Present status of underground thermal utilization in Japan

Utilization of low-enthalpy geothermal energy in Japan, especially with the application of geothermal heat pumps, is far behind other industrial countries. In 1998, a feasibility study was made of utilizing Japan's low-enthalpy geothermal resources. Since 2001 the Geo-Heat Promotion Association of Japan (GeoHPJ) began its activities with the objective of installing 140,000 heat pump systems in private houses by the target year of 2010. The Geothermal Research Society of Japan has also launched new activities in this sector. Research groups in universities and other national institutes have started geoscientific research on the utilization of low-enthalpy resources and private, academic and governmental sectors have consequently begun promoting geothermal heat pump utilization.     

Geothermal Power Project 2003–2004: European Union Energy Framework Programme—ALTENER

This paper describes the Geothermal Power research project supported by the ALTENER-Energy Framework Programme of the EU. Four Hungarian, one Austrian, one Portuguese, and an Icelandic partner will implement the project starting from spring of 2003. The main objectives of the project are to develop an integrated feasibility study on the installation of small-scale geothermal power plants in Hungary combined with heating applications and balneological use via a cascading system. The intention is to provide a model for extended application throughout the Accession Countries and the EU-15. The envisaged major target is to identify the most feasible group of boreholes for the implementation of mini-power plants. For this purpose detailed financial viability studies will be made, taking into due consideration physical, technical and environmental parameters. More detailed information is available on the project website: www.geothermalpower.net     

World geothermal power generation in the period 2001–2005

A review has been made of all the country update papers submitted to the World Geothermal Congress 2005 (WGC2005) from countries in which geothermal electricity is currently being generated. The most significant data to emerge from these papers, and from follow-up contacts with representatives of these countries, are: (1) a total of 24 countries now generate electricity from geothermal resources; (2) the total installed capacity worldwide is approximately 8930 MW_e, corresponding to about 8030 MW_e running capacity and electric energy production is nearly 57,000 GWh (early 2005 data); (3) Costa Rica, France (Guadeloupe), Iceland, Indonesia, Italy¹, Kenya, Mexico, Nicaragua, Russia, and the USA have increased the capacity of their power plant installations by more than 10% with respect to the year 2000; (4) the new members of the geothermal electricity generating community comprise Austria, Germany and Papua New Guinea; (5) the installed capacity in Argentina and Greece is now null since their geothermal power plants have been dismantled; (6) nineteen countries have carried out significant geothermal drilling operations since 2000, with 307 new wells drilled.     

Geothermal resource development in agriculture in Kebili region, Southern Tunisia

Geothermal energy in the Kebili region, south of Tunisia, is used in a number of applications, but mainly in agriculture. Approximately 95% of the thermal water is used for irrigation of oases and heating greenhouses. Generally, when the water temperature is less than 40–45 °C it is used directly for irrigation, but when it exceeds 45 °C it is cooled by means of atmospheric towers before being used to irrigate 16,000 hectares of oases (half of the total area of the oases in Tunisia). Geothermal energy is also used for heating and irrigating greenhouses, which are considered promising and economically feasible applications. The total area of heated greenhouses in the country has increased considerably and is today at 103 ha, 44% of which are located in the Kebili area. Utilization of the geothermal resources will, without a doubt, increase in the near future once we have implemented the last phase of the greenhouse project. By the end of 2003, 13 ha will be added in the region, representing an increase of 29%.     

Quarter century of hydrogen movement 1974–2000

A quarter of a century has passed since the beginning of the Hydrogen Energy Movement. Over the past 25 years, there have been accomplishments on every front — from the acceptance of the concept as an answer to energy and environment related global problems — to research, development and commercialization. The Hydrogen Energy System has now taken firm roots. Activities towards the implementation are accelerating.     

Renewable energy in India — a modelling study for 2020–2021

The energy requirement in India is steadily increasing and this requirement is being met by both commercial and renewable energy sources. Due to the non-availability of sufficient resources and a considerable amount of emission of pollutants from commercial energy, it is now being felt that renewable energy has to be utilized to a greater extent. An optimization model was developed to determine the optimum allocation of renewable energy in various end-uses in 2020–2021, taking into account commercial energy requirement. In lighting end-use renewable energy to an extent of 1.27×10¹⁵ kJ can be utilized. Scenarios were developed for various parameters and sensitivity analysis was performed on the model. It was found that for a 3% increase in social acceptance of bio resources, there was 65% decrease in solar PV utilization and to that extent bioresources were introduced. Similar analysis was performed on the model by changing the demand, potential, reliability, emission and employment factors. The analysis revealed the critical parameters for the utilization of a renewable energy source. Using the critical parameters, appropriate policies can be formulated for promoting renewable energy sources.     

HIDA databank — its development and future

Task 15 of the European Commission supported HIDA Project (BE1702) has involved the preparation of a post-processed databank to contain information on creep and fatigue crack growth characteristics on the materials studied in the project. It also includes information on plant operator experiences relating to component cracking/failure under steady loading and plant cycling conditions. The HIDA Databank is one of the few databanks initiated in this field of activity.The HIDA Databank has been released on CD as two computer files based on Microsoft^® Access 97 software and has a purpose built Graphical User Interface to allow easy addition of data and examination of existing information. The data included in the HIDA Databank are: (1) plant and research experience information collected from HIDA Task 2 (non-HIDA data); (2) HIDA test data generated from laboratory and feature tests; and (3) test specimen characteristics, product or component properties.The HIDA Databank also contains some post process parameters such as lower and upper bound scatter bands (as derived from the test data).The crack growth data stored in the databank has been used to develop the HIDA procedure for defect assessment and has also assisted in refining existing assessment methodologies. The HIDA Databank also acts as a data source for the Knowledge Based System developed in the HIDA project.This paper outlines the main development of the HIDA Databank and briefly considers how it will be used and developed in the future in order to act as an independent source of information on creep and fatigue crack growth, and component behaviour, in high temperature plant.     

Energy development in the Caribbean — options and necessities

The energy importing countries of the Caribbean have experienced substantial increases in the costs of the crude oil imports on which they largley depend. Their weak posiitons is mainly the result of a merge resource base But, argue Trevor Byer, Joerg-Uwe Richter and Joseph Vardi, Caribbean energy problems have been aggravted by inapproriate policies and institutional constraints. The most immediate way of improving the position is to concentrate on conservation and the substitution of indigenous fuels for imported energy, as far as is economically feasible. Approriate pricing policies and rational planning are essential if any lasting improvement is to be made. External assistance is also needed to develop the energy resource base, including hydrocarbons, and is available from bilateral and multilateral institutions.     

Wind energy development in China — Reality and market forces

Economic reforms in China started in 1978, which led to profound changes as a result of a consistent structural adjustment and stabilisation policy. The national economy is now characterised with high growth and low inflation. In 1997, GDP was US$ 767 billion and foreign exchange reached US$ 140 billion. This paper examines the outstanding contribution of rural industries to rapid growth of national economy and the consequences of increase of energy consumption and its environmental impact. It also emphasises the necessity and benefit of using renewable energy and wind energy in particular. The paper also addresses the issue of joint venture in farm development in line with Chinese market economy.     

Strategic cogeneration — fresh horizons for the development of cogeneration in Brazil

An earlier study (Szklo A, Soares J, Tolmasquim M. Economic potential of natural gas-fired cogeneration in Brazil: two case studies. Applied Energy 2000;67(3):245–67) that assessed the economic feasibility of gas-fired cogeneration systems in Brazil, indicated that the use of cogeneration in Brazilian malls tends to be small in the short-term. However, current experience is opening up the possibility of investments in cogeneration plants — despite their lack of economic feasibility — as part of the strategic actions of utilities in the energy market. The earlier study made no attempt to analyze this possibility, focusing solely on economic feasibility. This article supplements its predecessor by analyzing a type of cogeneration rated as strategic. This is a recent phenomenon prompted by the deregulation of Brazil's energy market. Within this new context, power utilities are taking up a defensive behavior as they battle to preserve their markets, in parallel to aggressive behaviors designed to expand and diversify their activities. This means that they may well invest in cogeneration for strategic reasons that may not be clearly reflected through an economic-feasibility assessment.     

Design of a sun tracker for the automatic measurement of spectral irradiance and construction of an irradiance database in the 330–1100 nm range

An automatic global and direct solar spectral irradiance system has been designed based on two LICOR spectroradiometers equipped with fibre optics and remote cosine sensors. To measure direct irradiance a sun tracker based on step motors has been developed. The whole system is autonomous and works continuously. From the measurements provided by this system a spectral irradiance database in the 330–1100 nm range has been created. This database contains normal direct and global horizontal irradiances as well as diffuse irradiance on a horizontal plane, together with total atmospheric optical thickness and aerosol optical depth.     

Computational battery dynamics (CBD)—electrochemical/thermal coupled modeling and multi-scale modeling

This paper reviews the development of first-principles based mathematical models for batteries developed on a framework parallel to computation fluid dynamics (CFD), herein termed computational battery dynamics (CBD). This general-purpose framework makes use of the similarity in the equations governing different battery systems, and has resulted in the development of robust models in a relatively short time. Here we review this framework, in the context of applications to the coupled modeling of the thermal and electrochemical behavior of cells, and to the modeling at three different scales, namely pore-level, cell-level and stack-level. The similarity and differences of our approach with other research groups are exemplified. Significant results from each of these advanced applications of modeling are highlighted with emphasis on the insights that can be gained from a first-principles model. In addition, we also demonstrate the usefulness of a combined experimental-modeling approach in describing cells. The models reviewed here are expected to be useful in predicting the behavior of advanced batteries used in electric vehicles (EVs) and hybrid electric vehicles (HEVs).     

Temperature dependence of the optical transitions in CdTe thin film – Investigation with photoresponse spectra

The CdTe thin films have been prepared by electrochemical method from a bath solution containing cadmium sulfate and tellurium dioxide. Schottky devices of the type Au/CdTe were prepared and the spectral response of the device has been investigated. The direct and indirect transitions in the 1.3–1.6 eV region were calculated from the normalized spectral response data. The temperature dependence of the band gap have been investigated and correlated with the theory. The band gap of CdTe at absolute zero temperature is estimated as 1.61 eV and that the rate of change of E_g with temperature is calculated as −0.4 meV/K. The 1.407 eV indirect transition involves a trap level near the conduction band edge. The indirect transition also exhibits temperature dependence.     

Geothermal systems in Iceland: Structure and conceptual models—II. Low-temperature areas

A review and assessment of data pertaining to the origin and nature of low-temperature geothermal activity in Iceland are presented. This activity is widely distributed in Quaternary and Tertiary formations on the American plate in western Iceland west of the active belts of volcanism and rifting but it is very sparse on the European plate east of these belts. Low-temperature systems occur in a few places within the active volcanic belts. Temperatures range from just above ambient to a little over 150°C. Generally speaking, resevoir temperatures decrease with increasing distance from the active volcanic belts. The distribution of the low-temperature areas can be correlated to a large extent with active tectonism. In Iceland the European plate is tectonically stable but in the American plate the shear stress field is complicated, leading to complex fracturing and faulting of the crust at present. No single generalized conceptual model describes the basic features of all low-temperature areas in Iceland. Low-temperature geothermal activity is considered to develop by one of the following four processes, or any combination of them: (1) deep flow of groundwater from highland to lowland areas through permeable structures driven by the hydraulic gradient; (2) convection in young fractures formed by tectonic movements in old and relatively impermeable bedrock; (3) drift of high-temperature geothermal systems out of the active volcanic belts in conjunction with their cooling and extinction of the magma heat source; and (4) magma intrusion into Quaternary or Tertiary formations adjacent to the active volcanic belts. Formation of permeable fractures by recent earth movements is probably the most common process responsible for the development of low-temperature activity through convection in these fractures. Convection in low-temperature systems with temperatures above some 60°C is probably mostly driven by pressure differences created by a relatively light hot water column within the system and a denser cold water column outside it. In systems of lower temperature the convection is driven by hydrostatic head in the recharge areas. The source of the low-temperature waters is largely meteoric. However, in some coastal areas a significant seawater-groundwater component is present, up to 10%. Waters not containing a seawater component are low in dissolved solids, or in the range 150–500 ppm. The reason is the low content of anions, particularly Cl, in the basaltic rock forming soluble salts with the major aqueous cations. Geothermal waters from the low-temperature areas in Iceland typically possess lower δD-values (more negative) than the local precipitation. This difference is variable; most often it lies in the range of 10–30% δD, but it may be as large as 70‰. This difference has been considered to indicate that the recharge areas to the low-temperature areas lie inland on higher ground, the distance being as much as 150 km. The interpretation favoured here is that at least some of the low-temperature waters contain a component of “ice-age water”, i.e. water that is older than about 10, 000 years. The “ice-age water” is depleted in deuterium relative to today's precipitation. When “ice-age water” is present in the geothermal water, deuterium cannot be used as a tracer to locate the recharge areas to the geothermal areas and in this way to deduce about regional groundwater flow.     

Contribution of wind power and CHP to exports from Western Denmark during 2000–2004

The experience of Denmark is used by the United Kingdom's anti-wind lobby to demonstrate that intermittency and inaccuracies in wind forecasting make wind power ineffective and expensive. A further assertion is that most of the power is ‘unwanted’ since up to 80% of it is exported. Here, available data for Danish energy production for 2000–2004 is used to assess the link between wind generation and exports and test the validity of these claims.Net exports in Western Denmark showed good correlation with wind production. However, they were more significantly correlated with the production from local combined heat and power (CHP) plants. In order to test the 80% export claim, a simple technique was devised to correlate and rank hourly net exports and generation from wind and local CHP. In the case where net exports were primarily attributed to (or blamed on) wind, 44–84% of annual wind production was deemed to be exported, with wind ‘causing’ 57–79% of net annual exports. For this extreme scenario, the percentage values are in line with those of critics. However, under the opposite extreme scenario in which exports are attributed to local CHP, 77–94% of exports were caused by CHP and only 4–32% of wind production was exported.Overall, this study shows that there is some degree of correlation between net exports and wind power, but that the claim that 80% is exported is unwarranted since it ignores the demonstrably stronger influence of local CHP.     

Thermal energy recovery of air conditioning system––heat recovery system calculation and phase change materials development

Latent heat thermal energy storage systems can be used to recover the rejected heat from air conditioning systems, which can be used to generate low-temperature hot water. It decreases not only the consumption of primary energy for heating domestic hot water but also the calefaction to the surroundings due to the rejection of heat from air conditioning systems. A recovery system using phase change materials (PCMs) to store the rejected (sensible and condensation) heat from air conditioning system has been developed and studied, making up the shortage of other sensible heat storage system. Also, PCMs compliant for heat recovery of air conditioning system should be developed. Technical grade paraffin wax has been discussed in this paper in order to develop a paraffin wax based PCM for the recovery of rejected heat from air conditioning systems. The thermal properties of technical grade paraffin wax and the mixtures of paraffin wax with lauric acid and with liquid paraffin (paraffin oil) are investigated and discussed, including volume expansion during the phase change process, the freezing point and the heat of fusion.     

Solar energy development in China—A review

The steady and maintainable electric power provides the development momentum of a country's industrialization, which is indispensable to every country at present. It is well known that China is the largest developing country in the world. With the rapid development of economy and society, energy demand of Chinese society is increasing in an incredible speed, i.e., the annual accumulative total capacity of electric energy is about 0.1 billion kW, and the most of them is provided by the fossil fuel resource, and the share is about 90% in China. Certainly, it is a very inappropriate energy structure, so the sustainable development of country is impossible in future, the status must be improved in order to achieve sustainable development. Fortunately, China has large country area, and there are abundant solar resources. Development and application of solar energy have been regarded by the government and ordinary people, and they thought that solar energy can provide more and more electric energy in future, and more and more actual examples have been applied in the last decades, which are supported by central government and local governments. This paper discusses the distribution zone and current developmental situation of solar energy in China. Then, some application practice is described, such as solar energy greenhouse, solar energy hearth, solar water heater, solar lighting system, solar water pump, distributed generation (DG), grid-connect photovoltaic generation (GPG) and wind–solar hybrid system. The policies and law of China central government and local governments are described in the following paragraph. At the end, the developmental prospect of photovoltaic (PV) in future China and the development barriers and recommendations are introduced.     

Solar absorption cooling with low grade heat source — a strategy of development in South China

Based on experiences with an operating solar cooling system in south China, a low temperature driven solar cooling system has been proposed, and a new model of two-stage lithium bromide absorption chiller has been developed. Test results have proved that the two-stage chiller could be driven by low temperature hot water ranging from 60 to 75°C, which can be easily provided by conventional solar hot water systems. Relying on the successes of the above system, an integrated solar cooling and heating system with two-stage absorption chiller was constructed (cooling CAPACITY=100 kW). Preliminary operating data of the system has indicated that this type of system could be efficient and cost effective. Compared to the conventional cooling system (with single-stage chiller), the proposed system with a two-stage chiller could achieve roughly the same total COP as of the conventional system with a cost reduction of about 50%.     

Joint supply — demand optimization in electricity supply

In most energy sub-sectors today a basic ignorance and lack of understanding of consumer response has meant that electricity supply systems have been conceived, planned, operated and priced mainly according to the basic criterion of engineering economics, ie cost-minimization. The few benefits taken into account have been included merely as negative costs. Recently this approach has been queried by energy policy makers. The cost-minimization process could be markedly strengthened by including further data, meanwhile information is methodically being gathered on consumer response to changes in electricity price and its should soon be possible to change over to the basic criterion of economic efficiency and welfare economics. A start can already be made, with joint supply-demand optimization in respect of the planning and operation of most interconnected electricity supply systems.