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In this essay we will discuss about the potential for energy conservation in agriculture sector.
The country inherited a stagnant agriculture at the time of independence. The traditional tools and implements relied mostly on human and animal power and used a negligible amount of commercial energy. However, successive governments realized the importance of agriculture and initiatives were taken for the growth of this sector. Increased investment in irrigation infrastructure, expansion of credit, marketing and processing facilities therefore, led to a significant increase in the use of modern inputs.
Till the 1950s, use of tractors for agriculture was very limited. Tractor manufacturing in India started in 1961. Joint efforts made by the Government and private sector have led to steady increase in the level of mechanization over the years.
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Given that rains are not always timely and evenly distributed, farmers prefer pump sets as a more reliable and assured source of irrigation; as a result, energization of pump sets have been increasing rapidly. As on today 1 millions of pump sets had been energized in India.
Maharashtra has the maximum number of energized pump sets, followed by Andhra Pradesh Earlier, the average capacity of the pump sets was 3.68 kW and a pump set on an average consumed 6000 kWh of electricity in a year (central electricity authority, 2005).
However, owing to insufficient electricity supplies, some farmers have also procured diesel pump sets as a standby. In the recent past, concerted efforts of the Government has led to an introduction of biomass and solar photovoltaic based pumping systems.
As a result of increased mechanization in agriculture, crop production and rural agro processing emerged as one of the major consumers of commercial energy. The share of mechanical and electrical power in agriculture increased from 40% in 1971/72 to 84% in 2003/04. The availability of farm power per unit area (kW/ha) has been considered as one of the parameters of expressing the level of mechanization.
Electricity consumption in agriculture sector has been increasing mainly because of greater irrigation demand for new crop varieties and subsidized electricity to this sector. Moreover, due importance is not given to proper selection, installation, operation and maintenance of pumping sets, as a result of which they do not operate at the desired level of efficiency, leading to huge waste of energy.
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Agriculture sector also consumes thousands of tonnes of High Speed Diesel (HSD) and LDO (light diesel oil).
Study shows that present energy-use efficiencies in the agriculture sector are low and there exists a great potential for energy conservation in this sector. By eliminating inefficiencies in the tube wells, huge quantity of high speed diesel and electricity can be saved yearly. Similarly, by improving tractor efficiency, huge quantity of fuel per year can be saved.
The summary of the energy uses in the agriculture sector is given in the following Table 5.7:
Energy Conservation Opportunities in Pumps Used in Agriculture Sector:
In the context of Indian agriculture sector, majority of the energy used particularly the electricity is in pumping water for irrigation purpose. Water withdrawal is an energy intensive operation throughout the agriculture sector.
In India, irrigation pumping electricity use is at the heart of the subsidy issue and along with other issues such as losses in power distribution are affecting the power sector performance. So, it is of utmost importance to conserve energy in all possible ways in water pumping area in agriculture sector along with efficient power supply distribution network.
In agriculture farms, water is mostly pumped from tube wells by using pumps which are operated by electric motor or are engine driven operated from fuel such as diesel. Sometimes tractor engine is also used to drive the pump by using suitable transmission.
In addition to this submersible pumps are also used, which are driven by specially designed motor fitted along with turbine and submerged in water and in some cases turbine is submerged in water and motor is mounted on the surface at ground level and motor-turbine connection is through shaft.
We see that the whole water pumping system for irrigation purpose involves tube well pump or submersible pump, electric motor or engine in case of tube well pump, transmission mechanism such as belts or pulleys, foot valve, piping network.
Hence, the overall performance and how efficient the whole water pumping system depend upon the performance of pump, electric motor, motor-turbine unit in case of submersible pump, types of pipes and piping layout and engine performance etc. So, there is an opportunity of energy saving in all of the above mentioned elements of water pumping system.
Following are few tips for energy conservation in water pumping system for irrigation purpose in agriculture sector:
(i) Foot valve:
Use properly designed foot valve. Foot valve with wider mouth and a larger area of opening are better as large valve helps save diesel and electricity as less fuel and power is needed to draw water from the well.
a. Use standard mark foot valve. It may be costlier, but pays back fast the extra cost by saving a lot of diesel.
(ii) Pipes:
a. Pipes with smaller dia offers high friction and more diesel or power is required to pump water. So use larger dia. pipe.
b. Use PVC pipes instead of galvanized iron pipe as PVC pipes offers less resistance.
(iii) Pipeline arrangement:
a. Use fewer bends and avoid unnecessary fittings as these offers high friction which results in more fuel consumption.
b. Avoids sharp bends as they offer more friction to the flow of water.
(vi) Pump location:
a. The tube-well pump works more efficiently when it is not more than 10 feet above water level. If the well is deep, the pump should be installed on a platform at the right height.
(v) Transmission system:
Transmission system in water pump involves belts which couples pump with engine.
The check points for efficient transmission are:
a. Reduce the number of joints in the belt.
b. Check and adjust belt tension frequently.
c. Check alignment of the pump with the engine.
These above said tips when followed in addition to the use of other efficient auxiliaries used in the water pumping system can save substantial amount of energy.
Selection of right type of pump set:
The various pump sets available in the market require different quantities of diesel for pumping water. Therefore, it is important to choose on ‘ISI’ mark pump. The pump selected should be suitable for the well and the water requirements. It is not necessary that the pump that is good for the neighbouring farm is good for yours.
If the following information is given to an expert, he would be able to help to choose the right pump:
(1) The depth of your well.
(2) The area of your field.
It is also necessary to select the right engine, which makes the pump run at the right seed. For this, consult an expert. The engine used should have sufficient Horsepower (HP) to operate the pump. The expert can calculate the amount of power needed for the particular engine. It is always better and beneficial to select a well-known and good quality engine.
To ensure a high-level of operational efficiency of the diesel powered engine, ensure the following:
i. Engine should not emit too much smoke.
ii. Use the correct grade of lubricant recommended by the manufacturer.
iii. Engine should be fitted with an oil filter.
iv. Engine should have an air filter, which should be cleaned regularly.
v. Engine-pump alignment should be correct.
Summary of the Energy Conservation Tips in Agriculture Sector:
Give below is the list of tips for energy conservation in agriculture sector:
1. Selection of right capacity of pumps according to the irrigation requirement.
2. Matching of pump set with source of water – canal or well.
3. Matching of motor with appropriate size pump.
4. Proper installation of the pump system – shaft alignment, coupling of motor and pump.
5. Use of efficient transmission system. Maintain right tension and alignment of transmission belts.
6. Use of low friction rigid PVC pipes and foot valves.
7. Avoid use unnecessary bends and throttle valves.
8. Use bends in place of elbows.
9. The suction depth of 6 meters is recommended as optimum for centrifugal pumps. The delivery line should be kept at minimum require height according to requirement.
10. Periodically check pump system and carryout corrective measures – like lubrication, alignment, tuning of engines and replacement of worn-out parts.
11. Over irrigation can harm the crops and waste vital water resource. Irrigate according to established norms for different crop.
12. Use drip irrigation for specific crops like vegetable, fruits, tobacco, etc. Drip systems can conserve up to 80% water and reduce pumping energy requirement.
13. Tune up your tractor and farm machinery regularly.
14. Service your tube well/pumping station regularly.
15. Do not use tube well in morning/evening peak electricity consumption hours.
16. Irrigation during day time results in vaporization of large quantities of water, which can be saved if crops are irrigated during night time.
17. Rewind the burnt tube-well motor with good quality wire which not only prolongs the motor’s life but also reduces your electricity bill.