More than a year ago, a company said it was launching an exciting new form of transportation in Knoxville: the first solar-powered, self-driving water taxi that would ferry riders across the Tennessee River between the south waterfront and Vol Landing. While the Greycraft water taxi from artificial intelligence startup Buffalo Automation is here in town and ready to transport riders, the ferry’s use has been stalled. “What seems to be a challenge that we’re working on is trying to find a commercial entity or a nonprofit or anybody who would be responsible for the boat: Own it. Operate it,” Buffalo Automation CEO Thiru Vikram told Knox News.