An Assessment of the geothermal potential of Bangladesh

Abstract

Bangladesh is one of the energy stricken countries of the world with only 236 kWh per capita electricity generation and only 49% of its population has access to that electricity. In the context of geothermal water utilization, Bangladesh is still at a very early stage. To date, no systematic study has been done to evaluate the geothermal resources of Bangladesh. However, in a few articles authors have stressed the potential of geothermal energy resources in Bangladesh. Geothermal energy exploration involves cash incentives in the early stages of exploration, but good planning minimizes risks and saves money. In Bangladesh many deep abandoned wells, originally drilled for oil and gas exploration, have been used to extract valuable information about the subsurface geology and temperature of areas of interest.

Analysis of the temperature data of these wells indicates that the average geothermal gradient along the southeast part of the Bengal Foredeep region varies from 19.8 to 29.5°C/km and along the northwest stable shelf from 20.8 to 48.7°C/km. An attempt was made to recalculate different geothermometer temperatures using the geochemical data taken from water samples of the basement aquifer of the Madhyapara hard rock mine area, and using acquired knowledge from this training programme. The predicted temperature is quite variable, ranging from 67 to 153°C, which may refer to a potential low-temperature geothermal field in the Madhyapara area. For assessment of the geothermal potential of Bangladesh, it is recommended that preliminary surface geological and geochemical studies be done followed by geophysical investigations (resistivity (MT), seismic, gravity, etc.) and drilling of shallow gradient wells to make a conceptual model of any geothermal systems before proceeding with the most expensive, as well as the most risky part, i.e. drilling of a deep well.