As UK Water and Sewerage Companies (WaSCs) progress through the AMP8 investment cycle, sludge treatment centres (STCs) face a pivotal decision: how best to utilise biogas generated from anaerobic digestion in an era of shifting policy landscapes and volatile energy markets. This paper presents a structured framework for evaluating the principal biogas utilisation pathways — biomethane grid injection, combined heat and power (CHP), direct boiler firing, and hybrid configurations — against a backdrop of evolving support mechanisms including the Renewable Heat Incentive (RHI), Green Gas Support Scheme (GGSS), and Green Gas Certification Scheme (GGCS). The analysis incorporates uncertainty modelling across key variables such as electricity prices, natural gas tariffs, and propane values, providing WaSCs with a decision-support tool grounded in realistic market scenarios. A whole-system carbon balance is presented for each pathway, enabling comparison on both financial and decarbonisation grounds. The paper draws on operational experience and financial modelling to offer practical guidance for asset managers and strategy teams evaluating STC enhancement programmes. The findings demonstrate that resilient biogas strategies are rarely reliant on a singular utilisation pathways and that navigating policy uncertainty requires a flexible, evidence-based approach tailored to each facility's thermal demands, existing assets, grid connectivity, and long-term carbon commitments.