Reduce cost while unlocking performance by integrating natural gas-fueled power plants with post-combustion carbon capture.
Why choose EGR?
Expected benefits with the integration of CCS and EGR
Through collaboration with carbon capture providers worldwide, GE Vernova has confirmed that integrating EGR into a combined cycle power plant with carbon capture improves overall system performance and efficiency. In addition to enhancing the carbon capture system, EGR also benefits the power plant itself. GE Vernova’s EGR system can be applied to both new and existing combined cycle power plants.
Less exhaust flow with a higher CO2 concentration means a smaller, less expensive carbon capture system.
Higher CO2 concentration in the exhaust flow = less energy required to separate CO2 from solvent, leaving more power for the grid.
Lower levels of oxygen in the exhaust flow reduces oxidation of the solvent, reducing the cost of replacement solvent.
Higher CO2 concentration in the exhaust flow can improve overall CO2 capture efficiency.
Reduced inlet bleed heat (IBH) results in improved part load efficiency.
At GE Vernova, our studies predict lower NOx, particulate matter, and CO emissions.
A closer look
How the system's components work
The EGR system is composed of several components. The system is broken out below in a step by step guide that explains how recycled flue gas goes from the exhaust back to the inlet.
Understanding the flow
Visualizing EGR: Integration across the gas turbine system
The animation above illustrates how EGR integrates into the gas turbine system. Below, we break down its impact across each key component—from inlet and flue gas mixing to controls and dampers.
- Inlet mixer: Cooled and cleaned recycled flue gas exits the EGR loop and is introduced into the inlet mixer through an entry duct. The inlet mixer is designed to thoroughly mix the recycled flue gas with ambient air.
- Gas turbine: The now blended stream of recycled flue gas and ambient air travels through the gas turbine. Due to the recycled flue gas, the gas turbine exhaust has a higher concentration of carbon dioxide than it would have without EGR.
- Heat Recovery Steam Generator (HRSG): The exhaust gas next travels through the HRSG. Instead of exiting the HRSG stack, the exhaust leaves the HRSG out of an opening in the back of the stack. At this point, the flow is divided. A majority of the flow is sent to the carbon capture facility. The balance of the flow is sent to the EGR loop.
- Dampers: A system of dampers is provided to route flue gas to the EGR and carbon capture systems. In addition, the dampers provide isolation when the EGR system is off.
- Flue gas fan: A fan drives the recycled flue gas through the EGR loop. Alternately, new units may be designed to eliminate the fan.
- Enhanced direct contact cooler: The DCC acts as a spray of cold water. This reduces the recycled flue gas temperature to improve performance. Furthermore, an enhanced DCC (eDC) reduces SOx, NOx, and particulate matter.
- Controls (not shown): The controls system has three primary functions: 1) manage startup and shutdown of the EGR system, 2) control the system during normal operations, and 3) provide protection during an unexpected event.
Adding value
Recycling exhaust to boost carbon capture performance and economics
Gas power plants, especially combined cycle power plants, are expected to play a key role in the energy transition due to their flexibility in meeting changing grid demands. The CO2 in the exhaust from these plants can be reduced by up to 95% using post-combustion carbon capture systems (CCS).
However, capturing CO2 can be costly. GE Vernova is working to improve the economics of carbon capture, including through techniques including exhaust gas recirculation.
With EGR, about 30–40% of the plant’s exhaust is cooled, cleaned, and fed back into the gas turbine. The remaining 60–70% goes to the CCS. This reduces the size and energy demand of the CCS, making it more cost effective and efficient.
Dive into EGR
Explore EGR technology in 3D
Take an interactive journey through EGR technology.
Rotate, zoom, and explore our interactive 3D model to see how this technology reduces the size and cost of carbon capture.
FAQ
Exhaust gas recirculation explained
Have questions about exhaust gas recirculation (EGR) and its impact on carbon capture, emissions, and plant efficiency? Explore our FAQ to learn the basics, understand the benefits, and discover how EGR can be applied to new and existing power plants.
General questions
What is exhaust gas recirculation (EGR)?
Exhaust gas recirculation or EGR is the process of cycling a portion of the gas turbine exhaust back to the gas turbine inlet to be recombusted. This reduces the volume of exhaust directed to the carbon capture plant and increases the exhaust’s CO2 concentration.
How does EGR affect the carbon capture process?
- EGR reduces the amount of exhaust directed to the carbon capture plant. This allows for smaller components within the plant, reducing the plant’s footprint and its cost. It also reduces the steam usage of carbon capture.
- EGR increases the CO2 concentration in the exhaust, resulting in a higher driving force during the capture process. Higher driving forces mean higher carbon capture efficiency which further reduces carbon capture plant size and steam usage.
- EGR decreases the O2 concentration in the exhaust, lowering oxidation driven degradation rates for the amines that capture carbon.
The benefits of EGR
How does EGR impact emissions?
In the example case of 40% EGR, 40% of the exhaust flow is redirected back to the gas turbine inlet. This reduces flow to the stack by 40%, thereby reducing absolute NOx, CO, and particulate matter (PM) base load emissions by approximately 40%.
How does EGR impact the net power plant output?
Net plant output increases with the addition of EGR due to lowered steam usage.
What are the economic impacts of EGR?
EGR lowers CapEx by reducing the size of the carbon capture plant.
EGR lowers OpEx by lowering degradation rates for amines and reducing steam usage.
Take a deeper dive
Can EGR be added to existing power plants?
Yes! EGR can be installed in both new and existing combined cycle power plants. Currently, it is commercially available for the 7HA.03 and 9HA.02 gas turbines. It can also be offered on a project-specific basis for select variants.
What other upgrades does GE Vernova offer to improve carbon capture efficiency?
GE Vernova also offers steam integration. With steam integration, the steam used in the carbon capture plant is extracted from the combined cycle steam turbine. This eliminates or reduces the need for an auxiliary boiler to generate steam which improves site fuel consumption, lowers the CapEx and size of the carbon capture plant, and reduces site CO2 emissions.
Featured video
Decarbonized power at scale: NZT Power and GE Vernova are leading the way
The world’s demand for energy is growing faster than ever—and renewables alone can’t meet it. That’s why we’re combining our industry-leading HA gas turbine technology with advanced carbon capture from Technip Energies and Shell to deliver reliable, low-carbon power at Net Zero Teesside Power in the UK. This first-of-its-kind project will capture around 95% of CO₂ emissions—up to 2 million tonnes annually—while generating enough electricity to meet annual requirements for one million UK homes. The project is also proof that it’s possible to scale flexible, safe, and sustainable power solutions for the future.
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