02-05-2011, 10:50 AM
PREPARED BY:
ANKUR.J.RANA
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ABSTRACT:
The performance of a solar water pumping system is discussed in this paper ;the system consists of a photovoltaic (PV) array, a permanent magnet (PM) DC motor and a helical rotor pump. The operation of the PV array is analysed using PSPICE. The efficiency of the system is improved with a maximum power point tracker (MPPT) and a sun-tracker. Simulation and field test results are presented.
1. INTRODUCTION
Energy is a key ingredient for the overall development of an economy. India has been endowed with abundant renewable solar energy resource. India is large country and the rate of electrification has not kept pace with the expanding population, urbanization and industrialization and has resulted in the increasing deficit between demand and supply of electricity. This has not only resulted in under electrification but also put heavy pressure on the governments to keep pace with demand for electricity. People not served by the power grid have to rely on fossil fuels like kerosene and diesel for their energy needs and also incur heavy recurring expenditure for the poor people in rural areas. Wherever the rural areas have been brought under power grid the erractic and unreliable power supply has not helped the farmers and the need for an uninterrupted power supply especially during the critical farming period has been has been a major area of concern. India receives a solar energy equivalent of 5,000 trillion kWh/year with a daily average solar energy incidence of 4-7 kWh/m2. This is considerably more than the total energy consumption of the country. Further, most parts of the country experience 250-300 sunny days in a year, which makes solar energy a viable option in these areas.
Decentralized renewable energy systems, which rely on locally available resources, could provide the solution to the rural energy problem, particularly in remote areas where grid extension is not a viable proposition
Solar energy, with its virtually infinite potential and free availability, represents a nonpolluting and inexhaustible energy source which can be developed to meet the energy needs of mankind in a major way. The high cost, fast depleting fossil fuels and the public concern about the eco-friendly power generation of power have led to a surge of interest in the utilization of solar energy. To evaluate the energy potential at particular place, detailed information on its availability is essential. These include data on solar intensity, spectrum, incident angle and cloudiness as a function of time.
2. USE OF SOLAR ENERGY:
Solar energy can be utilized in two ways:
Solar Thermal (ST) technologies where the heat produced are used to operate devices for heating, cooling, drying, water purification and power generation. The devices suitable for use by village communities include solar hot water heaters, solar cookers and solar driers.
Solar Photovoltaic (SPV) systems which convert sunlight into electricity for use applications such as lighting, pumping, communication and refrigeration.
The Solar Energy Programme is prominent among the technology-based renewable energy programmes of the MNES. Areas covered under this programme include solar thermal technology (hot water systems, cookers, dryers, solar passive architecture etc.), solar photovoltaic technology (lanterns, fixed systems, pumpsets) as well as information dissemination, marketing, standardisation of products and R&D. The support to the programme is mainly in the form of subsidies and technical support.
Currently the MNES is promoting solar PV (and other) devices through (a) State nodal agencies of the MNES, (b) NGOs/CBOs, © authorized outlets of the MNES and (d) through local entrepreneurs.
3. SOLAR ENERGY FOR AGRICULTURE
The demand for electrical energy is far outstripping supply, especially in the agricultural sector, and it is becoming increasingly difficult to meet this exponential growth in demand Agricultural productivity is closely associated to direct and indirect energy inputs and policies are required to consolidate this relationship to the benefit of farmers. If rural development is to be achieved, energy inputs must be made available, and this might require special efforts from the country as a whole, to develop and utilize renewable energy sources most important being the solar energy, to their potential which remains far from being tapped to the potential. Rural electrification has eluded the most far flung rural areas of the countries. It is cost-prohibitive for the Government to extend utility grid power to remote areas especially to meet agriculture loads. An integrated approach for irrigation with water conservation with scientific agricultural practices the solar water pumping systems assume relevance for optimum exploitation of the water resource and serving the small/marginal farmers for all time to come.
Intersectoral cooperation is necessary, and should include government, financial institutions/banks, CBOs/NGOs and the private sector. It would appear that there is a strong case for the design of institutional mechanisms for encouraging closer cooperation and collaboration between institutions, in particular between the agricultural and energy sectors.
4. SOLAR ENERGY BASED WATER LIFTING ANDPUMPING SYSTEMS FOR SMALL IRRIGATION PROJECTS
Among the solar technologies useful in agriculture are water lifting and pumping with solar photovoltaic systems. Water pumping by solar power is a concept which has won widespread interest since the early seventies. Solar energy can be utilized to operate pumps, utilizing either the thermal or light part of solar radiation. With a solar pump, energy is not available on demand, and the daily variation in solar power generation necessitates the storage of a surplus of water pumped on sunny days for use on cloudy days. In view of the fluctuating water demand of any irrigation scheme, solar energy needs to be reserved in the form of either electricity in batteries or lifted water in a storage tank. The suitability of solar power for lifting water to irrigate plants is undeniable because of the complementarity between solar irradiance and water requirements of crops. The more intensively the sun is shining the higher is the power to supply irrigation water while on the other hand on rainy days irrigation is neither possible nor needed.
Small scale irrigation is one of the most potential applications of solar power. The main advantage is that solar radiation is intense when the need for irrigation is high. Further, solar power is available at the point of use, making the farmer independent of fuel supplies or electrical transmission lines. The solar pumps have the potential to revolutionize small scale irrigation in the developing countries in the near future. The technical feasibility of solar (photo voltaic) pumps have been established.The major limiting factor has been the high cost and the lack of familiarity of the technology which require concerted effort in training of technicians and large scale introduction in a region with adequate technical support.However with the incentives and initiatives undertaken by MNES/State Govt the scheme may be propagated in rural areas for small irrigation system in far flung rural areas where electrification is a costly proposition.
The model scheme is to introduce solar water pumping and support irrigation schemes to provide a sustainable economic activity to farmers in unelectrified or under electrified rural areas .Various agencies and financial institutions are in place to assist in developing credit scheme targeted for unelectrified rural area
