See Candidate Page Julián Castro, Clean Energy, Climate, Iowa Castro tweets 9/4/19 In 95 out of 99 counties in Iowa, wind is the cheapest energy source. In the other 4 counties, it's solar.The transition to a green economy is already underway. We need to accelerate it to meet the urgency the climate crisis demands.#ClimateTownHall— Julián Castro (@JulianCastro) September 4, 2019