Market-focused UK innovation in fuel cells and H2, as funded by Innovate UK
Michael Priestnall, Innovate UK
Innovate UK is the UK Government's innovation agency. Global market opportunities for the products of UK research and Innovations are created by the need for clean, affordable and resilient energy. Commercially-focussed innovations in fuel cells and hydrogen technologies in development by UK business and research communities are in scope for the Energy Catalyst and other Innovate UK competitions. A selection of these innovations will be presented.
Natural and artificial photosynthesis and water splitting
Professor James Barber FRS, Imperial College London, UK
Demand for energy is projected to increase at least twofold by mid-century relative to the present global consumption because of predicted population and economic growth. This demand could be met, in principle, from fossil energy resources, particularly coal. However, the cumulative nature of carbon dioxide (CO2) emissions demands that stabilizing the atmospheric CO2 levels to just twice their pre-anthropogenic values by mid-century will be extremely challenging, requiring invention, development and deployment of schemes for carbon-neutral energy production on a scale commensurate with, or larger than, the entire present-day energy supply from all sources combined. Among renewable and exploitable energy resources, nuclear fusion energy or solar energy are by far the largest. However, in both cases, technological breakthroughs are required with nuclear fusion being very difficult, if not impossible on the scale required. On the other hand, 1 h of sunlight falling on our planet is equivalent to all the energy consumed by humans in an entire year. If solar energy is to be a major primary energy source, then it must be stored and despatched on demand to the end user. An especially attractive approach is to store solar energy in the form of chemical bonds as occurs in natural photosynthesis. However, a technology is needed which has a year-round average conversion efficiency significantly higher than currently available by natural photosynthesis so as to reduce land-area requirements and to be independent of food production. Therefore, the scientific challenge is to construct an ‘artificial leaf’ able to efficiently capture and convert solar energy and then store it in the form of chemical bonds of a high-energy density fuel such as hydrogen while at the same time producing oxygen from water. Realistically, the efficiency target for such a technology must be 10% or better. In his lecture Professor Barber will present the molecular details of the energy capturing reactions of natural photosynthesis, particularly the water-splitting reaction of photosystem II. Professor Barber will then describe how these reactions are being mimicked in physico-chemical-based catalytic or electrocatalytic systems with the challenge of creating a large-scale robust and efficient technology for storing solar energy in chemical bonds to provide fuel (e.g. green hydrogen).
The role of ‘green’ ammonia in decarbonising energy
Dr Rene Banares-Alcantara, University of Oxford, UK
The main challenge to substitute fossil fuels with renewable energy (RE) sources is the intermittency of the latter. Energy storage (ES) systems have been proposed as a solution to bridge intermittency as they can store RE, and use it when the energy demand is higher than the supply. Several types of ES technologies are available, and they differ in terms of their energy density, charge time, self-discharge, capacity, efficiency and cost. There are two important questions that need to be answered when selecting the most appropriate ES technology for a given problem: the amount of energy that needs to be stored, and the duration distribution of the stored energy. Both of these quantities depend on how well the RE and demand profiles match, but there is little discussion that both short and long term duration ES are needed in most situations.
We have been studying methods (a) to determine the distribution of short vs long duration storage requirements for different geographical locations, and (b) to size and cost long duration ES technologies. Our research focus has been the production of ‘green’ ammonia (using H2 produced via water electrolysis powered by RE) as opposed to ‘brown’ ammonia (using H2 from steam methane reforming (SMR)). ‘Green’ ammonia can be used as an energy storage vector, but in its current use as raw material for the production of fertilisers could also avoid the large amount of CO2 emissions originating from SMR (an estimated 1.3% of worldwide CO2 emissions).
The production of ‘green’ ammonia has been technically feasible for many years, but it has not been competitive economically. Recent models indicate that reductions in the cost of RE begin to make it possible to produce ‘green’ ammonia economically, but a competitive ammonia-based ESS would also need to account for the effect of intermittency as it affects the size and operation of the ESS. We have identified a number of key variables that influence the levelised cost of ammonia (LCOA) and have developed a model to quantify the dependence of LCOA with respect to those variables: energy source mix (solar PV, wind and grid), LCOE, electrolyser CAPEX, relative size of the ESS components, and load ramping capabilities for each of those components.
The talk will also briefly discuss future technologies that will provide further opportunities to reduce the cost of ‘green’ ammonia such as new electrolyser technologies and improved reactor design for ammonia synthesis.