History of Geothermal Energy Development in Nigeria
The history of Nigeria’s geothermal energy development is vague however available records indicates the journey must have begun in the 1970s with earliest known related works accredited to the Subsurface temperature distribution in the southern part of sedimentary province of Nigeria by Nwachukwu in 1975; 1976, Avbovbo in 1978 and the 1979 heat flow estimation by Verheijen and Ajakaiye in the centre of Ririwai ring complex of the granitic ring structures of Younger Granites Province of Northern Nigeria, located within Precambrian shield (Kurowska & Schoeneich, 2010). However, a major leap came in 2005 when the Nigerian government established the Renewable Energy Master Plan (REMP), setting a target of 20% renewable energy mix by 2020, in which geothermal energy was not exempted. This agency in collaboration with the Energy Commission of Nigeria (ECN) and the United Nations Development Programme (UNDP) resulted to the emergence of Research and Development Programme in Geothermal Energy in 2005 (REMP, 2005), and in 2012 a delegation of staff from the ECN were sponsored to Kenya for the “Short course Vii on Exploration for Geothermal Resources” organized by United Nations University-Geothermal Training Programme (UNU-GTP), in collaboration with Kenya Electricity Generation Company(KenGen) and Geothermal Development Company(GDC).
The workshop subsequently prompted the establishment of a Geothermal Unit at the National Centre for Petroleum Research and Development (NCPRD) in 2013, in a bid to join the global quest for geothermal resource. This unit was primarily saddled with the task of promoting the development of geothermal energy in Nigeria, collaborating with national and international stakeholders, and serving as repository for geothermal researches. This feast prompted the policy development aimed at promoting renewable energy development, including geothermal energy in 2015 (National Renewable Energy Policy. 2015), and in 2019 there was a special policy focusing on the development, exploration and the possible utilization of geothermal energy resources in Nigeria Geothermal Energy Development Policy. In the wake of this interest certain state actors have played significant roles in encouraging the assessment of geothermal sources in Nigeria for various applications: Geophysical and geological data such as aeromagnetic, aerogravity and geological data can be sourced from the Nigerian Geological Survey Agency (NGSA) while the Federal Ministry of Power Oversees renewable energy development, including geothermal energy.
Akiri Hot Spring is a geothermal Surface manifestations at Middle Benue Trough,.
Ruwan Zafi HotSpring
Akiri Hot Spring is a geothermal Surface manifestations at Middle Benue Trough,.
Wikki Warm Spring in Yankari Game Reserve
Geothermal Energy Distribution in Nigeria
All accessible heat flow data, determined using thermograms of deep boreholes and bottom hole temperature readings at intermediate positions of wells in drilling, as well as heat flow values determined from the spectral analysis of available magnetic field maps were used to compile a preliminary heat flow map for the whole territory of Nigeria. Small squares (studied deep wells) and circles (estimates derived from the magnetic field analysis) show positions of individual localities with available data (Akinyemi & Zui, 2020). Heat flow values range within the country approximately from 35 to 140 –145 mW/m2. A low heat flow anomaly of 40 –50 mW/m2 is traced in the central part of the Niger Delta. It increases in all directions outwards of this cold zone to 70 – 80 mW/m2
Map of the heat flow density in Nigeria
Geologic map of Nigeria showing the area subjected to most geothermal studies in the last 40 years
Photos taken at Wikki warm spring in Yankari National Park, Bauchi Nigeria.
Photos taken at Ikogosi warm spring, Ekiti, Nigeria (photo by Laaro Babatunde).
Project and Initiatives
Following the significant outcome recorded from various studies some of which are presented above, the Federal government of Nigeria through the Nigerian National Petroleum Company (NNPC) resolve to embark on the country’s geothermal resource assessment. To start with, the NNPC signed an MOU with the alliance of Greenthermal Energy ltd an indigenous company and two foreign geothermal companies from Italy and Kenya respectively. The phase 1 activities were supposed to commence first with feasibility study focusing on the oil and gas wells which may be repurposed for geothermal use. Other phases that were supposed to have followed include evaluation of all the geothermal potential terrain in Nigeria for geothermal energy development. However, the project is still pending commencement.
Current State of geothermal energy exploration in Nigeria
Although geothermal energy in Nigeria still maintains an infant state yet to leverage the opportunity of international partnership, several explorative researches have been done and few developmental initiatives are beginning to come to place to create relevant awareness towards substantial geothermal energy implementation and its long-term economic and environmental importance to the Nigeria raising the hope of its due consideration in the nearest decade.
Studies and evaluation of data from both the crystalline basement complex and the sedimentary basins of different ages indicate potentials for geothermal energy in Nigeria. Interpretation of Gravity, aeromagnetic and seismic reflection data has been used to estimate the depth to magnetic bodies, Curie point depth, heat sources, sediment thickness among others. Analysis based on geothermal gradients indicated high geothermal anomalies within sedimentary basins, the areas of geothermal anomalies with gradients above 5°C/100 m might be prospective for geothermal energy utilization. Many geological structures show promising temperature, temperature gradient and subsurface temperatures that are adequate for geothermal resource that might be exploited and used for some purposes. NNPC ltd is also now embarking on further activities that may lead to a practical use of geothermal energy in Nigeria.