Fit solar into electricity

Think of “roof”, and you see solar panels. Think of “solar”, and you see the energy generated during the day — powering appliances and even feeding into the grid, from which it can be brought back at night when the sun is not shining. It’s the world’s most uber solution, where each of us becomes a generator of electricity. It works because solar is modular: The panels can fit almost anywhere, unlike thermal or nuclear generators. While building utility-scale solar plants requires vast amounts of land, which is always scarce and often contested, in this model every available roof becomes a power plant.

- SUNITA NARAIN

You may ask why I am expounding on the known advantages of rooftop solar. I believe the potential is enormous. Then why is progress still not at a transformative scale, despite the Union government’s programme to incentivise rooftop solar in offices and homes? It is not the lack of policy or intent. The real question is: How will this technology integrate with existing distribution systems?

The challenge is not unique to India. All new technologies follow a similar path: They must find ways to displace the old to secure their place in the sun — in this case, quite literally. The fact is that solar technology, being intermittent and providing electricity only when the sun shines, requires some form of backup. Remember that nighttime energy consumption is often as high as, or even higher than, daytime, when natural light is available and there is typically less need for heating or cooling. The ideal arrangement is that solar panels generate electricity during the day, part of which is consumed on site, while the excess is either “exported” to the grid or stored in batteries, which are then tapped for use during non-sun hours. Since batteries are still expensive, exporting to the grid remains the most practical option. In this setup, the distribution company (discom) or power utility serves as the backup.