Countries Running on 90%+ Renewable Electricity

Roughly a dozen countries now run their electricity systems on over 90 percent renewables, some at 100 percent. They use hydropower, geothermal, wind, solar, and biomass in very different mixes shaped by local resources. This guide profiles the leaders, explains how they got there, and draws out lessons for markets still transitioning.

Reaching 90 percent renewable electricity is often treated as an aspirational future target. For a handful of countries it is already the current reality. The path to that outcome differs by country, but a few consistent patterns emerge. This guide covers what worked, what did not, and what other markets can learn without waiting for a decade of policy debate.

Countries above 90 percent renewable electricity

Data sources include the IEA data and statistics portal, national utility regulators, and Ember Climate. Numbers move year to year with rainfall and demand shifts.

The hydro dominant path

Most of the 90 percent plus countries got there via hydropower. This reflects three factors: hydro is the most mature large scale renewable, capacity factors are high, and geography historically dictates whether it is available. Norway, Iceland, Paraguay, Ethiopia, Nepal, Bhutan, DRC, Albania, and Zambia all belong to this pattern.

Costa Rica: the diversified example

Costa Rica runs its grid at 99 percent renewable electricity through a diversified portfolio: about 70 percent hydro, 12 percent geothermal, 15 percent wind, and 3 percent solar and biomass. The country has now had multi week periods of 100 percent renewable operation. The Costa Rican Electricity Institute (ICE) manages the mix using hydro reservoirs as effective storage that balances variable wind and solar.

Costa Rica policy roots trace back to the 1948 abolition of the military and reinvestment of the savings in electrification and education. The utility ownership structure and long term political consensus around renewable generation are as important to the outcome as the resource base.

Uruguay: the wind driven transformation

Uruguay is the most instructive case for countries starting today. In 2007 it was heavily dependent on gas and imported electricity. Between 2010 and 2018 it built out 1.5 GW of wind capacity, and now runs on roughly 97 percent renewable electricity with wind, hydro, solar, and biomass. The programme took about 8 years from policy commitment to 90 percent renewable operation.

Key ingredients: long term contracts with wind developers, transparent auction based pricing, and grid interconnection with neighbours (Brazil, Argentina) for balancing. The transition happened without a major grid reliability incident.

Denmark: the wind and interconnection model

Denmark grid electricity is roughly 85 percent renewable, dominated by wind. Denmark exports large amounts of wind power during high wind periods and imports hydro power from Norway during calm periods, effectively using Norway hydro as pumped storage. This bilateral trade is fundamental to the reliability of Denmark high wind grid.

Paths not yet demonstrated at scale

Several potential paths to 90 percent renewable electricity have not yet been demonstrated at national scale but are underway:

• Solar dominant with battery storage (Southwest US, Middle East, Australia).
• Offshore wind dominant with interconnection (UK, Northern Europe).
• Distributed rooftop solar plus community storage (parts of Germany, Australia).
• Enhanced geothermal base load (US, Europe, Africa).
• Green hydrogen buffered systems (Chile, Australia).

Common lessons from the leaders

The drought vulnerability

The storage role

Hydro reservoirs act as effective long duration storage. This is why the natural leaders are hydro heavy. Countries scaling variable renewables from a low hydro base need alternative storage: batteries for short duration, pumped hydro where geography permits, or hydrogen for long duration.

What comes after 90 percent

The last 10 percent of a fossil grid is often the hardest. It handles peak demand, provides grid inertia, and covers seasonal imbalances. Countries at 90 percent renewable are working on the last 10 percent through storage expansion, demand flexibility, sector coupling (heat and transport electrification), and interconnection.

What metric matters

Renewable share can be measured several ways: share of installed capacity, share of generation, share of consumption (net of imports and exports), and share of primary energy (including heat and transport). The numbers vary significantly between metrics. For grid transformation discussion, share of electricity generation is the most useful; for economy wide decarbonisation, share of primary energy matters more.

Global context

Frequently asked questions

Summary

A dozen countries already run their electricity systems on over 90 percent renewables. Most got there via hydropower geography; a growing number are transitioning via wind, solar, and diversified portfolios. Political consistency, transparent auctions, interconnection, and grid investment show up in every success. Drought is the biggest ongoing risk for hydro dependent grids. For countries starting today, Uruguay demonstrates that under a decade of transformation is achievable when policy is coherent and resources are sensibly matched.

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