Imperial College London and the climate change charity 10:10 have announced a project to investigate using track-side solar panels to power trains, bypassing the electricity grid so that the panels can provide power precisely when needed most.

Although this sounds quite straight forward, it is not being done anywhere in the world.

If successful, the work could have a wide impact with applications on electrified rail networks all over the world because many railway lines run through areas with great potential for solar power but where existing electricity networks are hard to access. 

Initially the project will look at the feasibility of converting “third rail systems”. These supply electricity to the locomotive through a power line running close to the ground. They have the advantage of matching the way electricity is supplied by solar panels as direct current and using a similar voltage to the rail network of 750V DC. Concentrating on the third rail will allow the project team to establish how to match the DC power of solar panels to DC railway lines without having to convert it to AC.

Even with the “simple” third rail system there are technical difficulties. Firstly, the third rail on most rail networks is also used for signalling purposes, so injecting power could lead to communications issues. There are also issues around safety and integration of a secondary power source and managing how and when the solar power is being sent to the third rail.