In Albania, water does almost all the work. In Iceland, hydroelectricity is supplemented by energy from deep underground. In Costa Rica, water, wind and geothermal sources coexist within the same electricity system; while Norway’s vast natural wealth of mountains, lakes and fjords has made renewables the very cornerstone of national energy production.
The new landscape of global electricity comes in many different shades and, above all, it does not follow a single model. It has been mapped out by Mark Z. Jacobson, director of the Atmosphere/Energy Program at Stanford University, who has spent years studying solutions for the transition towards energy systems powered by renewable sources.
His latest global snapshot takes into consideration wind, hydroelectric, geothermal and marine sources, photovoltaics and concentrated solar power: technologies which Jacobson groups together under the acronym WWS: Wind-Water-Solar.
The figures reveal just how quickly the global electricity system is changing. According to this analysis, based primarily on data from 2025, 64 countries and territories generate at least 50% of their electricity
from these sources, 14 of which exceed 95%. Albania, Bhutan, Nepal, Iceland and Lesotho have achieved 100%; while Ethiopia, the Democratic Republic of the Congo, Paraguay, Costa Rica and Norway fall just below that threshold.
What this ranking illustrates, above all, is a structural transformation: renewables are no longer merely an additional component in the electricity mix, but have become the very cornerstone of generation in many systems.
From hydroelectricity in Norway to wind in Denmark, and from Iceland’s geothermal power to the growing use of solar generation across major economies: there are now 64 countries and territories around the world that produce at least half of their electricity from wind, water, the sun and the Earth’s natural heat.
The weight of water. When analysing the figures, the significance of water stands out first and foremost. Albania generates over 94% of its electricity from hydroelectric power, while Bhutan can boast 100%. The share of hydroelectricity in Nepal reaches almost 99%, while it has exceeded 99% in Paraguay.
Then there is Iceland, representing a completely different model. Here, around 71% of generation comes from hydroelectricity, with geothermal power contributing over 29%. Together, they bring the WWS share to 100%.
Costa Rica has an even more diversified mix: around three quarters of its electricity is generated from water, whilst wind and geothermal power each account for around 12%. Norway, on the other hand, generates around 90% of its power from hydroelectricity and over 8% from wind power, bringing its total WWS share close to 99%.
As you move down the rankings, the composition also changes. Kenya comes in at 88%, largely thanks to a feature that makes it almost unique: geothermal power accounts for around 46% of its electricity generation, alongside hydroelectric and wind power. New Zealand exceeds 87%, combining water, geothermal and wind power.
The conclusion is simple: there is no one-size-fits-all solution: each system must make the most of its own geographical characteristics. Mountains and rivers are harnessed for energy in Norway and Paraguay; volcanic subsoils serve the same purpose in Iceland and Kenya; while the wind is ushering in a transformation in the electricity systems of countries bordering the North Sea.
Wind and solar power: widespread sources that pose new challenges for grids. Denmark is perhaps the clearest example of this variety. While hydroelectricity is virtually non-existent, almost 59% of electricity generation comes from wind power, with over 13% from solar power. Overall, wind and sunshine push the WWS share above 72%.
Portugal exceeds 74%, spreading its energy production across hydroelectricity, wind and solar sources. Uruguay stands at around 73%, with wind power alone accounting for over 40%. Spain has passed the 53% mark, thanks mainly to wind and solar power.
And then there are the major economies, where lower percentages nevertheless represent far greater absolute volumes of energy. Brazil has achieved a WWS share of more than 79% of its over 750 TWh of electricity generation thanks to hydroelectricity and, now, to a significant contribution from wind and solar power. China, the world’s largest electricity system, has reached 35%; considering its over 10,500 TWh of generation, this represents a colossal amount of electricity produced from water, wind and solar power. This is precisely where the transition takes on a different scale: no longer simply a matter of building new power stations, but of integrating them into continent-wide electricity systems, in which hundreds or thousands of kilometres may separate generation and consumption.
The new geography of electricity. A traditional thermoelectric power substation can be programmed to increase or reduce generation based on demand. The wind and the sun, on the other hand, vary with the weather. Above all, they generate energy only where the resource is available: on the windiest plains, along the coasts, at sea, and in the areas that receive the most sunshine.
The growth of renewables means that generation is scattered across ever-wider areas, making it necessary to transmit large quantities of electricity from the sites where it is produced to those where it will be consumed. At the same time, there is a growing need to link different systems so that a surplus produced in one region can help to offset a shortfall elsewhere. This is why the grid is gradually becoming the infrastructure enabling the transition.
Jacobson himself, in his studies on systems powered 100% by WWS sources, identifies the expansion of transmission and distribution grids as one of the elements essential for managing very high shares of renewables, alongside the development of storage, the management of demand and complementarity between different energy sources.
The challenge is no longer simply to produce clean electricity, but to ensure that this electricity can be used where and when it is needed.
Italy and the race towards renewables. Italy too is in the midst of this transformation. According to the international snapshot compiled by Jacobson, WWS sources account for around 43% of national electricity generation. This figure comprises approximately 16% from hydroelectricity, 17% from solar power, 8% from wind power and just over 2% from geothermal power.
At the same time, Terna’s data illustrate the speed at which the system continues to evolve. In 2025, renewable sources satisfied around 41% of Italian electricity demand. Photovoltaics generated over 44 TWh in annual production for the first time, representing a 25% increase over the previous year.
Then there are moments when the present provides a glimpse of the future. In May 2025, renewables satisfied 55.9% of Italy’s electricity demand — the highest monthly figure that had ever been recorded to date — and, for a few hours, renewable production actually exceeded 100% of demand.
These figures are radically changing the way the system operates, because the larger the increase in installed capacity
and generation from renewable sources, the greater the need to transport energy between different parts of the country, to overcome congestion, to manage generation peaks and to ensure a balance between supply and demand at all times. Italy’s energy transition therefore inevitably depends on the national transmission grid.
According to the scenarios underpinning Terna’s planning, renewable capacity is expected to increase by more than 65 GW by 2030 compared to 2023, to which a further 20 GW could be added by 2034. Over the next ten years, Terna also estimates that around 43 GW of new renewable capacity will be integrated directly into the high-voltage grid.
This is the scale of the infrastructure challenge. To tackle it, the 2025 Development Plan for the national electricity grid sets out over 23 billion euros in investments over ten years, which are also intended to increase transmission capacity and facilitate the integration of renewable sources.
Major direct-current connections such as the Tyrrhenian Link and the Adriatic Link, together with the strengthening of the electricity backbones, interconnections
with other countries, storage systems and the digitalisation of the grid, are helping to build a system capable of transferring growing amounts of energy between different areas and managing increasingly distributed and variable production.