Post-Combustion Carbon Capture Implications and Opportunities in Gas Fired Power Generation

Author: Clara Yuan (Process Engineer), Fluor Canada Ltd.

Over the past several decades, implementing carbon capture technology as a form of emissions abatement has become an increasingly common consideration for many industries. This includes industries like power generation, which continue to rely on traditional fossil fuels based on the advantages they present over renewable energy (e.g., availability). There is significant growth expected in natural gas fired power generation as a result of rising electricity demand, including the need for that electricity to have a low-carbon intensity. Technology solutions such as post-combustion carbon capture (PCCC) support the broad goal of reducing electricity grid emissions.

In 2025, the average electricity demand in Alberta was approximately 10,100 MW daily and electricity demand is expected to rise to 11,330-12,065 MW by 2035 based on projections from the Alberta Electric System Operator (AESO). This growth can be attributed to several factors:

• Macroeconomics, including continued growth in oil sands production in the province and new load connection projects from high-demand facilities, such as data centres.
• Electrification of different sectors of the economy (e.g., buildings and transportation), including growth in developing industrial sectors, such as hydrogen, and rapid adoption of electric vehicles in the long-term.
• Challenges in ensuring flexibility and resiliency in the power generation to meet seasonal peak demand requirements.

To meet these growing demands, gas-fired power generation will remain significant even as alternate technologies continue to emerge. Gas-fired power generation continues to be an attractive option when considering factors such as lifespan and system costs, deployment schedule, technological maturity, and high reliability.

To support decarbonization efforts, policies have been set by all levels of government to incentivize new carbon capture utilization and storage (CCUS) projects and penalize emissions. However, the changeability of these policies has caused uncertainty, and has resulted in delays in decision-making for many of these projects. An example is Alberta’s Emissions Reduction and Energy Development Plan, which comprises the Technology Innovation and Emissions Reduction (TIER) regulatory system.

In addition to policy drivers, economic considerations can also influence a company’s decision to implement carbon capture. The high cost of carbon capture is usually a barrier; however, for industries that produce high value products, this may be less of a deterrent. For example, there is currently a significant amount of interest from cloud service providers and artificial intelligence companies to build data centres in Canada, and it is expected that demand from data centres could account for 14% of Canada’s total power needs by 2030. In a study done by RBC’s Climate Action Institute, it was found that the gross domestic product contribution by data centres was $2,732/tonne of CO₂e emitted compared to $384/tonne of CO₂e emitted for the oil and gas sector. While this is not a direct comparison of the value of the products, it demonstrates the magnitude of difference, and the lower relative added cost of carbon capture that data centre owners contend with compared to owners from other sectors. This distinction may position the value proposition of decarbonized power for data centre projects more favourably.

When implementing carbon capture, design considerations that may pose challenges and need to be accounted for early in the design of the facility include:

• Plot Space Requirements – A carbon capture unit (CCU) requires a large footprint. Overall plant footprint can be comparable to, and in some cases, larger than the natural gas combined cycle (NGCC) plant.
• Utility Requirements – Typical utility requirements of a CCU include power, steam, and cooling water. When integrating power generation and carbon capture, considerations around utilities may include:
• Whether to add capacity for power generation for the CCU or have the existing facility absorb the power demand.
• Whether to add auxiliary boilers for steam generation or pull steam from the existing NGCC.
• How to achieve the significant waste heat rejection required by the CCU. Options include air cooling, water cooling, or hybrid, and the decision may depend on what is already available at site.
• Regional Growth – Determining if low load growth or large load growth is expected with multiple new facility additions can impact pre-planning of the capacity of the CCU.
• Phasing – Building the NGCC and CCU facility at the same time or planning for a phased approach (i.e., adding the CCU later). A phased approach has an impact on capital investment, as well as the design of the facility.
• Capital Costs vs. Operating Costs – The trade-off between capital cost and operating cost of equipment in the CCU and the impact on levelized cost of electricity should be considered.
• Operating Considerations – There are different degrees of complexity of operation depending on how integrated the CCU is with the power generation facility. This may include additional operation staff with familiarity with the CCU equipment that is unique compared to a typical power plant or vice versa. Operating flexibility may be included to take the CCU offline by isolation and utility adjustments but with an increase in operating complexity.

Carbon capture can be implemented on both existing and new build assets with each type of project requiring different considerations.

Retrofits

Retrofits have the advantage of staging capital investment and can leverage existing site assets, such as infrastructure and utilities.

On the other hand, retrofits may have lower overall efficiency and higher marginal operating cost than a built-for-purpose power plant with carbon capture. Both the electricity output penalty and the relative cost of installing a carbon capture unit may be higher if integrating the CCUS is challenging, or the existing facility electrical infrastructure was not designed to receive additional power.

Other important considerations for retrofits include how much longer the power generation facility will be operating and whether it is worth implementing carbon capture using metrics such as the levelized cost of carbon capture, as the residual life of the power plant may be limiting the lifespan of the CCU.

New Build NGCC Units with Added CCU

With a new build NGCC, there are opportunities to optimize the design and integrate the power plant and capture unit more efficiently by designing the power plant to synergize with the steam and power requirements of the capture unit.

New Build NGCC Units – Carbon Capture Ready

Another option is to design a new build NGCC unit that is intended to be operated without carbon capture at the start so that the initial capital investment is lower but with the consideration that it will be added later. This allows for pre-planning of a CCU as a retrofit in the initial design, which would allow for more efficient implementation and operation of the CCU alongside the power plant in the future. This could include allotting plot space for the CCU in the initial design, including provisions for tie-ins, considering heat recovery opportunities, and designing for additional utility integration and capacity.

Amine-based solvent carbon capture technology is the most proven commercially available technology for PCCC, but it is also important to consider that alternative PCCC technologies will influence retrofit or new build optimization and integration due to the utility, space and equipment requirements.

Fluor has performed multiple configuration scenarios for customers and can offer a variety of integration options. To compare options for implementation of carbon capture on a retrofit facility, the impact to key parameters of different methods of producing or obtaining the necessary power and steam for the CCU are presented in Table 1.

Table 1: Comparison of NGCC/CCU Configurations

*Based on option for grid import (350 kg/MWh) to maintain behind the fence base net power.

When the steam and power for the CCU are taken from the NGCC plant (Scenario 1), the overall design is more energy efficient compared to a design where the CCU remains a parasitic power load for the NGCC but includes a dedicated utility boiler for CCU steam generation (Scenario 2). The net heat rate, which is a ratio of the total fuel input and the net electricity produced, is higher for the latter because additional fuel is needed to produce steam from the utility boiler and the required capacity of the CCU is higher in order to capture the emissions from the boiler. Each facility will have unique project drivers to consider, and while Scenario 1 provides a more energy efficient design, the addition of a utility boiler reduces operational complexity and potentially lower capital investment compared to cogeneration alternatives.

Increase in demand for power is expected to continue in the coming decades and CCUS will continue to play a role in making new gas-fired power generation projects less carbon intensive, which is incentivized both by policy and economic drivers. There are challenges as well as opportunities to implement CCUS on existing and new build projects from a variety of perspectives, including degree of integration, plant efficiency and amount of capital investment or pre-investment. Ultimately, each project will have its own set of specific drivers that require consideration in the decarbonization strategy and carbon capture design.

Fluor Canada has relevant experience and the necessary engineering and construction expertise to provide solutions for your future carbon capture project needs. Having an engineering contractor that can identify and provide efficient solutions for the many challenges in implementing PCCC for an existing or new facility enables owners to optimize capital investment and improve project outcomes.