Clean Energy
Ranked: Which U.S. Utilities Have The Cleanest Electricity Generation?
Which Utilities Have The Cleanest Electricity Generation?
For the second year, Visual Capitalist and our sponsor National Public Utilities Council have developed the Annual Utility Decarbonization Index. The index quantifies and compares the status of decarbonization among the 47 largest investor-owned utilities (IOUs) in the United States, ranking them on six metrics based on publicly available 2021 data.
- Metric 1: Fuel Mix
- Metric 2: CO2 Emissions Intensity
- Metric 3: Total CO2 Emissions
- Metric 4: CO2 Emissions per Customer
- Metric 5: Decarbonization Goals
- Metric 6: Low-Carbon Investment
The graphic above gives a preview of the first metric’s results, which ranks U.S. utilities by the share of low-carbon sources in their owned electricity generations.
Let’s now dive into the included IOUs and their rankings.
Which Utilities Are Included In the Decarbonization Index?
The IOUs that were ranked in this year’s Utility Decarbonization Index are the 47 largest U.S. IOUs by their 2021 net owned and purchased electricity generations, which are as follows.
U.S. IOUs that had fewer than 2 million megawatt-hours (MWh) of owned generation were excluded from the report. Companies with blue outlines, on the other hand, represent those that have international operations in addition to their operations in the United States.
Which U.S. Utilities Had the Cleanest Generation in 2021?
The top 47 U.S. IOUs outlined above generated 2.7 billion MWh of electricity and served 68% of all U.S. electric customers in 2021.
Collectively, 60% of this generation came from fossil fuels such as natural gas and coal, whereas the remaining 40% came from carbon-free energy sources, such as nuclear, wind, and solar.
But each utility’s fuel mix looked very different across the board. Let’s see which ones had the cleanest owned generation.
| Company | Share of Carbon-Free Sources (Renewables, Nuclear, Fuel Cells, Combined Heat & Power) | Share of Fossil Fuels (Coal, Petroleum, Natural Gas, Petroleum Coke) |
|---|---|---|
| Constellation Energy (Exelon) | 90% | 10% |
| Avangrid | 86% | 14% |
| Consolidated Edison | 78% | 22% |
| Pacific Gas and Electric | 77% | 23% |
| Edison International (EIX) | 66% | 34% |
| Algonquin Power & Utilities | 66% | 34% |
| Public Service Enterprise Group | 57% | 43% |
| Avista Utilities | 54% | 46% |
| NextEra Energy | 53% | 47% |
| PNM Resources | 51% | 49% |
| NorthWestern Corporation | 50% | 50% |
| Xcel Energy | 49% | 51% |
| Dominion Energy | 48% | 52% |
| Evergy | 47% | 53% |
| Duke Energy | 42% | 58% |
| Entergy | 42% | 58% |
| Otter Tail Corporation | 41% | 59% |
| Berkshire Hathaway Energy | 37% | 63% |
| Pinnacle West Capital | 37% | 63% |
| DTE Energy Company | 33% | 67% |
| Hawaiian Electric Industries | 32% | 68% |
| Allette Energy | 31% | 69% |
| Southern Company | 30% | 70% |
| American Electric Power | 30% | 70% |
| TransAlta | 30% | 70% |
| MDU Resources | 29% | 71% |
| AES Corporation | 25% | 75% |
| Puget Sound Energy (PSE) | 23% | 77% |
| Alliant Energy | 21% | 79% |
| Ameren | 20% | 80% |
| NRG Energy | 19% | 81% |
| Portland General Electric | 19% | 81% |
| MGE Energy | 19% | 81% |
| Fortis Inc. | 17% | 83% |
| Black Hills Corporation | 17% | 83% |
| National Grid PLC | 17% | 83% |
| WEC Energy | 14% | 86% |
| Vistra | 11% | 89% |
| Consumers Energy | 9% | 91% |
| Emera | 9% | 91% |
| OG&E Energy | 6% | 94% |
| NiSource | 5% | 95% |
| PPL Corporation | 2% | 98% |
| Cleco Power LLC | 2% | 98% |
| CenterPoint Energy | 2% | 98% |
| FirstEnergy | 0% | 100% |
| Sempra Energy | 0% | 100% |
Overall, nuclear power was the single largest source of clean electricity among these utility companies in 2021. Conversely, 17 IOUs used fossil fuels for more than 80% of their owned electricity generation, and some as high as 100%.
Download The 2023 Annual Utility Decarbonization Report
The 2023 Annual Utility Decarbonization Report is a deep dive into the state of decarbonization across the investor-owned utility sector in the United States.
What else does the report include?
- The full Annual Utility Decarbonization Index 2023 with data breakdowns for each of the six metrics
- ESG Report Card 2023
- Sector highlights and challenges in 2021-22
- Six Reasons for Decarbonizing Utilities
- Decarbonization Strategies for U.S. Utilities
Clean Energy
Which U.S. Utilities Are Investing in Clean Energy the Most?
In this graphic, we show which U.S investor-owned utilities have allocated the most capital expenditure toward clean energy.
Which U.S. Utilities Are Investing in Clean Energy the Most?
Decarbonizing the power sector will require significant investments in clean energy as utilities replace existing fossil fuel infrastructure.
In this graphic, we show which U.S investor-owned utilities (IOUs) have allocated the most capital expenditure (CAPEX) toward carbon-free sources of electricity.
The data comes from the latest edition of the Annual Utility Decarbonization Index, created in partnership with the National Public Utilities Council, which quantifies and compares the status of decarbonization among the largest U.S. IOUs.
The Carbon-Free Investment Ranking
The Utility Decarbonization Index ranks companies on six metrics based on the latest available data, specifically those that pertain to their fuel mix, carbon emissions, and decarbonization goals.
The sixth and final metric measures the share of each utility’s planned CAPEX for carbon-free electricity generation, such as nuclear power and renewables.
Here are the top scorers out of the 47 IOUs included in the report.
| Rank | Company | Share of Planned Generation CAPEX Allocated To Nuclear & Renewables |
|---|---|---|
| #1 | NextEra Energy | 100% |
| #2 | Public Service Enterprise Group | 100% |
| #3 | Avangrid | 100% |
| #4 | Pacific Gas and Electric* | 96% |
| #5 | Alliant Energy | 94% |
| #6 | National Grid | 93% |
| #7 | AES Corporation | 92% |
| #8 | Constellation Energy | 90% |
| #9 | WEC Energy | 90% |
| #10 | Emera | 86% |
| #11 | Dominion Energy* | 84% |
| #12 | American Electric Power | 83% |
| #13 | TransAlta | 81% |
| #14 | MGE Energy | 78% |
| #15 | Duke Energy | 68% |
| #16 | Evergy | 68% |
| #17 | DTE Energy Company | 67% |
| #18 | Fortis Inc. | 67% |
| #19 | Consumers Energy | 66% |
| #20 | Southern Company | 63% |
*Planned CAPEX unreported, shows 2022 realized CAPEX
Avangrid climbed to first place in 2022, tying with NextEra and PSEG, who both maintained their 100% carbon-free investment plans from 2021. This marks an improvement from Avangrid’s 98% the year prior.
Meanwhile, National Grid pulled off the most significant percentage increase, from 3% to 93% from 2021 to 2022.
Overall, carbon-free investment is up 3 percentage points year-over-year from 63% to 66% for the top 47 IOUs.
Which Utilities Are Included in the Decarbonization Index?
The IOUs ranked in this year’s Utility Decarbonization Index are the 47 largest in the U.S. by their 2022 net owned and purchased electricity generations.
U.S. IOUs that had fewer than 2 million megawatt-hours (MWh) of owned generation were excluded from the report.
The 47 IOUs featured in the Index accounted for over two-thirds of the nation’s electricity generation in 2022. As a result, these utilities’ decarbonization efforts will significantly impact the 33% of U.S. emissions that come from the power sector.
Download the 2024 Annual Utility Decarbonization Report
In addition to the Decarbonization Index, there’s much more to explore in the 2024 report, including:
- Inflation Reduction Act impacts
- Market trends
- Year-to-year progressions
- Fuel mix rankings for the largest public utilities
- Gas utility emissions rankings
Are you interested in seeing the rest of the rankings? Download the 2024 NPUC Annual Utility Decarbonization Report now.
Clean Energy
Visualized: Renewable Energy Capacity Through Time (2000–2023)
This streamgraph shows the growth in renewable energy capacity by country and region since 2000.
Visualized: Renewable Energy Capacity Through Time (2000–2023)
Global renewable energy capacity has grown by 415% since 2000, or a compound annual growth rate (CAGR) of 7.4%.
However, many large and wealthy regions, including the United States and Europe, maintain a lower average annual renewable capacity growth.
This chart, created in partnership with the National Public Utilities Council, shows how each world region has contributed to the growth in renewable energy capacity since 2000, using the latest data release from the International Renewable Energy Agency (IRENA).
Renewable Energy Trends in Developed Economies
Between 2000 and 2023, global renewable capacity increased from 0.8 to 3.9 TW. This was led by China, which added 1.4 TW, more than Africa, Europe, and North America combined. Renewable energy here includes solar, wind, hydro (excluding pumped storage), bioenergy, geothermal, and marine energy.
During this period, capacity growth in the U.S. has been slightly faster than what’s been seen in Europe, but much slower than in China. However, U.S. renewable growth is expected to accelerate due to the recent implementation of the Inflation Reduction Act.
Overall, Asia has shown the greatest regional growth, with China being the standout country in the continent.
| Region | 2000–2023 Growth | 10-Year Growth (2013–2023) | 1-Year Growth (2022–2023) |
|---|---|---|---|
| Europe | 313% | 88% | 10% |
| China | 1,817% | 304% | 26% |
| United States | 322% | 126% | 9% |
| Canada | 57% | 25% | 2% |
It’s worth noting that Canada has fared significantly worse than the rest of the developed world since 2000 when it comes to renewable capacity additions. Between 2000 and 2023, the country’s renewable capacity grew only by 57%.
Trends in Developing Economies
Africa’s renewable capacity has grown by 184% since 2000 with a CAGR of 4%.
India is now the most populous country on the planet, and its renewable capacity is also rapidly growing. From 2000–2023, it grew by 604%, or a CAGR of 8%.
It is worth remembering that energy capacity is not always equivalent to power generation. This is especially the case for intermittent sources of energy, such as solar and wind, which depend on natural phenomena.
Despite the widespread growth of renewable energy worldwide, IRENA emphasizes that global renewable generation capacity must triple from its 2023 levels by 2030 to meet the ambitious targets set by the Paris Agreement.
Learn how the National Public Utilities Council is working toward the future of sustainable electricity.
-
Energy Shift1 year agoRanked: The Cheapest Sources of Electricity in the U.S.
-
Electrification2 years agoVisualized: How the Power Grid Works
-
Energy Shift2 years agoAnimated: 70 Years of U.S. Electricity Generation by Source
-
Clean Energy12 months agoBreaking Down the $110 Trillion Cost of the Clean Energy Transition
-
Clean Energy2 years agoThe 30 Largest U.S. Hydropower Plants
-
Clean Energy2 years agoBreaking Down Clean Energy Funding in the Inflation Reduction Act
-
Emissions2 years agoVisualizing Global Per Capita CO2 Emissions
-
Emissions5 months agoThe Most Polluted Cities in the U.S.