Carbon or Nitrogen-based e-fuels? A comparative techno-economic and full environmental assessment

Abstract

The increasing energy demand for mobility services and the growing concern about global warming have become significant drivers for these services’ decarbonisation. In this regard, the production and use of fuels obtained from just water, air and renewable energies instead of conventional fossil fuels have caught much attention within the research community. Recently, nitrogen-based e-fuels have been praised for their potential to satisfy mobility and transportation services with a reduced carbon footprint compared to their carbon-based analogues, given their carbon-neutral nature. To evaluate this hypothesis, we conducted a location-based, techno-economic and cradle-to-grave environmental assessment for solar methanol (MeOH) and ammonia (NH3) based on an optimisation model. Methanol and ammonia were considered for this study due to their relative ease of manufacture and lower production costs than complex fuels, e.g., FT-fuels, and the growing interest in using them as transportation fuels. From this analysis, we concluded that ammonia could have similar production costs, ca., 300 USD/GJ, but better environmental performance than methanol regarding global warming potential (GWP) and the three endpoint impact categories of the ReciPe 2016 LCA damage model, i.e., human health, ecosystems and resources. These results are highly dependent on the hydrogen storage options available; their costs and carbon footprints.