CarbonGuard

Inspiration

Voluntary carbon markets are crippled by greenwashing, unverified claims, and double-counting. Traditional carbon credits are frequently minted without cryptographic verification of physical IoT energy generation data, and retired credits are often re-traded across uncoordinated registries.

What it does

CarbonGuard bridges environmental IoT evidence and a Web3 carbon-credit lifecycle prototype. It validates bounded renewable-energy telemetry, calculates deterministic Scope 1/2/3 methodology emissions with a disclosed illustrative factor table, detects sensor anomalies, mints test credits in a real local EVM, and prevents a used attestation or retired credit from being reused inside its Solidity registry.

How we built it

Built with zero external production runtime dependencies in pure Node.js ESM. Added CarbonCreditRegistry.sol, compiled with solc and executed in a local EVM. It enforces oracle-only minting, single-attestation use, owner-only retirement, and irreversible status transitions. Backed by a native SHA-256 append-only linked block audit chain and an 18/18 passing automated test suite.

Challenges we ran into

Keeping the illustrative factor table explicit without misrepresenting it as certified carbon accounting, preventing edge-case replay attacks where delayed IoT packets could trigger duplicate credit minting, and ensuring the audit chain can be verified independently without high-latency blockchain queries.

Accomplishments that we're proud of

18/18 automated tests passing across the off-chain MRV pipeline and local EVM smart contracts. Zero npm vulnerabilities. A 1,796-byte optimized Solidity runtime with explicit revert tests for unauthorized minting, attestation reuse, unauthorized retirement, and second retirement.

What we learned

Architecting single-use cryptographic attestations between off-chain physical sensor data and on-chain smart contracts to eliminate double-counting vulnerabilities.

What's next for CarbonGuard

Deploying Solidity smart contracts on Ethereum and Polygon testnets for native ERC-721/ERC-1155 token minting, and integrating satellite vegetation index (NDVI) data feeds for reforestation project verification.

Built With

• ethereum
• evm
• github-actions
• iot
• javascript
• node.js
• sha-256
• solidity