The Power to Flex project aims to promote the development of storage possibilities from sustainable energy sources. Hydrogen is opted to be a feasible energy carrier, which can also be stored for prolonged times without further losses and can be transformed into electricity and heat when needed. Producing hydrogen from electrolysis processes has a low CO2 footprint, however the efficiency at both the system, stack and cell level still increases due to further research and development.Electrolysis is conventionally performed with direct current, of which the energy is usually supplied from the grid. Rectifiers are necessary to provide the energy source for electrolysis, which unfortunately waste some of the efficiency, albeit becoming more efficient. Although it is known that distortions, harmonics and ripple, in the current supply can cause decreased performance of the electrolysis, a fundamental understanding is often not provided in published research. Controlled modulation of the electrolysis process can however form a possibility to enhance the performance of electrolysis
Excess of renewable electricity from wind turbines or solar panels is used for electrolysis of water. To store this renewable energy as methane, the hydrogen is fed to an anaerobic digester to stimulate biological methanation by hydrogenotrophic methanogens. This workpackage focusses on the best ways for hydrogen delivery and the community changes in a biomethanation reactor as a result of hydrogen supply.
Wind and solar power generation will continue to grow in the energy supply of the future, but its inherent variability (intermittency) requires appropriate energy systems for storing and using power. Storage of possibly temporary excess of power as methane from hydrogen gas and carbon dioxide is a promising option. With electrolysis hydrogen gas can be generated from (renewable) power. The combination of such hydrogen with carbon dioxide results in the energy carrier methane that can be handled well and may may serve as carbon feedstock of the future. Biogas from biomass delivers both methane and carbon dioxide. Anaerobic microorganisms can make additional methane from hydrogen and carbon dioxide in a biomethanation process that compares favourably with its chemical counterpart. Biomethanation for renewable power storage and use makes appropriate use of the existing infrastructure and knowledge base for natural gas. Addition of hydrogen to a dedicated biogas reactor after fermentation optimizes the biomethanation conditions and gives maximum flexibility. The low water solubility of hydrogen gas limits the methane production rate. The use of hollow fibers, nano-bubbles or better-tailored methane-forming microorganisms may overcome this bottleneck. Analyses of patent applications on biomethanation suggest a lot of freedom to operate. Assessment of biomethanation for economic feasibility and environmental value is extremely challenging and will require future data and experiences. Currently biomethanation is not yet economically feasible, but this may be different in the energy systems of the near future.
In the course of the “energie transitie” hydrogen is likely to become a very important energy carrier. The production of hydrogen (and oxygen) by water electrolysis using electricity from sun or wind is the only sustainable option. Water electrolysis is a well-developed technique, however the production costs of hydrogen by electrolysis are still more expensive than the conventional (not sustainable) production by steam reforming. One challenge towards the large scale application of water electrolysis is the fabrication of stable and cheap (noble metal free) electrodes. In this project we propose to develop fabrication methods for working electrodes and membrane electrode stack (MEAs) that can be used to implement new (noble metal free) electrocatalysts in water electrolysers.
Surface Active Agents, or surfactants, are chemicals which provide a surface (interface) activity when dispersed in liquids. They have different purposes, can be used as herbicides, anti-foaming agents, adhesives, cleaning agents and softeners. For cleaning purposes, their function is to alter (decrease) liquid surface tension. In this function they are ubiquitous in both industrial processes (cleaning of production equipment, storage vats, packaging lines, and cooking units either during the manufacturing process) and domestic applications. ProtoNeat proposes an alternative way to decrease water surface tension without adding chemicals (surfactants). This can be done by charging the water (producing protonically charged water) [2], i.e. positive and negative Bjerrum-defect like charges [3, 4]. This phenomenon was experimentally observed by Fuchs et al [5] in anolyte and catholyte when doing high voltage electrolysis of highly pure water during the so-called ‘floating water bridge’ experiment. The work done by the authors, when working with this “bridge”, showed that, in case of positive excess charge, the hydronium ions migrate to the surface [8] thereby significantly lowering the surface tension [9,10]. However, for how long this effect can be maintained and how effective it is to produce such water is still unknown. ProtoNeat wants to tackle these two questions and investigate whether a continuous production of protonically charged water as an environmentally friendly and sustainable cleaning agent is possible.
