Solar Powered Irrigation Systems - Technology, Economy, Impacts
Background
Irrigated agriculture is the backbone of local economic development in the majority of developing countries. Reliable and affordable access to irrigation water is a crucial factor as the article on irrigation emphasizes already.
The technological option of solar-powered irrigation is rarely taken into consideration due to a lack of pertinent experience and the comparably high investment costs of the past. Nevertheless, as prices for solar modules have fallen substantially in recent years, governments, extension services and technical cooperation are reconsidering photovoltaic water pumps (PVP) to be employed in agricultural production and beyond. Demand in this regard will have to be largely generated from the side of rural farm households themselves.
As indicated by the Powering Agriculture Energy Grand Challenge (PAEGC), some barriers exist, which hinder the integration of “clean” energy technology in agriculture development:
- Farmers and extension services are not aware of the variety of new technologies that may be appropriate for them;
- Clean energy technologies are relatively new, therefore farmers have limited access to distributors for installation, parts, and service;
- Farmers often do not have the means to cover high capital costs associated with clean energy upgrades - and financing is seldom available.
The Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH is implementing BMZ’s contribution to this initiative and has commissioned a worldwide study on technical solutions and management practices related to solar-powered irrigation systems (SPIS). The study is developed in close cooperation with the sector program Poverty-oriented Basic Energy Services (HERA), which has more than three decades of experience in the field of energy access.
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Overview of Irrigation Technologies
This chapter gives an overview about modern irrigation technologies, their advantages and disadvantages, required energy sources as well as financial aspects:
- General types of irrigation
- Surface irrigation
- Sprinkler irrigation
- Drip irrigation
- Micro-sprinkler irrigation
- Surface irrigation
- Modern water-saving irrigation solutions
- Cropping pattern requirements
- Efficiency and durability
- Cropping pattern requirements
- Energy sources for water abstraction and pressurized irrigation
- General classification and description
- Hybrid solutions
- General classification and description
- Pumping technology for water abstraction and irrigation
- Comparative financial analysis of irrigation solutions
- Generic costs of irrigation solutions
- Financial impact on farm budgets
- Financial services requirements
- Generic costs of irrigation solutions
- Financial calculation models
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Technical Characteristics and Design of SPIS
The chapter technical characteristics and design of SPIS introduces the following aspects:
- Components of photovoltaic pumping systems
- Solar generator
- Mounting and solartracking systems
- Controller and motor
- Water pump
- Water storage tank
- Monitoring
- Solar generator
- SPIS plant concepts
- Variability of global solar radiation
- SPIS plant configurations and operation
- Suitability for drip irrigation
- Filter systems
- Fertigation systems
- Variability of global solar radiation
- Planning and sizing of SPIS
- Design data collection
- Estimation of PV generator size
- EXCEL-based system sizing
- Computer-based system sizing and simulation
- Design data collection
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Management Requirements of SPIS
For assessing the specific management requirements of PV irrigation systems, it is advisable to distinguish between strategic, tactical and operational management:
- Stakeholder in the SPIS management
- Impacts on strategic farm management
- Conventional irrigation
- Solar-powered irrigation
- Conventional irrigation
- Impacts on tactical farm management
- Solar-powered irrigation
- Solar-powered irrigation
- Impacts on operational farm management
- Solar-powered irrigation
- Solar-powered irrigation
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Financial Viability of SPIS
Financial viability is the ability to generate sufficient income to meet operating expenditure, financing needs and, ideally, to allow profit generation. Each irrigation technology choice has its limitations in terms of the range of crops it can support in production. On the other hand, the investment costs attached to the choice of technology limit the range of crops to select for production to a large extent. Pressurized irrigation systems in general and micro irrigation systems in particular are on the capitalintensive side of investments for irrigation infrastructure and equipment.
This chapter explains respective parameters for assessing financial viability and provides an exemplary financial analysis of eight SPIS systems.
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Ecological Impacts and Sustainability of SPIS
Apart from being a cost-competitive and reliable source of electricity, photovoltaic systems generate a number of ecologic benefits. This chapter describes the ecological impacts and sustainability aspects of SPIS, as well as associated water governance issues.
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Tools for Technical Design and Economic Assessment
In this chapter, a selection of the individual software tools will be presented. The information has been compiled from reliable documented and published references/resources as cited in the publication. The following tools are presented:
- Design and simulation tools for PV pumps
- Design and simulation tools for irrigation systems
- Calculation tools for irrigation requirements
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Country Case Studies
Country case studies were carried out in Chile, India, Kenya and Morocco as part of the stocktaking and analysis exercise. The selection of countries was made to have a worldwide bias and an insight into different markets and market scopes:
- Chile: Widespread utilization of PV pumping technology in irrigation, strong promotion of SPIS by government, main target group small tomedium farms (2 - 5 ha), but also larger farms up to 30 ha under PVirrigation;
- India: High level of water abstraction with pumps, ambitious government program to replace conventional pumps by PV technology, main target group small to medium farms (2 - 5 ha), local products/systems on the market;
- Kenya: Very high share of smallholders (< 2 ha) and high potential to develop dry lands by PV pumping from groundwater, local products on the market;
- Morocco: Main market for suppliers like Lorentz and Grundfos, medium (10 – 15 ha) and large size commercial farms utilizing PV pumping
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Potential and Barriers for SPIS Distribution
Several barriers need to be overcome in developing countries to develop their huge PV potential. This chapter gives a brief overview of key drivers for solar pumps and key hurdles that stand in the way of SPIS dissemination. An opportunity and risk assessment in the following aspects has been conducted:
Opportunity assessment:
- Global PV Market Growth
- Diesel Generator Replacement
- Greenfield Development
- Technology Access to Smallholders
- Bridging Grid Power Failures
- Job Creation and Local Production
- Innovation Potential
Risk assessment:
- High initial investment cost
- Lack of market-oriented financing
- Oil price development
- Lack of marked-oriented policies
- Lack of awareness and impact monitoring
- Lack of quality assurance and service
- Natural disasters and theft
- Summary of opportunity and risks
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Conclusions and Recommendations
The analysis in this report underline that photovoltaic powered irrigation is a technically mature option, even when it is not yet very widespread. Solar powered water pumping can be built into irrigation systems in different ways. The introduced case studies from different countries give an insight into the wide range of application of the technology. From a technical point of view, photovoltaic water pumping can be integrated into most irrigation concepts. The technological development on the side of the pump manufacturers is far advanced and the market can hence provide a suitable pumping solution for almost any requirement and condition. This includes the integration of PV pumps into hybrid systems.
The information collection and the analysis brought together in this report show that agronomic and financial feasibility requirements limit the range of application of PV technology in irrigation. The promotion of the technology will have to take these limits into account by departing from the fact that the utilization of PV technology requires a high initial capital investment and technological know-how for system design and development.
The absence of suitable financing products catering for the specific needs of SPIS development (high initial capital needs, no additional collateral options, long repayment period) is an obstacle to the dissemination of the technology. Good examples like in India and Morocco show that corresponding loan financing is an option, even though it may require a particular risk management.
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