  Quartierstrom creates a peer-to-peer marketplace for locally generated solar
power. The marketplace is implemented as a smart contract on a permissioned
blockchain governed by all prosumers. Two privacy-by-design concepts are
presented which guarantee that the users individual load profile is not leaked
to any third party despite using a blockchain. The first approach leverages
UTXO based coin mixing protocols in combination with an account-based on-chain
smart contract. The second approach relies on an off-chain smart contract
running in trusted execution environments.
