Potential for Lowering Greenhouse Gas Emissions With the Addition of Hydrogen or Ammonia to Different Natural Gas Compositions—Application in Internal Combustion Engines

Abstract

Internal combustion engines (ICEs) can be used in power plants to ensure flexibility in electricity generation. The use of carbon-free fuels, such as hydrogen and ammonia, in ICEs is a way to decrease greenhouse gas emissions gradually until new carbon-neutral technology has been fully implemented. By mixing small amounts of these compounds into natural gas (NG), the gas quality requirements can still be achieved and the modification work on the engine can be minimized. In this study, the CO_2eq emission intensity was calculated for different NG compositions blended with hydrogen or ammonia while the mixture was within the gas quality specifications. The results showed that the addition of ammonia reduces the CO_2eq emission intensity more than hydrogen and that the reduction depends on the NG quality. By utilizing H₂-NG and NH₃-NG mixtures as fuels in ICEs, the emissions can be reduced by 37%–44% and 3%–8%, respectively, compared to engines running on diesel oil or natural gas. The novelty of this study is to demonstrate the potential of cutting GHG emissions in power production using ICEs, new fuel blends, and fulfilling existing fuel requirements agreed on for engines.