A British solar power company is working on technology that could enable railways all over the world to be powered by renewable energy, with South Wales seen as a likely testbed for the equipment.
Riding Sunbeams is the company behind a project of the same name that is already delivering power to trains on Network Rail’s Wessex route from a site near Aldershot. That project is supported by the Department for Transport’s ‘First Of A Kind’ (FOAK) scheme to boost innovation in rail. The firm is now talking to the Welsh government about a possible role in electrifying the South Wales Metro.
Alex Byford is head of delivery at Riding Sunbeams with long experience of power projects. He explains that the Aldershot installation is quite small, at 37kW, but enables the company “to prove to Network Rail’s product assurance and safety teams that renewables could be integrated without causing any issues with the rail network.” A data logger at the site is gathering information about power quality, in particular, to ensure that the equipment will neither cause problems nor itself be damaged as a result of being connected to “quite a dirty supply” that has issues with harmonics, reactive power and voltage fluctuations.
Trains on the Wessex line are powered by a third-rail supply at 750V DC, so it’s surprising to hear that the solar installation uses inverters to convert its DC output to AC. Byford says this is a better way of doing things because Network Rail supplies the third rail from its own private distribution network at 33kV AC. Plugging directly into that enables the use of the same off-the-shelf inverters that are used by other solar sites to feed into the grid. It’s those inverters that are now going through the railway approval process.
Meanwhile, in Wales the devolved government and Transport for Wales are pushing ahead with plans to electrify 172km of what are known as the Valley Lines as South Wales Metro. The avowed aim is to do this with 100 per cent renewable energy, of which 50 per cent will be Welsh-generated. Work is currently in the technical design stages, addressing the physical requirements.