This is a complex topic, as islandable, most of their energy with renewables, and regularly sell energy back to the grid are specific criteria that not all renewable-heavy communities meet. “Islandable” refers to the ability to disconnect from the main grid and operate autonomously, providing power during outages. A community may generate all its power from renewables but not have the technical setup to island if the main grid goes down. Similarly, a city that uses 100% renewables might still need to draw power from the larger grid at times and therefore may not always have a surplus to sell back. However, based on the criteria, here are some notable examples: Microgrids and Islands Kodiak Island, Alaska: This island community is a prime example. It has transitioned to almost 100% renewable electricity using a combination of hydropower and wind turbines. The Kodiak Electric Association has also invested in battery storage to manage the fluctuating supply from wind, ensuring a consistent and resilient power supply. While its an island and not selling back in the same way a grid-connected microgrid might, it is a self-sufficient, renewable-powered system. Illinois Institute of Technology (Illinois Tech) in Chicago, Illinois: The Illinois Tech campus has one of the first functioning microgrids in the U.S. It incorporates solar panels, wind turbines, and other distributed generation sources. It is designed to be island able, allowing the campus to maintain power during large-scale outages. It helps to reduce peak demand and can provide services to the larger grid. University of California San Diego (UCSD) in California: UCSDs campus microgrid is a notable example that can both island from the grid and use energy arbitrage. It generates power from sources like natural gas turbines and solar panels. The system can buy energy from the grid at low prices and self-generate when prices are high, which is a form of interaction that benefits the campus and the wider grid. Alcatraz Island, California: Alcatraz has a solar-diesel hybrid microgrid that has significantly reduced its reliance on diesel generators. It uses solar panels and a battery bank to power the island, with diesel generators as a backup. While it may not sell back to the mainland grid, it is an excellent example of an isolated system using renewables to achieve a high degree of energy independence. Cities Greensburg, Kansas: After being devastated by a tornado, the town rebuilt itself with a focus on sustainability. It generates more electricity than it consumes, primarily through a wind farm, and sells the surplus power to the rest of the state. Burlington, Vermont: In 2014, Burlington became the first city in the U.S. to source 100% of its electricity from renewable sources, including hydropower, biomass, wind, and solar. The city’s utility, Burlington Electric Department, strategically integrates locally generated power and has a biomass plant that generates electricity to be sold back to the grid. Rock Port, Missouri: This town is unique as the first in the U.S. to meet all of its electricity needs with wind energy. It has capitalized on local wind farm projects and, in doing so, generates a surplus of power. Georgetown, Texas: Georgetown became fully powered by renewable energy in 2017 by entering into long-term contracts for wind and solar power. While it doesn’t have a small, islandable microgrid in the same way as a university campus, its commitment to purchasing 100% renewable energy demonstrates a large-scale shift that also allows it to participate in the energy market and sell power back to the grid.