Costarica

GREECE

AUSTRALIA

ARGENTINA

И D. GEOTHERMAL ENERGY IN DIFFERENT COUNTRIES OF THE WORLD

1. You will read the following texts about geothermal energy. Choose the most impor­tant facts from each one.

2. Write the summary of the texts.

Sources of high-temperature geothermal heat exist in western Ar­gentina, along the Andes range. Moderate to low-temperature ther­mal fields have been identified in other parts of the country. A 670 kW binary-cycle pilot plant has been in operation at Copahue (in the west-central province of Neuquen) since 1988. Direct use is made of hot water from the Domuyo geothermal field (located to the north of Copahue) in space heating and bathing in the Villa Aguas Calientes tourist complex. However, the amount involved is extremely small. There is a project for using the Copahue geothermal resource for space heating in the nearby village of Caviahue.

Australia's best resources of conventional geothermal energy are lo­cated in the Great Artesian Basin region of central Australia where there are many bores! which discharge water at high enough temperatures (above 80 °C) to operate a heat engine. Although these resources are not appropriate for large-scale electricity generation, they can be used to generate electricity for remote homesteads² and communities in this area. Examples include a district heating system at Portland (Victo­ria), a geothermal well providing hot water for paper manufacture at Traralgon (Victoria), power production (20 kWe binary cycle) from hot water aquifers³at Mulka station (South Australia), and a binary plant (150 kWe) at Birdsville (Queensland).

Section II. Supplementary Reading

D. Geothermal Energy in Different Countries of the World 127

Geothermal energy is also available from 'hot dry rocks' (HDR) buried several kilometres below the earth's surface. Recent studies of the prospects for HDR in Australia have established that a very signif­icant resource exists, particularly in eastern Australia. Moreover, the economics of energy extraction based on HDR in Australia appear to be favorable, owing to a very advantageous combination of geolog­ical factors: high rate of heat generation in the crust⁴, low-conductiv­ity sedimentary rocks which retain the heat, and horizontally oriented HDR reservoirs which provide the cheapest drilling access. Given the scale of the engineering required, the technology is likely to be most appropriate for grid-connected applications.

Geothermal exploration undertaken since 1970 has located numer­ous fields, both high-enthalpy' and low-enthalpy. Development ac­tivities during the last five years have concentrated on low-enthalpy fields in Thrace, Macedonia and central Greece. There is now a con­siderable area of geothermally-heated greenhouses in operation. A 2 MWe pilot power plant was built in 1986 at Milos in the Cyclades, but complaints²from local residents caused it to be shut down in 1988. Environmental problems continue to inhibit³ the exploitation of Greece's high-temperature geothermal resources.

1 - скважина; 2 — фермы; 3 - водоносный слой; 4 — земная кора

The Central American volcanic belt (пояс) passes through Costa Rica, evidenced by numerous volcanoes and a number of geothermal fields. In March 1994, a 55 MWe geothermal power station was brought into service at a site close to the Miravalles volcano, in the north-west of the republic. In January 1995, the 5 MWe Boca de Pozo plant came into operation at the same field. The construction of Miravalles II, with a projected capacity of 55 MWe, is under way; completion was sched­uled for end-2004.

EL SALVADOR

As does Costa Rica, El Salvador lies on the Central American vol­canic belt. Geothermal exploration began in 1954 and the first of its geothermal power plants came on line in 1975 at Ahuachapan (30 MWe), in the west of the republic near the border with Guate­mala. Further units were added in 1976 (30 MWe) and 1980 (35 MWe), bringing total generating capacity at Ahuachapan up to 95 MWe. The Berlin geothermal field in the eastern part of the republic was ex­plored from the 1960's onwards, eventually leading to the installation of two 5 MWe back-pressure plants in 1992. At first only one plant was run at a time but the drilling of additional wells now enables the two units to be run simultaneously.

1 - теплосодержание, теплоемкость; 2 — жалобы; 3 — тормозить

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