Public Release: 

Carnegie Mellon power sector carbon index sees double digit growth in solar power

College of Engineering, Carnegie Mellon University

PITTSBURGH--(October 26, 2018) The Power Sector Carbon Index, developed by Carnegie Mellon University (CMU) and Mitsubishi Hitachi Power Systems (MHPS) tracks the environmental performance of U.S. power producers and compares current emissions to more than two decades of historical data collected nationwide. It provides a comprehensive picture of the carbon intensity of electricity production during the previous twelve months, as well as a summary of how much electricity is being produced by coal, natural gas, nuclear, and renewable sources.

The latest data revealed the following findings: US power plant emissions averaged 890 lb. CO2 per milliwatt hour (MWh) in the second quarter of 2018, which was down 5 percent from the same timeframe in 2017. The rolling annual average carbon intensity was 949 lb CO2 per MWh, which is 28 percent lower than the annual average in 2005. The total annual rolling CO2 emissions were 1,775 million metric tonnes, which was 27 percent lower than in 2005.

Here are the highlights of the Index's most recent results:

  • Total generation was up 4% in 2018 Q2 when compared to 2017 Q2.

  • Coal generation was down 8% in 2018 Q2 when compared to 2017 Q2. Coal represented 26% of total generation in 2018 Q2.

  • Natural Gas generation was up 16% in 2018 Q2 when compared to 2017 Q2. Natural Gas represented 34% of total generation in 2018 Q2.

  • Hydro generation was down 7% in 2018 Q2 when compared to 2017 Q2. Hydro represented 8% of total generation in 2018 Q2.

  • Wind generation was up 9% in 2018 Q2 when compared to 2017 Q2. Wind represented 7% of total generation in 2018 Q2.

  • Solar generation was up 24% in 2018 Q2 when compared to 2017 Q2. Solar represented 3% of total generation in 2018 Q2.

  • Nuclear generation was up 6% in 2018 Q2 when compared to 2017 Q2. Nuclear represented 19% of total generation in 2018 Q2.

  • Other generation was down 5% in 2018 Q2 when compared to 2017 Q2. Other generation represented 1% of total generation in 2018 Q2.

  • Other Renewables generation was up 0% in 2018 Q2 when compared to 2017 Q2. Other Renewables represented 2% of total generation in 2018 Q2.

"Solar power generation had double digit growth this quarter compared to last year," said Costa Samaras, Assistant Professor of Civil and Environmental Engineering at CMU. "There was a time where energy analysts just listed the fraction of power from solar as 'about zero.' That is clearly no longer the case."

For the complete findings of the Index, please visit


About the College of Engineering: The College of Engineering at Carnegie Mellon University is a top-ranked engineering college that is known for our intentional focus on cross-disciplinary collaboration in research. The College is well-known for working on problems of both scientific and practical importance. Our "maker" culture is ingrained in all that we do, leading to novel approaches and transformative results. Our acclaimed faculty have a focus on innovation management and engineering to yield transformative results that will drive the intellectual and economic vitality of our community, nation and world.

About Carnegie Mellon University: Carnegie MellonCarnegie Mellon is a private, internationally ranked university with programs in areas ranging from science, technology and business to public policy, the humanities and the arts. More than 13,000 students in the university's seven schools and colleges benefit from a small faculty-to-student ratio and an education characterized by its focus on creating and implementing solutions for real world problems, interdisciplinary collaboration and innovation.

About Mitsubishi Hitachi Power Systems Americas, Inc.

Headquartered in Lake Mary, FL, MHPS Americas employs more than 2,000 people who design, build, install, monitor and service aero-derivative and heavy-duty natural gas, steam and geothermal turbines, generators, and environmental control systems throughout North and South America. MHPS Americas also collaborates with customers to deploy artificial intelligence and low carbon technologies to take the cost and carbon out of the electric power value chain. MHPS Americas is subsidiary of Mitsubishi Hitachi Power Systems, a joint venture between Mitsubishi Heavy Industries, Ltd. and Hitachi, Ltd. PW Power Systems (PWPS) and Mechanical Dynamics & Analysis (MD&A) are wholly owned subsidiaries of MHPS Americas.

Learn more about the Revolutionary Energy of MHPS Americas by visiting

MHPS is a subsidiary of Mitsubishi Heavy Industries headquartered in Tokyo, Japan. (7011:JP)

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