International Journal of Power and Energy Research

10

Authors: Nurul ‘Ain Hashim, Norzanah Rosmin, Aede Hatib Musta’amal, Ir Baharruddin Ishak, J. P. Barton

This paper presents the syngas performance of oil palm fronds (OPF) using a downdraft gasification method. So far, no biogas-OPF based power plant project has been developed in Malaysia even though the production of OPF is enormous. Initially, the empirical formula of OPF is determined before the gasification system can be modeled. The model of the gasification system in a downdraft gasifier is based on four zones; the drying zone, the pyrolysis zone, the oxidation zone and the reduction zone. The main advantage of the proposed method in this work is that the chemical reactions that occur in each zone are balanced using “kilogram” terms, thus eliminating the typical “mass” equations. Using “kilogram” terms overcomes the ambiguous process of chemical reaction during mole separation in each sub-model. In this study, the composition, calorific value (CV) and energy of syngas produced from OPF downdraft gasification are analyzed using Matlab/Simulink software. The model also takes into consideration the OPF moisture content as well as air fuel ratio. It is found that the CV of syngas reduced from 8.5 MJ/m3 to 6.387 MJ/m3 and the energy reduced from 2.224 kWh/m3 to 1.774 kWh/m3 as the moisture content increased from 5% to 20%. The CV also reduced from 8.132 MJ/m3 to 4.137 MJ/m3 and the energy reduced from 2.259 kWh/m3 to 1.149 kWh/m3 when air fuel ratio increased from 0.26 to 0.6.

12

Authors: Jacques Percebois

In Europe, the ability for nuclear power to compete in the energy market is undermined by two interconnected issues: a scheme of guaranteed purchase prices for renewable energy sources (wind and solar) and very low spot market prices. A feed-in tariffs system increases costs to end-users and moreover prompts decreases in the electricity price on the wholesale market. Low spot electricity prices jeopardize conventional power investments, particularly in nuclear energy. Consequently, to redress the balance between nuclear and renewable energy, it is necessary to cut subsidies for renewables and/or to help the nuclear sector through an arrangement, such as “Contract for Differences”, employed in the United Kingdom. Such a mechanism may guarantee profitability of nuclear investments in the future. This paper presents, in the introduction [1], the specificity of the French electricity sector; it analyses in a second step some “perverse effects” due to the “feed-in tariffs” mechanism implemented in the European Union, particularly in France because of the system of regulated prices for the end-user [2] and presents then some suggested solutions for restoring the competitiveness of nuclear energy, which is an important goal for France [3].

14

Authors: Mohamed M. Saied

This paper deals with the frequency characteristics of partially undergrounded mixed power networks, which include several cable sections replacing parts of the overhead lines. The analysis yields the voltage and current distributions along the normal and the partially undergrounded lines, as well as the frequency dependence of the networks’ input impedance. Moreover, the results will show eventually existing localized voltage and current concentrations. The study suggests an exact direct analytical distributed parameter method for modeling the lines and cable sections. Instead of representing a partially undergrounded line by the cascade connection of two-port networks, this paper proposes the use of a single equivalent nonuniform line. The non-uniform circuit parameters are represented by means of step functions in terms of the co-ordinates along the lines. The resulting expressions are substituted in the simultaneous voltage and current differential equations, for which analytical solutions are available in terms of Mathematica Parametric Functions.