Uber held its second Go-Get Zero event on Tuesday to highlight some of the company’s sustainability efforts. First and foremost, it says that there are now enough EV drivers using the service to make an EV-only option available (the current Uber Green includes hybrids). The all-electric Uber Green option, which will cost about the same as an UberX, will initially be available in 40 cities and the company plans to expand this over time.