The EU, UK and Scottish legislations are quickly establishing limits for emissions to reach the Paris agreement targets, which requires a fast decarbonisation of our energy systems, shifting away from traditional “fossil-based” energy sources, but also involves finding alternative routes for the sustainable production of chemicals and materials. To reach these goals, two deeply interconnected challenges need to be addressed: (i) new energy vectors that can act as clean and efficient energy carriers substituting fossil fuels are needed and (ii) the intrinsic intermittent nature of renewable energy sources needs to be buffered by efficient methods of energy storage and subsequent conversion (which includes, but is not limited to, storage in the form of an energy vector).
Storing energy from renewables as hydrogen is now widely regarded as a potential solution for the future of energy security and sustainability. Hydrogen is also a valuable feedstock for the production of other fuels and materials (ammonia, methanol) which result in CO2 emissions because they use hydrogen from reformate and/or because they require significant energy inputs. Currently, hydrogen is obtained primarily from non-renewable sources, i.e., methane reforming, producing so-called grey (without CCS) or blue (with CCS) hydrogen, due to its low price compared to water electrolysis. At the moment, there are challenges to promote the generation of green hydrogen and the implementation of hydrogen economies, which can be summarised as, but not limited to: (i) generation, separation, purification (reduction of price of electricity obtained from solar/wind, alternative and direct conversion methods for hydrogen from sunlight); (ii) transportation and storage (establishing a safe and cost-effective network for hydrogen distribution); (iii) usage (increase impact on final users, broadening H2 markets, consolidating vehicular/stationary power generation and developing opportunities for heat generation; costumers/society awareness). Overall, these actions target to reach estimated costs of hydrogen production to levels that are competitive without any support mechanism, and the integration in circular economies.
Depending on the final application, storage of electricity from renewables using batteries can be a better option. Current battery technology is dominated by Li-ion batteries and intense research is being dedicated world-wide to increasing their energy density. New electrolytes and other types of batteries (Li-air, Al-air, Li-sulfur, Na-ion, Mg-ion, etc) are being explored and although the challenges vary slightly depending on the actual technology, they can be summarised in three: (i) achieving sufficiently high energy and power density, (ii) safety (eliminate diminish danger of combustion or explosion) and (iii) cost/durability.
The most likely scenario for the future energy landscape is one in which hydrogen as an energy vector is combined with storage in batteries to target the necessities of each specific application and in Aberdeen’s CET we wish to contribute as much as possible to this transition.
- Establishing models for hydrogen production/consumption.
- H2 – electrical networks integration, smart cities.
- Selective materials/technologies for H2 separation.
- Development of new photocatalytic technologies (materials, processes) for direct conversion of solar energy to H2 and other chemicals.
- New catalytic and electrocatalytic process for H2 production/conversion into products (including hydrogenation of CO2 and N2).
- Renewable sources for hydrogen production other than photocatalytic (biomass, hydro, geothermal, solar, wind, biological).
- Mechanical/chemical optimisation for H2 transportation/storage.
- Underground H2 storage.
- Optimising existing and developing new electrolysers, fuel cells and battery technologies.
- Impact of H2 technologies on transport networks (refiling stations).