Every day, thousands of passengers heading southwest on trains leaving Aldershot station pass a cluster of solar panels nestled by the tracks. Few, if any, may notice the installation. But the train they are on is drawing power from it.
“On a sunny afternoon, if you are catching a train through Aldershot, a little bit of the energy for that train will come from those solar panels,” says Leo Murray, co-founder and chief executive of Riding Sunbeams, a start-up aiming to use renewable energy resources for rail electrification projects.
Riding Sunbeams built the Aldershot array in 2019. It’s small in scale at just 40 kilowatts – equivalent to roughly 10 of the rooftop solar arrays you would find on a typical British home.
However, it demonstrates how renewables can be directly integrated into the railways.
Not only that, Mr Murray says it is currently the only solar array in the country that delivers power directly to rail to move trains. “If you are a railway, this is the cheapest electricity you can buy,” he adds.
Around the country and the world, many trains still run on diesel, a fossil fuel. To go electric, rail operators have traditionally had two options: electrified rail or overhead lines that trains connect to with arm-like pantographs on their roofs. Installing either of these systems can be expensive and technically challenging.
But engineers are working on new ways of implementing such technologies, and completely different alternatives are also emerging, which could speed up electrification projects.
A key barrier to electrification is often the limitations of the local electricity grid – it’s challenging to access a significant connection for powering your trains. “That problem has only become much, much worse,” says Mr Murray.
This is why he views solar panels as so helpful in enabling railway electrification projects.
Mr Murray says that, after the Aldershot project, he had hoped Riding Sunbeams would go on to build a full-scale commercial pilot. But funding problems got in the way.
Now, however, Network Rail, which owns and maintains the railway infrastructure in Great Britain, is seeking suppliers for rail-side renewable energy projects.
“This is the big one,” says Mr Murray, explaining that his business is planning to bid for a contract.
Leo Murray would like to see more solar panels next to railway tracks
New projects bring new complexities, however. At Aldershot, the track was already electrified – it was a case of plugging solar panels into that existing system.
However, for trains that are switching from diesel to overhead lines, leveraging solar energy is more challenging.
This is because solar panels produce direct current (DC) electricity, whereas overhead lines use alternating current (AC).
Efforts are underway in England to develop a new converter device that could solve this problem, however.
Separately, Colton Junction between Leeds and York, the fastest railway junction in the UK – where trains speed through at up to 125mph – was electrified recently with the help of software developed at the University of Huddersfield.
The software creates a 3D model of the overhead line system, enabling engineers to plan its construction with precision – thereby reducing costs by eliminating the need for specific traditional testing and evaluation methods.
“Everything was specified in the software in terms of measurements,” says João Pombo, associate director of the university’s Institute of Railway Research. “All the trains have been running at maximum speed at that junction since August.”
Poland’s Nevomo has developed an electromagnetic propulsion system
But there are entirely different ideas for electrification out there. Polish start-up Nevomo has developed an electromagnetic propulsion system.
It’s retrofitted onto existing track by fitting a thick aluminium cable into an enclosure that runs between the rails. This generates a magnetic field strong enough to propel freight wagons equipped with magnets.
“We eliminate locomotives,” says Ben Paczek, founder and chief executive. “Each wagon becomes independent. They can also operate in groups.”
A key benefit of the technology, says Mr Paczek, is that it allows operators to bring freight wagons to a stop very quickly – and, as a consequence, that means they could, in principle, safely put lots of independently moving wagons relatively close together on one stretch of rail, increasing the density of freight transportation in a particular area.
