Defossilisation – The Next Chapter of the Energy Transition

Defossilisation – The Next Chapter of the Energy Transition Part 4: Hydrogen Powers the Future; Carbon Enables the Cycle The energy transition is increasingly looking to hydrogen as a future energy carrier. That direction has merit—but hydrogen alone does not answer one of the more fundamental questions facing the transition: What do we do with carbon? Carbon is not inherently the problem. Carbon is an essential element in fuels, chemicals, materials, agriculture and life itself. The deeper problem is our continuing dependence on new geological carbon extracted from coal, oil and natural gas and transferred into the active carbon cycle. This distinction is increasingly entering mainstream scientific discussion. In January 2026, Nature argued explicitly that achieving net zero means eliminating dependence on fossil sources rather than eliminating carbon itself, noting that carbon-based fuels and carbon-containing products will remain necessary in a net-zero economy. That is where hydrogen and circular carbon potentially become complementary. Hydrogen supplies energy. Carbon provides a carrier. Renewable hydrogen can provide chemical energy without introducing new carbon into a process. But hydrogen is difficult and costly to store, transport and integrate into some existing industrial and energy infrastructure. Carbon, by contrast, can form highly useful molecules such as methane and methanol. Instead of treating captured CO₂ simply as a waste requiring disposal, we can ask a different engineering question: Can recovered carbon become an inventory that is repeatedly circulated? For methane synthesis, the underlying chemistry is well established: CO₂ + 4H₂ → CH₄ + 2H₂O Hydrogen supplies the reducing energy. Carbon provides the molecular framework for the methane. The resulting methane can then be stored, transported and used through established gas infrastructure. If its carbon is subsequently recovered rather than continuously released, that carbon can potentially be returned to the synthesis process. The conceptual cycle becomes: Renewable electricity → H₂ → recovered carbon + H₂ → synthetic methane → useful energy → carbon recovery → synthetic methane again The important input progressively becomes energy, rather than replacement fossil carbon. Follow the carbon, not merely the fuel label Consider two methane molecules. Chemically they may be identical. One molecule may contain carbon freshly extracted from a geological gas reservoir. The other may contain carbon recovered from an engineered process and circulated for its second, tenth or hundredth cycle. Calling both simply “natural gas” or “methane” misses the fundamental difference in their carbon pathways. This is why I believe future energy accounting needs to examine three things separately: Fossil Carbon Intensity (FCI) — how much fresh geological carbon enters the system. Carbon Circularity (CC) — how effectively recoverable carbon is retained and reused. Carbon Emissions Intensity (CEI) — how much ultimately reaches the atmosphere. A system can therefore improve its carbon performance not merely by changing the fuel label, but by progressively reducing the amount of new fossil carbon crossing its system boundary. We can express that transition through a simple measure: Defossilisation Progress (%) = 100 × [1 − (FCI / FCI₀)] where FCI₀ represents the fossil-carbon intensity of the reference system. At the starting point, FCI = FCI₀ and defossilisation progress is zero. As recovered carbon increasingly substitutes for newly extracted carbon, FCI declines. If fresh geological carbon input eventually becomes negligible, defossilisation approaches 100%. Renewable hydrogen becomes increasingly important There is another reason to distinguish hydrogen from carbon. Today, global hydrogen production itself remains overwhelmingly fossil-based. The IEA reports that global hydrogen demand exceeded 100 million tonnes in 2025, while low-emissions hydrogen production was still below 1 million tonnes. Electrolysis capacity is growing rapidly, but low-emissions hydrogen represents only a little over 1% of expected global production in 2026. So simply saying “hydrogen” does not establish defossilisation. We must also follow the hydrogen. As renewable hydrogen expands, however, an interesting possibility emerges. Renewable hydrogen can increasingly provide the energy required to convert recovered CO₂ and CO back into useful carbon-based energy carriers. The transition can therefore move in two directions simultaneously: Fresh fossil carbon ↓ Renewable hydrogen ↑ while the existing carbon inventory continues circulating. This changes how we think about carbon capture Traditional carbon capture discussions often end at: Capture → transport → permanent storage. Permanent geological storage will undoubtedly have applications. But there is another pathway: Capture → recover → regenerate → reuse. These approaches need not be competitors. Different carbon streams will require different solutions. The important conceptual change is to stop assuming that every captured carbon atom is necessarily waste. Some carbon may be permanently stored. Some may become chemical feedstock. Some may become materials. And some may potentially remain within deliberately engineered energy cycles. This broader idea is gaining attention beyond energy systems. Research published in 2026 is examining the replacement of fossil feedstocks with alternative carbon sources—including captured CO₂—in industrial clusters, while Nature has described the need for sustainable non-fossil sources of carbon for the chemical economy. The destination is not a carbon-free civilisation Such a civilisation is neither realistic nor desirable. The destination should instead be an economy that requires progressively less new geological carbon. Hydrogen can supply increasing amounts of the energy required to make that possible. Carbon can continue doing what carbon does exceptionally well: forming molecules, carrying energy and providing essential industrial feedstocks. But rather than continually extracting it, using it once and releasing it, we should increasingly ask whether we can manage carbon as an inventory. That leads to a different vision of the energy transition: Hydrogen powers the future. Carbon enables the cycle. Defossilisation determines whether we have actually broken our dependence on fossil extraction. The next chapter will examine how this principle can move from a framework into an engineered system through Carbon Recycling Technology (CRT). #Defossilisation #EnergyTransition #Hydrogen #CircularCarbon #CarbonManagement #CarbonRecycling #SyntheticFuels #NetZero #CleanEnergy #CEWT Sources: Nature, 6 January 2026 and 18 February 2026; International Energy Agency, Global Hydrogen Review 2026, published 18 June 2026; Scientific Reports, 26 January 2026.