07 Alternative energy sources (wind energy)

requirements is to design and select PV panels so that their voltage- sensitive region (on the I-V curve) coincides with that required for a simple remote PV plant and for long periods.

00/01998 Solar thermochemical conversion of biomass Lede, J. Sol. E\tcjrX~,. 1998. 65. (I j. 3- 13. The standard route of biomass thermochemical conversion is reviewed. A discussion is also included on the possibility of using concentrated solar energy to provide the necessary heat for the processes. Gasification. fast and slow pyrolysis are described in more detail. They can be carried out for the preparation of a vast range of possible products that can be used as energy carriers and/or as a source of chemical commodities. The gasification processes are intended for the preparation of gas mixtures (CO, Hz) for chemical synthesis, heat, or electricity generation. The fast pyrolysis formerly carried out for gas production (CO, Hz, light hydrocarbons) is now mainly investigated with the aim of producing liquids (bio-oils). Slow pyrolysis is in use for a long time for the preparation of solids (charcoal). The nature and quality of the products depend mainly on the experimental conditions of the process (temperature, heating rates, residence times). The possibility of a solar entry in the gasification and pyrolysis processes is then analysed. The technical and scientific benefits, as well as the difficulties, are underlined, showing the necessity to design new forms of specific reactors. From a fundamental point of view the advantages of using concentrated radiation as a laoratory tool for studying the very fast primary steps of biomass thermal decomposition is also outlined.

00101999 Stability and photodegradation mechanisms of conjugated polymer/fullerene plastic solar cells Neugebauer, H. Sol. E~tergr Mur. & Sol. Ce//.r. 2000, 61. (I ). 35-42. Degradation studies of poly(2-methoxy-5-(3’.7’-dimethyloctylo~)-l.4-phe- nylene-vinylene) (MDMO-PPV), fullerenes ((6,6)-phenyl Chl - butyric acid methyl ester (PCBM) and C,,,). and mixtures, which are the photoactive components in plastic solar cells. are shown, The degradation processes of the individual components and of a I:3 mixture are characterized by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and by current/voltage (I 1’) measurements of devices under the influence of light and oxygen. A faster degradation rate was found for the polymer compared with Chl). In composites with fullerenes. the stability of MDMO-PPV is enhanced due to the fast electron transfer to ChO.

00/02000 STM investigation of the growth structure of Cu- phthalocyanine films with submolecular resolution Hiesgen, R. Sol. Encrgj, Mat. & Sol. Ce//.r. 2000, 61. (1). 73. X5 In this study Cu-phthalocyanine (CuPc) films have been investigated by scanning tunnelling microscopy to get a quantitative insight into the morphology of the films from the micrometer range down to nanometer resolution to see the arrangement of the molecules. The molecules on the surface have been found to be arranged in a slipped stacking order rather than in the expected zig-zag orientation normally found for CuPc crystals. The crystal structure could be identified to be an rr-polymorph. The STM image of the individual molecules on the surface is in good agreement with calculations of the charge density of the LUMO for an isolated molecule. A model for the growth of the crystals was derived from this study.

00102001 Synthesis of CulnS, films by sulphurization of Culln stacked elemental layers Bandyopadhyaya, S. Sol. E1trrg.i Mar. & Sol. C&1.\. 2000. 60. (4). 3233339. CuInSz films were synthesized by sulfurizaion of IniCu stacked elemental layers (SEL) deposited onto glass and MO-coated glass substrates by graphite box annealing at temperatures of 620-880 K. The films thus synthesized were characterized by measuring electrical, optical, microstruc- tural and photoluminescence properties. The microstructure and hence the physical properties of the films depended critically on the amount of sulfur incorporation. Nature of charge carriers depended on both Cuiln and SlCu + In) ratio and the carrier concentration varied between 10’J and IO” cm-s. Grain boundary scattering effects were critically studied by measuring the electrical conductivity and Hall mobility simultaneously on the same sample. The shape of the grains depended critically on the sulfur content. The PL spectra were dominated by the excitonic peak -788 nm followed by another peak at -892 nm which may be ascribed to the DA transition.

00102002 Texturized interface as a basis of surface-barrier heterostructure for solar cells application Dmitruk, N. L. Sol. Otcr,c~ Mot. & SIJ/. Cc//. 2000. 60. (4). 3799390. Simulation of the photocurrent of surface-barrier structures (SBS) with texturized interface has been performed on the basis of obtained theoretical expression for internal quantum efficiency of homogeneous SBS and the model of parallelly connected diodes. The role of various sources of recombination losses (in the semiconductor, at the interface and due to the emission of majority carriers into the metal) in solar energy convertors has been analysed. The complex method of characterization of SBS with texturized interface is proposed that includes an analysis of optical, electric and photoelectric characteristics. The possibility to increase the photosen- sitivity of the Au/GaAs SBS due to texturization and sulfur passivation of the interface for two types of microrelief (dendritic and quasigrating) obtained by wet anisotropic etching has been investigated. The morphology and statistical geometric characteristics of the interface were investigated by

atomic force microscopy (AFM). The ohtained results allowed to determine the change of optical and electronic (recombination) parameters of the interface caused by the used processing (texturization. passivation).

00102003 The effect of fullerene doping on photoelectric conversion using titanyl phthalocyanine and a perylene pigment Tsuzuki. T. .%I/. Oicr,trr MU/. & Sol. Cc,//\. 2000. 61. t I ). 1 X. The effect of fullerene (C,,,,) doping on photoelectric conversion using titanyl phthalocyanine (TiOPc) and a perylene pigment. N. ,2’-dimethyl-3.4: 9,IO-perylenebis(dicarboximide)(MPCl), wa\ investigated A new three- layer cell, ITO:MPClC,,,-doped TiOPc TiOPc’Au. exhibited a higher quantum yield for charge-carrier photogeneration than a two-layer cell without the C,,,,-doped TiOPc layer. IT0 MPCI TiOPc Au. upon ir- radiation with monochromatic light which TiOPc mainly absorbs The three-layer cell showed a high conversion efficiency of 0.63’!% for incident white light at an intensity of approximately 100 mW cm ‘.

00/02004 The feasibility of solar energy use in rural areas of Mongolia: solar ‘Ger’ Gonchigbat. I. Ort,irrm Or,q. R~WII U/?/C, ~Gw~,YI /‘I 1~1 /nr C’mrt I if. I YVX. 145-150. Edited by Gavasci R.. Zandary;ia S The Mongolian energy system is strongly drpcndcnt on indigenous coal and imported oil and requires the application of emerging energy efficient technologies. Rural centres often supply their inhabitants with the electricity by diesel, as they are still not connected to the centralized electricity system. However, the use of renewable energies is just being initiated, with the designing solar panels and wind generators for nomads. At present, in rural areas some nomadic families depend on a simple petrol generator or a small wind generator. In order to avoid degredation of the environment and improvement of life standards in rural areas. it is essential to supply the rural population with an adequate supply of electricity. Also discussed in this paper is the possibility of nomadic families employing photovoltaic technologies and solar panels in their home\

00/02005 Trapping solar heat Perlin. J. SO/U~ 70&r. 2000. 14. (I )_ I6 17 The increased use of glass during the eighteenth century made many people aware of its ability to trap solar heat. During this century. a glass solar heat trap called the hot box was designed and constructed and has become the prototype for the solar collectors of the late nineteenth and twentieth centuries - collectors that supply hot water and heat to homes and power for machines,

Wind energy

00/02008 Capacity development and profitability of wind turbines Morthorst. P. E. Erirr,ej, Po/i~~,~. lYV9, 27. ( 13). ‘779 787. The main objectives of the paper are to analyse and describe the driving forces behind the wind power capacity development. with Denmark as the specific case. Is it possible to estahlish a relation between turbine economy and the capacity expansion that could he used for regulatory purposes in reaching a specific policy-determined targrt for the deployment of wind power? Such relations are analysed with reference to three types of turbine ownership: Co-operatives. individuals such as tarmers, and utility compa- nies. The paper concludes that concerning individually owned turbines. a strong relationship between wind turhine prolitability and the annual capacity development does exist. With regard to investments in co- operatively owned turbines. only a weak relationship was found. Other determining factors, such as those related to the environment. might he more important as inputs to the decision-making process when turbine co- operatives are established. The turhines established by the utilities are not treated in detail here, because this capacity development is determined mainly by the power companies’ agreements with the Government. Finally, the paper concludes that the estimated relationship hetween profitability and capacity increase for individually owned turbines possibly might he used for regulatory purposes in reaching a <pecific target for capacity development. if it is done in an appropriatr: way.

00/02007 Indian wind energy programme: performance and future directions Rajsekhar. B. Orer,c~, Polic~r. 19YY. 27. ( I I). 66Y 67X This paper studies the characteristics of the Indian wind energy programmc while setting out the developments that have taken place so far. An outstanding start has been made in commercializing wind energy in India. India is the only developing country that has gained a high position in the world in terms of installed wind-power capacity. However, recently the market dynamics have changed. As a result, the pace of new additions is stalling. Major undercurrents to that effect in terms of policy, institutional and technical factors are analysed. New policy initiatives are suggested and they address the involved technical and commercial concerns of both the state-run utility and wind-power plant entrepreneurs to spur sustained development in the next millennium.

Fuel and Energy Abstracts July 2000 223