[en] This paper discusses the present state and the future potential of solar thermal and photovoltaic (PV) technologies, and examines both the environmental implications of these technologies and the economics which determine their viability in the energy market. Although some significant cost reductions have been achieved, particularly in PV technology, solar conversion technologies are still not generally competitive against conventional fuels, and future cost reductions may be limited. It is argued that fiscal measures will be necessary if solar conversion technologies are to make a significant global impact. (Author)

[en] To resolve the energy crisis efforts have been made in exploring and utilizing nonconventional energy resources since last few decades. Geothermal energy is one such energy resource. Fossil fuels are the earth's energy capital like money deposited in bank years ago. The energy to build this energy came mainly from the sun. Steam geysers and hot water springs are other manifestations of geothermal energy. Most of the 17 countries that today harness geothermal energy have simply tapped such resources where they occur. (author). 8 refs., 4 tabs., 1 fig

[en] Geothermal energy comes from the fusion of earth internal layers and the radioisotope decay. The geothermal zones are bound to tectonic plates and are to be found in volcano recent activity regions or where the earth's crust has become thinner. Geothermal heat sources have been widely used. It's not a renewable energy but a useful one. However geothermics use for electricity production has been only very limited. Present technologies are: direct use, electricity production. The seventies energy crisis promoted geothermal energy use which allows savings. Geothermal energy worldwide resources are extensive but the existing technologies must be improved. When geothermal energy is correctly used, it is renewable and generates no pollution, it is a clean energy because the recent reinjection technologies and the up-to-date geothermal systems exclude the toxic gas leaks towards atmosphere. Geothermal energy represents an important contribution in the developing countries which possess such resources

[en] Geothermal energy is a varied discipline that challenges many separate scientific domains. Geological constraints limit access to thermal reservoirs, strength of materials limits the ability to drill into hot strata, mechanical constraints limit the extraction of energy from fluid at a small temperature difference and environmental concerns restrict the fluids production because of the gases released. These problems are all being investigated, and progress is constant and hopeful. The uses of geothermal energy are varied. They range from direct use in space heating to using geothermal steam to power turbines. Ground source heat pumps are a popular alternative to conventional air conditioning systems, and water source heat pumps are another proven alternative. Many other applications are on the horizon, including absorption chillers able to operate at a small temperature difference, higher tonnage ground source equipment and new approaches to hot dry rock power production

[en] Province Balochistan is largest province of Pakistan with smallest density of population with little or no development. In Balochistan bulk is rural located and devoid of lives basic ingredients. In remote rural areas of Balochistan because of high cost and problems associated with grid extension or diesel power generation, solar electricity is viable alternate. Energy generated from the sun is world's most abundant and in-exhaustible source of energy PV cells sun light is converted directly in to electricity called solar PV energy. Solar energy through photovoltaic cells can be tapped to supply electricity to remote rural areas of Balochistan. In this paper author has examined the problems in more detail, showing by simple calculation of cost economics that solar PV systems are viable. (author)

[en] Geothermal conversion, as discussed here, is the conversion of the heat bound within the topmost three kilometres of the upper crust of the earth into useful energy, principally electricity. The characteristics of a geothermal reservoir and its individual technical features are highly site-specific. Applications therefore must be designed to match the specific geothermal reservoir. An estimate of the electric energy potential world-wide made by the Electric Power Research Institute (United States) in 1978 and based on sustaining a continuous 30-year operation is given in the box at the right for comparison purposes only. 8 refs, 5 figs

[en] More than 2000 million people, mostly in developing countries, live in rural areas without access to grid connected power. Conventional approaches to supplying power, whether through extension of existing grids or through stand-alone 'mini-grids' based on diesel generator sets, or even on renewable energy minigrids, require large investments which are unlikely to receive priority in competition with more economically and politically attractive investments in urban areas. Domestic PV lighting and broadcast reception kits (DLKs), comprising, typically, a 30-60 W panel, an automotive battery, a charge indicator, and dc fluorescent lamps can be furnished and installed for about $500. DLKs are now used in the Dominican Republic, Kenya, Sri Lanka and many other countries. DLKs provide a minimum essential service with low overheads. Given the necessary credit facilities, they can give better service at comparable costs in comparison with kerosene lamps and dry cell powered radios. They also permit a substantial degree of local manufacture, thus saving on foreign exchange. This movement is starting in many countries on a purely commercial basis. The process could be greatly accelerated if 'seed money' in the form of revolving funds could be made available. (author). 1 fig., 11 tabs

[en] Nucleon self-energies from the pion-ring series are studied in the relativistic mean-field theory of linear σ model with the ω meson and the Δ. Near the Fermi surface of nuclear matter, the pion rings generate attractive scalar and vector potentials of 10--15 % of the nucleon mass. These strongly energy-dependent potentials cause the nucleons to have a significant probability to be in a collective N-hole or Δ-hole configuration

[en] Short communication

[en] Seasonal storage for solar energy have been the object of intensive theoretical studies and practical experiments. Within the frame of the research programme of the International Energy Agency 11 objects were set up and tested in practice. It was the aim of this research and demonstration projects to examine thermal long term storage for the use of solar energy and waste heat from industrial processes. In the following the actual state of the art of long term storage of solar energy for district heating in buildings will be described and possibilities of its use in Austria will be assessed. (author)