Aproveitamento da casca de arroz em uma micro central termoelétrica avaliação dos impactos econômicos e ambientais para o setor arrozeiro do Rio Grande do Sul

Abstract

The rice husk production in Rio Grande do Sul, state responsible for more than half of this cereal s country production, leads to the need of an appropriate environmental management in view the impacts produced by this residue in the environment, whether they be local or global, like greenhouse effect impacts. Therefore, a rational utilization of this energetic resource in small thermal power plants may guarantee the environmental adequation of the company, filling the requirements needed to sustainable production, at the same time in which may provide financial attractiveness to necessary investments to this objective. The development of the technology known as MCT allowed existent small thermoelectrical potentials, originated from the decentralized husk production, to be attended in a satisfactory way, but needing an environmental and economical analysis. For that reason, this study had as objective the gathering of rice production and beneficiation data on the State which can provide the evaluation of the rice husk availableness and furthermore to grant a thermal electrical potential analysis current on Rio Grande do Sul. Intending to award the units which do not have this economic and environmental analysis, it has been continued the financial analysis of the MCT s investments, to power plants bellow 800 kW, including the economic impacts of the carbon credits (CC) trade. Through indicators as IRR, payback, NPV and generation cost, associated to the impacts of the environmental quality caused by the CC trade, it has been possible to prove that, for scales smaller than 400 kW, there is no economic feasibility, unless they receive tributary incentives, whether for a short period, as a diminish of the finance interest rate and/or the raise of the exceeding tradable energy selling price, as shown on the sensitivity analysis made. It has been also evaluated the operation and obtained results of the MCT installed on the city of São Pedro do Sul, which demonstrate the difficulties found in the small scale thermoelectrical biomass generation. These difficulties can be modified if they would be set as priority, by programs of incentive, the use of biomass on decentralized electric energy generation.