In Part 1, I looked at Japan’s CO₂ emissions and how they have changed over time, shaped by events like the Fukushima accident and the rapid growth of solar power. In this second part, I shift from where the emissions come from to how Japan plans to reduce them. The aim is to understand the approach Japan is taking toward decarbonization, why it differs from many other countries, and how this becomes visible in real engineering work.
Japan’s goal of reaching net-zero greenhouse-gas emissions by 2050 is set, but the pathway remains open. The current strategy (the 7th of its kind) combines several approaches, including efficiency improvements, fuel substitution (such as hydrogen and ammonia), and renewables like solar and wind. Natural gas remains part of the mix as a transition fuel to secure reliability while new systems mature, or as a fallback if renewable deployment does not expand rapidly enough.
Even though Japan sees a significant role for switching fossil fuels to low-carbon alternatives and carbon capture and storage (CCS), large-scale projects are yet to materialize. Solar, however, has advanced rapidly in the past decade (see Part 1 of this blog), indicating that solar (and wind), and battery storage are likely to shape much of Japan’s future electricity landscape (as in other countries).
On the other hand, what catches my attention is the fuel-switching pathway. It may be the aspect that most clearly sets Japan’s energy transition apart, but it is hard to disagree with what many others (see for example this recent analysis by Japan’s Renewable Energy Institute) have pointed out: converting large industrial or fossil-fuel plants to use ammonia or to capture CO₂ is technically complex and economically challenging, particularly when considering the infrastructure required for new fuels and the round-trip efficiency losses from converting electricity into fuel and back again. Still, Japan continues to test these options step by step, and I’m curious to see how the story unfolds. The question is whether Japan can drive down costs enough to make large-scale fuel switching viable, or whether the trajectory will converge with the broader trend of electrifying wherever possible and reserving solutions like hydrogen, ammonia, or carbon capture for the so-called hard-to-abate sectors such as cement, steel, and aviation.
To understand Japan’s somewhat different approach to decarbonization, it helps to look at the natural context it operates within.
Given these conditions, Japan’s interest in hydrogen, ammonia, and synthetic methane becomes easier to understand. They would allow low-carbon energy to be stored, moved, and integrated into parts of the infrastructure that already exist, easing the need for rapid, large-scale transformation of land use and the power grid, which no doubt is also needed.
Solar PV now supplies around 10% of Japan’s annual electricity generation, while wind contributes about 1%. Nuclear restarts have brought nuclear back to around 10% of supply. However, while renewables (including hydropower) and nuclear together now provide over one-third of Japan’s electricity, renewables alone are still around 27% (IEA, 2024). The government’s target is around 37% renewables by 2030, so reaching it will require a faster rate of expansion than in recent years, especially given that only five years remain (METI Strategic Energy Plan).
A longer-term perspective helps explain how Japan arrived at this point. The chart below (from ,Our World in Data, based on IEA statistics) shows how electricity production by source has evolved since the 1980s. Nuclear supplied a significant share until the Fukushima accident in 2011, after which all nuclear capacity was shut down before partially and gradually being restarted again. In the decade that followed, the lost output was largely replaced by coal and natural gas, increasing dependence on imported fossil fuels. At the same time, solar expanded rapidly, especially after the feed-in tariff was introduced in 2012, while wind grew more modestly. Only in recent years have nuclear restarts and ongoing solar additions begun to shift the balance again.
Figure 2: Electricity generation by source (Our World in Data) compared to 2008 production capacity of 1184 TWh.
Within the thermal power sector2, utilities are testing ammonia co-firing in coal units and biomass co-firing in both coal and dedicated boilers. At the Hekinan plant, JERA has demonstrated 20% ammonia co-firing and is evaluating the pathway to higher ratios in the 2030s (JERA announcement). Gas turbine manufacturers, including Mitsubishi Heavy Industries, are also developing turbines capable of burning increasing shares of hydrogen and synthetic fuels (MHI hydrogen plans). Meanwhile, LNG combined-cycle plants continue to receive efficiency upgrades because they remain central to balancing seasonal and daily variation in electricity supply (JERA LNG plans).
Rather than rapidly retiring coal capacity, Japan’s policy approach favours stepwise emission reduction. Existing coal and LNG plants continue operating while preparing for possible fuel switching in the future. The reasoning is tied to system reliability: coal and LNG currently provide inertia, dispatchability, and grid stability in ways that high shares of variable renewables and batteries cannot yet replace at full scale. This differs from approaches in parts of Europe, where faster coal phase-outs are made possible by extensive cross-border transmission interconnections and coordinated balancing markets. Japan, as an island grid with limited interregional transfer capacity, balances the goals of continued energy security with gradual emission reduction, resulting in this incremental strategy.
To summarize, Japan’s energy transition is not defined by one decisive shift. Instead, Japan appears to be exploring several pathways in parallel, so as not to close off options too early. From a plant engineer’s perspective, that is precisely what makes this phase interesting. It means working with real industrial sites and solving practical interface challenges, such as:
The economic challenges and constraints are real, and it is still uncertain which of these pathways will mature into long-term solutions. But at a global level, I think it is valuable that at least some countries invest in exploring these alternatives. Doing so can generate new technical insights, practical know-how, and system-level learnings that we may not yet anticipate. I believe we are capable of expanding electrification and renewables, while also testing options like fuel switching and carbon capture where they are technically and contextually justified.
For our team at Cyient, this means that early-phase work such as layout studies, process integration, estimating, and feasibility reviews often shapes what is possible long before detailed technology choices are made. Over the years, we have carried out numerous feasibility and concept studies related to low-carbon fuels, hydrogen infrastructure, and carbon-capture integration. These early studies often determine how new technologies can be adapted to existing plants and systems.
This is what makes Japan’s energy transition interesting to follow from the inside. Not because it is faster or slower than elsewhere, but because it is distinct, shaped by constraints, priorities and history that are not easily replicated. From an engineer’s point of view, it’s a place where the learning feels honest, hands-on, and worth paying attention to.
Japan’s energy transition remains a work in progress. The emphasis on flexibility, reliability, and cautious experimentation may appear slow when compared to regions with abundant land, hydropower resources, or deep cross-border (electrical) grid connections. Yet it reflects the realities of the Japanese context.
Whether low-carbon fuels such as hydrogen and ammonia become a significant part of Japan’s long-term energy mix or serve mainly as transitional tools will depend on economics, infrastructure, and public acceptance. What is clear is that engineers will continue to translate broad policy goals into workable solutions, one tie-in, one retrofit, and one system upgrade at a time.
1 Total energy supply refers to all energy required to meet demand across the country and is measured as primary energy input. Some sources are used directly (for example, oil in transport or gas in industry), while most are converted into fuels or electricity for final consumption. This differs from total electricity supply shown in Figure 2, which measures electrical energy output by source and therefore represents only one part of Japan’s overall energy system.
2Thermal power = electricity produced by burning fuel (or using heat) to spin a turbine.
About the Author
Johan Fagerlund (DSc, Tech) leads plant engineering delivery at Cyient Japan, focusing on sustainability and energy transition. As Global Energy Transition Manager, he drives decarbonization strategies across infrastructure sectors. With a doctorate in technology, Johan combines deep engineering expertise with a commitment to building a cleaner, more resilient future