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[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] Hawaii plans that geothermal will be a significant part of its energy mix to reduce its 90% dependency on imported oil for its electricity. The resource on the Big Island of Hawaii appears promising. However, the geothermal program in Hawaii continues to face stiff opposition from a few people who are determined to stop development at any cost. The efforts of geothermal developers, together with the State and County regulatory framework have inadvertently created situations that have impeded progress. However, after a 20-year effort the first increment of commercial geothermal energy is expected on line in 1992
[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] In this study, four potential methods are identified for geothermal-based hydrogen production, namely: i) direct production of hydrogen from the geothermal steam, ii) through conventional water electrolysis using the electricity generated through geothermal power plant, iii) by using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, iv) by using the heat available from geothermal resource in thermochemical processes. Here we focus on low-temperature thermochemical and hybrid cycles, due to their greater application possibility, and examine them as a potential option for hydrogen production using geothermal heat. We also assess their thermodynamic performance through energy and exergy efficiencies. The results show that these cycles have good potential and attractive overall system efficiencies over 50%. The copper-chlorine cycle is identified as a highly promising cycle for geothermal-hydrogen production. Furthermore, three types of industrial electrolysis methods, which are generally considered for hydrogen production currently, are also discussed and compared with the mentioned cycles. It may be concluded that the current technological status of all pathways of hydrogen production from geothermal requires further research and development on how to implement these first and how to make them more cost effective and efficient. (author)
[en] Geothermal energy has great potential as a renewable energy with low environmental impact, the use of heat pumps is becoming established in Italy but the national contributions are still modest when compared to other nations. Mature technologies could double the installed geothermal power in Italy at 2020.
[it]La geotermia presenta grosse potenzialita come energia rinnovabile a basso impatto ambientale, l'utilizzo di pompe di calore si sta affermando anche in italia ma i contributi nazionali sono ancora modesti se paragonati ad altre nazioni. Tecnologie gia' mature potrebbero raddoppiare la potenza geotermoelettrica installata in iatlia entro il 2020.
[en] The nontraditional power sources, including the problems on application the underground heat are discussed. The capacity of the first line of the geothermal power plant near Petropavlovsk-Kamchatskij constitutes 50 MW. The geothermal power plant operates the same way as the thermal one, only without a boiler, wherein the fuel is burnt. The geothermal resources of Russia are considered
[ru]Обсуждаются нетрадиционные источники энергии, в том числе и проблемы использования подземного тепла. Мощность первой очереди геотермальной станции около Петропавловска-Камчатского - 50 МВт. Геотермальная станция работает по той же схеме, что и тепловая, только без котла, где сжигают топливо. Рассматриваются геотермальные ресурсы России
[en] The article summarizes data and materials from the IGA News and from information supplied by the New Energy and Industrial Technology Development Organization (NEDO). (orig./HW)
[de]Der Beitrag fasst Daten und Materialien aus den IGA-News und verschiedenen Informationen der NEDO zusammen. (orig./HW)
[en] The results of analysis of the thermodynamical cycle of the geothermal NPPs secondary circuit with various versions of the geothermal circulation system are presented. It is shown, that the technological scheme with horizontal well is the optimal one. The conclusion is made that by further assimilation of thermal power with application of the experience, accumulated by petroleum specialist, it is necessary to built up geothermal circulation systems with horizontal wells. This will sharply increase the indices of the geothermal branch, its efficiency and competivity as compared to the traditional power engineering
[ru]Приведены результаты анализа термодинамического цикла вторичного контура геотермальных электростанций с различными вариантами устройства геотермальной циркуляционной системы (ГЦС). Показано, что оптимальной является техническая схема с горизонтальными скважинами. При дальнейшем освоении геотермальной энергии, используя опыт накопленный нефтянниками, необходимо строить ГЦС с горизонтальными скважинами. Это резко повышает технико-экономические показатели геотермальной отрасли, ее рентабельность и конкурентоспособность по сравнению с традиционной энергетикой