I know they heat their homes with the geothermally warmed water, but their electricity rates don't seem to be significantly different than most places.
"Iceland, March 2022: The price of electricity is 0.139 U.S. Dollar per kWh for households."
Iceland has the cheapest electricity in the world. They run heat under their roads so they don't need to be plowed. Aluminum is shipped to Iceland to be smelted just because the energy is so much cheaper.
Iceland's electricity usage per capita is 4x that of the United States, and more than 2x the next highest country (Norway). They're the largest producer per capita as well. The population is not large, mind you, but it's noteworthy.
If you're asking for some contextual explanation why that $0.139 is not a sufficient figure to explain the issue, consider reading the rest of my post past the first sentence.
"Iceland, March 2022: The price of electricity is 0.139 U.S. Dollar per kWh for households."