Geothermal exploration in Uganda - status report

Abstract

A secure and sustainable energy mix is one of the key challenges facing the Government of Uganda (GoU) as the entire world responds to the issues of climate change, energy security, energy independence and economic competitiveness. Based on current projection, energy demand could double or even triple in the next twenty years. GoU faces the need to increase its power generating capacity to meet the increasing energy demand. As a strategic intervention, GoU decided to grow its energy sources including renewable generation to mitigate the increasing energy demand. Among the renewables is geothermal energy, distributed in several districts all over Uganda. Once developed, geothermal has a potential to provide large scale, base load power 24 hours a day, 365 days a year. Geothermal exploration timeline has stretched too far dating way back to the 1950s when shallow wells were drilled in Buranga. Numerous donor support projects have been undertaken to support geothermal investigation surveys in Uganda. These have included UNDP, ICEIDA, BGR, IAEA, BGR, JICA, WB, ADB and UNEP. The situation warranted breakthrough techniques and technology to fast track geothermal development in Uganda. Experience has shown that successful geothermal development is related to four main elements: Policy, institutions, information, and finance. GoU initiated a four-pronged strategic intervention. GoU established a Geothermal Resources Department with a budget and logistics (survey equipment and tools). GoU is in final stages of putting in place a geothermal energy policy and bill. Since financial year 2011/12, GoU has committed funds to undertake government-led geothermal exploration in 4 high priority areas. Preliminary geothermal conceptual models have been developed for four areas and preliminary surveys have commenced at Ihimbo and Rubaare. There are key accomplishments and impacts.

A skilled geothermal workforce is in place but with capability gaps. There is a need to reinforce the skills mix by recruiting engineers, managers and technicians. It is mostly a workforce of geoscientists. It is now recognized that the western arm of the East African Rift System (EARS) is quite different structurally and tectonically from the eastern arm. The western arm is in initial stages of rift development as opposed to the eastern arm, which is in mature stage. Uganda’s geothermal systems are extensional deep circulation amagmatic systems that are driven by deep circulation of meteoric waters. This is attested by low Helium signatures and deep reaching boundary faults. Rift border faults are principal exploration targets, and more so where there is fault interaction, due to increased permeability, critically stressed zones and high fracture density. Exploration workflow applied includes a combined MT/TDEM survey, soil gas and gas flux measurements, shallow temperature probe, micro-seismic survey, reflective seismic data from oil and gas companies. Integrated models will be developed to aid well targeting. Thermal Gradient Holes (TGH) are recommended to confirm the sub-surface temperature anomaly prior to committing risky and cost intensive deep full diameter exploration. A drilling supervisor and contractor have been procured to supervise and drill TGH holes in Kibiro, Panyimur and Buranga areas to commence by end of 2019. Deep exploration test wells thereafter will be planned and designed for Kibiro and Panyimur. Data gap closure is planned for Katwe to qualify the field for temperature gradient drilling