Gargi Malik*
Agriculture continues to be the main source of livelihood for a large part of population in the country. Biomass, thus, is readily available widely across the country, thereby, overcoming regional limitations. Biomass, which implies biological material from living or recently living organisms, can be used as an important source of energy. It is a renewable and carbon natural source of energy. Biomass resources in India are estimated to be about 565 million tonnes per year. It includes agriculture residues and forest residues. Agriculture residues result from crop harvesting and processing. They include rice husk, bagasse, sugar cane tops and leaves, groundnut shells, cotton stalks and mustard stalks. Forest residues result from logging and wood processing. They include small trees, branches, tops and un-merchantable wood left in the forest.
The surplus biomass resources available for power generation annually are about 189 million tonnes, which could support roughly 25 GW of installed capacity. Further, co-generation plants provide both heat energy, used in the mill, and electricity, which is typically sold to the grid. It is estimated that about 15 GW of electricity generating capacity could be achieved through adding cogeneration capabilities in various industries including sugar mills, breweries, textile mills, distilleries, fertilizer plants, pulp and paper mills, and rice mills. In addition, there exists a potential of setting up 12 million family type biogas plants.
Types of Biomass
Biomass includes three distinct categories:
· Solid Biomass, which includes tree, crop residues like rice husk, bagasse, coconut shells, jute waste, etc. and animal and human waste.
· Biogas which is obtained by anaerobically digesting organic material to produce combustible gas methane.
· Liquid biofuels which are obtained by subjecting organic materials to one of various chemical or physical processes to produce usable combustible liquid fuels.
Biomass Conversion To Useful Energy
A number of technological options are available to make use of a wide variety of biomass types as a renewable energy source. Conversion may release energy directly in the form of heat/electricity or, may convert it into another form such as liquid biofuels or combustible biogas. There are basically three types of conversions:
· Thermal Conversion- A process in which heat is used to convert biomass into another chemical form.
· Chemical Conversion - A range of chemical processes may be used to convert biomass into other forms so that fuel may be used more conveniently, transported or stored.
· Biochemical Conversion- It involves anaerobic digestion fermentation and composting.
Benefits Of Using Biomass
· It reduces air pollution as biomass emits less Sulphur dioxide and Nitrogen Oxide than fossil fuels. Further, biomass fuels recycle atmospheric carbon, minimizing global warming impacts since zero net Carbon dioxide is emitted during biomass growth phase. Amount of carbon dioxide emitted is equal to the amount of carbon dioxide absorbed from atmosphere during growth phase of biomass.
· Using biomass decreases animal and municipal waste. Through anaerobic digestion process biomass in the form of waste is converted into useful energy.
· Using biomass as fuel reduces the landfill space required to dump the woody biomass, lumber mill waste, etc.
· It helps in creating local jobs in a rural areas.
Presently, biomass contributes to around 30% of the total primary energy supply in the country. The major source of energy for cooking for 85% of households in rural India includes firewood, chips, dung cake, etc. Moreover 20% of urban households still rely primarily on traditional fuels to meet their cooking needs. The Ministry of New and Renewable Energy (MNRE) has initiated various schemes and also promoted various NGOs to work in the field of energy from biomass. The initiatives can broadly be classified into two categories:
· Rural Areas Initiatives: National Biomass Cookstove Initiative(NBCI); Family Type Biogas Plant; Biomass Gasification System.
· Urban Areas Initiatives: Programme for Energy Recovery from Urban Waste; Biomass Gasifiers and Biomass Cogeneration (Non-Bagasse) Projects.
Rural Areas Initiatives
National Biomass Cookstove Initiative(NBCI): In rural areas a large percentage of population continues to depend on biomass. Clean and efficient energy is provided for energy deficient section of population through smokeless chulha, where different types of fixed and portable cookstoves are made available to rural household. In a case study on various Dhabas and roadside hotels in Andhra Pradesh, it was observed that fuel efficient stoves installed were able to conserve about 50-60% of fuel as compared to traditional stoves. There was reduction of smoke and thus increase in productivity with a positive impact on environment.
Family Type Biogas Plant: In family type biogas plants cattle and other organic wastes are used to produce energy and manure. India supports the largest cattle wealth and this scheme helps to answer the growing energy crisis. In this technology, anaerobic fermentation of biodegradable materials such as biomass , sewage, green waste, etc. is done to produce biogas which mainly comprises of methane and carbon dioxide. This biogas is used for cooking purposes in the households.
The National Programme on biogas development has multiple benefits. It helps to save tonnes of fuel wood every year. Biogas technology provides energy in a clean and unpolluted form and makes available enriched organic manure as a by-product for supplementing and optimizing the use of chemical fertilizers. Now-a-days institutional and night-soil-based biogas plants are being deployed increasingly. Toilet linked biogas plants are coming up in places like bus stands and educational institutions.
Biomass Gasification System: In the scheme various biomass gasification systems are set up in rural areas to provide electricity supply in villages as well as develop the industries there. Various gasifiers fed on rice husk, wheat husk , maze , etc are set up in the area depending on the sustainable source of supply available from agriculture or plantation. In gasification process organic material is converted into methane, carbon monoxide, hydrogen, carbon dioxide . It is obtained by reacting the material at high temperature (>7000C) without combustion with a controlled amount of oxygen / steam and the resulting gas mixture is called Syngas or Producer Gas which itself is a fuel.
India is known as an acknowledged leader in conversion of solid biomass into clean gaseous fuel. Small-scale biomass gasifiers of upto 500-600 KW capacity are eminently suited for off-grid electricity supply in our rural areas. A number of projects have already been initiated with private sector participation for supply of 6-8 hrs electricity daily through gasification for domestic lighting and 6-8 hrs for other commercial activities like water pumping for irrigation purposes and to micro enterprises and telecom towers. Projects are being carried out in Araria and Purnea districts of Bihar where Daincha/Ipomoea, maize residues and hardwood ensure perennial supply of feedstock.
Rice Husk based power generating units in the villages of West Champaran district in Bihar have been lighting up around 500-700 households spread over 20 villages in the district, and changing the profile of cluster altogether. The west Champaran experiment is supported by the Ministry and implemented by Husk Power System(HPS), an NGO. The technology employed is simple: It uses the Husk based gasifier technology to provide electricity using 32kWe ‘mini power plants’ that deliver power on a ‘pay-for-use’ basis to households in rice producing belt of India. The price paid to procure electricity generated by these mini power plants is very low, Rs 2 per day per household, located within a radius of 1.5 km. It results in a reduction of consumption of kerosene by as much as two thirds. Power is supplied from 5 pm till midnight each day. Success of this initiative has led to further planning for installation of such plants in Samastipur and Lakhisarai. The Ministry of New and Renewable Energy has now plans to take up the rice husk based electricity systems on a ‘Mission Mode’. It has enormous potential and even some of the larger rice mills can feed power to grid as well as distribute locally. More than 5000 to 10,000 industries can be benefitted in the next 2-3 years. These systems can lead to saving diesel to the tune of 200-250 million litres annually.
Urban Areas Initiatives
Biomass In Urban Areas and Commercial Applications: Crop residues and agro industrial wastes are used through biomass gasification technique for both electrical and thermal energy. Several industries like sugar, paper and pulp, fertilizers, food processing, etc. Require electrical as well as thermal energy for their operations. These requirements can be met through different energy sources or a single source. The simultaneous production of power and thermal energy from a single source is termed as Cogeneration. The Government is providing assistance for setting up of Biomass Gasification and Biomass Cogeneration (Non-Bagasse) Projects.
Programme For Energy Recovery From Urban Waste: According to a recent estimate, about 42 million tons of solid waste and 6000 million cubic meters of liquid waste are generated every year by our urban population. A total of 8 projects for energy recovery from urban waste i.e. an aggregate capacity of 19.05 MWeq have already been set up.
Biofuels
Biofuels are a type of fuel whose energy is derived from biological carbon fixation. It includes fuels derived from biomass conversion as well as solid biomass, liquid fuels and various bagasses. Biodiesel and bio-ethanol can be used as diesel additive and gasoline additive respectively.
Biofuel development in India mainly centres around the cultivation and processing of JATROPHA plant seeds which are very rich in oil (40%). Jatropha oil can be used directly in diesel generators and engines.
While a target of 20% blending of biofuels in diesel and petrol by the year 2017 has been indicated in the National policy on Biofuels announced in December 2009, a mandatory target of 5% blending of ethanol with petrol and recommendatory target of 5% blending of bio-diesel with diesel is in force since October 2009. Indian Railways has already started using Jatropha oil mixed with diesel for meeting the fuel requirements.
The potential of biomass energy is yet to be exploited fully for India. Considering the nature and current growth of economy and the future trajectory of growth, optimal exploitation of biomass energy will offer a great respite to India at energy front. (PIB Feature). *****
*Assistant Director (Media & Communication).
