Smart contracts

CO2ken has two core Solidity contracts: the ledger contract. which tracks the minting and retiring of CO2kens (co2ken.sol) and a storage contract (co2kenData.sol), which holds - most importantly - an ownable CO2ken price value.

co2ken.sol

• mint(string memory ipfsHash, uint256 amountTokens) public onlyOwner(): allows the owner to create new CO2kens
• withdraw() public onlyOwner(): allows the owner to withdraw monies received to the contract
• offsetCarbon(uint256 payment) public: allows anyone to pay a dollar-denominated value into the contract to offset carbon
• offsetCarbonTons(uint256 tons) public: allows anyone to pay a ton CO2 denominated value into the contract to offset carbon

co2kenData.sol

• setCO2kenPrice(uint256 _co2kenPrice) public onlyOwner(): allows the owner to set the price of CO2kens

green.sol

Contains the Green contract that can be inherited by others to make available the offset() modifier.

• offset(uint256 offsetThreshold): a modifier that accepts a threshold parameter to offset all accumulated carbon emissions of the function once it is crossed (batching)

Also contains the Polluter contract which is Green to demonstrate modifier functionality.

Contract addresses

Currently we're only deployed on Rinkeby. Mainnet coming soon!

Rinkeby

CO2kenData - 0x127AE08f45d687dA7887ceA369F2f4D95cb9baf2

CO2ken (for demo) - 0x93Ec2167Da2A83fbBE61567F67F71750C13B9C09

Polluter (is Green) - 0xb2306dC4fFa7ad9c028Ac7FcA686C1aBB8895C07

WEENUS (test ERC20) - collect test WEENUS by visiting https://rinkeby.etherscan.io/token/0xaff4481d10270f50f203e0763e2597776068cbc5#writeContract, connecting web3 wallet and write to drip()

Deployment

To deploy the contracts run the following commands:

1. npm install
2. cp .env.example .env
3. set the private key in .env
4. oz deploy