Explained · The Energy Transition

The Energy Transition

EnergyThe capacity to do work, and to power civilisations · TransitionA shift from one state to another · The global shift from fossil fuels to lower-carbon energy sources.

The energy transition is the rebuild of how the world generates, moves, and uses energy. Away from fossil fuels, which have powered industry for about two centuries, toward electricity drawn from lower-carbon sources including wind, solar, nuclear, and hydro. It is not a single policy, a single technology, or a single country. It is a direction of travel, pushed by climate science, energy security, and the falling cost of the alternatives, and pulled back by the practical difficulty of rewiring a system that took a century to build.

Offshore wind is not the whole answer, but it is one of the biggest moving parts, particularly for countries with long coastlines and strong winds. In the UK, offshore wind already supplies a meaningful share of electricity, and the pipeline of announced projects, if delivered, would reshape the grid over the next two decades. The decisions being made now, about where to build, who pays, which projects go ahead, and which get dropped, will set the shape of the energy system well past 2050.

A note on scope. EOS Omnia is UK based, and the pages that follow use the UK as the working example, because it is the market we know best and where our data is most complete. The underlying principles apply globally. The specifics, subsidy mechanisms, grid institutions, regulators, and cost levels, differ by country. Readers in Germany, the Netherlands, the US, Japan, Korea, Taiwan, or elsewhere will recognise the shape of the argument here, and should translate the details to local context.

How you read this page depends on why you are here. We have written the explanation four ways, not because the facts change, but because the questions do. Pick the entry point that fits you, or read more than one. Each page links to the others.

Twenty-five years, in numbers

What countries actually built, 2000 to 2025

Slogans are easy. Megawatts are not. Across the thirty-seven countries IRENA tracks at this level of detail, the world has built more electricity-generating capacity since 2000 than in the previous fifty years combined. It has also retired remarkably little of what was already there. The transition is real, it is large, and it is not yet a substitution. It is mostly an addition.

2,107 GW
Solar PV installed across the 37 tracked countries by 2025, from 1 GW in 2000.
91 GW
Offshore wind installed across the same 37 countries, from effectively zero in 2000.
+1.08 TW
Coal capacity China added in the same period. Most of the global growth, and still growing.
~61%
Renewable share of UK installed capacity in 2025. The renewable build has done most of its work on capacity. Generation share, and the firming around it, is the next decade.
Aggregated installed capacity, 37 IRENA-tracked countries, 2000 to 2025
Stacked area, megawatts. Bottom bands fossil, upper bands renewable.
Read the lower, darker bands as the fossil base, and the upper, warmer bands as the renewable build. The fossil base has not shrunk. It has flattened in some markets and grown in others, while the renewable build has piled on top. The transition picture, accurately, is one of stacking, not yet of replacement at the global level.

Three transitions, three different shapes

The same data sliced three ways. The UK retired coal at speed and replaced it largely with gas plus offshore wind. Germany doubled down on solar while retiring nuclear. China built more of everything than anywhere else, including more coal than any country has ever built, and more solar.

United Kingdom
2000 vs 2025, megawatts by technology
Coal collapse, offshore wind ramp, gas held steady as the firm backbone.
Germany
2000 vs 2025, renewable techs (fossil incomplete in IRENA)
Nuclear out, solar to over 100 GW, offshore added almost 10 GW.
China
2000 vs 2025, log scale recommended
Everything bigger, including coal. The renewable build out-scaled the coal build, but did not replace it.

Source, IRENA Electricity Capacity Statistics 2025, OnGrid plant only, 37 countries, 9 technologies. Fossil fuel data is incomplete in the IRENA file for Germany, Denmark, France, and Poland, where IRENA's coverage focuses on the renewable build.

Country-by-country detail, the energy-mix tab interface, and the offshore-in-context comparisons sit on the analyst page. Read the full data section on et-analyst →
For the Curious Reader

New here, want the basics

How we power things, why it is changing, no jargon

Starts from first principles. What the energy transition actually is, why wind and solar lead the new build, how a wind farm works, and honest answers to the questions you have probably already thought of.

Principium sapientiae, the beginning of wisdom.

For the Engaged Analyst

Show me the data and the tech

Capacity factors, grid limits, supply chain, tradeoffs

Written for readers who want the numbers, the technology, and the bottlenecks. Turbine size trajectories, fixed versus floating, the grid connection queue, critical minerals, intermittency. Evidence first, slogans last.

Per data ad veritatem, through data to truth.

For the Strategic Observer

Where is this going, who pays

Investment, policy direction, risks to the thesis

For readers thinking in decades, not news cycles. Investment flows, subsidy mechanisms, cost trajectories that have not always gone the expected way, who wins commercially, who pays, and the risks to the whole plan.

Quo vadimus, where are we going.

For the Concerned Local

I live near this, real questions

Bills, curtailment, coastal impact, community benefit

Straight answers for the readers closest to the projects. Why bills are high if wind is cheap, what curtailment payments actually are, what the coast will look like, and whether any of this money reaches the communities nearby.

Vox populi, the voice of the people.