Natural gas transportation in Africa is playing an increasingly important role in the continent’s economic and energy development. In 2023, North Africa, particularly Algeria and Egypt, dominates the sector with about 80% of the continent’s production. The African pipeline network extends over 30,000 km, including major projects such as the Trans-Saharan Pipeline (4,128 km planned) connecting Nigeria to Algeria. As of now, Africa has 7 LNG export terminals with a total capacity of 75.3 million tons per year, according to the Oxford Institute for Energy Studies. Mozambique is emerging as a key player, with LNG projects aiming to add 31 million tons per year of capacity by 2030. These transportation infrastructures are crucial for exploiting Africa’s vast reserves, estimated at 18.3 trillion cubic meters in 2022 by the BP Statistical Review, and play a vital role in regional energy integration and access to energy across the continent.

In Central Africa, investing in liquefied natural gas (LNG) projects could significantly enhance energy diversification and its share of continental production. Central Africa has significant natural gas reserves, estimated at about 290-350 billion cubic meters in 2024. However, regional consumption remains relatively low, accounting for less than 5% of total production. After extracting the gas through drilling and processing it at a plant, particularly to remove sulfur compounds and CO2, it must then be transported worldwide to consumers. Effective gas transportation is essential for maximizing these resources and stimulating economic development in Central Africa. However, the distance between reserves and consumption centers requires efficient and sustainable transportation solutions; thus, there is a need for continuous development of new infrastructure and transport strategies to meet the growing demand for natural gas. This article analyzes current and future technologies for natural gas transportation, focusing on their technical, economic, and environmental aspects.

1. The Role of the Central Africa Business Energy Forum (CABEF)

CABEF describes itself as a platform for fostering cooperation among Central African countries, aiming to use natural gas, a fossil fuel, to power homes, businesses, and the mining industry. This platform brings together public and private sector actors in the energy field to facilitate investments and infrastructure development.

With an estimated natural gas reserve of approximately 171.647 billion cubic meters in Cameroon as of April 2024, 764.5 billion cubic meters in Angola, and 100-120 billion cubic meters in the Republic of Congo, CABEF, through its Central Africa Pipeline System (CAPS) project, aims to create an integrated natural gas transportation network connecting the 11 Central African countries over a distance of 6,500 km. CAPS includes three multinational pipeline networks. The first, the Central North Pipeline System, connects Cameroon, the Central African Republic, and Chad; the second, the Central West Pipeline System, connects Equatorial Guinea, Gabon, and the Republic of Congo; and the third, the Central Southern Pipeline System, connects Angola, the Democratic Republic of the Congo, Rwanda, and Burundi. By establishing a series of hubs across Central Africa and creating interconnected pipeline systems capable of transporting various commodities, the region will be able to establish and benefit from an internal African market. To ensure flexible and efficient transportation in terms of energy, economic, and environmental aspects, the appropriate transport method for this project will consider innovations in materials and processes, distance, volumes to be transported, and geographical constraints to improve efficiency and offer new options for specific areas. In this context, the key issues will be:

  • Improving the energy efficiency of liquefaction and regasification processes;
  • Developing advanced materials for pipelines and storage tanks;
  • Optimizing CNG and hydrate technologies for commercial application;
  • Integrating advanced monitoring and control systems to enhance safety and reduce leaks.

2. Main Technologies for Natural Gas Transportation

The main current technologies for natural gas transportation are pipelines and liquefied natural gas (LNG) transport.

– Pipeline Transport

Pipelines represent a primary means of transporting gas. They are long pipelines that can extend over 3,000 kilometers, through which gas flows under pressure, typically between 80 and 200 bars for large transport networks. For safety reasons, these pipelines are usually buried underground but can also be installed underwater when transportation is needed in such locations. Pipelines are the predominant method for land-based natural gas transport.

Technical Aspects:

  • Pipeline diameter: Typically 20 to 48 inches (50 to 120 cm);
  • Materials: Mainly high-strength steel with corrosion-resistant coating;
  • Compression stations: Every 150-200 km to maintain pressure;
  • Losses: Primarily due to the consumption of compression stations.

Challenges:

  • Pipeline integrity: Prevention of leaks and corrosion;
  • Energy efficiency of compressors;
  • Costs: Initial investment costs (construction, equipment, impact studies, and permits); operating and maintenance costs, as well as end-of-life costs;
  • Better efficiency than road or rail transport for large quantities over long distances: Crossing geographically complex areas (mountains, rivers).

Environmental Challenges:

Pipelines present several environmental challenges:

  • Greenhouse gas emissions (Methane leaks, carbon dioxide emissions from burning gas to power compressors in compression stations);
  • Soil and water pollution (Risks of leaks and contamination, particularly during river crossings, use of chemicals for maintenance and corrosion protection);
  • Noise pollution (Noise from compression stations).

To mitigate these challenges, the industry is constantly developing new technologies and practices:

  • Use of advanced materials to reduce leaks;
  • Improvement of leak detection and repair systems;
  • Development of more efficient and less polluting compressors;
  • Increased use of clean energy to power compression stations.

– Maritime Transport of Liquefied Natural Gas (LNG)

LNG stands for liquefied natural gas. At temperatures below about -163°C and at atmospheric pressure, natural gas condenses. Its volume decreases six times more than when it is pressurized for pipeline transport. It then becomes more easily transportable by LNG carriers, which can be gigantic. Some have the capacity to transport more than 250,000 m³ of LNG. Upon arrival at the destination, LNG carriers unload their cargo at a terminal. The LNG is then regasified before being transported through pipelines to the distribution network.

Technical Aspects:

  • Liquefaction process: Typically a mixed refrigerant cascade cycle;
  • Cryogenic storage: Double-walled tanks with vacuum insulation;
  • LNG carriers: Typical capacity of 125,000 to 265,000 m³.

Challenges:

  • Energy efficiency of the liquefaction process (consumes about 10-15% of the treated gas);
  • Management of boil-off gas during transport;
  • Safety of cryogenic operations;
  • Emissions related to maritime transport: LNG carriers emit greenhouse gases and other pollutants;
  • Potential impacts on marine ecosystems in the event of an accident.
  1. Emerging Technologies

Considering the current challenges, new transportation technologies are under development, including:

– Transport in the form of Compressed Natural Gas (CNG).

Compressed Natural Gas (CNG) is natural gas that has been compressed, significantly reducing its volume compared to natural gas in its conventional form. Retaining all the properties of natural gas, CNG is stored in reservoirs that are up to 300 times the volume of its gaseous form.

CNG is compressed to about 250 bar using a compression station, and then stored in high-pressure tanks. It can then be distributed within a 400 km radius using specially designed trucks, providing an intermediate alternative between pipelines and LNG.

Potential Advantages:

  • Reduced processing and storage costs compared to LNG;
  • Increased flexibility for medium-sized markets;
  • Ambient temperature storage, unlike LNG which requires cryogenic temperatures;
  • For truck transport, CNG can lead to savings of around 30% on fuel.

Technical Challenges:

  • Development of lightweight and safe high-pressure storage containers;
  • Optimization of compression and decompression processes;
  • More costly to transport than gas via pipelines over long distances.

Emerging CNG Projects:

Although it is a new technology, several projects are already growing worldwide, including:

  • CNG Marine Transport: Developed by EnerSea Transport LLC in the United States, using specialized ships to transport CNG over medium distances.
  • Coselle CNG Project: Developed by Sea NG Corporation in Canada, which uses a coil technology to store CNG onboard ships.
  • ABS CNG Carrier: American Bureau of Shipping (ABS) has approved the design of a CNG carrier ship aimed at facilitating the transport of CNG over medium distances.

Hydrates Transport

Natural gas is mixed with water under controlled conditions to form hydrates, which are stored at atmospheric pressure and temperatures around -10°C to -20°C, and then transported in refrigerated ships, trucks, or trains. Upon arrival, the hydrates are warmed to release the natural gas. Transporting natural gas in the form of solid hydrates could increase the amount of methane transported while improving safety and facilitating transport at higher temperatures than LNG. Hydrates contain more methane molecules in a given volume than the gaseous form.

Potential Advantages:

  • Transport at higher temperatures than LNG (around -20°C);
  • Potentially higher energy density than CNG.

Technical Challenges:

  • Control of hydrate formation and dissociation;
  • Development of large-scale production processes.

The transportation of natural gas in the form of hydrates represents a potentially revolutionary innovation in the energy sector. This technology, at the intersection of chemistry, engineering, and logistics, offers a new perspective on how we can move and store energy globally.

These technologies could offer new options for natural gas transport, particularly for medium-sized markets or difficult-to-access regions.

In conclusion, the future of gas transportation in Africa is a complex and dynamic issue, influenced by numerous economic, political, and technological factors. The challenges and opportunities in this field include:

  • Financing: Infrastructure projects are large-scale and costly.
  • Energy Transition: To reduce greenhouse gas emissions, gas could play a « bridge » role towards renewable energies.
  • Political and Security Instability: Risks for large cross-border projects.

The choice of natural gas transportation method will remain a trade-off between technical, economic, and environmental factors, but technological advancements will continue to expand the available options for eradicating energy poverty in Africa by 2030.

References

The CABEF team