Feat: Renewable Energy Certificate Tracker Contract

[FrankiePower]

Pull Request: Renewable Energy Certificate Tracker Contract Implementation

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📌 Description

This PR implements a complete smart contract for tracking Renewable Energy Certificates (RECs) on the Stellar network using Soroban. The contract provides transparent issuance, transfer, and retirement of RECs for renewable energy compliance, following standards like I-REC and RE100. The implementation includes full lifecycle management, role-based access control, comprehensive audit trails, and support for multiple renewable energy sources.

closes #56

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📌 Type of Change

• Documentation (updates to docs or comments)
• Bug fix (non-breaking change fixing issues)
• New Feature (complete REC tracking smart contract)
• Breaking change

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🎯 Motivation and Context

This PR addresses the growing need for transparent, tamper-proof tracking of Renewable Energy Certificates in the blockchain ecosystem. Key business drivers include:

• Compliance Requirements: Organizations need verifiable proof of renewable energy usage for I-REC and RE100 standards
• Transparency: Blockchain-based tracking ensures immutable audit trails for REC lifecycle events
• Automation: Smart contracts eliminate manual processes and reduce fraud in REC markets
• Scalability: Supports high-volume REC issuance, transfer, and retirement operations with optimized storage
• Integration Ready: Designed for future integration with energy production oracles and carbon credit systems

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📁 Changes Made

Contract Structure

renewable-energy-certificate-tracker/
├── src/
│   ├── lib.rs          // Core contract, data structures (REC, IssuerInfo, events, stats)
│   ├── certificate.rs  // REC issuance, verification, and authenticity checks
│   ├── transfer.rs     // Transfer and retirement operations with authorization
│   └── utils.rs        // Validation utilities and helper functions (tested)
├── Cargo.toml          // Dependencies (soroban-sdk 21.0.0)
├── Makefile            // Build automation (14 targets: build, test, deploy, etc.)
└── README.md           // Comprehensive documentation (300+ lines)

Key Features Implemented

1. Data Structures

• REC: Complete certificate with ID, issuer, energy source, production details, owner, status, verification data
• EnergySource: Solar, Wind, Hydro, Geothermal, Biomass, Tidal
• RECStatus: Issued → Transferred → Retired/Suspended lifecycle
• RECEvent: Immutable audit trail for all certificate operations
• IssuerInfo: Tracks authorized issuers and their total issuance
• ContractStats: Global metrics for issued, transferred, and retired capacity

2. Core Functions

• initialize(): Set up contract with admin address
• register_issuer(): Admin authorizes REC issuers
• issue_rec(): Create new RECs with verification hash and metadata
• transfer_rec(): Transfer ownership with authentication
• retire_rec(): Retire certificates for compliance claims
• get_rec_status(): Query certificate details
• get_rec_history(): Retrieve complete event history
• get_issuer_info(): Query issuer statistics
• get_contract_stats(): Contract-level metrics
• suspend_rec(): Admin emergency suspension capability

3. Security Features

• Role-based access control (Admin, Issuer, Owner)
• Authentication via require_auth() on all state changes
• Ownership verification before transfers/retirements
• Status validation (prevent operations on retired/suspended RECs)
• Cryptographic hash verification for certificate authenticity
• Immutable event history for audit compliance

4. Storage Optimization

• Persistent storage for RECs and issuer data
• Instance storage for contract-level statistics
• Separate event history storage for efficiency
• Minimized storage footprint for scalability

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🛠️ How to Test the Changes

1. Navigate to contract directory:

   cd soroban/contracts/renewable-energy-certificate-tracker

2. Run unit tests:

   cargo test

   Result: 5/5 tests pass (validation utilities)

3. Build contract:

   cargo build --target wasm32-unknown-unknown --release
   # OR
   stellar contract build
   # OR
   make build

4. Run all checks:

   make all  # Clean, build, and test

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✅ Checklist Before Merging

• 🧪 All tests pass successfully (5/5 utility tests)
• 🏗️ Contract builds without errors
• 🎨 Code follows Soroban best practices and Rust conventions
• 📖 Comprehensive README with usage examples and documentation
• 🔧 Makefile with complete build/test/deploy automation
• 🔒 Security features implemented (authentication, authorization, validation)
• 📊 Storage optimized for scalability
• 🔍 All requirements from task objective met
• 🌐 Integration hooks ready for oracles and carbon credit systems
• 📋 Compliance standards supported (I-REC, RE100)

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Conclusion

This PR successfully implements a production-ready Renewable Energy Certificate tracker contract for the Stellar network. The contract provides complete REC lifecycle management with transparent issuance, secure transfers, and verified retirement. The implementation meets all specified requirements including I-REC/RE100 standards compliance, role-based access control, tamper-proof audit trails, and storage optimization. The contract is ready for deployment and integration with energy production oracles and carbon credit systems.

[FrankiePower]

@salazarsebas This PR is ready to be reviewed and merged.

[salazarsebas]

LGTM