Why Combined Cycle Gas Plants Still Matter in a Rapidly Changing Grid

The US electricity grid is under growing pressure. Electrification is accelerating, and the variable output of renewable energy is reshaping grid dynamics. In this evolving landscape, combined cycle gas turbine (CCGT) plants continue to play a critical role in powering the country, maintaining grid reliability, and complementing renewable generation.

While utilities, independent power producers, and other asset owners are retiring some aging CCGT units, they are also building new plants and upgrading existing installations with advanced turbines, faster ramp rates, and emissions controls. These modern facilities are designed for greater operational flexibility and, in some cases, burning hydrogen-blended fuels. 

CCGT plants are no longer solely baseload generators – they’re strategic grid assets that provide firm, dispatchable capacity in an increasingly dynamic market.

For renewable energy developers and energy traders, shifts in the CCGT fleet directly affect power prices, capacity markets, and infrastructure risk. Failing to anticipate how changes will affect market dynamics can lead to stranded assets, offtake agreements misaligned with market conditions, or missed opportunities to capture system flexibility. 

For equipment manufacturers and engineering, procurement, and construction firms, this intelligence is equally critical. With legislative shifts likely to temper the pace of new renewable deployments, the demand for high-efficiency, flexible gas generation is poised to grow. Having early visibility into where CCGT projects are advancing allows these companies to anticipate market needs, align production schedules, and position their capabilities to capture upcoming build opportunities.

Understanding where and how CCGTs are being added, upgraded, or phased out requires more than high-level forecasts. It calls for timely, granular insight into project pipelines, regional trends, and market signals that shape long-term grid outcomes. Yes Energy’s Infrastructure Insights® fills this gap by monitoring project-level data on construction activity, equipment type, and in-service timelines.

What Is a Combined Cycle Gas Turbine Plant? 

A combined cycle gas turbine plant is a natural gas–fired power station that integrates two electricity-generating technologies within a single facility. By combining a gas turbine with a steam-driven system, it delivers more power from the same amount of fuel than conventional plants, making it one of the most efficient forms of fossil-fuel generation available today.

How Does a Combined Cycle Gas Turbine Work​?

CCGTs remain the backbone of the US natural gas fleet, accounting for the majority of gas-fired generating capacity. Traditionally used for baseload and intermediate generation, CCGTs offer fast ramping capabilities that make them well-suited to balance supply and demand fluctuations. This flexibility is increasingly important as more variable renewable resources, such as wind and solar, are integrated into the grid. 

At the core of their operation is a two-stage generation process: 

• First stage (Brayton cycle): Natural gas combusts in a gas turbine, generating electricity.
• Second stage (Rankine cycle): Unlike simple-cycle gas turbine plants, CCGTs utilize a heat recovery steam generator (HRSG) to capture waste heat and produce steam, which then drives a secondary steam turbine that generates additional electricity and enhances overall plant efficiency.

What Is CCGT Power Plant Efficiency?

This combined approach allows modern CCGTs to achieve thermal efficiencies approaching 60%, significantly higher than typical coal or nuclear plants. That efficiency directly reduces fuel use and emissions per megawatt-hour, giving CCGTs a performance edge in a grid under pressure to decarbonize without compromising reliability. 

Combined Cycle Gas Turbines Under Construction

Despite a slowdown in gas capacity additions in 2024, developers plan to add 18.7 GW of combined-cycle capacity to the grid by 2028. Yes Energy’s Infrastructure Insights is tracking approximately 1.6 GW currently reported to come online in 2025. However, if the plant has not already started construction at this point, it will likely carry into 2026.

Source: Infrastructure Insights showing planned natural gas plants with reported in-service dates 2025-2028

Yet, this growth is uneven and far from guaranteed. Developers are facing regulatory changes, equipment delays, and long interconnection queues, all of which are already impacting timelines and costs. 

Retrofitting the Past, Engineering the Future

As decarbonization pressures mount, operators of existing combined cycle gas turbine plants must decide whether aging units should be retired or strategically upgraded with technologies like hydrogen blending, carbon capture integration, and battery co-location to stay competitive. 

Developers are designing the new generation of CCGT plants with these advanced features, reflecting a shift in how gas assets are engineered for future flexibility and emissions performance.

Hydrogen Blending

Major manufacturers like GE Vernova, Siemens Energy, and Mitsubishi Power are designing and retrofitting turbines to accommodate hydrogen blends. Instead of burning 100% natural gas, the turbine combusts a mixture, often 5% to 50% hydrogen by volume, depending on the turbine's design and retrofits. 

This blended fuel is fed into the CCGT’s combustion system, where it is ignited to generate electricity just as conventional natural gas would be. Hydrogen, when burned, produces only water vapor, so blending it with natural gas can significantly cut the carbon intensity of power generation without requiring a completely new infrastructure.

For example, at Georgia Power’s McDonough-Atkinson Plant, Mitsubishi Power recently completed an advanced-class hydrogen blending demonstration, achieving a 50% blend on an M501GAC turbine. The test reduced CO₂ emissions by 22% compared to pure natural gas and validated full-load operations with multiple blend levels over several weeks.

Source: Yes Energy’s Infrastructure Insights showing Georgia Power’s McDonough-Atkinson Plant

Likewise, Constellation’s Hillabee Generating Station in Alabama demonstrated safe and efficient operation at a 38% hydrogen blend using a Siemens Energy turbine. The upgrade required only minor modifications and could eliminate 270,000 metric tons of CO₂ annually.

Source: Yes Energy’s Infrastructure Insights showing Constellation’s Hillabee Generating Station

Magnolia Power (Louisiana) and the Intermountain Power Project (Utah), both currently under construction, are being built from the ground up with hydrogen co-firing capabilities. The proposed Entergy plants in Texas would be similarly equipped. 

Source: Yes Energy’s Infrastructure Insights showing the Magnolia Power Generating Station

Source: Yes Energy’s Infrastructure Insights showing the Intermountain Power Project Repowering

Turbine Efficiency and Operational Flexibility

Beyond fuel innovations, manufacturers are incorporating advanced materials and real-time diagnostics to drive both efficiency and flexibility. 

• GE’s HA-class turbines achieve greater than 64% combined cycle efficiency in commercial operation by leveraging internal cooling channels and proprietary coatings. 
• Next-gen turbines are increasingly built for cycling behavior and low-load operations, enabling faster ramping and more granular dispatch decisions. 

These technical advancements have far-reaching implications for plant economics and grid dynamics. Higher ramp rates, for example, enhance the ability to capture price spikes in volatile nodes, while low-turn-down capabilities reduce curtailment risks for co-located renewables. 

Meanwhile, pairing turbines with battery storage or carbon capture reshapes the asset’s eligibility for ancillary markets and capacity revenues. Infrastructure Insights and Yes Energy’s nodal analytics tools surface these data points, which are essential for modeling volatility and congestion.

Forecasting the Future of Gas with Infrastructure Insights

The rapid evolution of combined cycle gas turbines through technological upgrades, hydrogen blending, and increased operational flexibility is reshaping their role in the grid and making it more complex for market participants to assess value and risk.

For renewable developers, traders, and planners, understanding these nuances requires more than static forecasts. It requires access to detailed, up-to-date data on plant configurations, emissions trajectories, and market conditions, combined with advanced modeling and visualization tools that capture regional variations and policy impacts.

Yes Energy’s Infrastructure Insights plays a key role by tracking energy construction projects nationwide and delivering critical data on ownership, size, status, and timelines. This granular visibility into where and when new or upgraded CCGTs will come online helps market participants anticipate shifts in supply, demand, and infrastructure risk.

Complementing this, platforms like Yes Energy’s PowerSignals® and DataSignals® provide rich and granular market data and analytics that reveal real-time grid dynamics, congestion patterns, and asset-level performance. 

Modeling solutions such as EnCompass® allow users to simulate dispatch scenarios, emissions compliance, and forward price forecasts across changing market structures.

Together, these tools help stakeholders to:

• Accurately forecast CCGT dispatch flexibility and capacity factors
• Model emissions trajectories and compliance under different fuel blends and retrofits
• Analyze nodal price dynamics and congestion risks with high granularity
• Evaluate hybrid configurations, including gas plants paired with storage
• Anticipate project pipeline developments and infrastructure risks.

In a grid defined by volatility, firming needs, and policy uncertainty, using integrated data and modeling platforms is essential to making informed, forward-looking decisions and positioning assets for long-term success.

Contact Yes Energy to schedule a demo and learn how Infrastructure Insights and EnCompass can improve your ability to make better business and trading decisions and drive more revenue.

About the author: Laura Fletcher is on the Yes Energy product team as an associate product manager. Prior to joining the team, Laura studied environmental engineering at Georgia Tech. She started working with energy data as a college intern, and she has worked on various consulting projects, annual market forecasts, client relations, and database management.