Air pollution is a key environmental challenge for the UK. The energy sector is a major source of air pollutants. Several strategies have been proposed to move to net zero emissions and each will have different implications for air pollution in the future. Our aim is to understand how adopting hydrogen technologies is likely to affect UK air pollution in the future.

Hydrogen is most likely to be used in hard-to-decarbonise sectors such as freight and industry, where electrification is technically challenging, and to replace natural gas heating in some homes and offices. But there are numerous other potential uses for hydrogen, and the allocation of future take-up is very uncertain.

We will examine a range of scenarios up to 2050 with different levels of hydrogen take-up, in different sectors, to understand the consequences for air pollution. These scenarios will be produced using the UK TIMES energy system model at UCL, which represents all substantive energy flows and greenhouse gas emissions in the UK.

Using hydrogen will enable us to reduce our consumption of polluting fuels such as oil and natural gas, and be an alternative to biomass where, for example, wood used for domestic heating can be highly polluting. We will use the UK Integrated Assessment Model (UKIAM) at Imperial College to examine the changes in air quality that might occur in the future due to adopting hydrogen in our scenarios.

UKIAM has been designed to study future air pollution abatement scenarios in the UK. It works at a 1 km resolution and can map how air quality might vary across the country in the future with associated assessment of health impacts and economic costs. We will use it to estimate the health impacts across the country of adopting hydrogen.

Hydrogen is likely to be produced from low-carbon electricity or natural gas in the UK in the future, but could also be imported in the form of liquid hydrogen or as a hydrogen-rich compound such as ammonia. Ammonia could have widespread use as a shipping fuel and could also power industry and heavy-duty road transport.

We will examine global hydrogen energy scenarios using the TIAM-UCL energy system model to understand the extent to which the UK might import hydrogen and ammonia in the future. It will also enable us to understand whether ammonia-powered shipping might operate in UK waters, and the air quality implications of these. Finally, as hydrogen is an indirect greenhouse gas, we will produce projections of future global hydrogen leakage so we can estimate the greenhouse gas impacts.