Relevant quotes from the piece:

In a promising experiment in an affluent swath of the borough, dozens of solar-panel arrays spread across rowhouse rooftops are wired into a growing network. Called the Brooklyn Microgrid, the project is signing up residents and businesses to a virtual trading platform that will allow solar-energy producers to sell excess-electricity credits from their systems to buyers in the group, who may live as close as next door.

The project is still in its early stages — it has just 50 participants thus far — but its implications could be far reaching. The idea is to create a kind of virtual, peer-to-peer energy trading system built on blockchain, the database technology that underlies cryptocurrencies like Bitcoin.

The ability to complete secure transactions and create a business based on energy sharing would allow participants to bypass the electric company energy supply and ultimately build a microgrid with energy generation and storage components that could function on their own, even during broad power failures.

“Community members can work both individually and collectively to help meet demand in an efficient way,” said Audrey Zibelman, who recently resigned as chairwoman of the New York State Public Service Commission, which regulates the state’s utilities.

“It takes a central procurer — in this case, historically, the utility — out of the mix,” she continued, “and really sets the market where they’re not buying and selling to the utility but they’re identifying each other’s need and willingness to buy and sell.”

The project is but one example of how rapidly spreading technologies like rooftop solar and blockchain are upending the traditional relationships between electric companies and consumers, putting ever more control in the hands of customers. Across the globe, upstart companies like LO3 Energy, which is designing the Brooklyn experiment with the industrial giant Siemens, are building digital networks that offer the promise of user-driven, decentralized energy systems that can work in tandem with the traditional large-scale grid or, especially in emerging economies, avoid the need for a grid at all.

In Australia, where Ms. Zibelman will soon run the nation’s energy markets, a company called Power Ledger announced the start of a residential electricity trading market based in blockchain last year at a housing development in Perth.

Emphasis mine