17 Oct 2017 18:46 IST

Closing India’s energy deficit

Installing solar rooftop panels and wiring them with DC could help ensure supply to small villages

While the blackouts of the 1990s are no longer a frequent occurrence in the nation’s big metros, power supply to lower-tiered cities and rural areas continues to be unreliable. According to the World Bank, electricity access in India has improved dramatically — from about 45 per cent in 1990 to 79.2 per cent in 2014. But it is still a far cry from most western countries, where access is 100 per cent. Even China, with its vast land area and hundreds of thousands of villages, is fully connected to the power grid.

The traditional solution to close the energy gap is to generate electric power through mega projects, many of which are already under way. Conservation is also helping, as the country switches to more energy-efficient LED lighting (although people are consuming more power for their electronic devices, many of which stay on 24/7 and need regular charging).

A local solution

For a large country like ours, local solar generation is of great value to help close the energy gap. Small villages do not have to wait for all the electrical grid components — power lines, transformers, substations — to come to them. Instead, rural solar farms can generate enough energy locally to power the basic needs of a small community.

In this vein, a relatively new approach sounds especially promising: using rooftop solar panels on individual homes but wiring them with direct current (DC) power. Energy use from the public grid could plummet 25-30 per cent, thus giving a boost to the nation’s supply-demand equation.

Why DC power?

From our high-school science classes, we know that AC (alternating current) and DC are types of electricity used for conducting and transmitting electrical energy.

According to Karl Berggren, professor of electrical engineering at MIT, the fundamental difference between AC and DC is the direction of flow. DC is constant and moves in one direction; AC changes over time in an oscillating repetition.

​The lamp next to your bed, for example, uses AC. This is because the source of the current comes from somewhere afar, and the wave-like motion is needed to make energy travel efficiently to the destination. On the other hand, if you happen to use a more mobile device with lower power requirements, you are more likely a consumer of DC power. ​​

In a modern home, direct AC power use is limited to air-conditioning, refrigeration and powering large appliances. While these use some electronics circuitry, they also come installed with big electric motors or heating elements which can only be powered by AC.

A wasteful conversion

Our laptops, mobile phones, cordless phones, tablets, printers, fax machines, toys and LED lights, on the other hand, all work on DC. But since we don’t have a direct DC source, we use the highly wasteful process of converting AC power to DC.

So why not generate local DC power and pump it to all these smaller devices directly? Rooftop solar panels typically generate 24V DC. Rather than invert this to 220V AC (another wasteful conversion) so that it can be sent to the home grid, from where this is again converted to 12V DC power through the use of power converters, why can’t we build a DC power grid ​right at home?

There is also the question of safety. Many deaths occur each year because of accidental contact with a live 220V AC circuit. A 24V DC line is relatively harmless.

This idea is actually being implemented in a few Indian homes. Two weeks ago, I visited one such home in the Jayanagar suburb of Bengaluru. Such homes have two power supply circuits — the traditional AC system receiving energy from the electric utility, and a self-contained DC circuit, powered from a rooftop solar system, to which numerous electronic devices can be plugged. Many USB ports complete the ensemble.

The US is leading in innovating, testing and promoting this technology — although the focus currently is on office buildings. The Emerge Alliance has ‘emerged’ as an open industry association to help lead the rapid adoption of safe DC power distribution using the hybrid use of AC and DC formats. Public and private companies, and even non-profits, have teamed up with the alliance to demonstrate this technology’s viability.

If you happen to be in Lancaster, PA, and want to know how this works, head over to a facility managed by Armstrong World Industries to watch a demonstration. Over 50 such demonstration sites in North America and some parts of the western world are operational.

Taking a leaf out

Indian entrepreneurs should look at Emerge Alliance as a model for commercial exploitation. Each aspect of the energy cycle — micro financing homes to adopt such DC systems, developing a robust supply chain, delivering an end-to-end solution, and teaming up with real estate companies and the government — presents attractive business opportunities for deploying DC technology to individual homes and apartment buildings.

The Indian government will be glad to help such ventures. Schemes under the MSMED (medium, small and micro entrerprise development) Act could well underwrite the entire project, while technical assistance from the likes of the IISc and IIT can be free, thanks to the MSMED’s technology transfer programmes. For the government, not only do all the benefits of the MSMEs (as listed in last week’s piece ) result in a victory, it can also help close the energy gap at a far lower cost. If convinced, the government can even begin mandating the use of this technology at PSUs and government buildings.

Because, if there’s one constant, it is that India’s energy use will only grow with time.