Real Zero: Assessing the feasibility of a fossil free energy system by mid-century

Achieving net zero greenhouse gas emissions has become a dominant framework for climate action, with regions, countries and corporations all pledging to reach net zero by around mid-century. However, some net zero pledges rely heavily on carbon capture and storage (CCS) and carbon dioxide removal (CDR) to compensate for continued fossil fuel combustion, rather than eliminating fossil fuels entirely. This approach presents significant risks, as CCS faces fundamental technological and geophysical limitations, while available CDR capacity must be prioritized for temperature reduction rather than enabling continued fossil fuel emissions.

This study introduces the concept of "real zero"—the complete elimination of fossil fuels through replacement with zero-carbon alternatives—and assesses its technical feasibility across five critical sectors: road freight, steel production, international shipping, power generation, and light-duty vehicles. We analyse two complementary lines of evidence: (1) deep decarbonization pathways from global integrated assessment models, and (2) sector-specific bottom-up modelling and industry roadmaps.

Our analysis demonstrates that real zero is achievable in leading regions during the 2040s in many key sectors. The power sector shows the earliest dates of real zero, with multiple IAM frameworks achieving real zero by the late 2030s to early 2040s through solar and wind deployment. For trucking, real zero could be reached as early as 2040 in Europe, driven primarily by battery electric vehicles which offer superior economics and efficiency compared to alternatives. Light-duty vehicles follow a similar trajectory, with electrification enabling real zero by the early 2040s.

Steel production presents greater divergence between our lines of evidence, with the earliest IAM scenarios reaching real zero by 2040 in some regions, though broader literature suggests the 2050s as a more conservative target. A real-zero pathway here relies on expanding secondary steel production via electric arc furnaces and deploying hydrogen-based direct reduction for primary production. International shipping can achieve real zero by 2050, with ammonia emerging as the most viable zero-carbon fuel, complemented by direct electrification for shorter routes.

Beyond these findings, we will outline key parameters for an expanded research agenda on real zero, to help facilitate a community discussion on the analysis required to further interrogate the assumptions behind net zero targets.