Greenhouse gas and air pollutant emissions from power barges (powerships)

Power barges or powerships that operate on natural gas (NG) are an increasingly appealing easy-to-use solution to electricity deficits in Africa, Asia, the Middle East, and the Caribbean. Global generating capacity has increased from 0.1 to 2.6 GW, and 4.4 GW is under construction. South Africa has licensed three powerships to provide 1.2 GW generating capacity with foreign liquefied NG (LNG) over 20 years. To understand the importance of this source, we estimate lifecycle emissions of GHGs and air pollutants for South Africa and extend this to the global fleet. Annual lifecycle GHG emissions for 1.2 GW generating capacity total 2.6–3.8 Tg carbon dioxide equivalents (CO2e) using 100 year global warming potentials (GWPs). This increases to 4.0–7.1 Tg CO2e using 20 year GWPs, due to the potency of fugitive methane (CH4). Adoption of air pollutant emission control technology will need to be enforced to achieve compliance with national standards for fine particles (PM) and nitrogen oxides (NOx). A global fleet of 7.0 GW generating capacity reliant on domestic NG could emit 12 Tg CO2, 2.2–8.6 Tg CH4, 4.3 Gg NOx, and 2.6 Gg PM. Additional NOx and SO2 emissions would result from imported LNG, as LNG tankers burn dirty fuel oil, though SO2 emissions may be curtailed with recent stricter limits on the fuel sulfur content. These powerships could have important regional impacts, but emission estimates are uncertain. Characteristic emission factors, detailed operating conditions, and NG composition data are urgently needed to address uncertainties in emissions for air quality and climate modelling of this emergent source.