Moves to tap earth’s heat for electricity

With Sri Lanka having fully exploited its ability to generate hydroelectricity and now moving towards coal power which is not environmental friendly, geologists say the country has the potential of using geothermal power.

The geologists say world-renowned experts will begin a survey next week to locate these underlying geothermal energy sources and produce a resource map for Sri Lanka.

Geothermal power is extracted from heat stored in the earth. The earth is a natural source of heat and as one goes deeper, the temperature rises by as much as 30ºC for each km. In certain regions of the earth, particularly in volcanic terrains, the temperature increases quite rapidly.

According to the geologists, Sri Lanka, though not located in a volcanic terrain, has 11 hot springs associated with a geological and tectonic boundary that covers a 300-km stretch from Kinniya in Trincomalee to Hambantota. This can be the key to geothermal power generation.

The world experts led by Prof. Bruce Hobbs were expected yesterday. Prof. Hobbs is an authority on geothermal energy and conducted similar surveys in other countries.

The experts will be using a modern scientific technique known as Magneto Tellurics (MT) to map out the geothermal reservoirs. This geophysical technique is the latest non-invasive method in geothermal mapping and the British team is doing this survey bearing all the costs, geologists say.

“This is the first time that MT technique is being used in Sri Lanka for locating underlying geothermal energy sources and the results will be of great benefit to Sri Lanka,” said the project’s initiator, Prof. C.B. Dissanayake, Director of the Institute of Fundamental Studies (IFS).

He is the pioneer geologist who had promoted the use of geothermal energy for power generation as early as the 1980s. The preliminary studies done by Prof. Dissanayake with geologists from the University of Peradeniya revealed temperatures between 160 and 200ºC at a few km below the natural hot springs and this heat could be exploited for power generation.

According to Prof. Dissanayake, the tectonic areas that can be used for power generation run through some of the most underdeveloped regions of Sri Lanka and any energy source that could be used would be a most welcome resource.

Geothermal energy is widely regarded as renewable and clean energy. It is being used in more than 20 countries. This year, the United States also started tapping its geothermal sources for electricity production while Iceland’s power needs are mostly met by such energy.

Electricity generation is done by sending water through the geothermal source and running a turbine using the steam. Geothermal power is cost effective, reliable, sustainable, and environmentally friendly.
The MT survey will commence from the Southern region of the tectonic belt at Mahapelessa in Hambantota and will continue up to the North. The survey is scheduled to finish at the end of August and the Government Geological Survey and Mines Bureau is also joining hands with the IFS in this venture.

Temperature of different thermal springs in Sri Lanka Spring Temperature (in Celsius)

Rankihiriya 42
Kanniyai 42
Galwewa 61
Mahaoya 56
Marangala 44
Embilinna 34
Mahapelessa 44 published on SundayTimes on 20.06.2010

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