Abstract
Abstract Decarbonizing energy-intensive and other hard-to-abate sectors remains essential for meeting climate targets, yet these sectors continue to depend on fuels for high-temperature heat, chemical feedstocks, and energy-dense transport applications. This roadmap assesses the potential role of renewable synthetic fuels (RSFs) in supporting this transition, with a primary focus on the European context and on sectors including steel, cement, glass, aviation, shipping, and power generation. It reviews the current status of RSF combustion science, the high-fidelity experimental and numerical data needed to understand fuel behavior under relevant conditions, and the emerging hybrid physics-based and data-driven modeling approaches that can accelerate progress. Particular attention is given to digital twins and related cyber-physical tools as enabling technologies for process optimization, monitoring, scale-bridging, and industrial implementation. The roadmap also examines practical deployment barriers, including fuel availability, infrastructure, safety, regulatory and policy barriers, and data integration challenges. Developed in the framework of the CYPHER COST Action (CA22151), it highlights that large-scale RSF deployment will require coordinated action across research, industry, and policy, together with stronger business cases, policies that stimulate demand, and workforce development.