United Kingdom

• What has proved to be a valuable test facility, enabling study of the various compo­nents of the system under in-service conditions?

The UK has had one of the largest government-sponsored R&D programs on wave energy, covering a wide range of devices. However, this was greatly reduced in the early 1980's and most recent work has centered on a shoreline OWC system at Queen's University, Belfast (QUB).

Over the past few years, QUB have been monitoring and improving a 75 kWe shoreline gully OWC on the island of Islay, with support from the UK Department of Trade and Industry. It has proved to be a valu­able test facility, enabling study of the various components of the system under in-service conditions. Valuable lessons have been learned on all aspects of the scheme, leading to significant developments in several areas (e. g. device installation, turbine performance, system control and grid integration).

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.

Argentina

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

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).

126

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.

GREECE

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