Fuel Concentration: Which Grids Depend on One Fuel
Among 109 countries generating at least 10 TWh, Bhutan has the most concentrated grid: hydro supplied 100.0% of its electricity in 2024, an index of 10,000 out of 10,000, as if it ran on 1.0 equal sized fuels. Romania is the most diversified at 1,772 (5.6 equivalent fuels, hydro the largest at 24.3%) in 2025. The median country scores 4,465; 45 of 109 are very concentrated, 49 concentrated and 15 diversified. Over 10 years (each country's latest year against the year 10 before it), 72 of 109 countries became more diversified and 36 more concentrated; the median change is -362 index points.
Key Facts, Ember data to 2025
- 109 countries were scored: each generated at least 10 TWh in its latest Ember year (2025 for 82 of them).
- The index is the sum of squared fuel shares, 0 to 10,000: 10,000 means one fuel supplies everything, 5,000 is two equal fuels and 2,500 is four equal fuels.
- Bhutan was the most concentrated: 10,000, with hydro at 100.0% (2024). Next: Turkmenistan (9,994, gas 100%), Bahrain (9,947, gas 100%) and Paraguay (9,895, hydro 99%).
- Romania was the most diversified: 1,772, with hydro at 24.3% (2025). Next: Spain (1,855, solar 22%), Chile (1,876, solar 25%) and Germany (1,885, wind 27%).
- Largest source by country count in each country's latest year: gas 39, hydro 35, coal 17, nuclear 9, other fossil 3, wind 3, solar 2, other renewables 1.
- By size, the median index was 4,927 for 53 countries at 10 to under 50 TWh, 4,227 for 31 countries at 50 to under 200 TWh, 3,414 for 25 countries at 200 TWh and over.
- The median index moved from 4,708 to 4,465 over 10 years across 109 countries with both years (72 more diversified, 36 more concentrated, 1 unchanged).
- Belarus diversified most: 9,572 in 2015 to 4,562 in 2025 (-5,010).
- Venezuela concentrated most: 4,172 in 2014 to 8,339 in 2024 (+4,167).
- 106 of the 215 countries in the export were not scored: 106 generate under 10 TWh.
How to Read the Index
- Take each fuel's share of a country's electricity, in percent, and square it. Add the squares up. That is the index, from 0 to 10,000.
- One fuel supplying everything scores 10,000. Two equal fuels score 5,000. Four equal fuels score 2,500. Nine equal fuels, the most Ember's categories allow, score about 1,111.
- Divide 10,000 by the index and you get the equivalent number of equal sized fuels. The page calls this "equivalent fuels". A country at 4,000 behaves like one with 2.5 equal fuels, even if it uses seven.
- Bands used here: very concentrated is 2 equivalent fuels or fewer (an index of 5,000 or more), concentrated is over 2 up to 4 (2,500 to under 5,000), and diversified is over 4 (under 2,500). In this ranking: 45 very concentrated, 49 concentrated, 15 diversified.
- The index measures spread across fuels, not cleanliness or reliability. A grid run almost entirely on hydro scores near 10,000 and is low carbon; one run almost entirely on coal also scores near 10,000.
The Most and Least Diversified Grids
109 countries, latest Ember yearMost concentrated
| Country | Index | Largest fuel |
|---|---|---|
| 1. ๐ง๐น Bhutan | 10,000 | Hydro 100% |
| 2. ๐น๐ฒ Turkmenistan | 9,994 | Gas 100% |
| 3. ๐ง๐ญ Bahrain | 9,947 | Gas 100% |
| 4. ๐ต๐พ Paraguay | 9,895 | Hydro 99% |
| 5. ๐ณ๐ต Nepal | 9,769 | Hydro 99% |
| 6. ๐ฉ๐ฟ Algeria | 9,721 | Gas 99% |
| 7. ๐ช๐น Ethiopia | 9,316 | Hydro 96% |
| 8. ๐ถ๐ฆ Qatar | 9,233 | Gas 96% |
| 9. ๐น๐ณ Tunisia | 8,975 | Gas 95% |
| 10. ๐น๐ฏ Tajikistan | 8,938 | Hydro 94% |
Most diversified
| Country | Index | Largest fuel |
|---|---|---|
| 1. ๐ท๐ด Romania | 1,772 | Hydro 24% |
| 2. ๐ช๐ธ Spain | 1,855 | Solar 22% |
| 3. ๐จ๐ฑ Chile | 1,876 | Solar 25% |
| 4. ๐ฉ๐ช Germany | 1,885 | Wind 27% |
| 5. ๐ต๐ฐ Pakistan | 1,932 | Hydro 23% |
| 6. ๐ฉ๐ด Dominican Republic | 2,163 | Coal 29% |
| 7. ๐น๐ท Turkey | 2,179 | Coal 34% |
| 8. ๐ง๐ช Belgium | 2,189 | Nuclear 34% |
| 9. ๐ต๐น Portugal | 2,226 | Hydro 30% |
| 10. ๐ฌ๐ง United Kingdom | 2,261 | Gas 31% |
Each country at its own latest year, which is 2025 for 82 of 109. Only countries generating at least 10 TWh are ranked, so a small grid on a single diesel plant does not top the list; 106 smaller countries are left out. The next table splits the ranking by size of grid.
| Size of grid (latest year) | Countries | Median index | Median largest fuel share |
|---|---|---|---|
| 10 to under 50 TWh | 53 | 4,927 | 62.7% |
| 50 to under 200 TWh | 31 | 4,227 | 56.0% |
| 200 TWh and over | 25 | 3,414 | 48.8% |
Change Over 10 Years
109 countries with both years72 countries became more diversified, 36 more concentrated and 1 did not change. The median index moved from 4,708 10 years earlier to 4,465 in its latest year (middle values across the 109 countries with both years). The comparison is each country's latest year against the year 10 before it.
Became more diversified
| Country | Before | Now | Change |
|---|---|---|---|
| ๐ง๐พ Belarus | 9,572 2015 | 4,562 2025 | -5,010 |
| ๐ฆ๐ช United Arab Emirates | 9,953 2015 | 5,176 2025 | -4,777 |
| ๐ฏ๐ด Jordan | 8,607 2014 | 4,366 2024 | -4,241 |
| ๐ฑ๐ฆ Laos | 10,000 2014 | 6,389 2024 | -3,611 |
| ๐ต๐ฑ Poland | 6,416 2015 | 3,122 2025 | -3,294 |
| ๐ฒ๐ฟ Mozambique | 9,735 2014 | 7,035 2024 | -2,700 |
| ๐จ๐ฉ Democratic Republic of the Congo | 9,977 2014 | 7,333 2024 | -2,644 |
| ๐ง๐ฉ Bangladesh | 6,775 2015 | 4,744 2025 | -2,031 |
Became more concentrated
| Country | Before | Now | Change |
|---|---|---|---|
| ๐ป๐ช Venezuela | 4,172 2014 | 8,339 2024 | +4,167 |
| ๐ช๐จ Ecuador | 4,085 2015 | 6,405 2025 | +2,319 |
| ๐ฎ๐ฑ Israel | 4,729 2015 | 6,619 2025 | +1,890 |
| ๐ฎ๐ฉ Indonesia | 3,348 2015 | 5,044 2025 | +1,696 |
| ๐ฐ๐ฌ Kyrgyzstan | 7,415 2015 | 8,768 2025 | +1,354 |
| ๐ฑ๐พ Libya | 5,025 2014 | 6,202 2024 | +1,177 |
| ๐ฒ๐ฝ Mexico | 3,922 2015 | 5,067 2025 | +1,144 |
| ๐ต๐ญ Philippines | 2,850 2015 | 3,920 2025 | +1,071 |
The table shows how far the index moved, not why. Each country page shows the generation mix year by year.
Ember annual statistics, 2000 to 2024, 108 countries
| Year | Most concentrated tenth (90th percentile) | Median | Most diversified tenth (10th percentile) |
|---|---|---|---|
| 2000 | 9,659 | 5,344 | 3,015 |
| 2001 | 9,808 | 5,269 | 3,020 |
| 2002 | 9,854 | 5,205 | 3,039 |
| 2003 | 9,814 | 5,252 | 2,972 |
| 2004 | 9,839 | 5,375 | 3,029 |
| 2005 | 9,848 | 5,220 | 3,036 |
| 2006 | 9,708 | 5,110 | 3,070 |
| 2007 | 9,772 | 5,154 | 3,054 |
| 2008 | 9,710 | 5,107 | 3,099 |
| 2009 | 9,743 | 5,111 | 3,048 |
| 2010 | 9,822 | 5,062 | 2,982 |
| 2011 | 9,816 | 5,014 | 2,853 |
| 2012 | 9,838 | 4,950 | 2,832 |
| 2013 | 9,754 | 4,771 | 2,904 |
| 2014 | 9,722 | 4,925 | 2,983 |
| 2015 | 9,514 | 4,605 | 2,688 |
| 2016 | 9,353 | 4,625 | 2,766 |
| 2017 | 9,287 | 4,754 | 2,849 |
| 2018 | 9,269 | 4,763 | 2,728 |
| 2019 | 9,219 | 4,648 | 2,746 |
| 2020 | 9,167 | 4,695 | 2,501 |
| 2021 | 8,718 | 4,797 | 2,489 |
| 2022 | 8,565 | 4,679 | 2,450 |
| 2023 | 8,620 | 4,459 | 2,474 |
| 2024 | 8,408 | 4,405 | 2,462 |
Every Country
109 countries, biggest grid first| Country | Generation | Largest fuel | Its share | Index | Equivalent fuels | Index 10 years earlier | Change | Band |
|---|---|---|---|---|---|---|---|---|
| ๐จ๐ณ China | 10,506 TWh | Coal | 54.8% | 3,452 | 2.9 | 5,297(2015) | -1,845 | Concentrated |
| ๐บ๐ธ United States | 4,520 TWh | Gas | 40.0% | 2,376 | 4.2 | 2,606(2015) | -230 | Diversified |
| ๐ฎ๐ณ India | 2,080 TWh | Coal | 70.9% | 5,221 | 1.9 | 6,044(2015) | -823 | Very concentrated |
| ๐ท๐บ Russia | 1,194 TWh | Gas | 45.6% | 3,011 | 3.3 | 3,268(2015) | -257 | Concentrated |
| ๐ฏ๐ต Japan | 1,027 TWh | Gas | 32.7% | 2,366 | 4.2 | 2,986(2015) | -620 | Diversified |
| ๐ง๐ท Brazil | 764 TWh | Hydro | 52.1% | 3,213 | 3.1 | 4,158(2015) | -945 | Concentrated |
| ๐จ๐ฆ Canada | 660 TWh | Hydro | 52.8% | 3,415 | 2.9 | 3,798(2015) | -383 | Concentrated |
| ๐ฐ๐ท South Korea | 628 TWh | Coal | 31.1% | 2,666 | 3.8 | 3,213(2015) | -547 | Concentrated |
| ๐ซ๐ท France | 574 TWh | Nuclear | 68.3% | 4,890 | 2.0 | 5,937(2015) | -1,047 | Concentrated |
| ๐ฎ๐ฉ Indonesia | 528 TWh | Coal | 69.4% | 5,044 | 2.0 | 3,348(2015) | +1,696 | Very concentrated |
| ๐ฉ๐ช Germany | 497 TWh | Wind | 26.6% | 1,885 | 5.3 | 2,394(2015) | -508 | Diversified |
| ๐ธ๐ฆ Saudi Arabia | 471 TWh | Gas | 63.7% | 5,105 | 2.0 | 5,015(2015) | +90 | Very concentrated |
| ๐ฎ๐ท Iran | 399 TWh | Gas | 73.3% | 5,838 | 1.7 | 5,863(2015) | -25 | Very concentrated |
| ๐ฒ๐ฝ Mexico | 390 TWh | Gas | 70.0% | 5,067 | 2.0 | 3,922(2015) | +1,144 | Very concentrated |
| ๐น๐ท Turkey | 354 TWh | Coal | 34.3% | 2,179 | 4.6 | 2,964(2015) | -785 | Diversified |
| ๐ป๐ณ Vietnam | 329 TWh | Coal | 47.8% | 3,403 | 2.9 | 3,302(2015) | +101 | Concentrated |
| ๐ฌ๐ง United Kingdom | 294 TWh | Gas | 31.3% | 2,261 | 4.4 | 2,033(2015) | +228 | Diversified |
| ๐น๐ผ Taiwan | 289 TWh | Gas | 48.8% | 3,742 | 2.7 | 3,361(2015) | +381 | Concentrated |
| ๐ช๐ธ Spain | 288 TWh | Solar | 21.9% | 1,855 | 5.4 | 1,624(2015) | +231 | Diversified |
| ๐ฆ๐บ Australia | 286 TWh | Coal | 42.9% | 2,712 | 3.7 | 4,528(2015) | -1,816 | Concentrated |
| ๐ฎ๐น Italy | 265 TWh | Gas | 47.4% | 2,889 | 3.5 | 2,259(2015) | +630 | Concentrated |
| ๐ฟ๐ฆ South Africa | 243 TWh | Coal | 81.4% | 6,725 | 1.5 | 8,292(2015) | -1,567 | Very concentrated |
| ๐ช๐ฌ Egypt | 242 TWh | Gas | 76.1% | 5,954 | 1.7 | 5,555(2015) | +399 | Very concentrated |
| ๐ฒ๐พ Malaysia | 210 TWh | Coal | 44.9% | 3,414 | 2.9 | 4,048(2015) | -633 | Concentrated |
| ๐น๐ญ Thailand | 201 TWh | Gas | 61.5% | 4,229 | 2.4 | 5,274(2015) | -1,045 | Concentrated |
| ๐ฆ๐ช United Arab Emirates | 184 TWh | Gas | 68.0% | 5,176 | 1.9 | 9,953(2015) | -4,777 | Very concentrated |
| ๐ต๐ฑ Poland | 173 TWh | Coal | 50.6% | 3,122 | 3.2 | 6,416(2015) | -3,294 | Concentrated |
| ๐ต๐ฐ Pakistan | 171 TWh | Hydro | 23.1% | 1,932 | 5.2 | 2,907(2015) | -976 | Diversified |
| ๐ธ๐ช Sweden | 170 TWh | Hydro | 40.1% | 2,920 | 3.4 | 3,519(2015) | -599 | Concentrated |
| ๐ณ๐ด Norway | 161 TWh | Hydro | 90.0% | 8,171 | 1.2 | 9,224(2015) | -1,053 | Very concentrated |
| ๐ฆ๐ท Argentina | 153 TWh | Gas | 56.0% | 3,618 | 2.8 | 3,720(2015) | -101 | Concentrated |
| ๐ฎ๐ถ Iraq | 150 TWh | Gas | 53.0% | 4,869 | 2.1 | 5,935(2014) | -1,065 | Concentrated |
| ๐ณ๐ฑ Netherlands | 135 TWh | Gas | 34.9% | 2,385 | 4.2 | 3,187(2015) | -802 | Diversified |
| ๐ฐ๐ฟ Kazakhstan | 124 TWh | Coal | 58.3% | 4,227 | 2.4 | 5,362(2015) | -1,135 | Concentrated |
| ๐ต๐ญ Philippines | 123 TWh | Coal | 58.6% | 3,920 | 2.6 | 2,850(2015) | +1,071 | Concentrated |
| ๐บ๐ฆ Ukraine | 112 TWh | Nuclear | 55.8% | 3,709 | 2.7 | 3,783(2012) | -74 | Concentrated |
| ๐ง๐ฉ Bangladesh | 103 TWh | Gas | 64.3% | 4,744 | 2.1 | 6,775(2015) | -2,031 | Concentrated |
| ๐ฉ๐ฟ Algeria | 96.4 TWh | Gas | 98.6% | 9,721 | 1.0 | 9,717(2014) | +4 | Very concentrated |
| ๐จ๐ด Colombia | 90.4 TWh | Hydro | 69.1% | 5,032 | 2.0 | 4,416(2015) | +616 | Very concentrated |
| ๐ฐ๐ผ Kuwait | 89.5 TWh | Gas | 62.3% | 5,135 | 1.9 | 5,055(2015) | +80 | Very concentrated |
| ๐จ๐ฑ Chile | 88.5 TWh | Solar | 25.1% | 1,876 | 5.3 | 2,690(2015) | -814 | Diversified |
| ๐บ๐ฟ Uzbekistan | 86.7 TWh | Gas | 72.3% | 5,406 | 1.8 | 7,289(2015) | -1,883 | Very concentrated |
| ๐ซ๐ฎ Finland | 82.5 TWh | Nuclear | 39.8% | 2,728 | 3.7 | 2,191(2015) | +537 | Concentrated |
| ๐ฎ๐ฑ Israel | 82.1 TWh | Gas | 79.7% | 6,619 | 1.5 | 4,729(2015) | +1,890 | Very concentrated |
| ๐ป๐ช Venezuela | 80.1 TWh | Hydro | 91.1% | 8,339 | 1.2 | 4,172(2014) | +4,167 | Very concentrated |
| ๐จ๐ฟ Czechia | 75.5 TWh | Nuclear | 42.3% | 3,161 | 3.2 | 3,612(2015) | -451 | Concentrated |
| ๐ฆ๐น Austria | 73.2 TWh | Hydro | 51.9% | 3,222 | 3.1 | 3,948(2015) | -727 | Concentrated |
| ๐ง๐ช Belgium | 72.1 TWh | Nuclear | 33.5% | 2,189 | 4.6 | 2,681(2015) | -492 | Diversified |
| ๐จ๐ญ Switzerland | 65.0 TWh | Hydro | 52.3% | 3,780 | 2.6 | 4,585(2015) | -805 | Concentrated |
| ๐ต๐ช Peru | 60.5 TWh | Hydro | 56.0% | 4,461 | 2.2 | 4,447(2015) | +13 | Concentrated |
| ๐ธ๐ฌ Singapore | 60.1 TWh | Gas | 91.1% | 8,324 | 1.2 | 9,082(2015) | -758 | Very concentrated |
| ๐ฌ๐ท Greece | 57.9 TWh | Gas | 40.3% | 2,554 | 3.9 | 2,572(2015) | -18 | Concentrated |
| ๐ถ๐ฆ Qatar | 57.2 TWh | Gas | 96.0% | 9,233 | 1.1 | 9,938(2015) | -705 | Very concentrated |
| ๐ด๐ฒ Oman | 53.1 TWh | Gas | 91.5% | 8,411 | 1.2 | 9,489(2015) | -1,077 | Very concentrated |
| ๐ฑ๐ฆ Laos | 52.3 TWh | Hydro | 76.5% | 6,389 | 1.6 | 10,000(2014) | -3,611 | Very concentrated |
| ๐ต๐น Portugal | 51.1 TWh | Hydro | 29.7% | 2,226 | 4.5 | 2,105(2015) | +121 | Diversified |
| ๐ท๐ด Romania | 49.8 TWh | Hydro | 24.3% | 1,772 | 5.6 | 2,048(2015) | -276 | Diversified |
| ๐ง๐พ Belarus | 45.4 TWh | Gas | 56.1% | 4,562 | 2.2 | 9,572(2015) | -5,010 | Concentrated |
| ๐ต๐พ Paraguay | 45.4 TWh | Hydro | 99.5% | 9,895 | 1.0 | 9,946(2015) | -52 | Very concentrated |
| ๐ฒ๐ฆ Morocco | 44.2 TWh | Coal | 62.4% | 4,291 | 2.3 | 3,830(2015) | +462 | Concentrated |
| ๐ณ๐ฟ New Zealand | 44.0 TWh | Hydro | 54.0% | 3,586 | 2.8 | 3,681(2015) | -94 | Concentrated |
| ๐ณ๐ฌ Nigeria | 42.5 TWh | Gas | 68.0% | 5,619 | 1.8 | 6,854(2015) | -1,235 | Very concentrated |
| ๐ญ๐บ Hungary | 40.1 TWh | Nuclear | 40.1% | 2,807 | 3.6 | 3,431(2015) | -624 | Concentrated |
| ๐ง๐ฌ Bulgaria | 38.1 TWh | Nuclear | 39.1% | 2,466 | 4.1 | 3,303(2015) | -837 | Diversified |
| ๐ง๐ญ Bahrain | 38.0 TWh | Gas | 99.7% | 9,947 | 1.0 | 9,993(2014) | -45 | Very concentrated |
| ๐ญ๐ฐ Hong Kong | 37.4 TWh | Gas | 64.1% | 5,244 | 1.9 | 6,378(2014) | -1,134 | Very concentrated |
| ๐ช๐จ Ecuador | 36.6 TWh | Hydro | 77.9% | 6,405 | 1.6 | 4,085(2015) | +2,319 | Very concentrated |
| ๐ท๐ธ Serbia | 36.2 TWh | Coal | 65.3% | 4,813 | 2.1 | 5,940(2015) | -1,127 | Concentrated |
| ๐ฉ๐ฐ Denmark | 35.6 TWh | Wind | 56.9% | 3,891 | 2.6 | 3,286(2015) | +605 | Concentrated |
| ๐ฑ๐พ Libya | 34.6 TWh | Gas | 74.5% | 6,202 | 1.6 | 5,025(2014) | +1,177 | Very concentrated |
| ๐ช๐น Ethiopia | 33.4 TWh | Hydro | 96.5% | 9,316 | 1.1 | 8,555(2015) | +761 | Very concentrated |
| ๐น๐ฒ Turkmenistan | 33.0 TWh | Gas | 100.0% | 9,994 | 1.0 | 10,000(2014) | -6 | Very concentrated |
| ๐ฎ๐ช Ireland | 31.6 TWh | Gas | 47.4% | 3,688 | 2.7 | 2,914(2015) | +775 | Concentrated |
| ๐ธ๐ฐ Slovakia | 29.1 TWh | Nuclear | 66.4% | 4,698 | 2.1 | 3,656(2015) | +1,043 | Concentrated |
| ๐ฆ๐ฟ Azerbaijan | 27.8 TWh | Gas | 88.7% | 7,977 | 1.3 | 7,567(2015) | +410 | Very concentrated |
| ๐ฐ๐ต North Korea | 27.1 TWh | Hydro | 62.7% | 5,102 | 2.0 | 4,988(2014) | +114 | Very concentrated |
| ๐ธ๐พ Syria | 24.9 TWh | Gas | 52.3% | 4,694 | 2.1 | 4,981(2014) | -287 | Concentrated |
| ๐ฌ๐ญ Ghana | 24.3 TWh | Gas | 61.4% | 5,036 | 2.0 | 4,708(2014) | +327 | Very concentrated |
| ๐น๐ฏ Tajikistan | 24.0 TWh | Hydro | 94.4% | 8,938 | 1.1 | 9,815(2015) | -878 | Very concentrated |
| ๐ฏ๐ด Jordan | 23.7 TWh | Gas | 62.0% | 4,366 | 2.3 | 8,607(2014) | -4,241 | Concentrated |
| ๐ฉ๐ด Dominican Republic | 22.6 TWh | Coal | 29.1% | 2,163 | 4.6 | 3,841(2015) | -1,678 | Diversified |
| ๐น๐ณ Tunisia | 22.4 TWh | Gas | 94.7% | 8,975 | 1.1 | 8,556(2015) | +419 | Very concentrated |
| ๐ฒ๐ฒ Myanmar | 21.7 TWh | Gas | 46.1% | 4,276 | 2.3 | 4,970(2014) | -693 | Concentrated |
| ๐ฒ๐ฟ Mozambique | 19.8 TWh | Hydro | 82.4% | 7,035 | 1.4 | 9,735(2014) | -2,700 | Very concentrated |
| ๐ฟ๐ฒ Zambia | 19.7 TWh | Hydro | 86.2% | 7,552 | 1.3 | 9,358(2014) | -1,806 | Very concentrated |
| ๐ต๐ท Puerto Rico | 19.5 TWh | Other fossil | 49.0% | 3,537 | 2.8 | 3,889(2015) | -351 | Concentrated |
| ๐จ๐บ Cuba | 19.4 TWh | Other fossil | 82.3% | 6,972 | 1.4 | 6,822(2014) | +151 | Very concentrated |
| ๐ฑ๐ฐ Sri Lanka | 18.6 TWh | Hydro | 41.5% | 2,904 | 3.4 | 3,516(2015) | -612 | Concentrated |
| ๐ฎ๐ธ Iceland | 18.3 TWh | Hydro | 71.2% | 5,893 | 1.7 | 6,054(2015) | -161 | Very concentrated |
| ๐ฐ๐ญ Cambodia | 17.8 TWh | Coal | 56.6% | 4,216 | 2.4 | 4,578(2015) | -362 | Concentrated |
| ๐จ๐ฉ Democratic Republic of the Congo | 15.9 TWh | Hydro | 84.2% | 7,333 | 1.4 | 9,977(2014) | -2,644 | Very concentrated |
| ๐ฌ๐น Guatemala | 15.8 TWh | Hydro | 39.9% | 2,598 | 3.8 | 2,997(2014) | -399 | Concentrated |
| ๐ฆ๐ด Angola | 15.6 TWh | Hydro | 70.6% | 5,367 | 1.9 | 4,950(2014) | +417 | Very concentrated |
| ๐ธ๐ฎ Slovenia | 14.9 TWh | Nuclear | 39.4% | 2,667 | 3.7 | 3,010(2015) | -343 | Concentrated |
| ๐ธ๐ฉ Sudan | 14.8 TWh | Hydro | 77.9% | 6,477 | 1.5 | 6,441(2014) | +35 | Very concentrated |
| ๐ญ๐ท Croatia | 14.7 TWh | Hydro | 39.3% | 2,494 | 4.0 | 3,829(2015) | -1,334 | Diversified |
| ๐ง๐ฆ Bosnia and Herzegovina | 14.5 TWh | Coal | 55.8% | 4,465 | 2.2 | 5,458(2015) | -993 | Concentrated |
| ๐ฐ๐ช Kenya | 14.1 TWh | Other renewables | 45.9% | 2,939 | 3.4 | 3,674(2015) | -736 | Concentrated |
| ๐ง๐ด Bolivia | 13.6 TWh | Gas | 62.4% | 4,699 | 2.1 | 5,579(2015) | -880 | Concentrated |
| ๐ฌ๐ช Georgia | 13.5 TWh | Hydro | 78.9% | 6,640 | 1.5 | 6,552(2015) | +88 | Very concentrated |
| ๐ต๐ฆ Panama | 13.4 TWh | Hydro | 53.1% | 3,428 | 2.9 | 4,334(2014) | -906 | Concentrated |
| ๐จ๐ท Costa Rica | 12.9 TWh | Hydro | 74.9% | 5,892 | 1.7 | 5,772(2015) | +119 | Very concentrated |
| ๐ฐ๐ฌ Kyrgyzstan | 12.9 TWh | Hydro | 93.5% | 8,768 | 1.1 | 7,415(2015) | +1,354 | Very concentrated |
| ๐ญ๐ณ Honduras | 12.5 TWh | Other fossil | 44.1% | 3,048 | 3.3 | 4,357(2014) | -1,309 | Concentrated |
| ๐บ๐พ Uruguay | 12.0 TWh | Wind | 40.5% | 3,028 | 3.3 | 4,204(2015) | -1,176 | Concentrated |
| ๐ณ๐ต Nepal | 11.1 TWh | Hydro | 98.8% | 9,769 | 1.0 | 9,843(2014) | -74 | Very concentrated |
| ๐ง๐น Bhutan | 11.0 TWh | Hydro | 100.0% | 10,000 | 1.0 | 10,000(2014) | 0 | Very concentrated |
| ๐จ๐ฎ Cote d'Ivoire | 10.8 TWh | Gas | 70.9% | 5,801 | 1.7 | 5,480(2014) | +321 | Very concentrated |
| ๐ฟ๐ผ Zimbabwe | 10.3 TWh | Hydro | 55.6% | 4,927 | 2.0 | 5,024(2014) | -97 | Concentrated |
Column headings sort the table. Generation, largest fuel, index and band are for each country's latest year (2025 for 82 of 109); the year of the earlier index is shown beside it.
How This Is Measured, and Caveats
- Shares are each fuel category's generation in TWh over the total of the categories with positive generation that year. The nine categories are Ember's as this site stores them: coal, gas, other fossil, nuclear, hydro, wind, solar, bioenergy and other renewables. They are not merged, so wind and solar count as two fuels, and so do hydro and bioenergy.
- That choice matters. A grid that is 80% renewables spread over five categories looks diversified here even though it relies on weather; merging the renewable categories would raise its score. Equally, splitting fossil fuel into coal, gas and other fossil lowers the score of a fossil grid. Treat the index as a measure of spread across the categories shown, not across technologies.
- The index is the sum of squared percentage shares (the Herfindahl-Hirschman form used for market concentration). Equivalent fuels is 10,000 divided by the index. The largest fuel is the category with the biggest share; an exact tie goes to the first name alphabetically.
- Who is scored: countries generating at least 10 TWh in their latest year. 106 countries below that are left out of the ranking, 0 have no usable generation total.
- The change is the index in the country's latest year minus the index in the year exactly 10 earlier, so most countries compare 2015 with 2025 and a few a year earlier. A country that moved a lot in between and came back shows no change.
- The chart uses only countries with data in every year shown, and plots the middle country and the tenth and ninetieth percentile, so the lines are not any single country. Percentiles interpolate between neighbouring countries.
- Shares are of electricity generated in the country, not of electricity used: imports are not counted, so a country that imports a lot can be more concentrated here than the electricity its homes use. This is a description of the past, not a measure of risk.
Fuel Concentration FAQ
What is the fuel concentration index?
It adds up the squares of each fuel's share of generation, in percent, and runs from 0 to 10,000. A grid with one fuel scores 10,000; two equal fuels score 5,000; four equal fuels 2,500; nine equal fuels about 1,111, the lowest possible with Ember's nine categories. This is the Herfindahl-Hirschman index economists use for market concentration, applied to fuels instead of companies.
Is a concentrated grid a bad thing?
Not by itself. The index says how many eggs are in one basket, not whether the basket is clean, cheap or safe. A grid that is mostly hydro is concentrated and low carbon; one that is mostly coal is concentrated and high carbon. A diversified grid is less exposed to any one fuel failing or becoming expensive, but this page does not measure reliability.
Which country has the most diversified electricity?
Romania in 2025 among 109 countries generating at least 10 TWh: an index of 1,772, equal to 5.6 equal sized fuels, with hydro the largest source at 24.3%.
Why only countries above 10 TWh?
A small island or city state can run on one diesel plant and score 10,000 without telling us much. 106 countries generate under 10 TWh a year and are left out of the ranking, though their mix is on their own country pages.
Do Ember's fuel categories change the answer?
Yes. The index uses nine categories, with wind, solar, hydro, bioenergy and other renewables counted separately. A grid that is 80% renewables spread over five of those looks diversified here even though it relies on weather. Merging the categories would raise every score.
Source: Ember (ember-energy.org), licensed under CC BY 4.0. Data as of 2025. Annual statistics from Ember; each country read at its own latest year.
Related
Cite this page
APA 7
World Power Monitor. (2025). Fuel Concentration: Which Grids Depend on One Fuel. https://worldpowermonitor.com/fuel-concentration/
Plain text
World Power Monitor. Fuel Concentration: Which Grids Depend on One Fuel. Data as of 2025. Data from Ember. https://worldpowermonitor.com/fuel-concentration/
BibTeX
@misc{wpm_fuel_concentration_2025,
title = {{Fuel Concentration: Which Grids Depend on One Fuel}},
author = {{World Power Monitor}},
year = {2025},
note = {Data as of 2025. Data from Ember.},
url = {https://worldpowermonitor.com/fuel-concentration/}
} Permalink: https://worldpowermonitor.com/fuel-concentration/
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