Regional Focus: Balancing Africa’s world-class LNG projects and the environment

The construction of world-scale natural gas processing plants by three of Africa’s top natural gas producers has attracted scrutiny, despite efforts to commercialize the continent’s hydrocarbon resources and expand energy supply on the continent. This scrutiny has centered on how the project developers intend to achieve the overall goal of monetizing regional gas reserves while ensuring environmental sustainability.

The latest LNG projects in Mozambique, Angola and Nigeria, which are at various phases of implementation, have been forced to address adverse impacts such as liquid effluents, airborne noise, solid wastes, gas emissions, and even encroaching on land already settled or earmarked for settlement or other environmentally safer activities.

Multibillion-dollar gas processing projects include Mozambique LNG, Coral FLNG and Rovuma LNG (all in Mozambique), Angola LNG near Soyo in Angola, and Nigeria LNG Ltd.’s Train 7.

Project challenges in Mozambique. Mozambique LNG is operated by Total E&P Mozambique Area 1 Ltd., a wholly owned subsidiary of Total SA, with a 26.5% participating interest. Other partners include ENH Rovuma Area Um S.A. (15%), Mitsui E&P Mozambique Area 1 Ltd. (20%), ONGC Videsh Rovuma Ltd. (10%), Beas Rovuma Energy Mozambique Ltd. (10%), BPRL Ventures Mozambique BV (10%) and PTTEP Mozambique Area 1 Ltd. (8.5%).

Total, which had completed an estimated $16 B in funding for the Mozambique LNG project by July 2020, declared a force majeure on the project in April 2021 and withdrew all of its Mozambique LNG project staff from the Afungi site, after the security situation in the Cabo Delgado province deteriorated due to repeated insurgent attacks.

Meanwhile, the Coral FLNG project (FIG. 1) being developed by Eni and ExxonMobil involves producing and selling gas from the southern part of the Coral field, using a floating plant for liquefying natural gas with a capacity of 3.4 metric MMt, linked to six subsea gas producing wells. The vessel is set to depart the shipyard at the end of 2021, with production startup targeted for 2022.

FIG. 1. Eni and ExxonMobil’s 3.4-metric-MMt Coral South FLNG vessel is set to commence production in 2022. Photo credit: Eni.

Elsewhere, the 15.2-metric-MMtpy Rovuma LNG export project is earmarked for development to liquefy and market gas resources from three reservoirs in the Area 4 block of the Rovuma Basin offshore Mozambique. The project is owned by Mozambique Rovuma Venture, a JV of ExxonMobil, Eni and CNPC (70%), Galp (10%), KOGAS (10%) and Empresa Nacional de Hidrocarbonetos (10%).

Developments in Angola, Nigeria. In neighboring Angola, Chevron and Angola’s national oil company, Sonangol, are the co-leaders in the 5-MMtpy Angola LNG project west of Soyo. Other partners include Total, Eni and BP.

In West Africa, government-owned Nigerian National Petroleum Corp. (NNPC) has partnered with Eni, Total and Royal Dutch Shell to form the Nigeria LNG Ltd. consortium that is developing Train 7 of the Nigeria LNG terminal. With a capacity of 7.4 metric MMtpy, Train 7 will increase by 30% Nigeria’s total LNG output.

For Nigeria, one of the seven countries with the highest gas flaring rates in the world, the Train 7 project would enable utilization of associated gas that is co-produced with oil in the Niger Delta, but is largely flared to the atmosphere. However, according to the Train 7 Project Manager, Tony Attah, the construction of Train 7 will still increase the Nigeria LNG terminal’s overall greenhouse emissions.

The Train 7 project is located in Nigeria’s Bonny Island, where Attah says that “…climate change is materializing, increasing air emissions [that] threaten the ambient air quality, and [where] noise levels in urban areas approach the limits of acceptability.” Attah noted that investments in energy-efficiency improvements, dry-low NO_X technology and noise abatement are foreseen for the Train 7 project.

Environmental and social impacts. According to the World Bank, the ideal size for a gas processing plant to support reduction of flared gas is 0.3 MMsft³d–
25 MMsft³d. An estimated 400 MMtpy of CO₂-equivalent emissions (CO₂e/yr), including un-combusted methane and black carbon, are flared.

However, the LNG projects underway in Mozambique, Angola and Nigeria are world-scale, as opposed to the small-scale projects that the World Bank recommends for monetization of flared gas. Larger LNG projects, especially those in Mozambique, have been under scrutiny for their potential to adversely alter the sustainability of the environment or ecosystems where they are located, in addition to impoverishing communities around project sites.

For example, ExxonMobil says the Rovuma LNG project—which is expected to emit approximately 2.4 MMt of CO₂e/yr—has been classified as Category A because it has the potential for significant environmental and social impacts on the offshore and nearshore marine environment and the onshore area surrounding the LNG plant. The offshore environmental impacts of the project would include impacts on the marine environment due to the discharge of drill cuttings, residual muds and hydrotest water; increased marine traffic; and habitat modification.

According to ExxonMobil, key nearshore environmental impacts include dredging, increased noise, introduction of alien invasive species, waste discharges, and loss of estuary and associated mangroves. Furthermore, the company says that setting up a security (exclusion) zone around the LNG facility and associated nearshore infrastructure will impact artisanal fishermen, international maritime traffic, and national and regional marine traffic. Other anticipated impacts include those that trigger air emissions and noise, and those likely to affect visual landscape and impacts to soils, surface water, groundwater, vegetation, reptiles, amphibians, birds and mammals.

In 2014, a joint environmental impact assessment by Anadarko and Eni reported that the Mozambique LNG project would increase Mozambique’s greenhouse gas emissions from 0.4%/yr up to 10%/yr. “Given the scale and nature of the project … the overall significance of the impact is not expected to significantly change post-mitigation,” the companies wrote in their assessment report.

Meanwhile, a project brief indicates that works at the Angola LNG plant include the widening and deepening of the existing shipping channel at the mouth of the Congo River, the dredging of a turning basin for the LNG facility, and the improvement of the existing Kwanda basin. The dredged material is estimated at 28 MMm³.

In addition to dredging and land reclamation, the project involved the construction of 1.5 km of shore and slope protection, the installation of 4.5 km of drainage around the fill areas, the installation and monitoring of geo instrumentation, the installation of a concrete oil/water separator and flood valve, and the placing of navigation aids in the channel and basins.

Africa’s gas future. For Africa’s LNG projects, development of gas processing infrastructure to reduce flaring is a lesser driver compared to the increasing pressure on the continent’s gas producers to scale up production and processing to meet international export market demand, especially in Asia and Europe. Natural gas will also continue to be a key ingredient in Africa’s energy mix, as natural gas and LNG projects have the potential to generate essential electricity quickly, at reasonable prices.

Whether expanding Africa’s liquefaction capacity will support efforts to reduce gas flaring, expand sources of power generation or simply quench the global thirst for more LNG exports, environmental sustainability should remain a long-term concern issue for governments, project developers and consumers. GP