## 1 Introduction  
The combined heat and power (CHP) plant is an integrated energy system that is used in the power and manufacturing sectors to generate electricity and steam from a single fuel source and process. The CHP has generally been used to support the midstream and downstream operations in the oil and gas (O&G) industry. In the U.S oil refinery industry, gas turbine CHP is considered to be the most suitable technology for mitigating CO\({}_{2}\)[1] as well as for the reduction of the primary energy source (PES). The installed capacity of CHP plants in Mexico is 4042 MW, corresponding to 5.3% of the total capacity [2]. In the Mexican O&G industry (PEMEX), the CHP plants that cover the middle and high steam and electricity demands of gas processing, oil refinery, and petrochemical processes are suitable for reducing fossil fuel consumption and CO\({}_{2}\)[3]. However, on the supply side, the CHP plants face water supply competition between different users and sectors as well as moderate and severe water scarcity due to changes in land use in the middle and north of the country [4; 5], which could affect their operations. Indeed, recognizing the importance of these interlinkages between resources, externalities, and the territory with the economic process, it is advisable to use the conceptual water-energy-food (WEF) nexus to address inter-related issues at different scales and dimensions in order to perform a quantitative analysis of sustainability with a different approach [6; 7; 8]. In this sense, natural infrastructure (soil, aquatic, and terrestrial ecosystems, atmosphere as ecological resources) or ecological funds (EFs) have been recognized as key components for achieving the 2030 Sustainable Development Goals (SDGs). Ecosystem integrity is the cornerstone of the concepts of water security, food security, energy security, and their nexus [9]. A wide range of policies seek to build resilient cities, drive sustainable development, and to create a stable climate that includes nature-based solutions and green infrastructure strategies [10; 11]. This approach has been addressed since the early 1970s through a fund-flow (FF) model developed by [PERSON] [12]. The FF conceptual model has been applied to environmental accounting to assess the metabolic pattern of societies and ecosystems at different scales and dimensions [13; 14], which is important because the requirement of flows, stocks (oil, gas, coal, biomass), and natural infrastructure for the production and consumption of goods and services (technosphere) depends on the capacity of ecosystems (biosphere) to supply ecosystem services. However, there are challenges regarding how to accurately address and handle the integrated management of biotic and abiotic resources and energy systems or goods and services beyond using a simple indicator or number [13]. Finding emerging approaches to the water-energy-carbon (WEC) nexus analysis could contribute significantly to the goals of the Mexican energy sector that seek to attend to and achieve reductions in the supply of energy, water, and emissions [15; 16], as well as to address the requirements of the new PEMEX's Business Plan 2019-2023, which considers enhanced oil recovery (CO\({}_{2}\)-EOR) [17]. In this regard, the capture, use, and sequestration (CCUS) of CO\({}_{2}\) have been established as a narrative by several institutions [18; 19; 20] and authors [21; 22] as the only possible technological option of the electrical and industrial sector to mitigate climate change (CC). A contribution between 12% and 14% [20; 22] of total mitigation and cost of 30-60 USD/t for CO\({}_{2}\) capture [23] is estimated. Other studies support that this technology would only contribute 1% in the case of the chemical conversion of CO\({}_{2}\) and between 4% and 8% [24; 25] for EOR-CCS.