You could wire together a group of houses or neighborhoods with generators and batteries and make the electric company redundant by establishing contracts which buy and sell electricity between participants at rates which adjust in response to demand, forecast, and each battery’s reserves.

Ethereum’s ‘problem’ to solve is “how do you program value”. It’s a tool that has never been directly available to software engineers.

You can also look at MakerDAO’s DAI algorithmic stablecoin, which has used automatic management of collateral assets to maintain a peg through the worst market crashes so far. These contracts are battle-tested and require much less trust than Tether or USDC.