Decarbonization
The 2023 Utility Decarbonization Index

The 2023 Utility Decarbonization Index
Electric utilities and the power sector have a pivotal role to play in decarbonizing the U.S. economy, especially with the electrification of sectors such as transportation.
So, where do the country’s largest electricity producers stand on the path to decarbonization?
In collaboration with our sponsor National Public Utilities Council, we present the 2023 edition of our Annual Utility Decarbonization Index. The index uses 2021 data (the latest available at the time of data collection) to track the comparative decarbonization progress of the 47 largest investor-owned utilities (IOUs) in the United States.
In the graphic above, we give a preview of the top 10 rankers.
Methodology of the Utility Decarbonization Index
The Utility Decarbonization Index uses the following six metrics to track decarbonization progress:
- Fuel Mix
The share of low-carbon sources in a utility’s owned net electricity generation. - CO2 Emissions Intensity
The amount of CO2 emitted per megawatt-hour of owned and purchased net electricity generation. - Total CO2 Emissions
The absolute amount of CO2 emitted from owned and purchased net electricity generation. - CO2 Emissions Per Customer
The amount of CO2 emitted per retail, commercial, and industrial customer served. - Decarbonization Goals
An evaluation of the company’s interim greenhouse gas reduction and net-zero targets, with a 50% reduction in emissions by 2030 and net-zero by 2050 as baseline targets. - Low-Carbon investment
The share of planned capital expenditure for electricity generation dedicated to low-carbon sources.
All 47 IOUs in the Decarbonization Index are scored on a scale of one (lowest) to five (highest) for each of the six metrics, indicating whether they are trailing or leading compared to their peers. A utility’s final decarbonization score is an average of its scores across the six metrics.
The data for these metrics comes from company sustainability reports, quantitative ESG reporting templates from the Edison Electric Institute, and the Climate Disclosure Project’s Climate Change Questionnaire filings.
With the methodology in mind, let’s take a look at the 10 utilities that are leading the ranking in this year’s Utility Decarbonization Index.

The Annual Utility Decarbonization Index 2023
The 47 IOUs ranked in the Index are the largest electricity producers in the country, together representing over 58% of U.S. electricity generation in 2021 and serving 68% of all US. electric customers. Therefore, the decarbonization of these utilities can have a massive impact on the power sector and other electricity-consuming sectors.
However, it’s important to note that a score of five on the Utility Decarbonization Index does not indicate full decarbonization or net-zero emissions. Rather, it indicates that the utility is leading in decarbonization relative to its peers.
Here are the top 10 IOUs in this year’s ranking:
Rank | Company | Decarbonization score |
---|---|---|
#1 | Constellation Energy (Exelon) | 4.8 |
#2 | Avangrid | 4.8 |
#3 | Public Service Enterprise Group | 4.6 |
#4 | Pacific Gas and Electric | 4.5 |
#5 | Edison International (EIX) | 4.5 |
#6 | Avista Utilities | 4.2 |
#7 | NextEra Energy | 4.2 |
#8 | Algonquin Power & Utilities | 4.0 |
#9 | Puget Sound Energy (PSE) | 4.0 |
#10 | Consolidated Edison | 3.9 |
Constellation Energy, a newly formed subsidiary of Exelon, tops this year’s Decarbonization Index along with Avangrid. Constellation is the largest low-carbon electricity producer among the 47 IOUs, with 80% of its owned net electricity generation coming from nuclear power plants. The company also had the lowest CO2 emissions intensity of all utilities in the Index.
Avangrid, a clean energy-focused utility operating in the Northeast, ties for first place thanks to its low-carbon fuel mix and ambitious decarbonization targets to achieve carbon neutrality in Scope 1 and 2 emissions by 2030.
Download the 2023 Annual Utility Decarbonization Report
Are you interested in seeing the rest of the rankings? Check out the full report!
In addition to the Decarbonization Index, there’s much more to unpack, including:
- Six reasons why utilities must decarbonize
- Highlights and challenges to decarbonization from 2021–2022
- The data behind the six individual metrics
- The U.S. Utilities ESG report card
- Decarbonization strategies for U.S. utilities
Download the 2023 NPUC Annual Utility Decarbonization Report and find out everything you need to know about utility decarbonization.
Climate
Mapped: Global Temperature Rise by Country (2022-2100P)
In this set of three maps, we show the global temperature rise on a national level for 2022, 2050, and 2100 based on an analysis by Berkeley Earth.

Mapped: Global Temperature Rise by Country (2022-2100P)
Many scientific authorities, such as the Intergovernmental Panel on Climate Change (IPCC), often discuss the need to limit planetary warming to 2°C above pre-industrial levels.
But did you know that this warming will not be evenly distributed throughout the globe due to factors such as geography, weather patterns, ocean currents, and the influence of human activities?
To discover the current and projected nuances of this uneven warming, these three maps created in partnership with the National Public Utilities Council visualize the global temperature rise by country, using new and updated data from Berkeley Earth.
Current State of Warming
The three maps above visualize warming relative to each country’s average 1850-1900 temperatures.
Looking at warming in 2022, we see that average national warming (i.e. warming excluding oceans) is already 1.81°C above those numbers, with Mongolia warming the most (2.54°C) and Bangladesh warming the least (1.1°C).
As the map depicts, warming is generally more accelerated in the Global North. One of the reasons for this is Arctic amplification.
Arctic amplification refers to the disproportionate heating experienced in the Arctic compared to the rest of the planet. This amplification is fueled by multiple feedback loops, including decreased albedo as ice cover diminishes, leading to further absorption of heat and exacerbating the warming effect.
Arctic amplification. Source: NASA
Aside from modern-day observations, the effects of Arctic amplification are also clearly seen in climate models, where accelerated warming in countries such as Russia and Canada is seen through 2100.
Projected Warming in 2050 and 2100
Moving over to the second and third maps in the slides above, we discover country-level 2050 and 2100 warming projections.
These projections are based on the IPCC’s “middle-of-the-road” scenario, titled Shared Socioeconomic Pathway (SSP) 2-4.5. Out of the various established pathways, this one is the closest to expected emissions under current policies.
2050 Projections
Under the SSP2-4.5 scenario, average national warming is projected to be 2.75°C above average 1850-1900 temperatures in 2050. This includes Mongolia, with the most substantial warming of 3.76°C, and New Zealand, with the mildest warming of 2.02°C.
To put those temperatures into context, here are the risks that would likely accompany them, according to the IPCC’s latest assessment report.
- Extreme weather events will be more frequent and intense, including heavy precipitation and related flooding and cyclones.
- Nearly all ecosystems will face high risks of biodiversity loss, including terrestrial, freshwater, coastal and marine ecosystems.
- Accelerated sea level rise will threaten coastal cities, leading to mass displacement.
Let’s now take a look at 2100 projections, which would have significantly higher levels of risk unless fast and extreme mitigation and adaptation measures are implemented in the upcoming decades.
2100 Projections
2100 projections under the SSP2-4.5 scenario depict an average national warming of 3.80°C.
More than 55 countries across the globe are projected to have warming above 4°C in comparison to their 1850-1900 averages, and nearly 100 above 3.5°C.
Here is what those levels of warming would likely mean, according to the IPCC.
- 3-39% of terrestrial species will face very high risks of extinction.
- Water scarcity will considerably affect cities, farms, and hydro plants, and about 10% of the world’s land area will experience rises in both exceptionally high and exceptionally low river flows.
- Droughts, floods, and heatwaves will pose substantial threats to global food production and accessibility, eroding food security and impacting nutritional stability on a significant scale.
Generally, warming at this level is expected to pose substantial catastrophic risks to humanity, necessitating swift and bold climate action.
Learn more about how electric utilities and the power sector can lead on the path toward decarbonization here.
Clean Energy
Breaking Down the $110 Trillion Cost of the Clean Energy Transition
The clean energy transition will cost $110 trillion in global capital investments between 2021 and 2050. Here’s that sum broken down by sector.

The $110 Trillion Cost of the Clean Energy Transition
The Energy Transitions Commission estimates that achieving net-zero by 2050 requires an average annual investment of $3.5 trillion globally between 2021 and 2050.
That’s a total of $110 trillion in capital investment, or 1.3% of projected global GDP, over the next three decades.
The question then arises: where should this substantial sum of money be allocated?
In collaboration with the National Public Utilities Council, this graphic delves into the answers to that question utilizing data from the Energy Transitions Commission.
How Much Will the Clean Energy Transition Cost?
Of the $3.5 trillion dollars that needs to be invested annually into a net-zero economy, around $2.4 trillion should flow into the electricity sector, according to the Energy Transitions Commission. This accounts for 70% of the annual investment.
Decarbonizing the electricity sector holds significant importance as it can serve as a catalyst for the decarbonization of all other sectors, including:
- Buildings, which are becoming increasingly electrified through the growing use of heat pumps
- Electrified road transportation
- Electricity-intensive industrial activities, such as cement, steel, and chemical production
- Green hydrogen production
Now, let’s take a collective look at the avenues of investment needed to reach net-zero by 2050 in more detail.
Sector | Subsector | Average Capital Investment Needed Per Year 2021-2050 | Total Sector Investment Needed Per Year 2021-2050 |
---|---|---|---|
The Power Sector | Zero-Carbon Power Generation | $1300B | $2400B |
Power Networks | $900B | ||
Power Storage and Grid Flexibility | $200B | ||
Buildings | Retrofits | $230B | $500B |
Heat Pumps | $130B | ||
Renewable Heating | $140B | ||
Transport | Road Charging Infrastructure | $130B | $240B |
Aviation | $70B | ||
Shipping | $40B | ||
Carbon Removal | Natural Climate Solutions (NCS) | $100B | $130B |
Hybrid and engineered carbon removal solutions | $30B | ||
Clean Hydrogen | Production | $40B | $80B |
Transport and storage | $40B | ||
Industry | Chemicals | $40B | $70B |
Steel | $10B | ||
Cement | $10B | ||
Aluminum | $10B |
All figures are in real 2021 U.S. dollars
Overall, the diversity of the table above underscores the multifaceted approach required for a low-carbon transition.
Is the World on Track to Reach Net-Zero?
In 2022, the global capital investment in the clean energy transition totaled $1.1 trillion—approximately one-third of the required annual average to reach net-zero.
With that said, it’s important to note that the $3.5 trillion figure is an average across 29 years. Opportunities to catch up still exist, although the window is closing quickly.
According to the Energy Transitions Commission, investments must double from their current levels to around $2 trillion by 2025 and peak at around $4.2 trillion by 2040.
To remain on track to net-zero, therefore, we must make significant and rapid investments in all sectors, with a primary focus on the power sector.
Learn more about how electric utilities and the power sector can lead on the path toward decarbonization here.
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