Unlocking the benefits of natural gas conversion for coal-fired power plants

Oct 31, 2024

Converting coal-fired power plants to natural gas is helping utilities meet rising power demands, enhance reliability and lower emissions, while addressing regulatory pressures and leveraging existing infrastructure.

By Brian King, Burns & McDonnell

The energy landscape is undergoing a seismic shift, driven by federal regulations and increasing demand for more efficient power generation with fewer carbon emissions. For the first time ever the U.S. Energy Information Administration was unable to forecast the amount of new capacity for 2024, because the demand was changing so rapidly with the influx of onshoring, data centers, electric vehicles and coal retirements.

In today’s hot market, getting new generation online can be challenging due to permitting delays, interconnection queues and the limited availability of original equipment manufacturers. However, coal-fired power plants are increasingly being converted to natural gas. A wave of fuel conversions and gas additions is expected over the next five to seven years, with some of these projects serving as temporary solutions for future combustion turbine projects. As coal-fired power plants face growing pressure to retire or comply with stringent EPA restrictions, converting to natural gas offers a viable solution.

A power plant’s capacity factor, which measures its efficiency and reliability, is a crucial consideration when planning a conversion. Improving a plant’s capacity factor may trigger a new source review under current regulations, raising concerns among utilities about compliance and operational risks. Because of these concerns, it is essential to verify that increasing the capacity factor would not inadvertently trigger a new source review, as such a review could introduce additional regulatory and operational challenges.

Coal-fired plants frequently grapple with forced outages due to issues such as slagging or fouling. Soot blowers clear ash and slag during power generation, though frequent use may create operational inefficiencies.

Switching to natural gas reduces the frequency of maintenance and lowers the risk of equipment failures. Gas-fired plants provide greater reliability and efficiency, especially during peak demand, making them a more dependable option for modern energy production.

Technologies such as data centers and electric vehicles are driving higher energy consumption, which is putting increased stress on the electric grid. While coal-fired power plants have been a significant contributor to grid capacity, maintaining them will become more challenging due to stricter EPA regulations. When coal-fired power plants are retired, they leave a significant gap in both base load and dispatchable power, unlike weather-dependent renewable energy sources. Converting coal-fired plants to natural gas has become an attractive solution to fill this void, as natural gas is well-positioned to meet current demand with fewer emissions, greater operational efficiency and quicker dispatching.

One of the significant advantages of converting existing coal-fired plants to natural gas is that the interconnection to the grid is already in place. This eliminates the need for a new interconnection agreement or costly upgrades to transmission lines, which is often a major concern for greenfield development. In addition to this, many of the necessary environmental permits are likely to be retained, bypassing the lengthy process of securing new approvals. With these foundational elements already addressed, utilities can focus on prioritizing long-lead-time equipment, streamlining the conversion process.

Additionally, converting a coal-fired plant to natural gas allows utilities to re-use significant portions of their existing equipment, thereby reducing capital costs. Equipment like steam turbines, condensers and transformers can often be retained, while new components, such as gas or dual-fuel burners and controls, are installed to facilitate the fuel switch. By leveraging existing infrastructure, utilities can also save on long-lead procurement items, shortening project timelines compared to building a new plant from the ground up.

Dual-fuel or co-firing conversions, which enable power plants to run on both coal and natural gas, offer utilities a way to keep using assets. These conversions provide operational flexibility by enabling plants to switch between coal and natural gas or use a combination of both fuels, depending on market conditions. This capability allows utilities to manage operational costs more effectively when fuel costs fluctuate. Additionally, dual-fuel systems help power plants meet stricter environmental regulations by burning cleaner natural gas to reduce emissions while maintaining some or all of their original coal capacity.

Another benefit of converting existing plants is the potential to retain staff, as many operational and maintenance roles remain relevant after the switch to natural gas. Maintaining a skilled workforce supports local economies by preserving jobs, while also protecting institutional knowledge and reducing retraining costs. After coal operations end, plant staffing can often be adjusted, allowing clients to reassign employees to other roles within the company. This approach helps address the challenge of finding new employees to step into roles left by retiring staff.

Converting coal-fired power plants to natural gas represents a forward-thinking strategy for utilities navigating a rapidly evolving energy landscape. This transition not only addresses regulatory compliance and operational efficiency but also supports a reliable power supply to meet increasing grid demands. As the pressure to meet increasing power demands while reducing carbon emissions intensifies, natural gas plays a pivotal role in shaping a sustainable and resilient power generation sector.

Originally published by Burns & McDonnell.

About the Author: Brian King joined Burns & McDonnell in 1999, launching a career focused on improving boiler performance for energy clients. His experience includes project development, construction management and process design. Brian has technical knowledge in tuning and commissioning low-NOx burner systems, overfire air systems, selective noncatalytic reduction (SNCR) systems and activated carbon injection systems. Brian also brings his skills to coal-to-gas conversion projects, adapting coal-fired boilers for modern applications.