Prospects and challenges for utilisation of low- to medium-temperature geothermal resources in Tanzania

Abstract

The key purpose of this qualitative study is to explore the potential for effective utilisation of low- to medium-temperature (i.e., ˂150 °C) geothermal resources in Tanzania. Worldwide, these resources are mostly harnessed locally for direct use as a heat source. In contrast, high-temperature resources are mainly used for power generation, becoming an important component of the national energy supply. As a result, the development of the latter is more advanced than that of the former. In Tanzania, five geothermal resources have been chosen as priority areas for development. Three of them, Luhoi, Songwe, and Kiejombaka, are low- to medium-temperature resources, while the other two, Ngozi and Natron, are most likely to host both low- to medium and high-temperature systems. However, the progress is slow due to funding scarcity, insufficient knowledge of the geothermal systems, and a lack of understanding of how they can be effectively utilised to enhance economic development in the local communities. In investigating the most suitable methods for utilising low- to medium-temperature geothermal resources, the first step was to analyse the energy demand of the societies residing in the five above-mentioned areas by assessing their economic activities. Then, the most suitable methods to meet the energy needs and pave the way for new economic and social development opportunities were identified. It was found that the most effective way to harness low- to medium-temperature geothermal resources in Tanzania is to use them as the direct heat source in greenhouses, preservation of crops and animal products, hatcheries, aquaculture, geothermal spas, and balneotherapy. Binary (Organic Rankine Cycle) power plants might also suit small, isolated populations with low energy demands. Implementing these forms of utilisation is expected to stimulate economic growth by creating employment opportunities, promoting the development of agro-processing industries, and paving the way for new business prospects. Some major challenges include insufficient reservoir knowledge, high capital costs, shortage of funds and experts, and poor infrastructure. These challenges could be overcome if the government actively invests in developing low- to medium-temperature geothermal resources to benefit the local societies and the whole country. This qualitative study provides insight into the effective utilisation of low- to medium-temperature geothermal systems, obstacles and opportunities related to their development in Tanzania. However, a detailed quantitative economic analysis is required to evaluate the feasibility of the suggested applications.