Here comes the sun: India’s trains go solar

My time at The Engineer last week was dominated by repurposed trains and nuclear waste, and in the blog last Friday I signed off by suggesting nuclear-powered trains might become a reality at some point, potentially solving two problems at once. The wider point I was trying to make was about the need to maximise our infrastructure and resources, whether by refitting old London Underground stock, or extracting more energy from nuclear waste instead of burying it a kilometre under the ground.

In hindsight, a nuclear reactor on board a vehicle moving at several hundred kilometres per hour may not be the safest or most practical idea I’ve ever had.  Indian Railways (IR), however, has come up with a much more sensible way to harness nuclear fusion while maximising its infrastructure - solar energy.

Car ownership in India is low, with about 20 vehicles per 1,000 people. The railways are the lifeblood of the country, helping to keep the population moving and the economy ticking over. IR is also the fourth biggest employer in the world, providing work for over a million people. Having travelled on it fairly extensively myself many years ago, I can attest that the rail network is a huge source of national pride, and extremely well run.

Unfortunately, the diesel-powered trains are not exactly world-leading when it comes to energy efficiency, and IR consumed over 17.5 billion kWh of electricity during 2013-14. This works out at roughly 4000 MW, or about 1.8 per cent of the country’s total power generation. As part of a nationwide push towards integrating more solar into India’s energy mix, IR has been tasked with generating 1,000 MW of solar capacity within the next five years, alongside 200 MW of wind capacity. Considering that installed solar capacity across the whole country is only just over 4,000 MW, it’s an ambitious target.

Trains would still of course require diesel-run engines for locomotion, but the current plan is for solar to take on the lighting and cooling load. One report has claimed that a train using solar power could cut diesel consumption by up to 90,000 litres per year, reducing CO₂ emissions by over 200 tonnes. It may not save the planet in one fell swoop, but it’s a promising move in the right direction for a country that has become one of the world’s biggest polluters during its economic boom.  

A pilot project is underway, with one coach of the passenger train Rewari-Sitapur having solar panels fitted to its rooftop. The panels have been generating 17 kWh of electricity every day, which has been used for the lighting load. It’s about one billionth of the overall annual consumption of IR, but it’s only one carriage over one day. Extrapolate over every train carriage in India, over an entire year, and the picture begins to change. Add in plans for regenerative braking, LED lighting and the wider adoption of biodiesel, and the numbers could start to have some real impact. 

But trains aren’t the only assets that Indian Railways can gear up for solar. It’s estimated that the country has over 8,000 stations, and while it may not be practical or economical to outfit them all, there’s certainly a whole lot of juice out there to be harvested.  In the renewables mix, wind still outweighs solar by about six to one, but with some parts of India averaging more than 3,000 hours of sunshine per year, it’s a resource the country is increasingly looking to. What better place to start than on the country’s iconic rail network.