Ennio Peres da Silva

Electricity generation:: regulatory mechanisms to incentive renewable alternative energy sources in Brazil

The dissemination of renewable alternative energy sources for electricity generation has always being done through regulatory mechanisms, created and managed by the government of each country. Since these sources are more costly to generate, they have received incentives in response to worldwide environmental concerns, above all with regard to the reduction of CO2 emissions. In Brazil, the electricity generation from renewable alternative sources is experiencing a new phase of growth. Until a short time ago, environmental appeal was the strongest incentive to these sources in Brazil but it was insufficient to attain its objective. With the electricity crisis and the rationing imposed in 2001, another important factor gained awareness: the need to diversify energy sources. Within this context, this work has the objective of analyzing the regulatory mechanisms recently developed to stimulate electricity generation from renewable alternative energy sources in Brazil by following the experience of other countries such as the United States, United Kingdom, Germany.

Hydrogen from biomass gas steam reforming for low temperature fuel cell: energy and exergy analysis

This work presents a method to analyze hydrogen production by biomass gasification, as well as electric power generation in small scale fuel cells. The proposed methodology is the thermodynamic modeling of a reaction system for the conversion of methane and carbon monoxide (steam reforming), as well as the energy balance of gaseous flow purification in PSA (Pressure Swing Adsorption) is used with eight types of gasification gases in this study. The electric power is generated by electrochemical hydrogen conversion in fuel cell type PEMFC (Proton Exchange Membrane Fuel Cell). Energy and exergy analyses are applied to evaluate the performance of the system model. The simulation demonstrates that hydrogen production varies with the operation temperature of the reforming reactor and with the composition of the gas mixture. The maximum H2 mole fraction (0.6-0.64 mol.mol-1) and exergetic efficiency of 91- 92.5% for the reforming reactor are achieved when gas mixtures of higher quality such as: GGAS2, GGAS4 and GGAS5 are used. The use of those gas mixtures for electric power generation results in lower irreversibility and higher exergetic efficiency of 30-30.5%.

A cost-neutral energy strategy incorporating renewables and energy-efficiency for the city of Manaus in Brazilian Amazonia

Abstract We report an assessment of maximum feasible cost-neutral reduction in the environmental impacts of energy demand growth in the city of Manaus, Brazil. Manaus is a rapidly growing city located in the heart of the Amazonian rainforest (1500 km of rainforest in all directions!). Owing to its geographical isolation, it is attractive to explore the extent to which modern renewable and energy efficiency technologies can move it towards energy sustainability – or at least significantly reduce or delay the next expansion of its conventional energy supply project – without increasing the net present value (NPV) of the energy scenario from the societal perspective. Our results, based on collection and analysis of new and existing data, show that on a technical fix basis (ie, without political support for broader policy changes for reducing conventional energy use), about a quarter of conventional energy consumption for the year 2002 can be cost-neutrally replaced with efficiency and renewables.