One in four trains on Indian Railways could be powered by solar

Back in 2015 when Tom Parker of RepowerBalcombe and I first had the idea of plugging a solar farm directly into the railway tracks, I could scarcely imagine the global carbon-cutting potential this approach could hold. But our latest research from Riding Sunbeams - the impact enterprise we set up with Community Energy South to make this idea a reality - has started to show just how vast this potential could be. 

With our friends at the Delhi-based NGO Climate Trends, and my long time solar rail collaborator at consultancy Ricardo Energy & Environment, Dr Nathaniel Bottrell, we carried out a high level feasibility study to work out just how much of the traffic on Indian Railways could be powered by direct supply from new solar farms built alongside the tracks. This is an important line of enquiry for Riding Sunbeams because India is leading the world on two frontiers for keystone decarbonisation technologies right now  - solar PV deployment and rail electrification. 

In 2020-21 alone, Indian Railways electrified a record-breaking 6,015 route kilometres - almost equal to the total length of electrified railway routes in the whole of Great Britain today (6,049km)! They are on track to full electrification of their entire railway network by the end of 2023, which will make Indian Railways the biggest electrified rail network in the world. 

Meanwhile India has an abundance of solar radiation to exploit, and is busy making the most of it with their National Solar Mission. Begun in 2010, the Mission to make India a global leader in solar power is succeeding, and the country is well on its way to meeting its target of installing a whopping 100GW of solar generating capacity by 2022 - with 95GW already built or contracted. This compares with just 14GW of solar so far here in the UK!

There are other reasons why Indian Railways are a perfect target for Riding Sunbeams. The country still has weak power grids, causing problems for generators and electricity users alike, so the chance to connect GWs of solar directly to India’s biggest electricity consumer (Indian Railways used about 2% of all electricity in India) means avoiding many of those problems, and cutting costs in the process. The energy system in India is also still heavily dependent on coal power, the highest carbon way to generate electricity, while in the UK the biggest part of our national emissions reduction to date has been because we have pushed coal almost completely out of energy system. This means that every unit of traction energy we can supply direct to the railway from solar plants to move trains in India saves around four times as much CO2 as doing the same thing in Britain. 

Of course, because India is so much sunnier than Britain, and most of it is equatorial so there is no winter to contend with, a given solar panel will also generate nearly twice as much electricity each year in India as it would in the UK - one of the key reasons why India now has access to the cheapest solar power in history. 

The headline finding from our new study is that more than one in four trains on Indian Railways could be powered directly by solar connected to the tracks, on commercially attractive terms - saving nearly 7 million tonnes of CO2 every year, equivalent to the entire annual emissions of Uruguay! Integrating battery storage could push this share even higher, to over 40%. 

However, one of the most interesting and surprising things we discovered was that in the short term, India’s rapid switch from diesel to electricity to power trains will actually increase carbon emissions due to the very high share of dirty coal in their grid electricity supply mix. This shows how important Indian Railways’ Net Zero target is - and that electrifying the railways is no good if you’re still burning coal to make that electricity. Our research exposes how Indian Railways has been in a toxic long term relationship with coal, both as an energy source and as a freight commodity, and illustrates just how much value the Riding Sunbeams direct solar-to-rail proposition can offer to the world’s biggest electrified rail network.

You can read more in our two new sunbeam reports, one co-authored with Climate Trends and aimed at Indian policymakers which explores the scope for Indian Railways to contribute to India’s national climate change commitments, and the importance of moving rapidly away from coal and embracing solar instead; and the other with Ricardo Energy & Environment, setting out in detail our technical analysis of the potential for direct supply from solar farms to meet traction energy demand on a fully electrified Indian Railways. You can also share our infographic on the key finding. Enjoy!

Leo Murray, director of innovation September 2021

Report for policymakers:

wearepossible.org/RidingSunbeamsInIndia

Technical analysis:

wearepossible.org/SunbeamsIndiaTechnical