The goal of the Cardano project management team is to be the most environmentally friendly blockchain solution possible. Cardano uses a unique proof-of-stake consensus mechanism called Ouroboros, as opposed to the energy-consuming proof-of-work system currently used by, for example, the Bitcoin network.
ADA is a token on a distributed computing platform that, like Ethereum, enables users and developers to run smart contracts, decentralized applications, sidechains, multi-party computing, and metadata. The name of the project comes from the nineteenth-century mathematician Ada Lovelace, who is widely regarded as the first computer programmer.
ADA tokens supply the Cardano platform in a similar way as the ETH tokens supply the Ethereum platform. These tokens are used to pay transaction fees and are determined by reviewers (and delegators) who are willing to help maintain the security and stability of the entire network, and in return win awards.
In the future, ADA will also be used as a network management token to allow holders to vote on changes and updates to the Cardano platform.