By: Robert Buluma Rodatherm Energy has done something no other geothermal startup has attempted at commercial scale: swapped water for refrigerant in a closed-loop system. The claim is 50% higher thermal efficiency than water-based binary cycles, achieved by circulating a proprietary phase-change fluid through a fully cased, pressurized wellbore. The company emerged from stealth in September 2025 with a $38 million Series A—the largest first venture raise in geothermal history. Lead investor Evok Innovations was joined by Toyota Ventures, TDK Ventures, and the Grantham Foundation. The engineering thesis is elegant. The execution risks are significant. This is an Alphaxioms examination of both. II. The Thermodynamic Distinction Every geothermal company you've covered moves heat using water or steam. Rodatherm moves heat using a fluid that boils and condenses inside the wellbore. In a conventional closed-loop water system (Eavor's model), water circulates as a single-phase liq...
Tanzania’s Ngozi Geothermal Project Opens Major International Tender for Drilling Rig, Cementing and Mud Engineering Services
By: Robert Buluma
Tanzania’s geothermal ambitions are entering a decisive new phase after the Tanzania Geothermal Development Company (TGDC) officially invited international and local firms to participate in a major tender linked to the Ngozi Geothermal Project in the Mbeya Region. The announcement, published through TGDC’s official channels, signals a significant acceleration in Tanzania’s quest to unlock its enormous geothermal potential and diversify its national energy mix.
The tender, identified as Tender No. 70/2025/2026/NC/72, seeks service providers for the hiring of a drilling rig with accessories, cementing unit and accessories, and mud engineering services for the drilling of three slim wells at the Ngozi geothermal prospect. The project will be procured through an International Competitive Tendering framework, highlighting the scale and strategic importance of the development.
For East Africa’s geothermal sector, this is more than just another procurement notice. It represents a strategic step toward transforming Tanzania into one of Africa’s emerging geothermal powerhouses, potentially following the path already pioneered by neighboring Kenya.
Tanzania’s Growing Geothermal Ambitions
For years, Tanzania has remained one of Africa’s most underexplored geothermal frontiers despite possessing substantial geothermal resources spread across the East African Rift System. The country’s geothermal potential is estimated to exceed 5,000 MW, yet only limited exploratory activities have taken place compared to Kenya, Ethiopia, or Djibouti.
Now, momentum appears to be shifting.
The latest TGDC tender indicates that Tanzania is intensifying efforts to move from preliminary assessments toward deeper exploration and eventual commercial development. The decision to initiate drilling-related tenders for slim wells is particularly important because drilling represents one of the most expensive and technically challenging stages in geothermal development.
Slim wells are often drilled during exploration phases to gather critical subsurface information before larger production wells are commissioned. These wells help developers evaluate reservoir temperatures, permeability, fluid chemistry, pressure conditions, and overall geothermal viability.
The success of the Ngozi project could therefore determine the pace at which Tanzania expands its geothermal industry over the coming decade.
Why the Ngozi Geothermal Project Matters
The Ngozi geothermal prospect is located in the Mbeya Region within the southern highlands of Tanzania. The region sits along the geologically active East African Rift System, which is known globally for its vast geothermal potential.
Ngozi has long attracted scientific and commercial attention due to its volcanic and hydrothermal characteristics. Surface manifestations including hot springs, fumaroles, altered grounds, and geothermal fluids have suggested the existence of significant underground heat resources.
The prospect is strategically important for several reasons:
1. Energy Diversification
Tanzania continues to rely heavily on hydropower and natural gas for electricity generation. However, hydropower generation remains vulnerable to droughts and climate variability, while gas markets can experience price fluctuations and infrastructure challenges.
Geothermal energy offers stable baseload power generation that operates continuously regardless of weather conditions. Unlike solar or wind power, geothermal plants can provide electricity 24 hours a day.
Developing geothermal resources at Ngozi could therefore improve Tanzania’s energy security while reducing dependence on seasonal hydropower generation.
2. Industrial Growth
Reliable electricity remains a cornerstone for industrial expansion. Tanzania’s ambitions in mining, manufacturing, agriculture processing, and infrastructure development require dependable energy sources.
A successful geothermal project could support industrial clusters in southern Tanzania and potentially attract energy-intensive industries to the region.
3. Regional Integration
East Africa is increasingly becoming interconnected through regional power pools and cross-border electricity trade. Additional geothermal generation capacity could eventually strengthen Tanzania’s position within regional energy markets.
4. Climate Goals
Geothermal energy is considered one of the cleanest forms of baseload electricity generation. Expanding geothermal capacity could help Tanzania reduce future carbon emissions while supporting sustainable development objectives.
Details of the Tender
According to the invitation issued by TGDC, the tender covers the provision of services for three major operational areas:
- Drilling rig and accessories
- Cementing unit and accessories
- Mud engineering services
These services are essential components of geothermal drilling operations.
Drilling Rig Services
Geothermal drilling rigs are specialized systems capable of operating under extremely high temperatures and difficult geological conditions. Unlike conventional oil and gas drilling, geothermal wells often encounter corrosive fluids, fractured formations, and elevated thermal gradients.
The selected contractor will likely need to demonstrate extensive experience in geothermal or high-temperature drilling environments.
Cementing Operations
Cementing is critical in geothermal well construction because it stabilizes the wellbore, isolates geological formations, and protects casing strings from harsh subsurface conditions.
In geothermal environments, cement must withstand thermal cycling and aggressive chemical exposure over long operational periods.
Mud Engineering
Mud engineering services are equally vital. Drilling fluids help cool drill bits, stabilize formations, transport cuttings to the surface, and manage subsurface pressure conditions.
Geothermal drilling mud systems must be carefully engineered due to high temperatures and unique geological characteristics.
The Importance of International Competitive Tendering
One of the most striking aspects of the TGDC announcement is the use of International Competitive Tendering (ICT).
This approach opens the project to experienced geothermal service providers from across the world, potentially attracting major drilling contractors and engineering companies with expertise in geothermal exploration.
International tendering can offer several advantages:
- Access to advanced drilling technologies
- Enhanced technical expertise
- Competitive pricing
- Improved operational standards
- Knowledge transfer opportunities for local professionals
The inclusion of joint ventures (JV) within the tender structure is also strategically important. It creates opportunities for collaboration between local Tanzanian firms and international geothermal contractors.
Such partnerships can help build local geothermal capabilities while ensuring compliance with international operational standards.
Why Drilling Is the Defining Stage of Geothermal Development
In geothermal energy development, drilling is often referred to as the “moment of truth.”
Surface surveys, geological mapping, geophysical studies, and geochemical investigations can provide valuable insights, but only drilling can confirm the actual characteristics of a geothermal reservoir.
Drilling determines:
- Reservoir temperature
- Fluid availability
- Pressure systems
- Permeability
- Resource sustainability
- Commercial viability
This explains why geothermal drilling campaigns attract significant industry attention.
Globally, drilling costs account for a substantial portion of geothermal project expenditures. Exploration wells can cost several million dollars each depending on depth, geology, and location.
The fact that TGDC is now moving into this stage demonstrates a growing level of confidence in the Ngozi prospect.
Tanzania’s Potential to Become East Africa’s Next Geothermal Hub
Kenya has long dominated Africa’s geothermal sector, with installed geothermal capacity exceeding 1,000 MW. The country’s success has positioned it among the world’s leading geothermal producers.
Tanzania now appears determined to follow a similar path.
Several geothermal prospects across Tanzania have been identified over the years, including:
- Ngozi
- Songwe
- Natron
- Kiejo-Mbaka
- Luhoi
- Meru
- Manyoni
Many of these areas remain largely undeveloped despite strong geological indications.
If projects like Ngozi progress successfully, Tanzania could rapidly emerge as a major geothermal destination for investors, drilling contractors, technology providers, and energy developers.
The Strategic Role of TGDC
The Tanzania Geothermal Development Company plays a central role in the country’s geothermal ambitions.
Operating under the Tanzania Electric Supply Company (TANESCO), TGDC is tasked with spearheading geothermal exploration and development activities across the country.
Its responsibilities include:
- Resource assessment
- Exploration drilling
- Data acquisition
- Project development
- Investor engagement
- Technical coordination
The issuance of this international tender reflects TGDC’s growing operational momentum and its willingness to engage global geothermal expertise.
Global Geothermal Momentum Is Accelerating
The timing of Tanzania’s geothermal push is notable because geothermal energy is currently experiencing renewed global interest.
Several factors are driving this momentum:
Energy Security Concerns
Countries worldwide are seeking stable domestic energy sources amid geopolitical uncertainties and fossil fuel volatility.
Advances in Drilling Technology
Innovations originating from the oil and gas industry are increasingly being adapted for geothermal applications, reducing technical risks and improving drilling efficiency.
AI and Data Centers
The rapid expansion of artificial intelligence and data centers is increasing demand for reliable clean baseload electricity. Geothermal energy is increasingly viewed as a strong solution for powering next-generation digital infrastructure.
Climate Commitments
Governments and corporations are under increasing pressure to decarbonize energy systems.
As a result, geothermal investment is expanding across Africa, Asia, Europe, and North America.
Tanzania’s Ngozi project therefore enters the market at a time when global geothermal interest is intensifying.
Economic Opportunities Emerging from the Tender
The TGDC tender could generate substantial economic opportunities across multiple sectors.
Service Industry Expansion
Geothermal projects require a wide ecosystem of suppliers and contractors, including:
- Drilling services
- Logistics
- Engineering
- Equipment rental
- Transport
- Environmental consulting
- Civil works
- Safety services
This creates opportunities for local Tanzanian businesses to participate in geothermal supply chains.
Employment Creation
Drilling campaigns require geologists, engineers, technicians, machine operators, environmental specialists, welders, logistics coordinators, and numerous support personnel.
As geothermal activity expands, Tanzania could witness the emergence of a specialized geothermal workforce.
Skills Transfer
International partnerships often create valuable technical training opportunities for local professionals.
Knowledge transfer in areas such as drilling operations, reservoir engineering, geothermal chemistry, and well integrity management could strengthen Tanzania’s domestic geothermal expertise.
Challenges That Still Remain
Despite the optimism surrounding the Ngozi project, geothermal development remains a highly challenging sector.
High Capital Costs
Geothermal projects require significant upfront investment long before electricity generation begins.
Exploration Risks
Not all wells become commercially productive. Exploration drilling carries geological uncertainty.
Infrastructure Requirements
Remote geothermal fields often require roads, water systems, power infrastructure, and logistics support.
Technical Complexity
High-temperature geothermal environments demand specialized expertise and advanced engineering solutions.
Nevertheless, successful geothermal nations have demonstrated that long-term benefits can outweigh these challenges.
East Africa’s Geothermal Race Is Intensifying
East Africa is increasingly becoming one of the world’s most exciting geothermal regions.
Countries including Kenya, Ethiopia, Djibouti, Rwanda, Uganda, and Tanzania are all pursuing geothermal development strategies.
Tanzania’s latest tender signals that competition and collaboration within the region could intensify in coming years.
International geothermal firms may now begin paying closer attention to Tanzanian opportunities, especially as global demand for clean energy investments continues rising.
What Success at Ngozi Could Trigger
If the Ngozi drilling campaign confirms commercially viable geothermal resources, several major developments could follow:
Large-Scale Production Wells
Slim wells are often followed by larger production drilling campaigns.
Power Plant Development
Confirmed reservoirs could lead to geothermal power station construction.
Foreign Direct Investment
Successful exploration results often attract infrastructure financiers and energy investors.
Expanded Exploration
Positive results could accelerate development at Tanzania’s other geothermal prospects.
Regional Industrialization
Reliable geothermal power could stimulate economic activity across southern Tanzania.
Why This Tender Matters Beyond Tanzania
The TGDC announcement is important not only for Tanzania but also for the wider African geothermal landscape.
Africa possesses some of the world’s largest untapped geothermal resources, yet development has historically lagged due to financing constraints, technical barriers, and infrastructure limitations.
Projects like Ngozi demonstrate that African geothermal momentum is evolving from theoretical potential toward tangible execution.
The tender also highlights how governments are increasingly embracing structured procurement processes to attract international expertise and private-sector participation.
A New Phase for Tanzania’s Clean Energy Future
The invitation to tender for drilling rig services, cementing operations, and mud engineering at the Ngozi geothermal project may appear technical on the surface, but its implications are far-reaching.
It represents:
- A strategic move toward energy diversification
- A major step in geothermal resource validation
- A signal of Tanzania’s growing geothermal seriousness
- An opportunity for international geothermal collaboration
- A potential catalyst for long-term industrial growth
For geothermal developers, drilling contractors, investors, and energy analysts, the Ngozi project will now become one of East Africa’s most closely watched geothermal developments.
If successful, Tanzania could position itself as one of the continent’s next major geothermal success stories.
The East African Rift continues to reveal its extraordinary geothermal promise, and Tanzania now appears ready to drill deeper into that future.
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