A large number of homes (some estimates are up to 60 million homes) are still off-grid, and taking power-lines to these homes may be just too expensive. Many more have long power-cuts and could be categorized as near off-grid.

While decentralized solar at the roof-tops to generate power could be an option for such homes, the costs of a conventional solar PV system to provide basic light and fans (and cell-phone charger) have been high primarily because of (i) poor design, (ii) high AC to DC and DC to AC conversion losses associated with such solar and battery systems and (iii) high costs of batteries.

But, Solar-DC systems would save about 35-40% of the power as compared to a solar-AC system. Add to it the energy-savings associated with DC appliances, huge gains in efficiency becomes possible. This efficiency gains translate to lower sized solar panel and smaller battery and therefore cost-savings when compared to a solar-AC system. Such a set-up offers an economical and affordable solution for off-grid/ near off-grid homes (homes with large power-cuts), and could also be useful for grid-connected homes in saving power-bills as well as providing back-up power.

This is achieved by Solar-DC  Inverterless technology, conceptualized by IIT Madras.IIT Madras has implemented such decentralized Solar-DC systems within IIT Madras and in multiple locations in Tamil Nadu, Andhra Pradesh and Orissa.