Biogas plant is a unit which converts organic waste matter (living biomass) into useful gaseous fuel (methane and carbon dioxide) and organic fertilizer as byproduct in the form of slurry. The most common feed material in family size biogas plants is cattle dung.
The potential is about 12 million family type biogas plants based on estimated availability of cattle dung in the country
The Ministry is implementing a National Biogas and Manure Management Programme (NBMMP), for setting up of family type biogas plants, since 1981-82.
A total of 4.31 million family type biogas plants have been setup in the country.
State nodal departments and agencies are implementing the National Biogas and Manure Management Programme besides, Khadi and Village Industries Commission, Mumbai is also implementing the programme country-wise through its States’ offices.
The Government is giving:- (i) Central subsidy; (ii) Turn-key job fee linked with five years’ free maintenance warranty; (iii) Financial Support upto 50% of the applicable CFA, subject to sharing of 50% of the cost of repair by the beneficiary concerned for repair of old non-functional plants of more than 5 years; (iv Training of users, masons and entrepreneurs; (v) Administrative charges to State Government Departments and agencies implementing the programme; (vi) Regional level Biogas Development and Training Centres; (vii) Publicity, Communication/ Extension.
The Central subsidy is given in fixed amounts for different categories of areas/ States/ Regions. It varies from Rs. 4000/- to Rs. 8000/- per plant for general category States & Rs. 14,700/- per plant for North Eastern Regions States including Sikkim except plain areas of Assam.
The cost of biogas plant varies from place to place and size of the plant. Average cost of 2 cubic meter size biogas plant is about Rs. 17,000/- . It is generally high about 30 per cent more in hilly areas and about 50 per cent more in North Eastern Region States.
A three-tier monitoring mechanism is used: (i) States nodal department and agencies are sending monthly progress reports and quarterly reports on physical verification of biogas plants. (ii) The second-tier is sample inspection Biogas Development Training Centres. (iii) Evaluation study is also being conducted by independent organizations
Biogas Development Training Centres are providing technical and training support for revival of non-functional plants. Repair of non-functional biogas plants is being undertaken by State Departments/ Nodal Agencies/ KVIC etc who are implementing the NBMM Programme. The Government is providing financial support up to 50 per cent of the Central subsidy for repairing of non-functional plants subject to sharing of 50% of the cost of the repair by the beneficiary concerned.
An independent evaluation study carried out by Andhra Pradesh Industrial Training & Consultancy Organization (APITCO), Hyderabad in 2008-09 for family type biogas plants installed during the 10th Plan period under National Biogas and Manure Management Programme (NBMMP) in six representative states namely, Assam, West Bengal, Gujarat, Punjab, Kerala and Chattisgarh, indicated that on an overall average basis, 95.81% of surveyed plants were found in operational condition.
There are two types of cookers: i) Box solar cooker, and ii) Concentrating Solar Cookers In concentrating solar cookers there are further three types A) Dish Solar Cooker, B) Indoor Community Solar Cooker, C) Solar Steam Generating Systems.
A Box Solar Cooker is a static device that reflects the sunlight on the pots through the perpendicular mirror. It is a gradual form of heating device that may require anywhere between 2-5 hours to cook depending on the temperature, solar radiation and type of food cooked. In case of a dish cooker the solar radiation is focused at a given point using automatic or manual tracking. The temperature that can be achieved is upto 4000 C at the bottom of the vessel, thus rendering faster cooking. It has thermal efficiency of about 40%. For effective results the solar radiations and focusing of the sunrays play crucial role. The initial investment is high as compared to box cooker but renders faster cooking, however uses more space.
Box Solar Cooker: The Solar Cooker must be placed on an area which receives constant and ample sunlight. Open the box cover and position the solar cooker in such a way that the double glass lid receives direct sunlight. Adjust the angle of the mirror so that additional light falls evenly on the black tray inside the cooker and not outside it. Place the cooking containers with the food item filled inside the black tray and close the double glass lid. The black pot & the black tray absorb the heat thus cook the Now, lift up the double glass lid and support it with stand attached to the lid. Place the cooking containers inside and shut the lid firmly by pressing it down from all sides. As the direct rays of the sun fall on the glass. The sun’s heat passes into the Inner Cooking Box and it is trapped there. The mirror also reflects the sun’s rays on the glass thus providing additional heat. The black lids of the containers and the black tray absorb this heat quickly. As a result the temperature inside the cooker is maintained between 1100 -1200 C, which is adequate for cooking. Food cooked in this simmering heat, not only retains it nutritive value, but also enhances the natural flavours. Dish Solar Cooker: The items to be cooked are placed inside the pressure cooker. The pressure cooker is then fitted in the stand by setting the dish. This dish is preferably kept facing south and the angle of tilt is adjusted so as to focus the sunrays on the pressure cooker. Depending on the solar radiation and the quantity of the food items cooking time will vary between 30min to 2 hours. For static systems they should face southwards in order to obtain maximum radiation.
The time required to cook food in box solar cooker varies between 2-5 hours depending on solar radiation and quantity of food item. The time require to cook food in dish solar cooker varies between 1-5 hours depending on solar radiation and quantity of food item. Everything that makes up your daily meals and non-fried snacks plus some of the delicacies that brighten up festive occasions can easily be cooked in the Solar Cooker. Some of these are: • rice, khichadi, pulao, biryani • kheer, dudhpak, basundi, flavoured milk • dal, pulses, cereals • green and root vegetables • bread, biscuits, cake, nankhatai, cookies • dhokla, idli • fish, chicken, meat, eggs • soups • jam, and pickles. • sun dried vegetables, spices and condiments for preservation • ghee from white butter
The three types of solar concentrating systems are: i. Manually tracked dish solar cooker to cook food for 10-40 people. ii. Fixed focus E-W automatically tracked dishes for direct indoor cooking 50-100 people & for steam generation for the purpose of community cooking, laundry, space cooking etc. of any capacity. iii. Dual axis fully tracked Fresnel dishes for process heating, cooling
The temperature achieved at the bottom of the vessel will be between 350 oC to 400 oC which is sufficient for roasting, frying and boiling.
As a thumb rule 3 to 4 dishes of 16 m2. each should be sufficient for cooking food for around 250- 300 people depending on site
These systems are modular hence more dishes can be added if number of people are more. For example, a 10 dishes system (160 m2.) may be sufficient to cook food for around 1000 people. The cost will reduce proportionately due to lower heat losses
It can boil 2 to 3 liters of water for every 1.4 m2 of dish area.
i. Cooking time in the Solar Cooker varies according to the material to be cooked and the availability of sunshine. Changes in seasons and in the daily weather also affect cooking time and duration. ii. In winter months, the Solar Cooker can only be used in the morning hours between 9 a.m. and 2 p.m. iii. In summer,-both lunch and dinner can be prepared in the cooker. Material for the morning meal should be put in the cooker at 9 a.m. and for the evening meal at about 1 p.m. After 3 p.m. there is not enough heat to cook the food. iv. Baking is best done in summer since it takes too long in winter. For baking preheat the cooker for at least one hour before putting in the material to be baked. v. Once the food is cooked, if the mirrored lid is tightly shut, the food inside remains hot for at least three hours
The advantages of solar cooker are: i. It does not require kerosene, coal, cooking gas or firewood because it works with the heat energy received directly from sun. So no matchsticks, no lighters, no fuel bills. ii. It does not create pollution of any kind. Hence it keeps the atmosphere, the kitchen and the cooking utensils clean and sootfree. It does not emit any smoke or fumes and so it isn't a health hazard either. iii. It is the safest cooking device as there is no danger from fire, explosion, cylinder bursts, gas leakage or electric shock. iv. As cooking is done slowly and at a regular moderate temperature, the prepared food is tasty, retains its original flavour, colour and texture and its nutritious elements remain intact. The vitamin, protein and mineral contents of the food are preserved unlike in cooking with other media where either because of overcooking or high temperature these nutrients are destroyed. v. There is no fear of spills or of food being burnt or charred since the temperature is maintained at "SIMMER" level only. (The food must not be left much longer in the cooker than necessary because the water content can dry up). vi. There is no need for someone to be present during the process of cooking. Moreover four items can be cooked at the same time. vii. Since the Solar Cooker has a simple design with no moving parts and is easy to use, there is hardly any possibility of it going out of order. viii. The Solar Cooker needs little care and repair work is comparatively inexpensive and quickly done. With a little routine care, the cooker gives trouble-free performance for years together. ix. Once the food is cooked, just shut the cover of the cooker. The heat inside keeps the food hot for at least three hours