Lighting Up Lives

Solar innovation by IIT Madras drives economic growth in rural India

Rural India, home to about 833 million people, is gradually ushering in new growth opportunities for the corporate sector, and is set to become a vital cog in the country’s growth story over the next decade. However, one of the biggest hindrances to this narrative is the lack of access to good quality, reliable power supply.

Many studies have already established the direct link between energy access and higher incomes, thereby validating a high correlation between energy availability and human development, especially in developing countries. Today, nearly 300 million people in rural India lack access to grid-connected power while those who do have access, endure poor quality grid power, with either no power or power outages for a large part of the day. It is in this context that solar energy, when it is made affordable, introduces a completely new paradigm with an opportunity to directly target remote communities and bridge infrastructural, economic and social gaps.

India is blessed with a high level of solar irradiance. With the prices of solar panels falling rapidly, especially in the past few years, solar power is set to become commercially mainstream, encouraging many entrepreneurs as well as private investors. What is needed now is the development of energy-efficient systems, which can reduce the power requirement from solar panels and take advantage of the falling prices. Decentralised rooftop solar photovoltaic (PV) can offer the most affordable power solution, irrespective of whether the grid is present or not. Solar-DC Inverterless, a technology developed by the Indian Institute of Technology, Madras, is one such energy-efficient innovation that is lending weight to this narrative.

In a traditional alternating current (AC)-based solar power solution, direct current (DC) power generated at the solar PV panel needs to be converted to AC for being combined with the grid. An AC-to-DC converter is required when solar and grid power is to be used to charge the battery (which is inherently DC) and a DC-to-AC converter is needed to run AC appliances. Now, losses in each of these converters is at least 15 per cent at the lower power levels (less than 1 kW), and the total losses in the system would be nearly 45 per cent, excluding battery losses. As a result, the affordability of solar power takes a beating. Incidentally, all appliances today are becoming DC based and employ AC-to-DC drivers, adding to inefficiencies and costs.

Solar-DC Inverterless overcomes this challenge as it involves moving to DC appliances on a 48V DC internal distribution line within homes with charge controller (Inverterless), allowing the entire system to operate on DC. A single AC-to-DC converter is required to draw power from the grid, if desired. It leverages the power advantages that DC appliances bring and couples it with an extremely energy-efficient charge controller. This system is 90-94 per cent efficient and as a result, the system sizing requirement falls by more than half as compared to an equivalent AC-based solar solution. Ultimately, this results in a per unit cost of around Rs 4 and an energy bill saving of 50 per cent compared to its AC counterpart.

But what does this mean for rural India?

The solar-DC system broadly has three benefits. It reduces the power bill significantly for lower-income rural homes. It provides power backup for grid loadshedding and ensures 24×7 good quality power supply. Further, it makes decentralised solar the most affordable option for powering homes in the lower tier of the energy ladder.

Today, Solar-DC Inverterless is powering more than 10,000 households across 11 states in India. In Rajasthan, as many as 71 villages with 4,000 households in Jodhpur and Jaisalmer districts have been fully electrified using this technology. In Assam, as of August 2017, about 6,000 off-grid homes have been installed with these systems, leading to 100 per cent electrification in about 90 villages. It has also been deployed at several places that have grid connectivity but suffer from frequent and long hours of load shedding. Several other proof-of-concept deployments are being carried out in different states including Andhra Pradesh, Odisha, Tamil Nadu and Telangana. From villages in Rajasthan’s Thar desert to fluvial villages along the Brahmaputra river in Assam, from tribal hamlets in the Nilgiri forest reserve in Tamil Nadu to cotton farming hamlets in Telangana, Solar-DC Inverterless has made its way into different types of terrains and homes. In each of these places, there was a conscious effort to develop an ecosystem for the implementation of Solar-DC Inverterless technology to ensure the sustenance and evolution of the technology. A pool of local technicians for repair and maintenance work had to be developed, which, in turn, created a platform for budding local entrepreneurs. Consequently, feedback coming in from all these places is suggesting significant gains, not just in terms of power consumption but also in terms of education, health and rural entrepreneurship.

For instance, consider Belagavadi, a village two hours north of Bengaluru in Karnataka, with 220 homes running on this technology. The statistics available from the Bangalore Electricity Supply Company suggest that grid consumption in many of these households has reduced by 40 per cent post the deployment. More interestingly, a new dynamic emerged wherein more people chose to stay back in the village even during the hot summer months compared to the previous years when they would migrate to Bengaluru in search of temporary work during these months. As a result, local productivity is on the rise. This clearly points towards a correlation between good quality, affordable power and local jobs/business development, leading to a greater impact on the economic development of the poorest and the most vulnerable.

The more obvious benefits brought about by extending the hours of available light through solar energy were visible at all the deployment sites, with women taking up activities like making handicrafts and children studying even after sundown. A simple innovation is enabling vulnerable groups overcome an issue bigger than poverty – poverty of their aspirations. Therefore, it is crucial to build on the momentum that has been created by making available high quality, clean power to rural homes at an affordable cost. The need of the hour is the creation of a conducive financial and institutional environment to unlock the true potential of solar energy and bring about huge improvements in education, health care, irrigation, communication and tourism in rural areas.

Solar-DC Inverterless has shown how the most vulnerable population, operating with predictable access to power, can usher in economic activity that is otherwise not possible. It underlines how improving access to solar power can play a telling role in pulling communities out of poverty, and inspire socially and financially inclusive solutions. India is on the cusp of a solar power revolution. The time has come for India to leverage the promise of solar energy in its truest sense.


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