Solar in India

Solar in India: Top 5 uses

A one-size-fits-all approach doesn¡¦t work when it comes to deriving full benefits of solar energy. Each country has its own variabilities such as climate, socio-economic structure, terrain, skills, etc., and therefore, each area can benefit the most from different types of solar or solar applications.

In India, solar energy has loads of potential due to the high solar irradiation and more than 300 sunny days a year. The top five most beneficial uses for solar energy in India are (in reverse order) grid connected power plants, solar thermal, rooftop PV, solar irrigation pumps and rural micro-grids.

No. 5: Grid connected power plants

India needs to improve its grid infrastructure drastically to realize the real benefits of grid integrated solar plants.

Although the recently announced national solar mission policy in India aims to establish about 20GW of grid-connected solar power base by year 2022, it may prove to be one of the least beneficial uses for India. Around 16% of India¡¦s 600,000 villages are un-electrified. Due to lack of last mile connectivity in electrified villages, in reality about 42% of the rural households are not connected to the electricity grid at all. Power transmission losses are currently about 23% in India and it will defeat the purpose if out of the 20GW solar power generated, 4-5GW will be loss in grid transmission! These factors will be aggravated as solar power plants (CSP or PV) need to be setup in open barren lands that would be far from the main grid.  India needs to improve its grid infrastructure and move towards high efficiency and smarter grids if the real benefits of grid integrated solar plants are to be realized.

No.4: Solar thermal applications (direct utilization of heat)

Solar thermal technologies have a natural advantage in India due to the fact that the average radiation is 4.5 to 6 kWh/m2/day, with an average of 300 clear days in a year. Solar thermal applications are simple in design, inexpensive to manufacture, and have short payback periods. The use of solar dryers in agriculture can reduce wastage and improve the income of farmers. If hostels, hotels and other large institutions were to use solar energy for cooking, their savings on fossil fuel could be substantial. Also, solar box cookers can help families who do not have access to a clean energy source for cooking and reduce indoor pollution. Several industries that need low to medium heat energy can easily reduce their carbon footprint by replacing at least some of their fossil fuel usage by solar thermal technology. Solar water heaters have great potential in India as the technology is well matured and some state governments have mandated the use of solar heaters on all new buildings.

No.3: Roof-top PV (replacing diesel generators)

In urban India today, diesel generators (DG) are used by small commercial enterprises as well as large buildings (private and public such as malls, hotels, hospitals and nursing homes) to generate electricity during grid outage. The exact installed capacity of captive generation from diesel and furnace oil in the country is unknown, but it is said to run into tens of thousands of MW.  The gap of 10-20% of electrical power is mostly met by installing DG sets that cost at least 20 times more. This is an area where roof-top PV (RTPV) systems can achieve cost parity in near future. Cell phone towers in India (250,000 in total) use diesel for power and back-up. It¡¦s a segment can be easily replaced by solar PV systems of 3-5 kW power. The estimated potential of roof-top PV systems in urban India is at least around 140-150MW_p with unit area required for RTPV assumed around 10 sq. meters per kW_p.

No.2: Solar irrigation pumps

Almost 70% of India¡¦s population depends on agriculture either directly or indirectly. Most electrical consumption in this sector goes towards operating pump sets for irrigation. There are about 21 million irrigation pump sets in India, of which about 9 million are run on diesel and the rest are grid-based. The grid-based systems also often have power available only for a few hours and that too in the nighttime. Water demand for irrigation is correlated to bright sunny days and hence, solar-based pumps make sense. It will make the agricultural activity more productive and safer by utilizing more day-time hours. If it is assumed that a moderate 50% of the total diesel pumps in India (of the 9 million pump sets) are replaced by solar PV, the total potential for savings in diesel fuel will be approximately 185 million tons per year and a 470 million tons CO₂ abatement.

No. 1: Rural micro-grids

Grid transmission losses and inverter costs can be avoided by using solar powered micro-grids.

Due to the inadequacy of the grid, the alternative for villagers currently is kerosene, which is expensive, subsidized and has adverse environmental and health effects. By bringing the generation of electricity closer to the site of consumption, grid transmission losses can be avoided by using solar powered micro-grids. The electrical needs of rural households are relatively small (0.5-2.5 kWhr per day) and a micro-grid system of 20-35 kW would suffice a small village. Instead of having a 500 MW of power plants supplying to the state grid, the same capacity can be spread over to meet the needs of about 14,300 villages, each having a solar or hybrid solar-biomass micro-grid of 35 kW. Planning a micro-grid with DC power distribution will obviate the need for an inverter and hence can be very cost effective with lower capital requirements and much less losses.

Written by Nilesh Jadhav--Contributing Editor - India

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