Rooftop solar power generation in Manipur: Prospects & challenges

Oinam Nabakishore Singh *

10 KWp Solar Photovoltaic (SPV) power plant installed at Manipur University in Feb 2012 :: Pix - Huieyen Lanpao

India has an ambitious plan of achieving generation of 175 GW (1GW=1000 MW) of electricity from renewable sources by 2022. Of this target, 100 GW is through solar plants,60 GW from wind power, 10 GW from biomass power and 5 GW from small hydro power.Out of 100 GW of solar power to be installed by 2022, 40 GW is targeted to be grid connected rooftop solar power. Manipur Renewable Energy Development Agency(MANIREDA) is the nodal agency for promoting renewable energy in the state.

Before proceeding further, it may be worthwhile to explain the difference between off-grid solar plant and on grid or grid-tied or grid interactive or grid connected solar plant. In the off-grid plant, power is stored in batteries to supply electricity to the load(bulbs, fans, appliances) when there is no generation of power from solar plant in the night or periods of rain and clouds.

Batteries are expensive, have limited life and requires maintenance. Because of these reasons, off-grid solar plants have failed to add significant capacity in generation of power. Such plants have been installed in limited number of locations. The whole scenario of solar power generation changed with on grid solar power generation. In this arrangement, grid replaces the backup battery by supplying power to the consumers when solar panels stop generating power.

The consumers enjoy uninterrupted power supply for 24 hours. It may be also good to know the science behind solar energy.The source of energy is the Sun, which has been giving us sunlight and heat for billions of years. According to the National Aeronautics and Space Administration (NASA), the Sun is 4.5 billion years old and it will continue to give us sunlight for another 5 billion years.

How does the Sun give us light and heat? The answer lies in the thermonuclear fusion reaction taking place at the core of the Sun. Photons in the sunlight excite the electrons on the Silicon Cells in the Solar module or panels to create a potential difference and produce direct current(DC)electricity. If we connect DC appliances to the DC from the solar panels, it is possible to run them directly.

Many solar water pumps installed on the field for irrigation purposes run on DC from solar plants. However, all our appliances at home, bulbs and lights are powered by alternating current(AC) even though it is possible to use DC bulbs as in torch light, fans, etc. In order to convert the DC into AC, the DC wires are connected to an Inverter.

Besides converting DC into AC, an inverter has various other important functions like synchronization of frequency of AC very close to the frequency in the Grid (50 Hertz), production of AC in voltages very close to the Voltage in the Grid and to measure various parameters like current in amperes, saving of carbons and revenue earned. High quality Inverter will help in stable production of power.

Another important function of Inverter is isolation of the grid from the solar panels. In the grid interactive or grid connected solar plants, Inverter cuts off supply of power from solar panels to the grid as soon as grid is switched off. This arrangement is to ensure safety of people working on the grid when power is switched off. After the Inverter, the energy is supplied to both the load at home or business for consumption.

In case the load of home and business is less than solar power generation, the excess power is exported to the grid through a bidirectional meter called net meter. Net meter measures both export of power to the grid or import of power by the generator or consumer. Overall, it also helps in determining the status of power consumption. In line with the National Policy to promote rooftop solar power generation, the State Government of Manipur framed State Policy on the same in December, 2014.

It has provisions for Gross metering and net metering, which is indeed a very progressive policy. Further, the State Government of Manipur is the first in the North East to have the levelized tariffs fixed by the Joint Electricity Regulatory Commission for Manipur and Mizoram for different categories of investment, namely with or without subsidy from the government. The tariffs are arrived at by applying the same discount rate of 13.73% for all categories of investment.

At the tariff fixed by the Commission and present generation of power by solar panels, the payback period(time period to recover the investment) is about 6 years. Since the life of solar panels to generate power is accepted by all to be 25 years, the promoter will continue to generate power for the another 19 years after recovering the investment in 6 years without any additional cost and will continue to earn or offset power bills.

Because of the looming and continuing threats of climate change and global warming, there is global consensus for taking measures to reduce emission of greenhouse gases. Major source of greenhouse gases and global warming is burning of fossil fuels-coals, oil and gases. Major source of power/electricity is thermal power plants, which mainly burn coals and natural gas. Vehicular pollution due to emission of various gases from tailpipes is also another cause for global warming.

The long-term sustainable solution for the climate change lies in switching over to renewable energy. Wind and solar energy are the most viable renewable energy being produced in several countries. Electricity generated from these two sources are clean and green and it helps in arresting global warming. It is also worth noting that generation of renewable energy also generates huge employment. The International Labour Organisation (ILO) has estimated in a report that over 300,000 workers will be employed in the solar and wind energy sectors in India to meet the country’s target of generating 175 gigawatts of electricity from renewable sources by 2022.

In Manipur too, about 50-70 workers and technicians must be employed in installation of solar plants across the state by various empanelled firms. During my visit to Germany in 2016, we saw a firm offering services of maintenance and repairing of solar panels, etc. As we go along the way and with increased installation of solar plants, there will be need for maintenance resulting in employment generation. For North Eastern States like Manipur, the Government of India provides subsidy of 75% of the cost of installation of Rooftop Solar Plants for residences, educational Institutes, Hospitals and Community Centres.

Based on the present benchmark cost of Rs. 70,000.00 per Kilowatt of solar plant, Ministry of New and Renewable Energyextend subsidy of Rs.49,000 per KW. State Government of Manipur provides an additional assistance of Rs. 10,000.00 per KW subject to the ceiling of Rs. 20,000.00 for two KW. After taking all subsidies into account, the contribution from promoter per KW of solar plant is about Rs.20,000.00 now. It will continue to decrease with fall in prices of solar panels.

In order to avail the financial assistance and to install solar plant on the rooftops, one has to visit the website of MANIREDA and fill the application online at manireda.com. By clicking the box, “rooftop solar” on the top panel, any existing customer of MSPDCL can apply for installation of the plant. As on 16th May, 2018, according to MANIREDA, total installed capacity in rooftop solar in Manipur is 1180 KW comprising of 445 KW in domestic/community/institution, 20 KW in commercial establishment, and 715 KW in Government buildings.

It is reported that a 5 KW grid connected solar plant was inaugurated by Deputy Chief Minister on 15th May, 2018 at United Club & Library, Uripok. The state has several community halls in various villages and localities. We should fruitfully use the space on rooftop for installation of solar plants. Injection of power from individual solar plants also help in improving the quality of power supplied in the locality.

There are many other benefits of solar plants. For far-flung villages in the hills of Manipur, we may plan to have a micro-grid with solar plants to supply electricity to the household in that village. If we do this with power backup through storage batteries, the hurdles of transmission lines and sub-stations, problems associated with long transmission, etc. can be overcome. We need to design power supply plan keeping the local terrain and other difficulties in mind.

Manipur must be leading in rooftop solar generation in the entire north east. The difficulties and hurdles are being continuously removed by officials of MANIREDA and MSPDCL. With concerted effort of officials, empanelled partners and with generous subsidies from both the Central and State Governments, it will be possible for us to be self-sufficient in power generation through solar plants of various combinations-rooftop and ground mounted. However, we have just started the journey. Our goals are still far.

[Views expressed here are personal].