Barriers and opportunities for the deployment of CO₂ electrolysis in net-zero emissions energy systems

As energy systems across the globe transition toward net-zero emissions, the decarbonization of hard-to-decarbonize sectors, e.g., industry and transportation, is becoming more crucial. Renewable power-driven carbon dioxide (CO2) electrolysis has the potential to facilitate this transition by (1) substituting carbon-intensive petrochemical and fuel production and (2) using CO2 otherwise emitted from industrial processes or CO2 from the atmosphere; however, because of existing technical and economic challenges, the industrial deployment of this technology is not yet imminent. Here, we present an overview of CO2 electrolysis technologies to identify key hurdles in view of the industrial deployment of this technology in net-zero emissions energy systems. From the technology standpoint, catalysts should be developed with enhanced activity, selectivity, and stability/durability as well as membranes and reactors that prevent carbonate formation or crossover, achieve higher reaction rates, e.g., >1 A/cm2, and demonstrate long-term stability, e.g., >5 years. Conversely, from the system integration standpoint, impurity-tolerant CO2 electrolysis systems need to be developed and tested under relevant conditions, e.g., CO2 streams with traces of impurities (NOx, SOx, O2, N2, H2S, etc.). Additionally, the quantification of pros and cons of different integration pathways for CO2 capture and CO2 electrolysis requires further research. Moreover, the integration with variable renewable power sources—e.g., wind and solar photovoltaic power—and electricity markets requires a better understanding. For instance, the value of CO2 electrolysis flexibility in view of variable renewable power supply or dynamic electricity prices is not well understood.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ChemE/Materials for Energy Conversion and StorageChemE/Product and Process Engineerin

Review of wind generation within adequacy calculations and capacity markets for different power systems

The integration of renewable energy sources, including wind power, in the adequacy assessment of electricity generation capacity becomes increasingly important as renewable energy generation increases in volume and replaces conventional power plants. The contribution of wind power to cover the electricity demand is less certain than conventional power sources; therefore, the capacity value of wind power is smaller than that of conventional plants. This article presents an overview of the adequacy challenge, how wind power is handled in the regulation of capacity adequacy, and how wind power is treated in a selection of jurisdictions. The jurisdictions included in the overview are Sweden, Great Britain, France, Ireland, United States (PJM and ERCOT), Finland, Portugal, Spain, Norway, Denmark, Belgium, Germany, Italy and the Netherlands.Energy & Industr

Closing the Loop: Unexamined Performance Trade-Offs of Integrating Direct Air Capture with (Bi)carbonate Electrolysis

CO2 from carbonate-based capture solutions requires a substantial energy input. Replacing this step with (bi)carbonate electrolysis has been commonly proposed as an efficient alternative that coproduces CO/syngas. Here, we assess the feasibility of directly integrating air contactors with (bi)carbonate electrolyzers by leveraging process, multiphysics, microkinetic, and technoeconomic models. We show that the copresence of CO32- with HCO3- in the contactor effluent greatly diminishes the electrolyzer performance and eventually results in a reduced CO2 capture fraction to ≤1%. Additionally, we estimate suitable effluents for (bi)carbonate electrolysis to require 5-14 times larger contactors than conventionally needed contactors, leading to unfavorable process economics. Notably, we show that the regeneration of the capture solvent inside (bi)carbonate electrolyzers is insufficient for CO2 recapture. Thus, we suggest process modifications that would allow this route to be operationally feasible. Overall, this work sheds light on the practical operation of integrated direct air capture with (bi)carbonate electrolysis.ChemE/Process Systems EngineeringChemE/Materials for Energy Conversion and Storag