Padmashree Prof. Dr. P. K. Jena
(Former Director General, CSIR, India)
Chairman
Institute of Advance Technology & Environmental Studies (IATES),
80A – 81A, Lewis Road, Bhubaneswar – 751 002,
Email: [email protected]
All over the world the manufacturing industries use nearly 33% of the total energy being used in all sectors. About 75% of energy used in manufacturing industries are consumed in energy intensive units like extraction of metals, production of chemicals, petro- chemicals, pulp and paper etc.. Over and above, these industries by using mostly fossil fuel based energy, produce a lot of green house gases which are responsible for global warming. During the next four decades, it is expected that, the industrial production may increase by a factor of four. In view of this, it is very much necessary not only to improve the technology to reduce the energy consumption but also to replace the fossil fuels- based energy by renewable energy produced from various sources like biomass, sun, wind and hydro power.
At present, biomass contributes maximum amount of renewable energy to the industry. In 2007, nearly 8% of the energy used in various industries was from biomass. It has been estimated that by applying better technology the long term potential for use of renewable energy from biomass in industrial sector, can come up to more than 21% by 2050.
The use of biomass primarily for process heat has a great potential in pulp and paper industry. Other sectors including chemicals, petro chemicals and cement also have potential to increase their use of biomass. It has been predicted that, by the year 2050, biomass may constitute 22% (9 Ej per year) of final energy use in chemicals and petro chemicals sectors and 30% (5 Ej per year) in cement sector. Similarly, by that period, solar thermal energy has the potential to contribute about 5.6% per year to various industries. At present, renewable energy are not cost competitive particularly where fossil fuels based energy are subsidized. Therefore, it is necessary from environmental point of view and also due to abundance of renewable energy, to encourage the use of all types of renewable energy in place of fossil fuels.
Renewable energy which is abundant in nature from sun, wind and biomass, can be substantially and economically harnessed by using advance technology and as a matter of fact in some advance countries these are being used increasingly in various industries. This would help to conserve a large amount of fossil- fuels based energy for other special purposes where renewable energy cannot be used. Further, by using minimum amount of fossil fuels, the earth along with all living beings can be saved from the effect of global warming caused by green house gases released from these.
Solar Energy
Solar energy is used particularly in food industry in low to medium temperature range (<1500C) to (1500C to 4000C) and is similar to that produced and used in heating the building and other similar low temperature requirements. For industries requiring temperatures higher than 4000C, advance concentrated solar heat energy can be produced and used. There are two main principles which are applied to harness solar energy, namely, photovoltaic (PV) and solar thermal. In PV technology, the radiant energy contained in sun’s rays is converted into electrical energy when light falls on a semi conductor material causing electron excitation which strongly enhance the conductivity. In solar thermal technology, solar heat is used directly. This heat can be used for heating purposes and also can be used for generating electricity. In view of this, the solar thermal non electric can be used for drying, air heating, water heating etc. The solar thermal electric is used to produce steam for generating electricity which is known as concentrated solar power (CSP).
The industries like food, beverage,paper, textile, chemicals and plastic operating with low and medium temperatures (about 600C to 2500C) accounts for 45% of the total industrial process heat used. In such industries, solar thermal system has a very significant role to play. Solar thermal technology can also be applied for cooling processes in food and tobacco sectors. Cooling is done by electric chillers.
The world’s largest system for cooking using solar energy in community kitchen has been installed at Shirdi Saibaba temple to cook food for 20,000 people per day. In this system nearly 4000 kg of steam are produced saving around 60,000 Kg of LPG every year. The largest solar process heating plant today is the 32 MWth solar thermal plant in a copper mine in Chile installed in 2013. This supplies around 85% of heat demand of the plant. Similarly, a 9 MW system for a textile plant has been set up in 2008 in China, and 5.5 MW food processing plant developed in 2012 in the USA. It is encouraging to note that in India, about 61% solar thermal capacity is being used for industrial processes.
Biomass Energy
Liquid bio-fuels include ethanol produced from fermentation of sugar and biodiesel produced through transesterification of vegetable oils. It is reported that, 57 kilotonnes (Kt) of production capacity is in operation and about ten plants each with capacity between 50,000 tons and 300,000 tons are coming up very shortly in different parts of the world. At present, in some coal- based thermal power plants significant quantities of biomass are also cofired with coal. For example, a plant in Netherlands produces 600 MW of electricity and 350 MW equivalent of heat by cofiring 35% of biomass in the form of wood pellets with 65% of coal.
The two forms of gaseous bio fuels namely biogas from anaerobic (without oxygen) digestion of organic matters including agricultural and domestic wastes and producer gas or synthetic gas (SYN) from biomass gasification, are finding commercial application in recent years. The biogas produced from anaerobic digestion of organic matters containing mostly methane and carbon dioxide after purification, can have similar composition to natural gas. Biomass gasification produces a synthetic gas which can be used in combined cycle gas turbine plant for power generation or can be used for production of liquid fuels through Fischer-Tropsch process.
Cement manufacturers can use a good amount of biomass including organic wastes in their process. As a matter of fact, European cement companies derived 3% of their energy needs from waste fuels in 1990 and 17% in 2005. Cement producers in some of these countries like Belgium, France and Germany have been able to use biomass ranging from 35 to 80% of the total energy required. The share of alternate fuel use in clinker production in cement industry in Netherlands, Switzerland, Australia, Germany and Norway are 84%, 49%,48%, 36% and 28% of organic waste as fuel respectively. It is suggested that, other countries particularly the developing ones should use more amounts of biomass preferably the domestic and agricultural organic wastes in cement manufacturing units. The gasification of biomass is a proven technology which can be used in a gas engine for generating electricity and thus increasing the use of biomass.
Wind Energy
All over the world, various efforts are being made to harness wind energy economically by using advance technology. Harnessing wind energy is the fastest growing sector with an average annual growth of 25%. The installed capacity of wind energy generation in the world has increased from 60 GW in 2002 and 160 GW in 2010 and was expected to be 460 GW by the end of 2015.
At present, nearly 83 countries in the world are harnessing wind energy and supplying the power to electricity grid. In 2010, the production of electricity from wind energy was 2.5% of the total electricity used in the world. A small country like Denmark is generating more than 25% of their total electricity demand from wind power. The total global installed capacity of wind energy was 296,065 MW by the middle of 2013.
In the mining sector all over the world, the application of wind energy is increasing at a very fast rate. In North America, the Glencore at its Raglan mine has set up a 3 MW wind turbine which is expected to meet about 5% of its total energy requirement. The Glencore is planning to install more wind turbines for generating about 9 to 12 MW of energy and is expected to reduce nearly 40% of their diesel consumption in near future. The Diavik diamond mine, Canada, has set up wind energy farm of 9.2 MW capacity with an annual production of 17 GW per hour which constitute about 8.5% of the power required in their mining activities. The Rio-Tinto’s Diavik diamond mine has setup wind turbines in North Western region of USA in 2013 to cut down significantly the use of diesel fuel. The wind energy reduces diesel demand by 10% with a saving of about 5 million dollars per year and the project is expected to pay back in 6 years.
Though China is rich in fossil fuels yet it is the leading country in the world to produce wind energy with an installed capacity of 62,733 MW by the end of 2011. The countries with next higher production of wind energy are in the order Germany, France, Canada, USA, UK and Spain. World Wind Energy Association (WWEA) had estimated that, the global wind energy capacity by end of 2020 would be 15,00,000 MW.
The civilized world needs energy for various socio- economic activities of which industrial sector is the major one. At present, nearly 80% of the energy used in industrial sector is produced from fossil fuels. Besides limited availability of fossil fuels in the nature and with its increasing cost, it produces a lot of environmental pollution. On the other hand, nature has given us huge amounts of clean renewable energy resources like sun, wind, biomass and hydro power for a better living. Unlike fossil fuels these energy are unlimited and freely available in nature. We have to only develop techno- economically viable processes to harness these. It is very encouraging that, a lot of advance technology have been developed to economically harness energy from these renewable resources.
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