Sustainability-First Distributed Ledger Systems: Six Reference Designs and a Shared SFC Engineering Profile

Six original distributed-ledger system designs addressing ecological challenges across supply-chaincertification, healthcare and pharmacy interchange, paperless billing, recycling and material recovery,cross-operator roaming for telecom and EV charging, and carbon-credit measurement, reporting andverification. All six share a single Sustainability-First Consensus (SFC) engineering profile that turns sustainabilitycriteria into verifiable engineering properties rather than claims: an annual network energy budget,hardware-lifecycle constraints excluding single-use hardware, signed on-chain EnergyAttested andCarbonAttested events carrying a Net-Zero invariant, a conformance API for machine-readable disclosurealigned to CSRD and ESRS-E1, and a qualification rule separating hot-path ledgers from anchor-only layers. Each project is documented as four companion files: README (motivation, architecture, data flow,sustainability and policy alignment), PRD (problem, personas, requirements, KPIs, milestones), SPEC(identifiers, schemas, event envelope, REST API, smart contracts, conformance tests) and ARCH(components, sequences, trust boundaries, deployment, failure modes), with architecture and data-flowdiagrams. All work is documented at design level. No system described here is implemented or deployed, and nofigure in these documents is a measurement of a running system; values are design targets or are citedfrom published external sources. This deposit records the engineering profile and the six architectures that apply it. The underlyingfour-criterion framework is defined separately in Besleaga (2026), "Sustainability-First Consensus"Ledgers for a Green Digital Future, Association for Computing Machinery, doi:10.1145/3809296 (accepted;in press). Deployments building on these designs should cite both.