- in Technology
solar power

solar power

Solar power used in conjunction with existing power plants and the proposed river linking network can lead to an energy revolution that can double India’s energy production


A quarter of the people in India lack access to electricity (International Energy Agency’s 2011 World Energy Outlook report). Even those who are connected to the national grid experience frequent blackouts. To cope, many homes and factories install diesel generators. But this is possible only for those who can afford it like residents of luxury apartments; but for those who lack the resources, there is little hope. Solar power offers a way out of the crisis.

Until recently, solar power had a reputation of being expensive, but not anymore. In India, electricity from solar has become cheaper than that from diesel generators. Generators could soon be on their way out. In India, the cost of electricity from solar supplied to the grid has fallen to just Rs 8.78 per kilowatt-hour compared to Rs 17 for diesel. The cost of solar power is still declining. Hence, inefficiency of solar cells will be a moot point very soon.

Figures from market analysts Bloomberg New Energy Finance (BNEF) show that the price of solar panels fell by almost 50 per cent in 2011. They are now just a quarter of what they were in 2008. If present trends continue, solar power may soon be a viable alternative to electricity grids, especially in remote rural areas. In fact, the Rajasthan Government has just announced solar power has reached parity with grid power in the state.

Learning from history

Fifty years ago, it was widely believed that India would never be able to feed its people. In fact in 1961, the country was on the brink of mass famine. Seeking drastic improvements in India’s agricultural production, the Government, jointly with the Ford Foundation, started a pilot project in Punjab to demonstrate that higher yields were possible using special varieties of wheat and with better agricultural practices.

The experiment was soon extended to rice by adapting IR8— a variety of semi-dwarf rice developed by the International Rice Research Institute in Philippines. By 1968, Indian agronomist S.K. De Datta had shown that by combining the IR8 seeds with the proper use of fertilizers and appropriate irrigation methods, it was possible to more than double the yield per acre. From a near famine situation in 1961, India by 2006 had become one of the world’s largest rice exporters shipping 4.5 million tons in that year alone. This is now hailed as the Green Revolution.

In energy production, India stands today where it stood with regard to food grain production in 1961. Most cities face scheduled and unscheduled power outages while in rural areas, one would be lucky to receive even a few hours of electricity a day. Luxury apartments invariably include diesel power generators to deal with power outages. They burn diesel inefficiently and foul the atmosphere. As demand for electricity increases, more fossil fuels like coal and oil get burnt, putting a strain on India’s limited coal supplies and adding to the oil import bill.

The situation demands an energy revolution on the scale of the Green Revolution and the later White Revolution that created abundant milk supplies. Thanks to solar, this is now within reach. Advances in solar power technology and ready availability of inexpensive solar cells make it possible to think in terms of doubling the generating capacity of many existing power plants, especially hydroelectric plants.

Harvesting solar power

While India is poor in fossil fuels, it is extremely rich in solar, much more so than any other country of comparable size including the U.S. and even China. The problem is not lack of supply – for the Sun delivers many times more energy than we need or we can use – but its conversion into usable electricity. Scientists have calculated that 5000 trillion kilowatt hour energy is available over India’s land area, with most parts receiving from four to seven kWh per square meter per day.

There are two sides to this: any solar plant requires an area that receives sunlight; as a corollary, any area that receives sunlight but is not being used for solar power generation is wasting solar energy. Worse, this unused energy is heating living areas that need cooling by energy-consuming equipment like coolers and air conditioners. Solar plants not only generate precious energy, they also reduce the need for cooling by acting as heat absorbers.

A solar power plant installed in conjunction with a hydro power plant can significantly add to its generating capacity as well save the precious water stored in its reservoir. This is because every hydroelectric plant has a large reservoir for storing the water that is needed to drive its turbines. The reservoir covers hundreds and even thousands of acres of land that receives abundant sunshine. This sunlight can be tapped to supplement the generating capacity of the power plant. Solar panels mounted on the reservoir would convert sunlight into electricity and feed into the same power grid as the hydro generators.

This means the generators would not be running and therefore not drawing any water from the reservoir when sunlight is adequate for solar panels to feed the grid. Thus the water stored in the reservoir would last much longer. This calls for the installation of solar panels, possibly floating, on the surface of the reservoir. These would not only feed the grid and make the stored water last longer, but also reduce evaporation by acting as a shield. Karnataka with its abundant hydroelectric resources is especially well-suited to reap the benefits of solar.

Solar power technology has advanced to the point that it is viable on a commercial scale. A solar plant can be installed anywhere the Sun shines: on land or on water. Any vacant area on which the Sun shines that is not being used for solar power generation should be seen as wasted space. This has given rise to the concept of harvesting solar energy by turning agriculturally unproductive land into ‘solar farms’. The practice is becoming particularly popular in the Western United States where the land is poor but sunlight is abundant (though not as abundant as in India).

The U.S. experience suggests that the value added to otherwise unproductive land by solar plants can be one of the major incentives for land owners to turn to ‘solar farming’.  The U.S. has vast tracts of desert and semi-desert land in states like Texas, California, Nevada, Arizona and others. Some landowners even in less arid areas like Ohio are beginning to switch from agriculture to solar farms. They are attracted by the prospect of a continuous income from a one-time capital investment with little or no annual expenditure. A solar farm installation company in California notes:

“Solar farming is the process of turning unused or underused land into an electricity production farm. Solar farming allows individuals with vacant or otherwise unusable land to make a very good return on investment. Imagine making 12% or more guaranteed return for 30 years with no out of pocket money and cash flow positive from day one.”  Utilities (power companies) typically sign a 10 to 20 year power purchase contracts with solar farm operators. PG&E, the company which supplies power to part of California, buys power from solar farm operators at $0.15 to $0.18 per kWh. At these rates a five- acre parcel can generate about $300,000 profit per year.

The concept of ‘solar farms’ can be extended beyond farms to buildings and water bodies. Unlike in real estate development or setting up a manufacturing plant, a solar plant does not ‘consume’ the land: solar panels can be installed at a considerable height from the ground and do not interfere with ground level activities. For example, there is no technical reason why solar panels cannot be installed over a shopping mall which can continue to function as a shopping mall. The idea is: land that cannot grow food can grow solar energy.

River network and solar network

In a bold initiative, the Gujarat Chief Minister Narendra Modi has built and dedicated to the nation, a solar power plant with an installed capacity of 605MW in the solar park at Charanka village in Patan district of Gujarat. Of this total, 214MW of it is already operational, making it the world’s largest photovoltaic plant. Spread over 3,000 acres in the dry, remote region of the State, it is a pointer to how agriculturally unproductive land can be made productive by ‘harvesting’ solar power. The Karnataka Government has announced a similar project in a village in the arid part of Bijapur district. This could be extended to other parts of the state and also to reservoirs.

In India, land is always at a premium although there is no shortage of agriculturally unproductive land that can be turned into productive solar farms. To supplement land-based solar farming, the Government in Gujarat has begun a project to use sections of the Narmada Canal for solar plants. A multipurpose pilot project generating one megawatt of electricity from solar panels mounted above the Narmada branch canal was recently dedicated to the nation by Chief Minister Modi. This approach will spare valuable land that would otherwise be needed if the solar power project were land-based. In addition, panels, by acting as heat shield will save a huge quantity of water in the canals from evaporation.

This appears to be a unique innovation that has not been tried in the U.S. or anywhere else. It has considerable potential and can be used in irrigated and agriculturally productive areas where land cannot be spared for solar farms. It has been suggested that the Karnataka Government may similarly use irrigation canals in the Mysore and Mandya districts as well as several reservoirs in the area for solar projects. Such ‘overhead solar farms’, as we may well call them, can generate solar powers as well as reduce water loss due to evaporation.

Viewing solar farming as a multipurpose program can be made national in scope by combining it with the river linking project that has just been mandated by the Supreme Court. This will mean the joint development of a solar power grid to go with the national river grid. If undertaken, this could prove to be one of the largest public works programs in history, comparable in scale to the U.S. Interstate Highway program under President Dwight Eisenhower. The proposed solar-river linking project would eventually yield benefits in flood control, irrigation, river transportation and power generation.

A public works program of river linking with solar grid would generate employment at all levels including tourism and sports made possible by waterways, reservoirs and added power capacity. The scientific, engineering and management experience acquired in the process would be of great value in future projects.

Both the technology and the economic factors already exist to wean the country away from its excessive and ultimately infeasible dependence on fossil fuels. The science behind solar power is not new and constantly improving. What will be new is the design and implementation of a multipurpose grid of linked rivers and solar plants. This will call for political leadership and management talent of high order. India has no choice but meet the challenge; otherwise the future is bleak. Gujarat has already shown how it can be done, but it is only a beginning.

About the author

You may also like

Somanjana Chatterjee

Somanjan Chatterjee is San Francisco based consulting editor