Ina few days from now, IIT-Madras will begin a project in a few hundred houses in the southern states aimed at eliminating load-shedding forever. IIT-M has developed a method that will let electricity boards provide a small amount of uninterrupted power to every house in the country, enough to run three lights, two fans and a mobile charger. The pilot project, which would go on for a few months, is expected to generate enough data for the power ministry to take a decision on extending the programme to the rest of the country.
It is based on a disarmingly simple idea: run a low-power direct current (DC) line from every sub-station into houses. This will feed into a separate meter, and then on to a set of lights and fans, or other low-power devices such as chargers or TVs. The rest of the house is run on regular alternating current (AC) power that is metered separately.
The 100 watts of power fed into these DC lines is so low the electricity boards will never need to shut this down, except to repair technical faults. Blackouts are thus eliminated at one stroke, or converted to what IIT-M calls ‘brownouts’.
As a side effect, it could also eliminate the need for inverters. The project is the brainchild of IIT-M Director Bhaskar Ramamurti and electrical engineering professor Ashok Jhunjhunwala. IIT-M had involved the Central human resources and power ministries, the four electricity boards in south India, and some DC equipment manufacturers.
IIT-M has signed a memorandum of understanding (MoU) with Tamil Nadu, Karnataka, Andhra Pradesh and Kerala. The Centre has formed a committee to oversee the project, headed by the former Atomic Energy Commission chairman Anil Kakodkar.
Says Ramamurti: “It is a simple idea but it required some thought and engineering.” Consumers who opt for this scheme will have to spend around Rs 1,000 for a device at home, apart from buying LED bulbs and fans that run on DC power. Jhunjhunwala and his team will meet consumers in Tamil Nadu and Karnataka this week. If they decide to buy into this idea, and agree to spend the money to take part in the project, the IIT-M technical team will start rewiring their houses and tweaking the transformers that feed into them.
“It is a critical pilot project,” says former power secretary P Umashankar. “I see this as a game-changer for the country.” In fact, it was Umashankar who seeded the idea in the minds of the IIT-M professors. Just before retiring, he had attended a conference organised by IIT-M. They had then shown him their work on DC power and solar energy, and told him how it would improve energy efficiency in the country. “Umashankar told us that it will not solve our fundamental problem of blackouts,” says Jhunjhunwala.
“It will also not create a pull factor for solar energy in the country.” The IIT-M team went back to the drawing board and thought about the problem. They then had their Eureka moment: why not separate the DC power from the main AC circuit? Jhunjhunwala and Ramamurti were telecommunications engineers, so they asked their power systems colleagues whether it was possible to run DC and AC power together in the transformers.
They answered in the negative, but soon enough, came up with a solution: run a low voltage AC line out of the transformer and then convert it into DC. Inside the home, the voltage is scaled down to 48 volts, which will then run lights and fans. “The idea was stunningly elegant,” says Venkat Rajaraman, CEO of Solarsis India, which makes devices for houses and sub-stations. Apart from Solarsis, two other companies joined the project.
One was LED company Intelizon, which made special lamps that converted low-power DC into the even lower levels used in LED lights. The other was Crompton Greaves, which made DC fans. At present, DC fans cost twice as much as AC fans, but the cost is expected to come down to the same level once volumes pick up. IIT-M wired some rooms in its own campus and tested the idea.The plan is to test it in a few hundred houses in one locality in each state.
The elegance of the project flows from the multiple benefits of DC power. It is known to be more efficient than AC power, but the latter became the standard due to transmission efficiencies. Currently, many home appliances run on DC power, such as LED lights, after conversion. So do TVs. Mobile chargers also operate on DC power. Inverters convert AC into DC and then back again. All this means wasted energy. Efficiencies improve if DC can be used directly in devices.
This was Jhunjhunwala’s original idea presented to Umashankar. With the advent of solar power, there is a renewed push globally for DC power being used directly. Over a period of time, the IIT-M solution could create demand for solar energy. Currently, solutions exist to run entire houses — barring airconditioning — on solar energy.
But they cost around Rs 1 lakh. The IIT-M technology could augment DC power and run most home equipment at one-fourth that cost. Consumers can then adopt solar energy incrementally, avoiding large one-time investments.
“We have now created the pullfactor for solar that Umashankar told was missing in the first place,” says Jhunjhunwala. The efficiency of the system is such that even large complexes can consider supplementing basic DC with solar power, and reduce dependence on expensive diesel generators. In the long run, this system can even run alongside the smart meters being considered now. “I think the idea is very sound and can coexist with smart meters,” says Kakodkar. The future of the project now depends on consumers: will they pay a few thousand rupees extra in return for uninterrupted power?