Hydrogen vs. Hydrogen-Free: Unveiling the Dynamics of Carbon Capture & Utilization (CCU) Comparison
Authors: M Basri Ana Hasrinatullina , Ismail Wan Rokiah , Terath Kumar Omporkas , Veloo Sominidevi 
Published: April 2024

Objective
Carbon capture and utilization (CCU) stands at the forefront of innovative solutions to combat climate change. This manuscript exploring into the promising realm of CCU, showcasing its role in transforming them into valuable products. The marriage of environmental sustainability and economic growth is the crux of CCU's appeal. This work conducts a comparative analysis of CCU methods, dissecting those with hydrogen integration and those without. By examining respective challenges, and potential driver for Carbon Capture and Utilization (CCU) deployment, insights will be provided that contribute to the ongoing discourse in Malaysia.
The urgency to address climate change has fueled the exploration of innovative solutions, with CCU emerging as a frontrunner. Interest in Carbon Capture, Utilization and Sequestration (CCUS) in Southeast Asia has been growing in line with international trends. The renewed momentum for CCUS has been driven by strengthened climate commitments from governments and industry, including ambitious net-zero targets. Beyond the conventional approach of capturing CO2 emissions, CCU offers a dual benefit by repurposing the captured carbon into valuable products. This paradigm shift not only aligns with environmental sustainability goals but also opens avenues for economic growth, creating a synergy between climate action and financial viability.
CCU with H2 hydrogenation is a way of converting CO2 into useful products or energy sources. Hydrogenation is a chemical reaction that adds hydrogen atoms to a molecule, usually to increase its stability or reactivity. In this case, hydrogenation of CO2 produces various fuels and chemicals, such as methane, methanol, ethanol, dimethyl ether, and hydrocarbons. There are different types of catalysts that can be used for CO2 hydrogenation with H2, such as metal oxides, metal sulfides, metal phosphides, and metal carbides. The choice of catalyst depends on the desired product and the reaction conditions.
Direct use of CO2 for utilization without hydrogen is another way of converting CO2 into useful products or energy sources. There are different ways to achieve this, such as using CO2 as a feedstock for chemical synthesis, building materials, or enhanced oil recovery. Unlike CO2 based Fuel processes which requires large input of energy due to splitting or reduction of CO2 molecule processes, incorporating CO2 molecule into the product such as CO2 in building materials require low energy. However, the estimated potential for the scale of CO2 utilization in fuels varies widely, from 1 to 4.2 Gigatonnes of CO2 per year while CO2 utilization pathways in concrete building materials are estimated between 0.1 and 1.4 Gigatonnes of CO2 per year over the long term[7]. Early commercial opportunities to use CO2 to cure concrete or in the production of aggregates are already being realized – in some cases demonstrating improved cost and product performance relative to conventional production. This process can enhance the strength and durability of the concrete, as well as reduce the amount of cement and other materials needed.
By converting CO2 into products with economic value, CCU fosters a circular economy, where emissions are repurposed, contributing to a more sustainable and resource-efficient model by ensuring the final emissions to be appropriately repurposed or captured and the cycle continues.