What does this nebulous claim about the power generator source actually mean? They ran on 100% renewables for 10 minutes or indefinitely? If they are running on 100% renewables going forward do they have dedicated wind plants that they are storing and then using doing peak times? Or have they used a financial derivative to fund the construction of sufficient wind power to meet their energy needs over the long run? What does this cost? Wind power tends to have a very distinctive generation shape daily and seasonally and rapid transit systems have a very unique load shape. The two are almost surely never matched.