Reducing CO2
with Gen-CAT™

Challenge

Carbon dioxide and other greenhouse gases (GHGs) in the atmosphere continue to increase at alarming rates. To combat the climate change crisis, these emissions must be reduced dramatically. Research suggests that energy industry operations directly account for nearly 10 percent of GHG emissions as well as downstream emissions. It is clear that real progress isn’t possible without the buy-in of the oil and gas industry.

Our client recognized this, becoming one of the first majors to aim for net-zero by 2050. To meet this pledge, the company needs to remove about half a billion tons of carbon emissions a year, which means immediately transforming existing operations to minimize Scope 1 (direct operational) emissions.

When our client initiated a greenfield-brownfield expansion of their existing offshore and onshore assets in Southeast Asia, carbon reduction was at the forefront. So were we, eager to meet the challenge with our proprietary emissions assessment tool Gen-CAT™.

The project scope involved assessing multiple development concepts encompassing onshore and offshore elements, brownfield modifications to various facilities and new greenfield components. Overall, accurate emissions estimates needed to be generated to capture all these elements within the rapid timescale of an early phase conceptual project.

 

Understanding

To successfully undertake the project, it was essential that emissions forecasting, including GHG and methane, was conducted alongside technical and economic assessments. We used our proprietary tool Gen-CAT™ to support and facilitate the process.

To estimate the emissions footprint for each concept, the first operational emissions associated with each new unmanned offshore facility had to be quantified.  This included power generation and export during operations and maintenance, offshore fugitive emissions, offshore facility venting and emissions from walk-to-work vessels used during maintenance campaigns.

Understanding the impact of the new onshore facilities on existing emissions was key to providing a holistic overview of multiple concepts. This required capturing opportunities that arose through exporting steam and power surpluses to the aging facility and reducing the load on less efficient forms of power generation.

Ultimately, significant variations in production throughput over the design life meant year-on-year emissions forecasts were required to accurately predict total emissions for each concept.  These forecasts were generated taking into account parallel operating equipment, equipment sparing, the potential for turndown and impacts on facility availability to reflect long-term options.

 

Solution

Throughout the study, the transparent, robust and flexible operation of Gen-CAT™ provided the speed and accuracy to rapidly estimate GHG emissions for each of the proposed configurations.

The ability to input site-specific existing emissions factors into Gen-CAT™ enabled steam and power surpluses generated by incorporating waste heat recovery with gas turbine compressors (GTCs) and a new combined cycle power plant (CCPP) to be translated into relative emissions savings for the facility.

Integrating production profiles and standalone mechanical modeling enabled Gen-CAT™ to account for changes in power load over time. This refinement allowed subtle variations between cases through full field life to be determined including:

• Parallel unit operation and its impact on facility availability and flaring and venting volumes;
• Impact on emissions due to equipment operating in recycling until throughput allowed for parallel trains to be shut down;
• Emissions forecast providing transparency on throughput versus operating points to identify future optimization steps such as compressor rewheeling.

Finally, the ability to fine-tune Gen-CAT™ to client standards ensured the basis of the emissions used for all project work remained consistent and comparable with client portfolio assessments, allowing results to be incorporated directly into company targets.

 

Results

The output of the Gen-CAT™ assessment enabled complete, holistic concept screening and selection with a full understanding of the carbon implications and impact of each concept being considered. A preferred concept was ultimately identified for each element for further design and assessment.

This project demonstrated the strength and flexibility of Gen-CAT,™ showing our client a detailed breakdown of potential emissions savings and optimized operational variations. This clarity allowed strategic development solutions to be successfully generated that fit the client's carbon reduction goals and operational and budgetary needs.

 

Gen-CAT™ brings carbon CO2e assessments into the concept screening stage with flexible models that can be refined and adapted as projects mature to design optimization, FEED and beyond.