LONG DISTANCE TRANSMISSION PIPELINES FOR GEOTHERMAL WATER IN ICELAND (20-60 KM)

Transcription

1 LONG DISTANCE TRANSMISSION PIPELINES FOR GEOTHERMAL WATER IN ICELAND (20-60 KM) By Thorkell Erlingsson Sverrir Þórhallsson Workshop for Decision Makers on Direct heating Use of Geothermal Resources in Asia, Tianjin, China. 15. May 2008 tilefni kynningar dd.mm.áááá

2 OWERVIEW Introduce long pipelines for geothermal water in Iceland. 1) Husavik, 19 km pipeline, DN350 mm 2) Akranes-Borgarnes 62 km pipeline, DN450 mm 3) Reykjavík Energy, 23 km pipeline, DN900 mm 4) Small rural district heating systems using long pipelines Conclusions.

3 INTRODUCTION Geothermal energy is widely used in Iceland for space heating. There are 30 geothermal district heating systems in Iceland. There are 200 geothermal networks in rural areas in Iceland Now about 90% of all houses are heated with geothermal water. All district heating systems are community-owned and operated. It is common to pump hot geothermal water long distances in insulated as well as uninsulated pipes for space heating.

4 Húsavík, northern Iceland Green houses Farms Geothermal heating started in 1970 Inhabitants in Húsavík 2,500 people Pipeline uninsulated DN350 asbestos Initial water flow 150 m³/h (40 l/s) Temperature drop 15 C Hot spring and well

5 In the year 2000, 30 years after the project started, a decision was taken to renew the pipeline in Húsavík. New DN400 mm steel pipe, insulated was installed. Maximum flow rate 530 m³/ (147 l/s) Temperature drop of only 3 C along the long pipeline. Two new wells, average temperature 125 C. Install a turbine to produce 2 MWe of electricity with the Kalvin technology. Introduce multi use of the geothermal fluid.

6 Longitudinal section of pipeline from the tank at the wells to the tank in the town of Husavík. Water temperature in pipeline at the end station with regards to water flow in pipeline.

7 heiti glæru Texti

8 AKRANES AND BORGARFJÖRÐUR DISTRICT HEATING SYSTEM Old hot spring in Reykholt was used for bathing around the year Deildartunga hot spring closed by is 650 m³/h (180 l/s) Temperature is 96 C The villages of Borgarnes is in 34 km and Akranes in 62 km from the hot spring. Decisin taken in 1975 to pump the water to these villages for space heating.

9 heiti glæru Population of towns; Hot spring Akranes 5,200 Borgarnes 1,700 District heating system constructed in Pipeline is DN450 to Borgarnes and DN400 from there. Pipeline insulated partly with 50 mm rockwool.

10 HAB, Cross section Geothermal of pipeline waters in Iceland (20-60 km) Cross section of the asbestos transmission pipeline Total length of pipeline 62 kilometers Pipe diameter DN450 and DN400 mm.

11 HAB, Cross section Geothermal of pipeline waters in Iceland (20-60 km) Pipes on surface crossing a stream. Pipes insulated with 100 mm rockwool. Asbetos pipes produced in Spain Pipes on harbour ready to be installed.

12 Repair of pipeline. Breaks in pipeline 20 to 30 each year. New section replaced and insulated. Repair takes only few hours and consumers does not notice in most cases.

13 Reykjavík Energy - Nesjavellir Power Plant Nesjavellir Powr Plant

14 Reykjavík District Heating Started operation in 1930 by heating a school, 50 m³/h, 87 C. Today some 26,000 houses are heated and 183,000 inhabitants are served with hot geothermal water. In 1987 the power plant at Nesjavellir started operation. 23 kilometer long pipeline to Reykjavík pumping 6,000 m³/h (1,680 l/s) of hot water to Reykjavík producing 120 MWe of electricity

15 Reykjavík Energy - 23 kilometer pipeline 23 km pipeline Nesjavellir power plant

16 Reykjavík Energy Nesjavellir Power Plant 23 km pipeline. 900 mm in diameter. up to 6,700 m³/h hot water. very good rock wool insulation with aluminium coat on outside. temperature drop of 3 C along the 23 km pipeline. pipeline mostly above ground.

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18 RURAL SMALL DISTRICT HEATING SYSTEMS Some 200 rural district heating systems, typically few farms. Long mains up to 10 km. Branches up to 1 km to each farm. Pipe diameter in coils up to 75 mm Greater then 75 mm in insul. steel. Pipe comes on 500 m long coils. Pipes pre-insulated PEX pipes. Pipe ploughed into ground.

19 RURAL SMALL DISTRICT HEATING SYSTEMS Work can just as well be done in winter time. Electrical cables are often ploughed into the ground at the same time as hot water pipe. Fiber Optic is here ploughed into ground with the hot water pipe. This method of ploughing into ground applies only for soft soil.

20 CONCLUSION Long pipelines are often the only solution for communities to utilize the geothermal water. Long successful experience is in operation of long transmission pipelines for hot water. Often high investment cost but always economical and sometimes very economical. Now 90% of all houses in Iceland are heated with geothermal water.

21 Thank you