Biomass can be easily converted to fuel gases rich in CH4, CO, and H2, depending on the biomass treatment in anaerobic digestion, thermochemical conversion, or fermentation. The direct use of biomass-derived fuel in high-temperature fuel cells for combined heat and power (CHP) promises significantly higher electrical efficiencies of 55 to 60% and ultra-clean exhausts. Unlike for gas grid injection, the CO2 content in biogas does not have to be removed from the fuel stream, but can on the contrary be used as reforming agent (dry reforming) and increase the electrical efficiency. This greatly simplifies the system layout and avoids the supply of steam for reforming. In addition, separation of leftover bio-CO2 after the CHP generation process will be straightforward and can bring significant benefit to the use of High Temperature Fuel Cells (HTFC) CHP systems in future CO2 valorisation scenarios. For all of these reasons HTFC systems have the potential to achieve technical, environmental and economic advantages relative to currently available biogas conversion technologies.
The use of HTFC is currently being demonstrated in ongoing projects. In particular, the FCH 2 JU funded project DEMOSOFC is demonstrating the use of biogas from a wastewater treatment plant for heat and power production using a HTFC. In this project, the HTFC requires to first clean-up and purify the biogas to grid quality prior to conversion into power and heat. This represents a significant added cost to the overall system, hindering cost-effective exploitation of the technical and environmental advantages of the use of raw biogas in HTFC.
Biogas is primarily methane (CH4) and carbon dioxide (CO2). Depending on its origin, it usually contains small amounts of hydrogen sulphide (H2S), moisture and siloxanes, or also significant amounts of nitrogen in the case of landfill gas. The removal of pollutant and CO2 for the purpose of grid injection is increasingly applied for wastewater treatment plants, which often are located close to the gas grid and present significant volumes of gas. However, biogas from distributed sources such as agricultural waste and manure, or dilute gases like from landfill, are rarely injected. Farms are usually not connected to the gas grid, and in the case of landfill gases, it is rarely economic to concentrate the methane to grid quality. In the latter case, it is even common practice to add methane to the biogas to flare(burn) the gas in order to prevent the methane to vent directly to the atmosphere. This transforms a primary fuel in an energy consumer.
HTFC are in principle able to able to exploit the contained CO2 to increase the conversion efficiency by using the CO2 as reforming agent. The so-called dry-reforming process is replacing then either steam-methane reforming or the catalytic partial oxidation commonly used in fuel cell systems. HTFC as electrochemical energy conversion devices have a high resilience to inert gases such as nitrogen compared to combustion engines. The fuel cell exploits directly the chemical energy contained in the fuel without a combustion process. Independent from above elements, the pollutants such as sulphur components, halogens and siloxanes still need to be removed.
The challenges addressed is to perform the pollutant removal for the HTFC in a simple, low-cost, modular manner, capable to operate on multiple feedstock sources of biogas (organic fraction of urban waste, agricultural/farming residues, landfill, etc.). The removal needs to be able to cope with seasonal or geographical variations, and to reduce significantly complexity and costs related to biogas pre-processing. On the level of system integration, the appropriate conditions for the use of dry-reforming instead of steam reforming with a minimal changes with respect to standard HTFC systems is a further challenge, as only limited customisation can be economically justified. Furthermore, HTFC system operation strategies need to be elaborated to allow system operation with dilute fuels, again with ideally no hardware changes with respect to standard HTFC systems.
The scope of the project is to design and engineer an integrated biogas-fed fuel cell system architecture with minimal gas pre-processing. The aspects of low-cost pollutant removal and thermal integration of the system to increase the system efficiency by using the inherent CO2 of the biogas should be the focus of the project. Operation strategies allowing the system to use dilute gases should also be studied.
Proposals submitted under this topic should focus on the conceptual and detailed design of a HTFC-CHP system optimised for raw biomass-derived gaseous fuel operation in a real environment, processing different types of biogas feedstock, coping with gas composition fluctuations and pollutants. More than one type of biogas should be considered, especially considering applications where conversion to bio methane and injection into the natural gas grid is not feasible. In the design, gas fuel pre-processing should be kept to the absolute minimum, integrating potentially processing catalysts for pollutant removal and fuel pre-reforming. The interface between the raw (2nd generation) biomass processing reactor and the fuel cell hot module should be a unique, one-stop appliance that is able to process the full range of bio fuel-gas compositions expected from a given bio-waste valorisation chain. The output gas has to match the requirements of the fuel cell module optimized for bio fuel-gas conversion.
To this effect, targeted tests on clean up, reforming and HTFC materials and components (catalysts, supports, adsorbents, membranes, cells/stacks), where not available from the state-of-the-art, are within the scope of the project. They aim to provide pollutant tolerance level of the critical components of a HTFC system and will provide the base for the final design specifications of the gas cleaning unit. The impact of dry reforming on anode electrodes, to avoid auxiliary steam supply in the system should be evaluated at laboratory scale and reported according to procedures developed in relevant FCH 2 JU projects.
The one-stop bio fuel-gas processing stage should take into account outcomes of previous projects investigating this coupling, such as DEMOSOFC. Where applicable, thermal integration between the FC module and the bio fuel-gas generation should be considered in the system architecture to maximize process efficiency.
Developments that directly modify and adapt the stack and/or reformer to increase their pollutant tolerance levels should only be planned where reduced total cost of ownership for the generated electricity can be expected. This is always to be analysed in comparison with the current base method of purification for pollutant removal.
The design of full-scale FC-CHP units for installation at biogas production sites should be addressed in the project. This should include pathways for the use of bio-CO2 produced. The selection of the size of full-scale should be based on existing market analysis with clear indications of the technical and economic advantages in comparison to both other power conversion technologies (e.g. combustion engines) and gas grid injection.
TRL at start: 3 and TRL at end: 5-6.
At least 2 HTFC manufacturers should participate to open an opportunity to exploit the built-up competences in biogas pre-treatment independently from the FC system manufacturer, offering a business opportunity for specialised actors.
Any safety-related event that may occur during execution of the project shall be reported to the European Commission's Joint Research Centre (JRC) dedicated mailbox JRC-PTT-H2SAFETY@ec.europa.eu, which manages the European hydrogen safety reference database, HIAD.
Test activities should collaborate and use the protocols developed by the JRC Harmonisation Roadmap (see section 3.2.B "Collaboration with JRC – Rolling Plan 2018"), in order to benchmark performance of components and allow for comparison across different projects.
The FCH 2 JU considers that proposals requesting a contribution of EUR 1.5 million would allow this specific challenge to be addressed appropriately. Nonetheless, this does not preclude submission and selection of proposals requesting other amounts.
A maximum of 1 project may be funded under this topic.
Expected duration: 2 years
The use of HTFC-CHP systems is well aligned with European energy and waste related policies. The EC communication on “The role of waste energy in the circular economy”  prioritises the use of advanced conversion technologies to obtain bio-derived gas especially for the treatment of biodegradable waste. The expected impact of biomass driven HTFC is therefore very high being a very significant entry market for the deployment of renewable sources-driven HTFC in the medium industrial scale. Based on the modularity of fuel cells, they will likely address initially smaller, distributed power ranges, before addressing at a later stage the large quantities of low quality gases of landfill and retired coal fields.
To profit from this opportunity, the specific impacts the proposed design should achieve are then:
Footnote  Brussels, 26.1.2017 COM(2017) 34 final
Type of action: Research and Innovation Action
The conditions related to this topic are provided in the chapter 3.3 and in the General Annexes to the Horizon 2020 Work Programme 2018– 2020 which apply mutatis mutandis.