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East Delhi Commissions Hydropower Plant Powered By Sewage Effluent

Delhi is getting its first hydropower plant, but it’s not harvesting the energy of running water in the traditional hydroelectric model, as this new system uses falling water from a treated sewage effluent pipe to spin its turbine.

Recapturing some of the energy in flowing water that is generated by existing processes, such as municipal water supplies, is one non-traditional step for hydropower, and cities such as Portland have begun experimenting with this sort of ‘smart water pipe infrastructure.‘

The new hydropower plant, in East Delhi, India, is built onto the Delhi Jal Board’s 9 MGD sewage treatment plant at Chilla, and is said to be the first of its kind, not only because it’s being powered by effluent water, but also because it’s the first hydropower plant in the city. According to the Delhi Jal Board (DJB), this pilot project was set up “free of cost,” and the estimated annual 20,000 kWh of electricity produced by the hydropower installation will be used directly at the sewage treatment plant.

“The use of fossil fuels leads to the generation of carbon dioxide which in turn leads to Green House Effect and Global Warming. However no fossil fuel is being used in the generation of the power through Hydropower at Chilla, therefore this technology is termed as “pollution free technology.”” – Delhi Jal Board

The treated effluent water falls from a height of 4.8 meters at the sewage treatment plant, which is sufficient to spin the turbine and generate clean electricity, and this ‘Green Power Generation’ energy technology will help to reduce both air pollution and electricity costs. No additional specs, other than the estimated 20,000 kWh of electricity annually, for the installation were available. According to DJB, the Board is also looking to replicate this hydropower setup at its other installations in the future.

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.