Non Conventional sources of energy are generally renewable sources of energy. This type of energy sources include anything, which provides power that can be replenished with increasing demand for energy and with fast depleting conventional sources of energy such as coal, petroleum, "natural gas etc.
The non- conventional sources of energy such as energy from sun, wind, biomass, tidal energy, geo thermal energy and even energy from waste material are gaining importance. This energy is abundant, renewable, pollution free and eco-friendly.
It can also be more conveniently supplied to urban, rural and even remote areas. Thus, it is also capable of solving the twin problems of energy supply in a decentralized manner and helping in sustaining cleaner environment.
However, the importance of the renewable energy or non-conventional sources of energy was recognised in the early 1970s. But now, it has been accepted that renewable energy resources can provide the basis for sustainable development.
During the past quarter century, a variety of renewable energy technologies have been developed and deployed in villages and cities. In India, a separate Ministry of Non-conventional source of energy has been created for planning, promoting and coordinating relating to all aspects of renewable energy resources.
India today has one of the largest programmes for non- conventional sources of energy. According to energy experts, India's non-conventional energy potential is estimated at about 1, 95000 mw. An estimate of 31 percent of this potential comes from the Sun, 30% from ocean thermal, 26% from bio-fuel and 13% from wind. During the last two decades, several renewable energy technologies have been developed and deployed in villages and cities.
However, the major non-conventional energy sources that are being used for power generation are:
(i) Solar Energy:
Sun is the source of ail energy on the earth and most parts of our country have bright sun throughout the years except a brief monsoon period. According to an estimate, India receives solar energy equivalent to-over 5000 trillion kHz per year which is far more that the total energy consumption of the country.
The exploitation of this vast solar energy can be done through both the thermal and photovoltaic routes for a variety of applications like cooking, water heating, drying of farm produce, water pumping, home and street lighting, power generation for meeting requirements in villages, schools, hospitals etc.
For this purpose, various solar water heaters and dryers, solar cooker and solar photovoltaic cell have been developed. Solar photovoltaic technology enables direct conversion of sun light into electricity without causing pollution.
(ii) Wind Energy:
Wind is another important source of non-conventional energy. According to the estimates of the Ministry of Non-conventional Energy Sources, the wind energy potential in India is 45,600 Mw. This energy system requires cost inputs only at the initial stage but once the power generation starts the cost free power is available for about 20 years.
The first wind farms in India were installed in 1986 in coastal areas in Tamil Nadu, Gujarat, Maharashtra and Orissa. But the largest installation of wind turbines in the country so far has been established near Kanyakumari in Tamil Nadu and another big one has been commissioned in Satara district in Maharashtra. India has large coastal areas and desert areas where wind energy plant can be established to a great extent.
(iii) Bio gas:
Biogas is based upon the use of cow dung to produce gas which is used as domestic fuel especially in rural areas. The biogas techniques are generally based on the decom-position of organic matters which contain methane 55% and carbon dioxide 45%.
This energy can be used for cooking and lightening in rural areas. India has also huge resource of biogas, which can be used for replacing diesel oil. Biogas has higher thermal efficiency than kerosene, firewood, charcoal etc. The Community and Institutional Biogas plants programme was initiated in 1982-83.
(iv) Small Hydro Power:
Generation of electricity from small sized hydro power sources is a low cost, environment friendly and renewable source of energy. Small and mini hydel projects have the potential to provide energy in remote and hilly areas, where extension of grid system is uneconomical. India has an estimated small hydro power potential of about 15,000 mw.
The Ministry of Non-conventional Energy Sources has also launched a comprehensive state- wise study to identify the potential sites for small hydro projects up to 25 mw projects during the 10th Five Year Plan.
(v) Geothermal Energy:
There are vast potential of geothermal energy in the country. About 340 hot spring localities have been identified in the country. Extensive surveys are being conducted to develop geothermal energy for direct heat and power generation. In India, a number of geothermal plants have been commissioned such as Manikaran in Himachal Pradesh, Puga valley of Ladakh, Jammu and Kashmir, Tatapani.
(vi) Tidal Energy:
It is estimated that India possesses 8000-9000 mw of tidal energy potential. The Gulf of Khambhat is the best- suited area. This is followed by Gulf of Kachch and Sundarbans.
(vii) Wave Energy:
Wave energy potential in India is estimated at about 40,000 mw. One wave energy power plant has been installed at Vzhinjam near Thiruvanthapuram and another one wave energy plant is being set up in Andaman and Nicobar Island.
(viii) Ocean Thermal Energy Conversion:
India's ocean thermal energy is estimated at 50,000 mw. The first ever plant for ocean thermal energy conversion with a capacity of 100 mw is being proposed to set up along the coast of Tamil Nadu, (ix) Energy From Waste: The quantity of waste generated in class-I cities of the country has been estimated to be about 30 million tonnes of municipal solid waste. In addition, large quantities waste is produced by industries, sugar mills, pulp and paper mills etc. According to an estimated total energy, waste can be of about 2700 mw.