A 6,300-acre farm owned by Bill Gates in Madison County could become the site of one of the nation's largest solar farms. Renewable energy company Savion has an option to buy the property for what is being called Oak Run Solar Project, according to Madison County property records. The option expires on Oct. 31, 2024. The project is in its early days. How big it would be, how much it would cost, when it would be built, and whether Savion will even proceed are decisions that have to be made. Savion has yet to seek approval from state regulators.