Environmental sustainability of renewable hydrogen in comparison with conventional cooking fuels

Hydrogen could be used as a 'cleaner' cooking fuel, particularly in communities that rely on biomass and fossil fuels, to reduce local pollution and related health effects. However, hydrogen must be produced using sustainable feedstocks and energy sources to ensure that local impacts are not reduced at the expense of other impacts generated elsewhere in the life cycle. To this end, this paper evaluates life cycle environmental impacts of renewable hydrogen produced in a proton-exchange membrane electrolyser using solar energy. The aim of the study is to find out if hydrogen produced in this system and used as a cooking fuel is environmentally sustainable in comparison with conventional cooking fuels typically used in developing countries, such as liquefied petroleum gas (LPG), charcoal and firewood. The results suggest that hydrogen would reduce the climate change impact by 2.5–14 times to 0.04 kg CO2 eq./MJ compared to firewood (0.10 kg CO2 eq./MJ) and LPG (0.57 kg CO2 eq./MJ). Some other impacts would also be lower by 6%–35 times, including depletion of fossil fuels, summer smog and health effects from emissions of particulates, both locally and across the rest of the life cycle. However, some other impacts would increase by 6%–6.7 times, such as depletion of metals and freshwater and marine ecotoxicity. These are mainly due to the solar photovoltaic panels used to generate power for the electrolyser. In terms of the local impacts, the study suggests that hydrogen would reduce local pollution and related health impacts by 8%–35 times. However, LPG is still environmentally a better option than hydrogen for most of the impacts, both at the point of use and on a life cycle basis.