A Geothermal Energy Feasibility Study in East Africa
Introduction
East Africa’s unique geological features present an opportunity for geothermal energy to take root and provide sustainable development in its energy supply. This potential is further highlighted by the global shift towards renewable energy sources over traditional methods of energy production, i.e. fossil fuel-based sources.
East Africa is uniquely poised to take advantage of geothermal energy’s stability with the area being part of the Great Rift Valley. This is in comparison to the inherent intermittency of other renewable energy sources, such as solar and wind, all whilst geothermal energy being a sustainable source.
The shift towards renewables is majorly driven by the over reliance of fossil fuels and the need to reduce their harmful by-products. The U.S is an example of an area where geothermal energy is among the fastest growing energy sources and is being supported by rapid technological advancements along with economic incentives that could serve as a model for East Africa to emulate.
The dynamics and specific advantages of geothermal energy can be useful to East Africa in harnessing a source of energy that is clean and aid in the further development and economic stability of the region.
Identifying Potential Sites
The identification of potential geothermal sites in East Africa involves a range of technologies and surveys targeted at finding underground hot water and steam reservoirs through the analysis of geological data to evaluate the distance to faults and magma bodies, the flow of heat, and seismic activity that can all help point to a presence of a geothermal source.
Comprehensive methodologies for geothermal resource assessments such as favorability maps, developed by the U.S. Geological Survey (USGS), use fault data, heat flow, and the presence of magmatic bodies to locate sources of geothermal potential.
Enhanced Geothermal System technologies are currently a topic of interest for the USGS and involves the process of developing realistic models to evaluate both natural and engineered geothermal reservoirs for the production of energy.
The significant heat flow and volcanic activity that the rift systems in East Africa are known for, present an opportunity for the region to increase its energy production by mapping these resources accurately and building a list of viable sites for geothermal power plants, all whilst reducing the some of the risks that come with exploration and increasing the feasibility of the projects.
The methodologies outlined by the USGS that can be adopted by East Africa involve a combination of geological, geochemical, and geophysical surveys. Below is a brief breakdown of what these methodologies entail:
Geological Mapping: This is the mapping of potential sites’ surface and subsurface for any geological features that is crucial in identifying formations that are known to have geothermal systems such as fault lines, hot springs, and volcanic centres.
Geochemical Techniques: Metrics such as pH, temperature, and the concentration of dissolved minerals in the analysis of water and gas samples from hot springs, wells, and other geological formations, are what provide the clues about subsurface geothermal activity.
Geological surveys: Magneto-telluric (MT) surveys, gravity measurements, and seismic surveys are an example of techniques that can be used in the mapping of subsurface structures.
Utilisation of favorability maps: With the help of machine learning and data driven models, favorability maps can be created with the use of geophysical and geological indicators to point out areas of high geothermal potential.
Environmental Impact Assessments
The importance of environmental impact assessments (EIA) cannot be understated in the development of geothermal energy in East Africa. These assessments will help to ensure that the projects being undertaken are done in a manner that minimises any impact on the environment whilst maximising any socio-economic benefits for the surrounding communities.
Kenya, a leader in the exploitation of geothermal resources, has over 25% of its electricity supply delivered through geothermal energy. The ability to have a strong and somewhat constant source of electricity not only aids Kenya in building a base for implementing other sources of renewable energy but it also serves as a model for neighbouring countries – Ethiopia, Uganda, Rwanda, and Tanzania – to follow in harnessing their own geothermal potential (Stanford Doerr School of Sustainability). However, this expansion of geothermal energy needs the careful implementation of environmental impact assessments to identify any environmental and social impacts.
The International Renewable Energy Agency (IRENA) has underlined the role of EIAs in the development process of geothermal energy plants. The assessments outlined are crucial for ensuring the sustainability of the projects from the inception stage to the operational phase (IRENA). Focus on impact on local water sources, biodiversity, and the emissions of greenhouse gases are some of the key environmental concerns that are to be considered when considering geothermal energy projects.
Environmental Impact Assessments (EIAs) need to focus on the specific features of East Africa’s landscape and its social settings. Many sites suitable for geothermal energy plants are in places with a lot of biodiversity or close to communities that depend on the land. These areas could be affected by the development of these energy plants.
The utilisation of EIAs in East Africa is thus an essential part of the development process and aids in the environmental protection of areas with potential impact whilst also providing social and economic advancement in the region.
Economic Analysis
Geothermal plants can prove to be costly due to their high upfront cost of conducting extensive geological surveys and drilling to prove the reserves of the potential sites. However, once proven, the running costs of a geothermal plant are low due to their high reliability and long-term operation due to the stability of supply (World Bank Documents).
Other than cost of geothermal energy, the economic benefits also prove to be enticing to some East African countries as it can lead to the reduction in fuel imports all whilst increasing energy security and as it stands, the current percentages of fuel imports in East Africa for the year of 2021, range from 21% to 14% of total merchandise imports. Moreover, geothermal projects can create direct and indirect employment in the surrounding communities and also lead to the starting of ancillary industries as shown by the Menangai Geothermal Project in Kenya which led to an estimated 34 jobs per installed megawatt.
With the rising cost of fossil fuels and the global push towards sustainability, geothermal energy is uniquely positioned to replace a lot of fossil fuel burning sources while providing a favourable return on investment (ROI) due to the low operational and maintenance costs once the plant is up and running (World Bank).
Menangai Geothermal Plant
One notable example of a geothermal plant in the East African region is the Menangai geothermal project in Kenya, a direct result of a public-private partnership model, where the Geothermal Development Corporation (GDC), spearheaded the exploration and development phases of the project. The development of the Menangai Steam Field will provide a significant amount of power to hundreds of thousands of households and businesses while supporting economic growth through its stable supply of energy and job creation.
Conclusion: Future Outlook and Development Strategies
The African Development Bank (AfDB) and the International Renewable Energy Agency (IRENA) provide valuable insights and recommendations to guide the development of geothermal energy plants such as strategic investments, innovative policies, and research efforts that all aim to harness this abundant renewable resource.
An example of the strategic investments is the AfDB’s initiatives in Africa’s Energy Market Place and their pledge to transforming Africa’s energy sector through the combined participation of governments, the private sector, and development partners to enhance energy access, improve the state of our energy security, and support the economic growth of the continent.
IRENAs report emphasises the importance of robust energy policies for East Africa's geothermal future. It suggests clear, predictable regulatory environments and incentives for renewable energy investments to attract investment and effectively manage geothermal resources, thereby accelerating the region's geothermal development.
Further to that, IRENA emphasises the importance of ongoing research to address technical and environmental challenges in geothermal energy. They suggest continuous improvement in geothermal technologies and localised strategies considering East African countries' unique geology and socio-economic contexts. This includes exploring new sites, enhancing technology efficiency, and understanding socio-economic impacts.
To conclude, the future of geothermal energy in East Africa is promising, with potential for growth facilitated by strategic planning and international cooperation. The AfDB and IRENA offer financial backing, policy guidance, and research insights to enhance the region's geothermal capabilities. Adhering to these recommendations and investing in geothermal research can significantly improve East Africa's energy security and sustainable development goals.