Decarbonisation Technology - November 2021

entities and corporate mandates. These are the emissions that are created by the fuel and power that is consumed or purchased by a given entity to convert their raw materials to a final product for either processing by another entity or use by the final consumer. Therefore, whether it be the purchased electricity from the local power grid, use of natural gas or coal for steam and power generation by the plant directly, or the gasoline and diesel used by the vehicles associated with the entity, all these combine into the Scope 1 and 2 emissions. Scope 3 emissions are more challenging to account for, as they relate to the entire energy required to produce and transport the raw material, as well as the raw material itself, and then the emissions created by the next processing entity through to the final product. To track, understand, and identify improvement opportunities, the entity must have a clear understanding of their entire value chain and the associated carbon footprint, which is no small feat. The trend continues to increase of those entities that are required to track and report these emissions. Most energy companies and firms are beginning the process of identifying ways to improve and reduce Scope 1 and 2 emissions, especially those who have set substantial reduction targets by 2030 to 2035, as well as tracking and understanding their upstream and downstream Scope 3 emissions. To begin the process, a multi-layer and bi-directional process is recommended (see figure above). As with any entity, underlying performance starts at the equipment level. Therefore, measuring and tracking energy usage and identifying improvements must start here. Once the consumers and producers are clearly understood, one can move out several levels to the unit, intra-unit, and site-wide levels. For some organisations, these distinct levels may not exist, but within the modern refinery, petrochemical plant, or factory, multiple units must work together to produce the final product slate and having a clear understanding of their integration, both in process and energy, will illuminate improvement areas. Finally, with these levels and associated integration defined, the entity can evolve to examine the entire value chain to address Scope 3 emissions, both actual and potential improvement. Though not an exhaustive list, the following areas can be considered as part of finding improvement opportunities:

• Replace existing natural gas, coal, and/or fuel oil with renewable fuel sources like green/blue hydrogen or biomethane/biogas, not only for fired heaters but also for gas turbine and cogeneration facilities. • Examine heat integration opportunities, not only within process units but also between process units and sites • Replace existing steam heating exchangers with process heat or electrical heaters and ensure live steam usage is at the optimal rates and pressure/ temperature level • Minimise flaring and steam venting • Swap high carbon intensity raw materials for those raw materials with a renewable component, including processing of renewable vegetable oils and animal fats to product renewable diesel, gasoline, naphtha, and off-gas • Examine opportunities to reduce transportation requirements and processing steps to reduce energy usage • Ensure maximum potential heater efficiency through proper design and maintenance for fired equipment, as well as training for front-line operations staff on proper heater balancing and tuning • Map out and evaluate site-wide steam and power cycle efficiency to examine opportunities to replace steam-based shaft work with electrical shaft work • Diversify energy input and the product portfolio to create emissions off-sets • Examine novel technologies for energy generation and production, as well as within the production value chain, to enhance efficiencies and leverage ‘green’ opportunities Examining opportunities like these in a holistic way can generate the forward path needed to meet one’s Scope 1, 2, and 3 emission reduction targets.