FlowPhotoChem (FPC) is an EU-funded research project that aims to design, develop, and translate to market new materials (photoabsorbers, catalysts, membranes) and flow reactors which can use solar energy and CO2 to produce non-fossil chemical feedstock and high-value chemicals, such as hydrogen (H2) and ethylene (C2H4), through more efficient management of sunlight, more efficient reactors, and longer-lasting catalysts. The FPC system combines three types of flow reactor modules, namely Photoelectrochemical (PEC), Photocatalytic (PC), and Electrocatalytic (EC), producing mainly H2, CO and C2H4, respectively, focusing on efficiency, scalability, and sustainability to minimise resources use and waste generation and meet the increasing demand for sustainable processes in the chemical industry.
The FPC Project follows the sustainable-by-design principles by including environmental criteria from an early stage of the technology conception and development.
In the FPC research stage, a preliminary environmental assessment has been carried out for the selection of the candidate materials (e.g., HER catalysts, OER catalysts, membranes). The energy and mass balances required to produce the materials, as well as their performance, production capacity, lifetime, and stability, have been identified and translated into potential environmental impacts. Two main challenges have been encountered: i) inventory data are available at laboratory scale with certain limitations as they are not reflecting e.g., higher efficiencies of large-scale production and ii) the lack of inventory datasets for some chemicals in Life Cycle Analysis (LCA) databases. To overcome this, i) laboratory-scale data have been scaled up to pilot and demo scale based on knowledge of technical WPs and using simulation systems, leading to LCA results more representative and closer to reality and ii) inventory datasets for some missing chemicals have been created using stoichiometric ratios. In addition, the project aims to develop catalysts based on non-critical raw materials (CRM); therefore, resource criticality defining a unitary supply risk is also assessed complementing the LCA environmental impact category of resources use, minerals and metals.
In the second phase, at the demonstration level, each individual reactor (PEC, PC and EC), including the respective associated materials, is analysed, environmental hotspots are identified and recommendations for improvement are provided. For the three reactors, a comparison is made with competitive reference technologies. For example, in the case of the PEC reactor, the environmental impacts are analysed and compared with H2 production by wind-driven water electrolysis, so that we can see the impacts and benefits associated with both technologies. The integrated FPC system is assessed to produce our target chemical, C2H4, and compared to reference technologies. Given that the FPC technology is solar-powered, its optimal operation and performance depend on sufficient solar radiation. A sensitivity analysis is performed by exploring various scenarios of FPC operation across diverse global regions under different solar capacity conditions.
To provide a holistic view of the sustainability profile of the FPC system, a social and economic assessment is also being carried out using lifecycle-based methods, i.e., Social-LCA and Life Cycle Costing (LCC), respectively. The LCC assesses all relevant costs over the lifetime of the individual reactors and integrated FPC system, distributed by CAPEX (capital investment), OPEX (operation and maintenance) and end disposal costs (wastes) accounting for financial costs. The S-LCA assesses the potential social impacts associated with individual reactors and the FPC integrated system throughout their life cycle. It assesses at two different levels, the social impacts associated with (i) the supply chain (using social hotspots databases) and (ii) the implementation of the technology on-site (using targeted surveys of stakeholder groups). It is a systematic assessment framework that combines quantitative and qualitative data. Social impact categories (e.g., health and safety and labour rights) relevant to the project are defined, as well as key stakeholders (e.g., chemical feedstock industry and consumers).
In conclusion, FPC emerges as a promising modular and flexible solution, that converts CO2 and sunlight into high-value chemicals, avoiding the use of fossil fuels, critical raw materials, recycling wastes, water and the thermal energy generated between the individual reactors. The biggest challenge identified from a scientific-technological point of view, often seen with innovative solutions, is for FPC to reach industrial levels of production capacity and penetrate the market in competition with established incumbents. The technological transition involves the development of green policies for sustainable chemicals, as well as attracting investor interest in this type of technology. In terms of sustainability assessment, we are also facing the challenge of upscaling the FPC to full-scale commercialization. Leveraging techniques, learning curves, proxy technologies, and expert knowledge should be applied. Collaborative efforts are vital, fostering cooperation among experts from diverse fields, including technology developers, LCA specialists, and engineers. Given the nature of FPC as an emerging technology that is going to be deployed at a certain point in time, temporal consideration is crucial in both the inventory and impact assessment phases. With this in mind, the next step would be to evaluate the FPC system from a prospective approach, including the uncertainties associated with different predictive environmental and socio-economic scenarios, from the present to the future.
FlowPhotoChem researchers contributing to this work include Dr Ana G. Ramirez-Santos of the Leitat Technology Center, Dr Thomas Van Rensburg and Dr Luis Garcia Covarrubias of the University of Galway on the socioeconomic assessment and Dr Susana Leão of the Leitat Technology Center leading the working group and the cost and environmental assessments.