The Increasingly Important Role of Gas Turbines in the Energy Transition

Gas turbines have long been a cornerstone of energy production, traditionally running on fossil fuels such as natural gas or fuel oil, and in some cases, even crude oil. At first glance, these machines might not seem to fit into the vision of a decarbonized energy future. However, a deeper dive into the capabilities and potential modifications of gas turbines reveals a significant role they can play in the energy transition. As we strive to transform and decarbonize our energy systems, it becomes clear that gas turbines are not only relevant but essential in several key aspects.

Firstly, gas turbines are pivotal in the transition from coal- and oil-fired power generation. Natural gas is a cleaner burning fossil fuel, producing significantly lower CO2 emissions compared to coal and oil. By retrofitting existing coal and oil-fired power plants with gas turbines, we can achieve substantial reductions in greenhouse gas emissions – in some cases up to a 70% reduction! ?This switch is a crucial step in the broader strategy to reduce the carbon footprint of our energy systems while maintaining reliable power generation.

Moreover, gas turbines are increasingly being adapted to utilize alternative, "green" fuels such as hydrogen (H2). ?Hydrogen, when produced using renewable energy sources, is a zero-emission fuel that can be burned in modified gas turbines to generate electricity without CO2 emissions. This capability positions gas turbines as a versatile and future-proof technology that can evolve alongside advancements in fuel production and storage. The integration of hydrogen into the energy mix not only supports decarbonization but also enhances energy security by diversifying fuel sources.

In addition to fuel flexibility, gas turbines can be combined with carbon capture, storage, and utilization (CCUS) technologies to further mitigate their environmental impact. CCUS involves capturing CO2 emissions produced during combustion and either storing them underground or repurposing them for industrial applications. When paired with gas turbines, CCUS can create a near-zero-emission power generation solution. This combination is particularly valuable in regions where renewable energy deployment is challenging due to geographical or climatic constraints.

Furthermore, gas turbines play a critical role in stabilizing the grid and ensuring a reliable power supply, especially as the share of intermittent renewable energy sources like wind and solar increases. Gas turbines can quickly ramp up and down in response to fluctuations in electricity demand and supply, providing the necessary flexibility. They also provide the inertia needed for a stable grid. This capability is essential for integrating higher levels of renewable energy into the power system, as it helps to smooth out the variability and maintain grid stability during periods when renewable generation is low.

Enabling the Coal- and Oil-to-Gas Shift

The transition from coal and oil to natural gas relies strongly on the use of gas turbines, which offer substantial potential to reduce CO2 emissions even with existing power plants. By simply switching the fuel type from coal or oil to natural gas, we can achieve substantial environmental benefits. Natural gas burns cleaner than coal and oil, producing fewer greenhouse gases and pollutants.

In the case of an oil-to-gas switch, it can even be implemented in many existing power plants, making it a cost-effective and efficient way to reduce emissions without the need for entirely new infrastructure. Many gas turbines currently running on oil can be modified, which might involve retrofitting the turbines with advanced components or implementing new technologies that allow them to utilize natural gas more efficiently.

In some cases, a complete exchange of the whole turbine set might be necessary. Replacing these turbines with modern, high-efficiency gas turbines can provide a substantial boost in performance and environmental benefits. Additionally, in the case of a switch from using coal to gas, building new gas turbine plants to replace phased-out steam power plants is often required. This approach is being adopted in many countries around the globe, where new gas turbine plants are being constructed to ensure a reliable and cleaner energy supply.

Beyond supporting the coal and oil-to-gas shift, raising the efficiency of existing gas turbines is another lever to reduce emissions. Continuous innovation has led to the development of more efficient gas turbines that can generate more power with less fuel. The good news is that it is often possible to modify and upgrade older gas turbines to reach these new levels of efficiency. By doing so, we can achieve significant fuel savings and emission reductions, contributing to a more sustainable energy future.

Cleaner Energy: Hydrogen in Gas Turbines

Switching from natural gas to hydrogen in gas turbines holds immense potential for decarbonization. Hydrogen, with its zero-carbon combustion, can significantly reduce CO2 emissions when used as a fuel in gas turbines. This transition is not only feasible for new installations but also for the existing fleet of gas turbines currently in operation. Many of these turbines can be upgraded to be hydrogen-ready, allowing them to burn hydrogen either partially or fully.

The ability to retrofit existing gas turbines to utilize hydrogen is a game-changer. It means that we can leverage the current infrastructure while making substantial strides towards a cleaner energy future. These modifications involve addressing the unique combustion characteristics of hydrogen, such as its higher flame temperature and faster flame speed, as well as faster ignition. These properties make hydrogen a highly reactive fuel, creating numerous challenges for gas turbine combustion systems. When implementing hydrogen co-firing, several factors must be considered to ensure full flexibility from pure natural gas to pure hydrogen firing. The complexity extends beyond the gas turbine itself. Using hydrogen affects other components of the power plant, necessitating a thorough assessment and ensuring compatibility, as discussed in my article on H2.

Transforming Power Plants with CCUS

Carbon Capture, Utilization, and Storage (CCUS) holds immense potential for making existing gas turbine plants emissions-free. By integrating CCUS technology, we can capture CO2 emissions right at the point of emission. This involves incorporating capture units into the processes of the power generation plant, making it a more effective solution compared to capturing CO2 directly from the atmosphere, which is both expensive and inefficient.

Basically, there are three main technological paths for capturing CO2 at the source: pre-combustion, where carbon is removed from the fuel gas; oxy-combustion, where fuel gas is fired in an oxygen-rich environment; and post-combustion, where CO2 is captured from flue gas at atmospheric pressure. Today, post-combustion is the preferred pathway for capturing CO2 across most power generation applications.

The potential of CCUS in existing gas turbine plants is transformative. By retrofitting these plants with CCUS components, we can achieve near-zero emissions. This not only helps in reducing greenhouse gas emissions but also extends the operational life of existing infrastructure. For instance, projects like Cane Run 7 demonstrate the feasibility of integrating CCUS with gas turbines, capturing substantial amounts of CO2. This approach ensures that gas turbines remain a vital part of the energy mix while contributing to the decarbonization journey.

Enabling the Increased Infeed of Renewables

Gas turbines play a crucial role in stabilizing the grid, especially as the share of intermittent renewable energy sources like wind and solar increases. One of the key advantages of gas turbines is their ability to provide power during times when renewable energy generation is low. Unlike renewables, which depend on weather conditions, gas turbines can quickly ramp up and down in response to fluctuations in electricity demand and supply. This flexibility ensures a reliable power supply, filling the gaps when renewable energy is insufficient and maintaining grid stability.

Another critical aspect of gas turbine plants is their contribution to grid inertia. Traditional power generation methods, such as coal and oil-fired plants, provide rotational inertia, which is essential for balancing the grid system. However, as these traditional methods are being utilized less frequently and generators are shutting down, their contribution to providing rotational inertia, short circuit power, and voltage control diminishes. This loss of inertia poses a significant challenge for grid stability, especially with the increasing infeed of renewables.

Gas turbine plants can help address this challenge by providing the necessary inertia to stabilize the grid. They can act as large synchronous generators, maintaining the rotational inertia needed to balance the grid. This capability is crucial for managing fluctuations in power supply and demand, ensuring that the grid remains stable even as the share of renewable energy increases. By providing both power during low renewable periods and the necessary inertia for grid stability, gas turbine plants are indispensable in the transition to a more sustainable energy system.

Gas Turbines: A Key for the Energy Transition

In conclusion, while gas turbines may initially appear to be at odds with the goals of the energy transition, their potential for modifications and upgrades makes them a vital component of a sustainable energy future. By facilitating the switch from coal and oil to natural gas, enabling the use of green fuels like hydrogen, incorporating CCUS technologies, and supporting grid stability, gas turbine plants are poised to play a significant role in reducing CO2 emissions and advancing the decarbonization journey. As we continue to innovate and invest in these technologies, gas turbines will undoubtedly remain a key player in the evolving energy landscape.