Tribological contributions to achieving carbon neutrality in Japan

As nations pursue carbon neutrality targets, tribological innovations represent a significant yet under-recognized pathway for emissions reduction. While renewable energy deployment and electrification dominate climate mitigation discourse, friction-related energy losses persist across transport, industry, and energy conversion sectors. This study quantifies tribology's potential contribution to Japan's 2050 carbon neutrality goal through systematic literature review and sector-specific modeling. A comprehensive review of 77 peer-reviewed studies established tribological intervention potentials across six key sectors: transportation (road and aviation), renewable energy, energy production and electrification, hydrogen technologies, industrial operations, and manufacturing. These interventions encompass friction reduction through advanced lubricants and coatings, wear mitigation via surface engineering, and lifecycle extension of mechanical components. Sector-specific reduction potentials are modeled using Japan's 2022 emissions baseline (964 Mt CO₂) and projected energy transition pathways according to national policy documents, with sensitivity analysis across conservative, central, and ambitious deployment scenarios. Results indicate that tribological optimization could reduce Japan's annual emissions by between 42 and 167 Mt CO₂ by 2050, representing 4.4 to 17.4% of baseline emissions. Transportation systems show the highest absolute potential (30–38% of tribological reductions), while renewable energy demonstrates strong proportional contributions in conservative scenarios. Industrial operations and electrification exhibit increasing importance under ambitious technological advancement scenarios. This study demonstrates that tribology functions as a cross-sectoral enabling technology rather than a standalone solution, amplifying the effectiveness of renewable energy, electrification, and hydrogen systems. Policy integration, targeted R&D investment, and lifecycle-based standards are recommended to mobilize this pragmatic, engineering-grounded pathway toward carbon neutrality.