Stand-alone Power Plant Research Articles

Hydrogen-photovoltaic stand-alone power stations: A sizing method

Abstract Photovoltaic conversion appears as a very promising technology in order to achieve the technical and economic goals for penetration into the electric energy market. Nevertheless, a serious limit to the very large diffusion of PV systems is due to the intermittence of solar radiation. Hydrogen produced via water electrolysis can be considered as an useful means to store solar energy and overcome this limit. With reference to a stand-alone power plant configuration, a PV system, integrated with electrolytic hydrogen production and a fuel cell reconversion line, is examined in order to check the technical suitability of supplying electricity to a load with time continuity. A mathematical method, which utilizes as input data the monthly average values of solar energy density on a horizontal surface is presented, which permits us to size the PV array as a function of the annual load diagram for a given solar site. The results demonstrate that PV-H 2 systems are suitable for realizing a modular stand-alone solar power station able to supply continuously generic loads.

Prospects of early commercialization of MHD power plants

The International Conference on MHD Electrical Power Generation, which is held once every 3 yr, and yearly Symposia on Engineering Aspects of Magnetohydrodynamics (SEAM) provide a useful forum for presentation and discussion on the MHD activities in various countries. The summary of the MHD activities in various countries up to the 8th International Conference on MHD Electrical Power Generation, held at Moscow during September 1983, has already been presented by the author [Energy Convers. Mgmt 25, 225 (1985)]. The 9th International Conference on MHD Electrical Power Generation was held at Tokyo, Japan during November 1986, and the 25th SEAM was held at Bethesda, U.S.A. during June 1987. In this period from 1983 to 1987, considerable progress has taken place towards the early commercialization of MHD power plants. The aim of this paper is to critically review the recent developments in various countries and to assess the future direction for achieving early commercialization of MHD power plants. The direction of the Indian MHD programme is also discussed. The U.S.S.R. is going ahead with establishing the first 500 MWe MHD commercial power plant by 1990. However, outside of the U.S.S.R., the preference appears to be for a suitable size MHD retrofit plant as an intermediate step towards large scale (200–500 MWe) MHD stand-alone power plants. Results of all tests conducted in the U.S.A. so far, have not identified any technical barrier that would prohibit the development of MHD. The major constraint to-day, however, appears to be of a proper level of funding for the development of large scale MHD power plants. It is hoped that the successful commissioning of the U.S.S.R.'s 500 MWe plant would change this funding situation.

Influence of current rate onto a lead-acid cell performance in photovoltaic applications

Stratification created during charge-discharge cycling in stationary lead-acid batteries supposes serious drawbacks to the system, affecting the performance, reducing the cycle efficiency and shortening lifetime. This phenomenon appears in both charge and discharge half-cycle, but it is much more important in the former. Several methods have been traditionally used to overcome this problem, especially in stand-alone installations and photovoltaic power plants. In this work the concentration gradient dependence on current rate has been studied as well as its influence on general lead-acid cell performance.