This project supports the City of Stuttgart in developing the analytical foundations for a municipal negative-emissions strategy. Stuttgart has identified residual emissions that cannot be fully eliminated through conventional mitigation measures and therefore require targeted carbon dioxide removal, utilisation or permanent storage. The project provides a structured assessment of CDR technologies relevant for an urban context, evaluates Stuttgart-specific resource and infrastructure conditions, and develops guidance on how negative emissions can be transparently accounted for within municipal greenhouse gas accounting frameworks.
Key activities include:
- Technology Landscape Review: Preparing a concise overview of CDR technologies relevant for cities, including biochar, ecosystem sinks, CO₂ storage in construction materials, and carbon capture with storage or utilisation at biogenic CO₂ sources.
- Stuttgart-Specific Technology Portfolio: Confirming and assessing priority CDR pathways for Stuttgart, including pyrolysis with biochar production from residual biomass, BECCUS at waste-to-energy facilities, carbon storage in construction materials, biochar use in urban greening and tree planting, and forest-based or natural sinks.
- Residual Emissions Context: Translating Stuttgart’s remaining residual emissions into concrete technological pathways and assessing how different CDR options could contribute to addressing these emissions over time.
- Value Chain and Resource Mapping: Mapping relevant value chains for each technology, including input materials, CO₂ sources, infrastructure needs, storage durability, local resource availability and links to Stuttgart’s circular economy and bioeconomy objectives.
- Comparative Technology Assessment: Comparing selected technologies according to technological readiness, removal or storage potential, permanence, reversal risks, infrastructure compatibility, resource competition, costs, implementation barriers and strategic co-benefits.
- Economic and Market Analysis: Reviewing current and expected cost corridors for different CDR options and assessing broader carbon removal market developments relevant to municipal strategy design.
- Municipal Accounting and Credibility Framework: Analysing how negative emissions can be reflected in municipal greenhouse gas accounting, including the relevance of BISKO, the Global Protocol for Community-Scale Greenhouse Gas Inventories (GPC), GHG Protocol guidance and related accounting approaches.
- Double Counting and Communication Guidance: Assessing risks related to double counting, offset versus contribution claims, certificate quality, corresponding adjustments and credible external communication of municipal negative-emissions activities.
- Strategic Recommendations: Developing practical recommendations for Stuttgart on priority technologies, implementation pathways, quality criteria, accounting approaches and possible next steps for operationalising a municipal negative-emissions strategy.