Decarbonisation Technology - May 2024 Issue

Renewable energy

CO point sources

Direct air capture

Sustainable biomass, bio waste

Water electrolyser

Shell R everse W ater G as S hift P rocess

Torrefaction

Solids gasication

CO + H

Shell Fische r– Tropsch P rocess

Shell W ax H ydroconversion P rocess

Shell technology: in development

Ex-Shell technology: Shell expertise

Shell technology: commercially proven

Figure 4 The Shell XTL Process features three line-ups: PTL, BTL, and a PTL/BTL hybrid

Some of the least advantaged locations are those with offshore wind not backed up by a stable solar power supply, such as locations in North West Europe. These studies demonstrate that the most promising opportunities are in locations with available sustainable bio-feedstock and/or low-cost renewable power, particularly, 24/7 stable hydropower or complementary wind and solar profiles. Key requirements For bio-SAF and/or eSAF production to become a viable and economically attractive option, it is necessary to address challenges across the entire production chain. For initial projects, establishing a clear and consistent regulatory framework specifying acceptable (bio and waste) feedstocks, emissions standards, power and carbon sources, and other environmental considerations is paramount. Understanding the expectations of end users, including industries and consumers, is also crucial. Critical technical considerations include: • The availability of water electrolysis technology at scale and low cost. • Establishing a reliable and affordable supply chain of bio-feedstocks that meet sustainability and GHG criteria (as defined under RED II). • The scaling of CO₂ conversion and feedstock gasification technologies. Another essential requirement, and the primary anticipated cost factor, involves securing access to renewable power derived

from sources such as solar, wind, or hydropower at an acceptable cost. Ideally, this power should be available at a large scale and exhibit round-the-clock stability. Solar parks and offshore wind farms experience intermittency challenges. Mitigating this entails advancing and de-risking solutions such as hydrogen and battery energy storage systems or adopting flexible operational strategies for synthesis plants to cope with energy fluctuations. As CO₂ is an essential feedstock for eSAF, its efficient and cost-effective supply from point sources and the development of DAC technologies are imperative for minimising the carbon footprint and cost of PTL production. Finally, optimal integration of all processes and utility building blocks, including off- gas recycling, and synergies with existing assets, such as chemical plants and refineries, should be explored to capitalise on shared infrastructure and resources, thereby contributing to overall cost-effectiveness. Technology development level Many technology building blocks for the production of eSAF and bio-SAF from biowaste residues are commercially proven, while others are at the advanced de-risking stage. There is also significant know-how about process and utilities integration (for instance, from commercial gas-to-liquids (GTL) plants). However, there is more to be learned and de-risked, in particular around integration with renewable power supply.