Duke Energy Faces Challenges to Its Push for New Natural Gas Plants

At-a-Glance:

Duke Energy’s plan to build gigawatts’ worth of new natural gas generators to supply its grid over the next 15 years has already drawn fire from clean-energy advocates who say it violates the utility’s long-range decarbonization goals and could leave customers paying for power plants that can’t economically compete with cleaner alternatives. To learn more, read Duke Energy Faces Challenges to Its Push for New Natural Gas Plants.”

Key Takeaways:

  • In Duke’s integrated resource plan (IRP) for its Carolina utilities, only one of six pathways for reaching net-zero carbon by 2050 avoids building new natural gas plants. The rest propose between 6.1 – 9.6 gigawatts of new natural gas capacity.
  • The IRP also notes that Duke is planning a massive build-out of clean-energy capacity, including between 8.7 – 16.4 GW of new solar and 1 – 7.5 GW of new energy storage, depending on each scenario’s targeted levels of carbon emissions reduction.
  • A key issue highlighted by Duke’s critics is that its IRP appears to have inflated its peak electricity demands and underestimated the amount of resources available to meet its winter loads.
  • A second key issue is that Duke’s IRP appears to undervalue solar power, batteries, demand-side management, and energy efficiency as cost-effective alternatives to building new power plants.
  • An independent analysis by Synapse Energy Economics found that taking a solar-battery path could reduce overall system cost by $7.2 billion, out of a range of 15-year costs; reduce carbon dioxide emissions by tens of millions of tons per year; and provide enough capacity to carry Duke through its electric-heating-driven winter peaks without threatening grid reliability.

Path to 100% Perspective:

Duke is facing the challenge of the pressure to decarbonize quickly, all while maintaining reliability for their customers. Fast-start, flexible thermal plants can help utilities meet rigorous carbon reduction targets, maintain grid reliability and minimize costs. They are designed to burn natural gas today and convert to renewable fuels produced using power-to-methane (or hydrogen) in the future. Power-to-methane (PtM) is one of a growing number of power-to-gas processes. PtM sequesters carbon from the air through direct-air carbon capture. This process is coupled with electrolysis for hydrogen, and a methanation process to combine carbon and hydrogen into synthetic methane. The electricity used to power this process comes from excess renewable (e.g., wind and solar) or carbon-free (e.g., hydro or nuclear) sources. Thus, the fuel produced from PtM is renewable.

 

Photo by American Public Power Association on Unsplash

San Antonio Utility Taking Steps Into An Ultra-Green Future

At-a-Glance:

Electric utilities are making efforts to reduce and end carbon emissions. But right now, they’re struggling with the overselling of alternatives when they don’t have enough essential backup in the form of storage. They also have the huge imperative of maintaining service — in lay terms, keeping the lights on. CPS Energy, San Antonio’s municipally owned electric and gas utility with over 860,000 electric and 358,000 gas customers, is putting its best big green foot forward, but wants to avoid being trapped into rigidity. To learn more, read “San Antonio Utility Taking Steps Into An Ultra-Green Future.”

Key Takeaways:

  • CPS Energy has canvassed the world, seeking ideas that will best deliver 500 MWe of new technology, 900 MWe of solar power and 50 MWe of storage.
  • In response to the CPS Energy July request for information (RFI), the utility has received nearly 200 expressions of interest from around the world.
  • The responses break down this way:
    • Refined gas-powered generation, turbines or reciprocating engines
    • Compressed-air energy storage
    • Liquid air (cryogenic) energy storage
    • Thermal energy storage, using mostly waste heat in concrete or rock hosts
    • Underground pumped hydro, using abandoned oil wells and mines for the drop
    • Kinetic storage with flywheels
  • These technologies promise longer duration, higher efficiency, and less degradation than today’s available battery storage, CPS Energy leadership said.

Path to 100% Perspective:

CPS has developed a Flexible Path plan with goals of reaching an 80 percent non-carbon-emitting energy portfolio by 2040 and reaching net-zero carbon emissions by 2050. The Texas municipal utility plans to add about 900 megawatts of solar, 50 megawatts of energy storage and 500 megawatts of new technology solutions, to include alternative fuels.

 

Photo by Johannes Plenio on Unsplash