technology transport

Solar railways are on their way

Back in the spring I wrote about the possibility of direct solar powered trains. The idea came out of RePower Balcombe, where a community energy project had discovered that the national grid was at full capacity in their village and there was nowhere to plug in their planned solar farm. There was a railway substation though. Could they build their solar farm and sell the power to the railways?

There are a bunch of reasons why that makes sense, but strangely enough, nobody in the world has ever tried it. So 10:10 have spent the last three years talking to engineers, pushing doors open at Network Rail, and raising funds for a proper feasibility study. Last night was the launch of that study at the London Transport Museum. I went along, and the message that I heard loud and clear is this: it’s not just technically possible, it’s a really smart idea that’s going to go a long way.

Electrified trains either run on overhead wires, which are alternating current (AC), or on third rail systems, which are direct current (DC). Solar panels produce DC, and they just happen to produce it at the right voltage for the rail network. Solar farms could be installed on land adjacent to railway lines, connected to the substations that are already in place every few kilometres along the DC line, and you’ve got yourself a solar powered train.

The South of England has a DC line. MerseyRail in Liverpool and London Underground are also DC. So are the tram systems in Edinburgh, Manchester and a number of others. Solar power could play a role here, and 10:10 have already been working with local community energy groups in the south of England to map potential sites. From this initial study, 15% of the line could be solar powered. MerseyRail could reach 20%.

That’s in Britain, where most of the rail network is AC and where we don’t get much sun for large parts of the year. But other countries have extensive DC networks or are yet to electrify their railways. When you consider the solar potential of countries like India, Mexico or Brazil, we’re talking about a technology with global applications. In some places it could prove a leapfrog technology, allowing electrification of rail networks without having to build a grid.

So when can we look forward to seeing our first solar powered train? The economics of it look good, rail travel is growing in Britain and there’s a demand for more power. It’s a great business opportunity, both for local cooperatives, energy firms and the rail industry itself. There’s a potential lifeline for community energy here too, which has stalled in the last couple of years as government support has evaporated.

On the other hand, Network Rail have an extensive and slow testing regime. The price of getting things wrong is very high, both in safety and in delayed journeys, so we’re going to have to be patient. Since it’s not been done before, there are contractual complications. Safety regulations around trackside land made it very unlikely that we’ll be able to use embankments or railway property. As far as Britain is concerned, it’s going to be a few years before this can be integrated, even if the rail industry leaps at the opportunity.

Other countries will be able to implement the idea much quicker. Now that the feasibility study is out there to download, others will be studying it and adapting it. Last night we heard from historian Dan Snow as he listed some of the world firsts that had come out of Britain’s railways, but I doubt we’ll be able to add solar trains to the list. With their extensive rail network, huge solar ambitions and willingness to experiment, my money’s on India getting there first. But who cares? To borrow the title of 10:10’s study, I’m just looking forward to riding sunbeams.


  1. Yes, and it is time DC made a comeback for railway electrification. The DC can be fed direct to the trains’ motors, so there is less equipment on the trains, which otherwise have to be fitted with transformer and rectifiers.

    Low voltage DC is easy to install and avoids the sort of hideous and very expensive overhead wiring systems which have led to a stop on further electrification in Britain. It would also work well with battery packs under carriages to bridge gaps in the electrification.

    Solar powered feeder stations could help to overcome the principal disadvantage of low voltage systems.

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