Resumo:
Combined cycle power plants are increasing their role in the electricity generation
worldwide. These plants stand out for their higher efficiency, lower electricity production costs
and relatively low greenhouse gas emissions. In Brazil, a country with mostly renewable energy
generation, these plants have been increasing their participation in electricity production. It is
noteworthy that combined cycle power plants can show off as an alternative to diversify the
Brazilian energy matrix and increase the reliability of the system, preventing supply crisis just
like happened in the past. In this context, this works performs an energetic, exergetic and
exergoeconomic analysis of a combined cycle power plant, using a full-scope simulator, which
digitally and faithfully reproduces the operation of the EDF Norte Fluminense Power Plant,
located in Macaé-RJ. Briefly, the simulator presents an exact duplicate of the real power plant
and its operation is identical to the operation of the EDF Norte Fluminense Power Plant.
The results show that the energy efficiency of the studied plant is equal to 51.47% and
the exergetic efficiency is equal to 49.25%. In addition, it was found that the equipment parts
that are responsible for the main irreversibilities are: combustion chamber, gas turbines and
heat recovery steam generators. From the exergoeconomic analysis, it was found that the cost
of electricity production, for the base case, was calculated to be 0.3891 R$/MWh, which is 10%
lower than the CVU calculated by ANEEL for the studied power plant. Finally, it was found
that a longer plant’s annual operation time imply in the reduction of the cost of electricity
production, which may motivate the use of combined cycle power plants as base load power
plants, reducing the hydroelectric power plants dependence and providing to the final consumer
lower tariffs than those observed in conventional thermal power plant operation.
