Decarbonisation Technology November 2026 issue

However, accessing it requires more processing. Freshly captured biogas is saturated with water vapour and contains CO 2 alongside corrosive hydrogen sulphide (H₂S). Studies of POME-derived biogas report H₂S concentrations commonly in the low thousands of ppm. For example, Saputro and Sudibandriyo report approximately 1,500-3,000 ppm, reinforcing the need for gas cleaning before engine use or upgrading (Saputro & Sudibandriyo, 2020) . Processing and utilisation pathways for captured biogas u Raw wastewater intake: Liquid effluent is collected from milling operations and fed into a sealed anaerobic digester. v Biogas capture and conditioning : Raw biogas (CH₄, CO₂, H₂S, moisture) is scrubbed of corrosive H 2S and dried to protect downstream equipment. w Utilisation pathway A (on-site CHP power): Scrubbed gas powers engines to provide base- load electricity and steam for mill operations, replacing fossil diesel. x Utilisation pathway B (RNG upgrading): Gas undergoes membrane separation or pressure swing adsorption to achieve >95% purity CH₄ for pipeline injection or heavy transport fuel. Raw biogas must be treated before hitting downstream equipment. Biological or chemical scrubbers remove the corrosive H₂S, while chillers strip out moisture. Once purified, the gas follows one of two main value pathways: Pathway A: On-site CHP generation For energy-hungry applications like palm mills, generating power on-site is an immediate win. Mills require electrical power for heavy machinery and thermal energy (steam) for fruit sterilisation. A typical facility handling 60 tonnes of fruit per hour generates enough POME to power a 1.5-2.0 MW CHP engine. This allows the mill to remove expensive diesel generators, cutting Scope 1 carbon intensity and running costs. Waste heat harvested from the engine exhaust is fed back into mill operations, while excess electricity can be exported to local grids. Pathway B: Upgrading to renewable natural gas (RNG) Where facilities sit near gas pipelines or heavy

transport corridors, upgrading biogas to RNG opens even bigger markets. Stripping out CO₂ boosts methane purity above 95%, matching natural gas grid specifications. Industrial upgrading technology includes: • Membrane separation: Polymer membranes separate gas molecules under pressure based on permeability. • Pressure swing adsorption (PSA): Adsorbent media selectively binds CO₂ while releasing pure methane. • Water scrubbing: Uses high-pressure water washing to dissolve CO 2 . Upgraded RNG can be compressed (CNG) or liquefied (LNG) to fuel heavy truck fleets, creating a closed-loop transport ecosystem that displaces fossil diesel across the value chain. There is an additional advantage here for palm oil operators. By reducing diesel exhaust fumes, it can help to prevent mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) contamination, keeping levels within legal limits. Verifying reductions for CSRD and CSDDD compliance While generating energy delivers solid operational return on investment (ROI), tighter regulation is largely driving faster corporate action. Voluntary Environmental, Social, and Governance (ESG) pledges are giving way to mandatory, financial-grade reporting mandates. Two key legislative acts are leading the way: • Corporate Sustainability Reporting Directive (CSRD): Mandates comprehensive disclosures on environmental impacts for thousands of companies operating in or exporting to the EU, requiring audited Scope 1, 2, and 3 footprints based on verifiable primary data. • Corporate Sustainability Due Diligence Directive (CSDDD): Requires large enterprises to actively identify, prevent, and mitigate environmental risks across their global supply chain, with heavy financial penalties for non- compliance. For companies buying palm oil, mill wastewater emissions represent a massive chunk of their supply-chain carbon footprint. Historically, downstream buyers relied on spend- based estimates and generic industry averages. Under CSRD and CSDDD, those vague