What Fraction of the Fuel Consumed by a Heat-and-Power Cogeneration Facility Should Be Allocated to the Heat Produced? Old Problem, Novel Approach

The question of what fraction of the fuel consumed by a cogeneration plant is to be allocated to either the heat or the electricity is still open, leading to some arbitrariness in the quantification of the economic value of the different cogenerated goods and of the subsidies often granted to such facilities. In this work, we first evidence the drawbacks of the conventional allocation methods such as Incremental Electricity-Centered Reference (IECR), Incremental Heat-Centered Reference (IHCR) and Separate-Productions Reference (SPR), in that they use fixed partial primary energy factors chosen by some authority to represent the reference efficiencies of heat and /or electricity production technologies that can be different from the local energy portfolio. Here we propose a slightly more elaborate, but self-consistent method whereby the allocation is adaptive and self-tuned to the local energy scenario by sharing the fuel savings on the basis of the average primary energy factors for electricity and heat in the given local area including the cogeneration facility of interest. We call it the Self-Tuned Average-Local-Productions Reference (STALPR) method. We finally show by means of a representative case study that the classical methods might provides unfair, distorted figures that become increasingly important as cogeneration gains higher fractions of the energy market in a given local area.