The Energy Roadmap states that electricity will have to play a much greater role as a source of power for transport if greenhouse gas emissions are to be cut by more than 80% by 2050. As the Community of European Railway and Infrastructure Companies (CER) points out, about 50% of the European rail network is already electrified and there is no technical barrier to electrifying the rest of it. By contrast there are considerable technical challenges to electrifying road transport.