The option allows to recover heat into electric power. For example, 1 MW heat from cooling of the engine is converted to extra 80 kW of electric power. The system uses Organic Rankine Cycle (ORC). The working fluid with low evaporation temperature is heated and evaporated, and then passed through a turbine where it is finally re-condensed.

ORC increases plant electric output up to 8%. The cost of the ORC system is 15-20% extra to the cost of the biogas plant.