
Energy transition
The largest infrastructure change in history
Description
Industrial civilization runs on fossil fuels. Roughly 80% of global energy consumption in 2025 comes from coal, oil, and natural gas. These fuels power electricity generation, transportation, heating, industrial processes, and agriculture. They are deeply embedded in every aspect of modern life, from the factory that made your phone to the fertilizer that grew your dinner. Replacing them building a new energy system that produces equivalent output without emitting carbon dioxide is probably the largest infrastructure project in human history. It will require trillions of dollars of investment, reshaping multiple major industries, redesigning cities and transportation networks, and coordinating changes across every major economy. The transition has begun, is proceeding at specific rates, and needs to accelerate substantially to achieve the climate outcomes scientists argue are necessary.
The scale is easy to underestimate. The global energy system has been built up over roughly 250 years of industrial development, with investments measuring in the tens of trillions of dollars in current physical infrastructure power plants, refineries, pipelines, ports, vehicle fleets, buildings, industrial facilities. Replacing it requires not just building new clean-energy infrastructure but retiring the old infrastructure earlier than its natural lifespan would suggest. The specific economics of stranded assets (infrastructure that becomes economically worthless before its physical lifespan ends) is a central feature of the transition, and one of the largest sources of political resistance from industries that would bear the costs.
The transition is also not a single project but many simultaneous transitions across different sectors, each with specific dynamics. Electricity generation is transitioning relatively quickly as renewable costs have collapsed. Road transportation is transitioning more slowly, driven by electric vehicle adoption. Heavy industry (steel, cement, chemicals), aviation, and shipping face more difficult technical challenges. Heating and cooling are constrained by building stock turnover rates. Each sector has specific constraints, specific policy needs, and specific timelines. Understanding the transition requires understanding these specific sectoral dynamics, not just aggregate trends.
The question we're asking: what is the energy transition, what has been achieved, and what remains?
What we'll see: the scale of the system, the progress so far, the harder sectors, and the broader political economy.
Table of contents
01The scale of the system
Global primary energy consumption was roughly 600 exajoules in 2023 a quantity that is hard to visualize but corresponds to the energy equivalent of roughly 14 billion tons of oil per year. Of this, fossil fuels supplied roughly 80%. Coal alone supplied about 25%, oil 30%, natural gas 23%. Nuclear supplied about 4%, hydropower about 6%, other renewables (wind, solar, biomass) roughly 12%. These proportions have shifted slowly over decades, with renewables growing substantially in recent years but still representing a minority share of total energy. The specific numbers vary across sources but the overall picture is consistent.
Electricity is roughly 20% of total energy use but the sector where the transition has progressed furthest. In 2023, roughly 30% of global electricity came from low-carbon sources, with solar and wind growing rapidly. Some European countries generate most electricity from renewables; France depends substantially on nuclear. The remaining 70% still comes from fossil fuels. Electrification of sectors currently on direct fossil use (transportation, heating, industry) increases electricity demand, adding to the challenge even as it shifts from multiple fuel streams to one.
02The progress
The cost trajectory of renewable energy is the most transformative development of recent decades. Solar photovoltaic costs have fallen roughly 90% since 2010, primarily through scaling in China combined with continuous manufacturing improvements. Wind power costs have fallen similarly. Lithium-ion battery costs have fallen by similar magnitudes, enabling electric vehicles to become cost-competitive with internal combustion and enabling specific grid-scale energy storage that was not economical a decade ago. These cost declines were not predicted by most analysts twenty years ago, and they have reshaped what aggressive decarbonization actually costs. Many analyses now conclude that the cheapest way to decarbonize electricity is cheaper than continuing with fossil fuel generation, even without considering climate benefits.
Deployment of renewables has accelerated substantially. Global solar and wind capacity now exceeds the installed capacity of coal power globally. China has led most categories of clean energy deployment, building more solar, wind, and electric vehicles than any other country. The US has grown less dramatically but still substantially, particularly in Texas wind and Sun Belt solar. Europe has maintained steady growth. India, traditionally a major coal consumer, has begun substantial renewable investment. The specific absolute numbers are impressive the renewable capacity added each year now exceeds the total renewable capacity that existed globally in 2010.
03The harder sectors
Steel, cement, and chemicals are the main hard-to-abate industrial sectors. Steel production requires extremely high temperatures and uses coal both as a fuel and as a chemical reducing agent; current technology cannot easily replace the coal chemistry even with electric heating. Cement production releases CO2 directly through the chemical transformation of limestone, independent of what fuel is used. Chemicals production uses hydrocarbons as feedstock, not just fuel. Decarbonizing these sectors requires specific technologies green hydrogen for steel, alternative cements, carbon capture for cement and some chemicals that exist at demonstration scale but have not yet been deployed at industrial scale. The specific timelines for full decarbonization are probably 2040s or beyond for these sectors.
Aviation is particularly difficult. Jet fuel's energy density is hard to match. Batteries are too heavy for long-haul. Sustainable aviation fuels can work but are expensive and their carbon benefits depend on production pathway. Hydrogen and ammonia have been proposed but face technical challenges. The airline industry has set 2050 net-zero goals but faces skepticism about whether the technology scales. Behavioral changes less flying, more teleconferencing may be unavoidable regardless of fuel developments.
04The political economy
The fundamental political challenge is that transition costs are concentrated in specific industries and regions while benefits are diffuse and delayed. Coal miners, oil workers, and communities dependent on these industries face specific losses. Regions like West Virginia coal country have organized political opposition. The 'just transition' framework has tried to address these concerns through retraining and economic diversification, but actual investments have been modest relative to the scale of disruption.
International coordination is essential and difficult. Individual countries have incentives to delay their own transitions if other countries are moving faster, because they will get the benefits of global decarbonization without bearing their share of costs. The Paris Agreement's nationally determined contributions framework has produced commitments that are collectively insufficient to meet stated temperature targets. Border adjustment mechanisms (specifically the EU's Carbon Border Adjustment Mechanism) are emerging attempts to harmonize carbon policies across jurisdictions, but they face specific political resistance from affected countries.
05Conclusion
The energy transition is proceeding at a pace that is historically unprecedented but slower than what climate science argues is necessary. Costs of key technologies have fallen dramatically, deployment is accelerating, and the specific technologies to address most sectors either exist or are in advanced development. The transition is no longer technically uncertain; what remains uncertain is whether the political economy can accelerate adoption fast enough to limit warming to levels that avoid the worst climate outcomes. The specific gap between current trajectory and the pace needed is substantial but not inconceivably large, which is why the coming decade is particularly consequential.

