With more than 200 sources of hot water at temperatures of 40-100 degrees centigrade, Vietnam has the potential to develop a strong geothermal energy system. 

Great potential

Dr. Doan Van Tuyen from the Institute of Geological Sciences of the Vietnamese Academy of Science and Technology commented, "Compared with the rest of the world, Vietnam has medium potential for geothermal energy development. However, geothermal energy resources are available not just in one place, but throughout the country. Therefore, most localities can make use of this type of energy."

Presently, there are more than 200 sources of hot water at temperatures of 40-100 degrees centigrade in Vietnam. Thermal reserves in the Red River Delta alone can be utilized to generate 1.16 percent of the country’s total electricity production output. In Hanoi, the production output of commercial electricity is about five billion kWh each year, half of which is used to operate air conditioners. Utilizing geothermal energy to produce electricity would save VND800 billion and prevent the emission of more than 250,000 tonnes of CO2 each year.

The technology required to utilize geothermal energy is not as complicated as the technologies needed for other types of renewable energy resources. To exploit geothermal energy in areas where the temperature of water is about 200 degrees centigrade, wells 3-5km deep are drilled to heat up water for supply to power generators.

Geothermal energy resources at temperatures from 80 to below 200 degrees centigrade can be used directly to dry agricultural and aquatic products and warm up residential apartments or factories. Geothermal energy resources at temperatures of less than 80 degrees centigrade can be used to cater to medical treatment demands or tourist activities.

Dr. Tuyen continued, "Vietnam can make use of geothermal energy resources in three ways: First, geothermal energy can be used to operate the Organic Rankine Cycle (ORC) and Kalina Cycle power generation systems (at a temperature of around 100 degrees centigrade - this temperature is available at a depth of 2km from the earth’s surface almost entirely throughout the country);

Second, geothermal energy can be used to provide hot mineral water for park complexes, urban areas and eco-tourist sites. This not only brings socioeconomic benefits but is also good for the environment. Third, geothermal energy can be utilized by using ground source heat pumps (GSHP) for air conditioning and energy conservation purposes."

The application of geothermal energy is harmless to the environment because most of the equipment used to harvest it operates underground.

Largely untapped

While other countries are making effective use of geothermal energy resources, Vietnam still lacks the scientific bases to make a detailed assessment on the potential of this type of energy.

Professor Nguyen Lan Dung said, "In 2007, the Federal Institute for Geosciences and Natural Resources (Germany) surveyed geothermal potential in six places: Tu Bong (Khanh Hoa), Phu Sen (Phu Yen), Hoi Van (Binh Dinh), Nghia Thuan (Quang Ngai), Thach Tru (Quang Ngai), and Kon Du (Kon Tum), and did research on methods to utilize it effectively.

In 2008, Ormat, a leading US geothermal group, applied for a license to build five geothermal power plants in Le Thuy (Quang Binh), Mo Duc, Nghia Thang (Quang Ngai), Hoi Van (Binh Dinh), and Tu Bong (Khanh Hoa). The capacity of these plants is proposed to total 150-200MW.

However, construction has yet to start and the primary reason is that Electricity of Vietnam (EVN) buys electricity at very low prices and competitiveness is not yet realizable."

To encourage scientists to do more research on geothermal energy, the State must implement policies to support them. More attention must be directed at the use of geothermal energy to serve socioeconomic development.

PV