According to
this calculator when 36HP is heated up it produces ~290K Mj per bucket of biofuel.
It says that the calculations are incorrect, so I did it by myself, using
this data:
Let's calculate fuel usage for 36HP at 1000 Celsius:
Base Fuel Usage Per Tick (base) = ( (6.4 - numTanks * 0.08) / ( 16 LP or 8 HP ) ) * numTanks
Fuel/tick = (6.4 - 36*0.08)/8 * 36 = 15.84
One bucket of biofuel gives 32000 fuel units. So, it will last for 32000/15.84 ~ 2020 ticks
We know that it produces 144 MJ/tick (18 Industrial Steam engines), so, one bucket of fuel equals 144*2020 = 290880 MJ.
So, yeah. ~290K MJ/bucket.
According to
this page, combustion engines produce 200K Mj per bucket of biofuel. You know what does it mean? That's the thing that called efficiency. It's not that kind of efficiency like HP boiler vs. LP boiler. That difference becomes less noticeable as the time goes by. This is different. To have the same MJ output you have to produce more fuel if you are using combustion engines.
And don't tell me about heatup stage. If I'm setting up a boiler, I want it to run forever. If extra fuel is the price I have to pay for long-term efficiency I'm on it. Even in SSP.