Geothermal energy remains one of the most underutilized yet promising sources in the global energy mix. Generated from the Earth’s internal heat, it offers a constant and reliable supply of baseload electricity, operating around the clock and emitting minimal carbon—making it a powerful tool in the global push toward decarbonization.
Like fossil fuels, geothermal energy is widely distributed, with heat stored in magmatic rocks beneath the Earth’s crust. This heat is transferred to the surface through water and steam circulating in porous and permeable rock formations. When these conditions align and a convective current is established, a geothermal reservoir is formed.
Such systems involve convective water in confined spaces transferring heat from hot rocks to the surface. Where dry rock dominates, fluids can be injected to facilitate heat transfer. Despite its potential, geothermal energy remains largely untapped, particularly in developing countries like Nigeria, where energy shortages are acute.
Nigeria’s electricity consumption is 80% below what would be expected based on its population (over 300 million) and income levels (Climate Policy Initiative 2024). Approximately half of all electricity consumed in Nigeria is self-generated highlighting a vast unmet demand and the urgent need for alternative energy sources (Fagorite and Omefe 2024). Geothermal energy could be part of the solution.
A study, led by me, N.C. Izuwa, and Ngozi Nwogu (SPE 203643), employed a rigorous mathematical model to estimate the quantity of recoverable geothermal heat in Nigeria’s subsurface formations. We first calculated the total heat in place using geological and thermal parameters, then accounted for heat losses during extraction through wellbores of varying diameters.
Engineering the Energy Transition
We used data from abandoned oil wells in the Niger Delta to model geothermal gradients and heat flow. Estimating the quantity of geothermal energy in place involves a fundamental thermodynamic approach, using the equation Q=ρVCpΔT, where ρ is the density of the rock, V is the volume, Cp is the specific heat capacity, and ΔT is the temperature difference derived from the geothermal gradient. In a representative case, the rock density is averaged at 2,550 kg/m³, with a specific heat capacity of 1,000 J/kg°C. The rock volume under consideration spans 5000 m in length, 3000 m in width, and 60 m in thickness.
With an average geothermal gradient of 3.6°C per meter, the temperature differential across the rock mass becomes significant, enabling a substantial thermal energy estimate. The rock’s porosity is 0.25, and its permeability is 100 millidarcies, indicating favorable conditions for fluid movement and heat exchange.
However, not all the energy in place is recoverable due to inevitable heat losses during extraction. In geothermal systems, heat is lost primarily through conduction and convection, particularly along the wellbore. Heat loss by conduction occurs in both the tubing and casing, depending on the completion design.
The findings were striking. Using a 1-in.-diameter pipe, up to 92% of the geothermal heat could be recovered (Fig. 1). Even with larger 2-in. and 3-in. pipes, recovery rates remained high at 84 and 76%, respectively. These efficiencies are among the highest reported in geothermal engineering and suggest that Nigeria’s geothermal resources are not only viable but potentially transformative.
The rate of heat loss per unit length of tubing is calculated using the equation:
Where Rh is the specific thermal resistance, Td is the bulk fluid temperature, Ta is the ambient temperature, Z is the depth, and a is the geothermal gradient.
For tubing, Rh is defined as
while for casing, it is given by
incorporating the earth’s thermal conductivity k, thermal diffusivity α, and the overall heat transfer coefficient U. These equations account for temperature and pressure variations due to friction, as well as radiative and convective losses. Units are standardized across BTU and Joules for consistency. Importantly, heat-loss rates are higher during transient periods before stabilizing. The recoverable geothermal energy, therefore, is the net energy after subtracting these losses from the total energy in place, expressed as
This methodology provides a rigorous framework for assessing the viability of geothermal resources, ensuring that energy planning is grounded in realistic, data-driven projections.
By applying thermodynamic principles and accounting for heat loss through conduction and convection, the team estimated that a single geothermal reservoir could yield 4.5×1017 joules of recoverable heat. When converted using a thermal efficiency of 16%—typical for high-temperature geothermal systems—this translates to 74 MW of electricity over a 30-year plant lifespan.
Implications for Nigeria’s Energy Landscape
Nigeria’s energy landscape is at a critical juncture. With over 85 million people lacking access to electricity and persistent grid failures disrupting even urban centers, the country faces a deepening energy crisis. The implications of integrating geothermal energy into Nigeria’s power mix are profound, offering a pathway not only to energy security but also to economic resilience and environmental sustainability.
Geothermal energy stands out for its reliability. Unlike solar and wind power, which are intermittent and dependent on weather conditions, geothermal systems provide a continuous, stable supply of electricity. This makes them ideal for baseload generation—power that is consistently available to meet minimum demand. In a country where power outages are routine and diesel generators are a costly and polluting fallback, geothermal energy could offer a dependable alternative that reduces reliance on fossil fuels and enhances grid stability.
Another transformative aspect of geothermal energy is its potential for decentralization. Small- to medium-scale geothermal plants can be deployed in rural and off-grid communities, bypassing the need for extensive transmission infrastructure. This is particularly significant in Nigeria, where many remote areas remain disconnected from the national grid. By enabling localized power generation, geothermal energy can empower communities, stimulate local economies, and reduce transmission losses that currently plague the national system.
From an environmental perspective, geothermal energy is one of the cleanest sources available. It emits minimal greenhouse gases and has a much smaller land footprint compared to coal- or gas-fired power plants. For Nigeria, which is increasingly vulnerable to the impacts of climate change, adopting geothermal energy aligns with global climate commitments and supports a transition to a low-carbon economy.
The economic implications are equally compelling. Developing geothermal resources can create jobs in exploration, drilling, plant construction, and maintenance. It can also attract foreign investment and foster technological innovation. Moreover, by reducing the need for imported fuels and cutting the cost of self-generation, geothermal energy can improve Nigeria’s trade balance and enhance energy affordability for households and businesses.
Scientific studies have already identified promising geothermal sites across Nigeria, including warm springs in the Benue Trough, the Jos Plateau, and the Anambra Basin. These findings suggest that the country possesses the geological conditions necessary for viable geothermal development. However, realizing this potential will require coordinated efforts in policy, investment, and capacity building.
This is more than a scientific study, it’s a blueprint for energy independence. With the right investment and policy support, Nigeria can lead Africa in geothermal innovation.
Policy Implications
The advancement of geothermal energy in Nigeria carries far-reaching policy implications that could transform the nation’s energy landscape. We urge the Nigerian government, energy regulators, and private sector stakeholders to prioritize geothermal exploration and development as part of a broader national energy diversification strategy. In doing so, policymakers must craft a dedicated geothermal policy framework that includes incentives for research, investment, and capacity building.
A key recommendation is the repurposing of existing oil and gas infrastructure—particularly the vast number of abandoned or underutilized wells scattered across the Niger Delta and other regions. These assets present a cost-effective opportunity for geothermal retrofitting, enabling faster deployment while reducing initial capital investment. This approach aligns well with a just energy transition, leveraging legacy infrastructure for clean energy without displacing local livelihoods.
Moreover, there is a pressing need for enhanced geophysical data collection and sharing. The Chad and Sokoto basins, for instance, have shown promising geothermal gradients but remain underexplored due to limited temperature and subsurface data. National geological surveys should be expanded and digitized, with open access to encourage academic and private sector engagement.
Institutionally, the Nigerian Electricity Regulatory Commission (NERC) and the Federal Ministry of Power should integrate geothermal energy into national planning documents such as the Renewable Energy Master Plan and the Energy Transition Plan. Funding mechanisms, including green bonds and public-private partnerships, should be mobilized to support pilot projects and technology transfer.
“This research lays the groundwork for a geothermal revolution in Nigeria,” said researcher N.C. Izuwa. “It’s time to move from potential to production.” With the right policy mix, Nigeria could unlock a stable, baseload renewable energy source that supports economic growth, reduces emissions, and strengthens energy security.
For Further Reading
SPE 203643 Estimating the Quantity of Recoverable Heat in a Geothermal Reservoir in Nigeria by N. Okeifufe, N.C. Izuwa, and Ngozi Nwogu, Federal University of Technology Owerri.
Landscape of Climate Finance in Nigeria 2024, Climate Policy Initiative.
Understanding Nigeria’s Electricity Challenges by V. Fagorite and V. Omefe, Clean Technology Hub.
