Issue: October 2016
 
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Cover Story
Textiles’ – the word brings up images of beautiful drapes – cotton, silk, chiffon, lace. Whether it is the material draped on the figurine of the lady...
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  Tapping Sustainable Energy Alternatives
  The second lead article, which is also focus article, is written by Shri N Bhadran Nair. Citing a report of the World Health Organisation, the author has advocated for tapping sustainable energy alternatives
  Financing Renewables in India
  The third article is written by Shri P C Maithani, Adviser, Ministry of New and Renewable Energy. He has focussed on renewable energy resources
  Steps to Achieve India’s Solar Potential
  The special article is written by Sumant Sinha, Chairman and Managing Director of ReNew Power. He opines that India must also honour its global commitments on curbing greenhouse gas emissions
 
 
  RENEWABLE ENERGY SOURCES-EMERGING TECHNOLOGIES
Dr Manas Ranjan Senapati
Introduction

Mankind is using up energy resources of mother earth in a way no other animal has ever done. The largest contributions to current energy sources in the world come from oil (31per cent), coal (26per cent) and natural gas (19per cent). At the present rate of consumption, oil reserves will last for 40 years, gas reserves will last for 60 years, coal reserves will last for 125 years and uranium reserves will last for 1000 years. India has 17per cent of the world’s population, but only about 0.8per cent of the world’s known oil and natural gas sources. Based on the progress visualized for the nation during the next two decades, the power generating capacity has to increase to 4, 00, 000 MW by the year 2030 from the current 3,01,965 MW in India. This takes into consideration energy economics planned and the design and production of energy efficient equipments and systems. New and emerging technologies like hydrogen energy, fuel cells, biofuels, electric & hybrid electric vehicles, geo-thermal energy and tidal energy hold major promise for mitigating the energy crisis in the country, especially for power generation and transportation as such to achieve energy independence. These are renewable and do not get depleted with use like fossil fuels. Innovation in technology, development and applications has to drive the renewable energy (Green Power) marketplace. Over 1.64 billion people world across lack access to electricity. For those people, who cannot be provided with electricity by extending the grid their hope rests in innovation and as such the emerging technologies. Presently installed generation capacity of renewable energy is 85,510 MW from various sources which is approximately 28.9per cent of total installed capacity in the country and contributing to around 3per cent of total national electricity generation. The stupendous growth stimulates enhanced energy requirements.

HYDROGEN ENERGY

Pure hydrogen and hydrogen mixed with natural gas (HYTHANE) have been used effectively to power automobiles. Hydrogen can be obtained from water, natural gas, coal, sewage, coal gas etc. Hydrogen is also available as a by-product from several chemical processes, plants or industries. Hydrogen can also be produced by thermal decomposition of water through solar energy or nuclear power. Hydrogen has high energy content and can be used either directly in IC engines or through fuel cells for production of motive power and electricity. Hydrogen powered vehicles will last longer without any pollutant gas emissions. There is no emission of Carbon dioxide and as such this will reduce global warming trends. There is one drawback that hydrogen has negative net energy, which means it takes more energy to produce than it contains.

FUEL CELL

A fuel cell is an electrochemical device that converts energy into electricity and heat without combustion. Fuel cell systems generally operate on pure hydrogen and air to produce electricity with water and heat. There are five main types of fuel cells depending upon the nature of electrolytes i.e. alkali fuel cells, molten carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC), proton exchange membrane fuel cells (PEMFC) and solid oxide fuel cells. Fuel cells produce direct current (DC) electricity without the conventional combustion reaction. Many fuel cells are usually assembled into a stack to produce more current.

GEOTHERMAL ENERGY

The geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. It is clean and sustainable. It is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. Geothermal energy is generated in the earth’s core; about 4000 miles below the surface. Geothermal energy can sometimes find its way to the surface in the form of volcanoes and fumaroles (holes where volcanic gases are released), hot springs and geysers. Geothermal energy can be harnessed for power generation, space heating and other thermal applications. The direct use of hot water as an energy source has been in use since ancient times specially by the Romans, Chinese and Native Americans for bathing, cooking and heating. Geothermal power plants do not burn fuel to generate electricity, so their emission levels are very low (less than 1per cent of carbon dioxide).

WIND ENERGY

Wind pumps that use mechanical energy from wind primarily for water pumping purposes are in use since long. Generation of electricity from wind was initiated at the end of the 19th century, in 1891. Poul La Cour built the first electricity generating wind turbine. During World War I and II it was being used to supply energy. At present wind turbine of capacity 5 MW is in use. Global wind power grew from 4800 MW to 59, 322 MW. The statistical report prepared by the Global Wind Energy Council (GWEC) shows that the global wind power capacity is expected to be more than double its capacity by 2010 and one-third of world’s electricity needs by 2050. The power carried by a mass of air that is called wind can be converted to mechanical energy by the turbine. Wind energy is environment friendly and does not pollute the atmosphere unlike coal fired thermal power plants. Though it appears to be eco-friendly there are no studies on the effects of reduced wind speeds.

TIDAL ENERGY

Tidal energy is one of the oldest forms of energy used as evidence of tide mills from before 1100 AD have been found along the coast of France, Spain and the UK. Tides are formed by the gravitational pull of the sun and moon on the oceans of the rotating earth. Tidal energy is the utilization of the sun and moon’s gravitational forces. Energy can be extracted from tides by creating a reservoir or basin behind a barrage and then passing tidal waters through turbines in the barrage to generate electricity. France is currently the only country that has significantly harnessed tidal energy and has the largest tidal power station in the world. India being surrounded by sea on three sides has a high potential to harness tidal energy. In India, Gulf of Kutchh and Gulf of Cambay in Gujarat and delta of Ganga in Sunder bans, 24 Parganas district, West Bengal are potential sites for generating tidal power. The overall potential of tidal energy in India is estimated at 8, 000 MW with Gulf of Cambay accounting for over 90 per cent. Tidal energy is clean and renewable unlike fossil fuels.

SOLAR ENERGY

Solar energy has been used since prehistoric times, but in a most primitive manner. When we hang out our clothes to dry in the sun, we use the energy of the sun. In the similar manner, solar panels absorb the energy of the sun to provide heat for cooking and for heating water. Plants use the solar light to make food. Animals eat plants for food. Fossil fuels are in fact the solar energy stored millions and millions of years ago. Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC Fig. Solar Panel electricity. This electricity can either be used as it is or can be stored in the battery. India receives solar energy equivalent to over 5000 trillion KWh/year, which is far more than the total energy consumption of the country. India is one of the few countries with long days and plenty of sunshine, especially in the Thar Desert region. On a bright sunny day, the sun provides approximately 1,000 watts of energy per square meter of the planet’s surface. One disadvantage is that except for desert areas and rooftops of buildings solar cells cannot be installed on a large scale. Use of solar cookers particularly in rural areas can save a lot of fuel wood and hence the environment.

BIO FUEL

Bio fuel is defined as solid, liquid or gaseous fuel obtained from relatively recently lifeless biological material and is different from fossil fuels.

• First generation bio fuels (bio ethanol and bio diesel) are made from sugar, starch and vegetable oils (edible and non edible) and thus refer to those feed stocks within the food cycle, e.g. maize grain, palm oil, rapeseed etc. using conventional technology. Two dry land species, e.g. Pongamia pinnata, a leguminous tree; and Jatropha curcas, a more drought tolerant shrub produce fruits containing about 35per cent oil suitable for bio diesel. Fig.

Bio diesel Plant Bio diesel is monoalkyl ester of long chain fatty acids made by transesterification process. Bio diesel can be used as a transportation fuel in compression-ignition diesel engines without any modifications. Bio diesel is currently used as 20per cent blends (B 20) with petroleum diesel. In early 2005, Gujarat became the first state to put bio diesel to commercial use. A state-owned transport utility began commercial service of buses that run on a diesel blend containing 5 per cent bio diesel (B 5) from Jatropha. Shatabdi train was run from Delhi to Amritsar using B5 (5per cent biodiesel) blend and no problem was observed during the run. Fig. Shatabdi Express Trial Other non-edible oils like Karanja, Mahula, Neem, Kusum etc can also be converted into biodiesel. In India it is the usual practice to produce biodiesel from non-edible oils. Rapeseed and soybean oils are mostly used to produce biodiesel in USA.
• Second generation bio fuels (cellulosic bio fuels) refer to feedstock produced utilizing non-food biomass like crop residues, wild grasses based on bioconversion techniques such as enzymatic breakdown of ligno-cellulose to make ethanol.
• Third generation bio fuels (algae fuels)

are made by bioconversion process Bio fuels have enormous environmental benefits in comparison with conventional sources of energy, i.e. petrol and diesel. The fourfold benefit is easing poverty, reducing air pollution, mitigating global warming and rehabilitating wastelands. In Oct. 2005, the Union Ministry of Petroleum and Natural Gas (MPNG), announced the bio diesel policy from Jan.2006. The Public Sector oil marketing companies viz. Indian Oil, Hindustan Petroleum & Bharat Petroleum were to purchase bio diesel from private operators at Rs. 26.50/litre. The purchase price had reportedly come from estimates of the Planning Commission and twenty purchase centers were set up in fifteen states by the oil companies. A National Bio diesel Mission was launched by the Government of India to cover 5 lakh hectares in the country. The Government of India has fixed a target of replacing 20percent petro-diesel with bio diesel up to 2017 by producing 13.38 MT of bio diesel annually through plantation of jatropha in 11.19 million hectares. It would generate employment in the rural areas. The government proposes to encourage farmers and landless labourers to plant non-edible oil seeds to boost the production of bio-diesel and bio-ethanol. The agricultural produce would be procured by public or private processing entities through the Minimum Support Price mechanism.

CONCLUSION


Nuclear energy has the potential of meeting a significant percentage of India’s electricity requirements. India has developed technologies and necessary infrastructure for its exploitation. Increase in nuclear installed capacity in India is of importance not only for India but for the world in view of its climate change implication.”. A renewable energy economy is desired and the next decade should become the age of renewable energy. Private-sector support and international cooperation will be needed for more stringent government policy initiatives. This will require programmes to promote technology transfer, capacity building and collaborative research and development. Innovations in renewable energy sources will allow developing countries to leapfrog into modern and sustainable energy systems and technologies.
About the author: The author is Professor and Head, Department of Chemistry, Trident Academy of Technology, Bhubaneswar, Odisha
E-mail : dr_senapati@yahoo.com


 


 
 
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