New plants are using high pressure boilers (up to 92 bar) and their electricity surplus has grown considerably, in a very competitive setting. However, about 90 per cent of the mills still use 22-bar boilers and other sugar plant equipment produces less surplus power. Actually, such internal combustion motors, which can work on an Otto-cycle, may be of a smaller size than those of conventional trucks using diesel oil. Since the truck wheels are driven by very high torque electric motors, the smaller internal combustion motors have lower torque requirements than the present diesel motors. Hybrids are particularly appropriate for short-haul and stop-and-go transportation and, as battery technologies improve, hybrid trucks will also be able to work as plug-ins, using off-peak power generated at the sugar mill.