Emission Offset Automation

What it does:
Automatically calculates, purchases, and retires emission offsets based on verified emission data, ensuring real-time and transparent carbon neutrality.

Why it matters:
Eliminates manual offset reporting, prevents double counting, increases trust in carbon neutrality claims, and aligns real-world emissions with verifiable on-chain offsets.

How it works:

  • Emission sources (companies, facilities) register emission profiles

  • Approved oracles report verified emission data on-chain

  • Smart contract calculates required offset amounts

  • Carbon offset credits are purchased automatically

  • Offsets are retired (burned) on-chain to prevent reuse

  • Offset history and balances remain auditable

  • Integrates with carbon markets and ESG reporting tools

      // SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/**
 * @title EmissionOffsetAutomation
 * @author Nam
 * @notice Automates carbon emission offsetting and credit retirement
 */
contract EmissionOffsetAutomation is Ownable {

    IERC20 public paymentToken;
    IERC20 public carbonCreditToken;

    struct Emitter {
        bool registered;
        uint256 totalEmissions; // tons CO2e
        uint256 totalOffsets;
    }

    mapping(address => Emitter) public emitters;
    mapping(address => bool) public approvedOracles;

    uint256 public pricePerTon = 1e18; // example price

    // -------------------- EVENTS --------------------

    event EmitterRegistered(address indexed emitter);
    event EmissionReported(address indexed emitter, uint256 amount);
    event OffsetPurchased(address indexed emitter, uint256 tons, uint256 cost);
    event OffsetRetired(address indexed emitter, uint256 tons);

    // -------------------- CONSTRUCTOR --------------------

    constructor(address _paymentToken, address _carbonCreditToken) {
        paymentToken = IERC20(_paymentToken);
        carbonCreditToken = IERC20(_carbonCreditToken);
    }

    // -------------------- ORACLE MANAGEMENT --------------------

    function approveOracle(address _oracle) external onlyOwner {
        approvedOracles[_oracle] = true;
    }

    function revokeOracle(address _oracle) external onlyOwner {
        approvedOracles[_oracle] = false;
    }

    // -------------------- EMITTER REGISTRATION --------------------

    function registerEmitter() external {
        require(!emitters[msg.sender].registered, "Already registered");

        emitters[msg.sender] = Emitter({
            registered: true,
            totalEmissions: 0,
            totalOffsets: 0
        });

        emit EmitterRegistered(msg.sender);
    }

    // -------------------- EMISSION REPORTING --------------------

    function reportEmission(address _emitter, uint256 _amount) external {
        require(approvedOracles[msg.sender], "Not authorized oracle");
        require(emitters[_emitter].registered, "Emitter not registered");

        emitters[_emitter].totalEmissions += _amount;
        emit EmissionReported(_emitter, _amount);
    }

    // -------------------- OFFSET AUTOMATION --------------------

    function offsetEmissions(uint256 _tons) external {
        Emitter storage e = emitters[msg.sender];
        require(e.registered, "Not registered");

        uint256 remaining = e.totalEmissions - e.totalOffsets;
        require(_tons <= remaining, "Exceeds emissions");

        uint256 cost = _tons * pricePerTon;
        paymentToken.transferFrom(msg.sender, address(this), cost);

        // Simulate purchase + retirement
        carbonCreditToken.transfer(address(0), _tons * 1e18);

        e.totalOffsets += _tons;

        emit OffsetPurchased(msg.sender, _tons, cost);
        emit OffsetRetired(msg.sender, _tons);
    }
}