As of March 15, a beta release of the lightning network implementation developed by the San Francisco-based tech firm Lightning Labs is live on the Bitcoin mainnet.
The term "lightning network" does not refer to a specific network, but rather to a type of network that is in conversation with but distinct from a blockchain. A lightning network is comprised of many payment channels, which are essentially environments in which two blockchain users can transfer funds back and forth between each other without needing to record each transaction to the chain.
By creating a web of these channels, developers enable users to send funds to parties with whom they have no payment channel open by routing the payment through a set of existing channels. Funds sent through such a network are generally expected to arrive almost instantaneously.
While there are several companies working to develop their own versions of a lightning network, Lightning Labs' co-founder and CEO Elizabeth Stark says that her firm's software, called Lightning Network Daemon, now represents the "the first Lightning mainnet beta for Bitcoin." The platform can apparently also support transactions in Litecoin, a cryptocurrency with a codebase partially cloned from Bitcoin's.
In addition to offering rapid payments, a lightning-like network could also help blockchain platforms like Bitcoin and Ethereum scale to the point that they can process many more transactions than they are capable of handling today. Without significant scaling, it appears doubtful that Bitcoin or Ethereum will ever be viable candidates for mainstream adoption as payment systems, or as platforms that support other kinds of activities that involve millions upon millions of users.
One project, called the Raiden Network, seeks to build a lightning-like platform specific to the Ethereum environment. A derivative system that relies on unidirectional payment channels, called µRaiden, is under development as well. Versions of this platform have been deployed twice on the Ethereum mainnet with the goal of identifying bugs in its code.
Another use case that these platforms can support is a system of payments or micropayments between nodes in an IoT network. It recently emerged that Chubu Electric Power, a leading Japanese utility, has partnered with a small tech company called Nayuta to trial a system that would allow people to pay for the use of electric vehicle charging stations through a lightning network. Nayuta CEO Kenichi Kurimoto told ETHNews that the pilot is currently being conducted on a closed testnet, and that Chuden, as the electric company is known, initiated the discussions with his firm that eventually led to the collaboration.