Elon Musk and Tesla are taking the expanding Supercharger network off-grid, with an end goal of one day running almost completely off of solar power and batteries. Since the electric grid is still mostly powered by coal and natural gas, disconnecting from allows them to go green in a more meaningful way, at least for now. The Supercharger network is a critical selling point for Tesla customers, giving them a way to completely power a vehicle within 30 minutes.

Musk tweeted about this issue Friday in response to recent criticism of Tesla’s plan, which powers the network of Superchargers, slated to double by the end of 2017, with the fossil fuel-based energy of the grid. All Superchargers are being converted to solar/battery power. Over time, almost all will disconnect from the electricity grid. — Elon Musk (@elonmusk) June 9, 2017 Now, it’s still better for overall vehicle emission levels to drive an electric vehicle rather than one that burns traditional fossil fuels. However, charging EVs with natural gas, coal, and nuclear power is a clear weakness on the road to fighting climate change. Decarbonizing the grid is a longer-term goal than Tesla’s plan to go off-grid, but luckily Tesla drivers will probably be able to drive without the grid long before it’s decarbonized.