In the paper the authors analyse how the application of an extended environomic procedure, based on charges linked to the pollutant activities of energy systems, influences the energy behaviour of energy systems.
If in the economic balance of an energy plant a cost is assigned only to the pollutant emissions (Environmental Cost), it can be shown that this choice allows a good promotion of the abatement devices and of the switching fuel approach, but the efficient utilization of energy resources is not sufficiently promoted.
The extended approach, here analysed, takes into account both the pollutant emissions and the inefficient use of energy resources. In the proposed method, on the basis of thermodynamic considerations, a cost is assigned to the exergy rate destroyed inside the system and to the exergy flows rejected into the biosphere with the plant wastes (Efficiency Penalty).
Many calculations have been developed using different sets of both the Environmental Cost and the Efficiency Penalty; assigning different weights to them. The calculations have been applied to a 30 MWel gas turbine cogeneration power plant (CGAM), and to an existing 350 MW combined cycle, considering the pollutant emissions of CO, NOx, SOx and CO2. The obtained results show that this approach can become a real energy policy instrument: in fact it allows to stimulate high efficiency design of conventional plants and advanced high-efficiency low-pollutant energy systems, becoming an opportunity to disseminate advanced technologies that still have difficulties to compete in the energy market due to their high investment costs.