# Use Cases and Reference Implementations **Building a registry for clean commodity certificates**: Today many commodities—from electricity to liquid fuels, steel or aluminum, or even digital assets—are adopting technologies to reduce their carbon footprint. Commodities that are produced in a sustainable manner can be differentiated from conventionally produced alternatives if they can be digitally tracked throughout their lifecycles. Green Proofs has been implemented in several of these use cases already: * [24\*7 Renewable Electricity](/legacy-documentation/solutions-2023/green-proofs/use-cases-and-reference-implementations/24x7-renewable-electricity.md) * [Sustainable aviation fuel](/legacy-documentation/solutions-2023/green-proofs/use-cases-and-reference-implementations/clean-commodities.md) * [Green Proofs for Bitcoin](/legacy-documentation/solutions-2023/green-proofs/use-cases-and-reference-implementations/green-proofs-for-bitcoin.md) * [Sustainable maritime shipping fuels](/legacy-documentation/solutions-2023/green-proofs/use-cases-and-reference-implementations/decarbonizing-shipping.md) --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.energyweb.org/legacy-documentation/solutions-2023/green-proofs/use-cases-and-reference-implementations.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.