Renewables expert Dr. S. P. Gon Chaudhuri says new policy process will mainstream off-grid energy in India

Reading time: 6 minutes
20 July 2015

The Climate Group interviews Dr. S. P. Gon Chaudhuri, an electrical engineer from Jadavpur University and expert in renewable energy who heads several research projects on renewables for the governments of Tripura and West Bengal, to find out more about the decentralized renewable energy market in India.

The off-grid PV system with mini-grid concept that you’ve developed has received renowned recognition. What in your opinion are the most viable technology options for off grid energy and most promising emerging technologies to scale up in the future?

When I started the off-grid program in the 1990, the concept was to replace kerosene lanterns with solar lanterns and in the next phase with solar home lighting systems. In time, solar home lighting systems became very popular. However, I always intended to provide AC electricity to rural people through the photovoltaic (PV) route. At the time I was convinced that unless I gave alternating current (AC) electricity to the rural people, I would not be able to totally satisfy them.

In time, I was able to prove it through field level surveys and conceived the idea of a mini-grid based on solar or biomass power, in 1991. This was one transition of solar PV system technology in India (i.e., small solar DC systems changed to moderate capacity solar AC system and mini-grid). This was also a major revolution in the solar sector since at that time we were able to introduce the country’s first solar tariff concept through metering. With the availability of AC power in the village, the economic activity generated was raised, with people starting to ask for more power. The limitation of a mini-grid is that it has a limited generation capacity and it is unable to cater to the growing demand.

As a result, today the mini-grid AC systems are also becoming unacceptable for rural people. In today’s context I believe there should be another transition, such as with standalone solar mini-grids. This is now more viable since in the 1990s almost 80% of villages in India were not covered with electricity but the scenario has now changed.

At this stage more than 90% of villages in India have grid power. The problem is the poor voltage in rural areas. The grid interactive mini-grid solar power plant can play a dual role. It may provide limited hours of electricity in rural areas and when the grid is available it may improve the tail end voltage significantly.

As such, I feel we should now concentrate more on the development of smart controllers and also keep provision in the inverter on grid integration as and when necessary. When the plant will be connected to the grid the entire power of the plant will be exported to the grid, and when there is no grid power, only a minimum quantity of power will flow to the local grid from the solar power plant through a smart controller.

So the smart controller, with its latest storage technology and integration compatibility, coupled with the grid, are major challenges for the next generation off-grid solar power plants. This concept will really scale up off-grid programs in India to a great extent.

OGE (off-grid energy) and grid integrated systems are seen as two isolated systems. Is an OGE ecosystem required to be aligned with the policies and plans for grid-integrated systems? What are the potential linkages and synergies between the two systems? 

The off-grid project will start with the current expectation of rural people. However, all provisions should be kept to satisfy future expectations of rural people otherwise the project will not be sustainable. In other words, the off-grid project should initially be treated as a generation and distribution project, and as it progresses it will become primarily a generation project that will only export power to the grid at a special tariff to be determined by the regulators.

A very new idea may come to the country to improve the tail end voltage by installing renewables projects in rural areas. In fact, regulators may direct the DISCOM to encourage such power plants in the country to ensure proper voltage in rural areas. Installing a transformer at the tail end may not always be a good solution. A transformer is not a generating device. In conclusion there should be a synergy between off-grid and grid connection, but in a dynamic way.

You have been a proponent of reducing costs from the demand side of the renewable market. How can this be achieved effectively? 

Renewable energy power generation is still relatively expensive in spite of its various advantages. Hence in order to make renewable energy cost effective demand side management is very important.

Use of efficient lighting systems etc are very common, we must do it. But I would suggest something different: We must avoid battery storage of solar energy as far as possible. The daytime power should come from sun directly with only batteries in the floating conditions. Intelligent controllers are important tools in this context. The water storage of solar energy is also a good option. No pumping system should run from a solar power plant during night time. Passive solar architecture should be adapted to reduce the day time cooling load as far as practical. Day time and night time load in a solar mini-grid should be properly segregated through the smart controller.

The decentralized renewable energy market in India is dependent on regulations related to distribution and tariff. What policy framework would you recommend to overcome current barriers and make renewable energy a leading market determinant?

To begin with, there is a policy by the government of India which states that if any Indian in a grid-connected area is in need of electricity he/she should get grid connection within 15 days, otherwise the distribution companies would be penalized, however this does not apply to non-electrified areas.

Having said this, I recommend there should instead be a policy that any Indian living in any part of India should be provided with decentralized generation electricity (one month within date of application) by the DISCOM, or in the longer run work out a model for the electricity to reach them.

In a scenario like this, the DISCOM would automatically approach the sub-distribution of interest; inviting some people to pick up distributed generation and provide electricity through them, meanwhile the DISCOM would take care of the tariff plan. There should be a mandate provision, when this power plant gets the grid connected, the power should be purchased by the DISCOM at a certain rate, which should provide the investor a certain level of comfort.

In urban areas we request DISCOMs to purchase our rooftop solar power. Ideally the reverse thing should happen in rural areas. DISCOMs should look for prospective generators to purchase solar power from rooftops so that DISCOMs can keep their commitment to providing “Electricity for all by the year 2017”. This will serve three purposes:

1) DISCOM will keep their commitment.

2) People will get access to electricity.

3) Off grid renewable will be promoted automatically.

If the Indian government adopts this policy process, it will greatly help in making off-grid energy mainstream, which is currently not the case. Adoption of such a policy initiative would also help scale-up the off-grid market.


Dr. S. P. Gon Chaudhuri is an electrical engineer from Jadavpur University, who has worked for 27 years in the field of renewable energy. Working in academic and professional government bodies, and energy development institutions, he has become renowned for his outstanding contribution to the growth of renewable energy in India. He is also member of the advisory board of the Bijli – Clean energy for all project.

Dr. S. P. Gon Chaudhuri previously worked on the planning board of the Tripura government in devising renewable energy strategies, and was Managing Director of the West Bengal Green Energy Development Corporation, as well as Special Secretary under the Government of West Bengal.

Outside of being an adjunct professor at Bengal Engineering and Science University, he is also Chairman of The Ashden India Renewable Energy Collective and Chairman of the NB Institute for Rural Technology in Kolkata; Director of the West Bengal Renewable Energy Development Agency; a member of the Tripura Government Planning Board; and Renewable Energy Consultant to the Lakshadweep Administration. He is also now Director of West Bengal Green Energy Development Corporation and Development Consultant Private Ltd.

In promoting sustainable energy development through numerous published scholarly articles and for his leadership on the subject in international forums and conferences, Dr. Gon Chaudhuri has been awarded a number of international and national awards, including the Ashden Award for Sustainable Energy in 2003 from the Ashden Award Trust (UK).

Dr. Gon Chaudhuri currently heads a number of research projects on renewable energy for the Governments of Tripura and West Bengal.

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