Swappable Hydrogen Storage Tanks for Land Mobility

Climate change from anthropogenic carbon dioxide emissions to the atmosphere from fossil fuel combustion poses a major threat to civilisation. Data by the World Bank shows transport accounts for roughly 23 % of global CO2 emissions and of this, motor vehicles are responsible for the majority. Yet there is currently a lack of lack of suitable alternative fuel, this must change to meet the Paris COP-21 agreement reduction targets.

Hydrogen has been identified as a promising energy vector able to bring renewable energy into homes, industry and transport which are areas that so far have struggled to adopt more sustainable technology. It is a flammable gas that can be renewably generated from the electrolysis of water or processing of other sources like biomass. Hydrogen can be liquified and in that form is a popular rocket fuel with potential for commercial aviation.

Hydrogen fuel-cell vehicles commonly use a PEM-type fuel-cell to convert hydrogen gas and oxygen into water vapour generating electrical energy that can drive an electric motor to propel the vehicle forward without the harmful emissions that are associated with an equivalent fossil fuelled combustion engine. This provides an immense benefit to both local air quality and global progress towards reducing carbon emissions.

Currently there are many challenges to utilising renewable energy for a vehicle with alternatives like electric batteries suffering from issues like low energy-density, high costs of materials and relative immaturity of the technology. Hydrogen on the other hand is most gravimetrically energy dense fuel available storing more energy per kilogramme than any other chemical fuel.

However, it suffers from a very low volumetric density, meaning that the gas is impractical to use as fuel without being compressed or liquified resulting in a storage challenge that must be addressed. Current rapid high-pressure or liquid hydrogen refuelling methods require significant infrastructure investment, lower well-to-wheel efficiency and have safety concerns towards the user.

The objective of this project is to address one of the biggest parts of the storage challenge which is the refuelling of the storage tank on the vehicle, developing a novel method in the form of swappable refuelling whereby tanks are swapped out and then refuelled externally. Analysis into the feasibility of such a system will be carried out as a desk-based study with key factors such as the hypothetical performance, infrastructure required as well as the carbon and energy savings possible compared against current methods.

The development of a digital twin and desk-top prototype is key to determining the viability of such a system and for demonstration purposes.

A swappable system has the potential to make renewable propulsion technologies more viable for everyday use bringing a direct reduction to carbon emissions by overcoming the existing challenges of range and refuelling holding back current vehicle offerings. Benefits like increased safety, lower energy consumption and increased accessibility of refuelling infrastructure can come from this project.

This is relevant to the EPSRC goals of delivering sustainable innovations that improve everyday life and tackle climate change.