Revision as of 13:36, 16 October 2014 by
***** (***** | *****)This article provides an overview of the strengths, weaknesses, opportunities and threats of photovoltaic pumps (PVP). The factors listed are not exclusive - further input is welcome.
Introduction
PV powered water pumps (or photovoltaic pumps, PVP) lift water by converting solar energy to electricity which is fed to a pump. A system for agricultural use normally consists of a PV array, controller, pump, storage and an irrigation system (see Figure 1). Some parts of the system can be modified, according to the specific demands that the system is set out to meet.
Figure 1. Solar irrigation system (Practical Action, 2012)
Choosing the right pumping system (in terms of resource, capacity, distribution, etc.) always depends on the given circumstances. This article provides an initial overview of the key factors that need to be taken into account when the installation of a solar powered water pumping system is considered.
Strenghts, Weaknesses, Opportunities and Threats of Solar Powered Water Pumps
Successful application of any water pump (whether powered by human or animal muscle, gravity, fossil fuels or renewable sources) requires a balanced match between the demand for water and supply of the resource chosen to run the pump. In the case of PVP, solar energy is plentiful available in many dry areas of the world. However, due to cloudy periods causing disruption in the water supply, the installation of water storage is advisable.
Nonetheless, PVP are able to provide an economic and ecologic alternative to small to medium sized Diesel pumps, in particular as PV-module prices are falling. Despite higher upfront investment costs (compared to Diesel pumps), economic feasibility is met due to the significantly lower costs. The following table lists the strengths, weaknesses, opportunities and threats of PVP.
SWOT of PVP
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Strengths
- Coupling of resource supply with demand as water demand and solar irradiance tend to correlate
- Low maintenance
- Easy installation
- No fuel costs nor volatility of fuel prices
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Weaknesses
- Relatively high upfront investment costs
- Less established in the markets
- Lower interest from the farmers
- Water storage is required for cloudy periods
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Opportunities
- Falling PV-module prices improve the economic competitiveness of PVP
- Electricity can be used for other purposes in the off-season with relative ease
- Potential micro-market for excess water
- Increased harvest
- CO2 reductions compared to Diesel-powered pumps
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Threats
- Faulty installation (Direction of panels, wiring, etc.)
- Lack of maintenance (clean panels, yearly checks on the pump and power controller) will lead to reduced output
- Skills for repair not available in many parts of the world
- Overuse of water resource
- Theft of equipment (panels etc.)
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Ultimately, the choice of the right pumping technology depends on the local circumstances, in particular concerning the available ressource (Solar, Diesel, etc.) and the respective demand for water. For example, if the crops cultivated by the farmers only require 3 months of irrigation, then Diesel pumps may be more feasible due to the greater flexibility of matching the supply with the demand.
Source: http://www.thewaterchannel.tv
References
Practical action offers a good technical brief on solar powered water pumps here.
See also this article
Further Reading
Numerous technology examples for small-scale solar water pumps can be found on the website of the Greenpeace challenge for replacing Diesel-powered pumps in Bihar, India:
https://greenpeacechallenge.jovoto.com/ideas?scope=rating
