Solar Power as Energy Source in Agrifood Systems

Introduction

Solar energy is the energy the earth receives from the sun, primarily as visible light and other forms of electromagnetic radiation. Solar power is among the readily available renewable energy sources on earth, but its availability and characteristics vary strongly from one region to another.

The solar power potential is highest in regions close to the equator, which overlap with many countries of the Global South. Especially in off-grid areas, the use of solar energy in agriculture, can considerably enhance livelihoods, enabling access to irrigation, cooling, drying and other agri-food processing devices. Despite the suitability of these regions for solar power and the potential to improve living standards, many barriers still hinder end users from adopting this clean energy, among others, the lack of information and access to finance. To overcome these obstacles, different approaches have been developed with the aim of mainstreaming access to solar power. Read more ...

Technologies

Depending on the solar resource potential and its quality, solar energy can serve different purposes, leading to a large diversity of solar technologies. They can be either passive or active, depending on how sunlight is captured, converted and distributed. Active solar technologies include solar photovoltaic and solar thermal systems; which convert sunlight into useful energy. Passive solar techniques involve designing buildings, materials and spaces in a way that allow optimizing the use of solar energy, such as orienting a building towards the sun or selecting materials with favourable thermal conductivity or insulation properties. Read more…

Solar photovoltaic energy can be used to power pumps in irrigation systems (see next section) , improving agricultural yields and saving costs for other fuels like diesel. It can also power refrigerators (see below), overcoming the problem of electricity shortages, which interrupt the cold chain, enhancing access to cooling equipment in ‘off-grid’ regions and reducing post-harvest losses. Read more…

Solar thermal energy is used in agri-food processes like drying. As opposed to sun-drying, solar drying avoids contamination of the harvest with impurities from the ground and increases energy efficiency. The latter can be enhanced by using photovoltaic energy to power artificial aeration systems .

Solar Powered Technologies for Irrigation

Among renewable energy, solar power is the most attractive option for irrigation. As prices for solar modules have fallen substantially in recent years, solar powered irrigation systems (SPIS) have become more attractive from an economic perspective.

Solar-Powered Water Pump

There are different approaches of integrating renewables in pumping systems. The solar powered water pump, running on photovoltaic energy, shows especially good results in equatorial regions, where insulation is highest all year long. It uses solar energy to pump up water from the source to an elevated storage tank. Once water is needed for irrigation, it is released gravitationally at a certain pressure dependent on the height difference from the tank to the irrigated area, which can be regulated by pipe diameter and length, and the type of emitters employed. As solar panels become cheaper, this technology is increasingly accessible to most smallholder farmers in the Global South, allowing expansion of agricultural production to originally off-grid areas, and enhancing stepwise rural electrification through mini-grid projects. Read more…

Micro-Solar Utilities for Small-Scale Irrigation

However, despite the abundance of solar resources in countries of the Global South, a lack of information and of financing options hinders especially smallholder farmers from adopting solar-powered irrigation systems. In Senegal, farmers currently use the labour-intensive method of flood irrigation with wells and buckets, or cost- and energy-intensive diesel-powered motor pumps. Nevertheless, the country has immense solar resources that can be used to provide clean energy for irrigation practices. Earth Institute’s solution allows a small group of farmers to use a central solar energy unit to power multiple AC pumps for irrigation. This approach takes advantage of the benefits of solar without the high costs associated with DC-powered pumps and battery storage. Being accessed by farmers with prepaid electricity cards, this micro solar utility allows customers to cover their appliance loans in small payments, overcoming the major obstacle that hinders farmers from the adoption of the technology, which is financing. The three shared systems that were implemented until 2016 served 21 farms, which have experienced 29 percent average increase in agricultural production, and resulted in 24 tons of CO2 equivalent. The project is now seeking partnerships for scaling up, adoption and local maintenance contracts. Read more…

Solar Powered Technologies for Cooling

Cooling is a substantial step in agricultural value chains of crops grown in warm climates. These regions often lack the access to a reliable grid supply, fundamental for the cold chain, which hinders their products from accessing local and global markets in acceptable conditions. Using solar energy to power cooling technologies therefore has a high potential to increase farmers’ revenues while reducing post-harvest losses.

The Solar Ice maker

The solar ice maker uses solar energy to feed a refrigeration system where water can be frozen and used in refrigeration devices. This technology can find different kinds of uses: it can be used for milk chilling, cooling down vegetables during harvest, and much more. Examples of different value chains where solar ice making devices have been employed are listed further below under Case Studies. Read more ...

The Water Chiller

Another cooling example that involves ice making is the Water Chiller. Using a renewable energy source like solar energy it can freeze water and create cold air that is blown to a storage room for commodities like vegetables.

Solar Powered Technologies for Drying

Perishable products like fruits, vegetables, tubers or even meat and fish, can be saved from spoilage by drying, using the thermal energy of the sun. Especially in countries where industrial technologies for conservation are not available, such simple solutions like solar drying bare a high potential.

Solar drying consists of accumulating the sun’s energy inside a heat collection device, leading the hot air flow through natural or forced convection to the products. Thus, it is using the thermal energy from the sun. When passing the food, the warm dry air removes moisture which is led outside through a chimney device at the other end. Depending on the requirements of the end product, solar drying can be more or less sophisticated. While traditional solar dryers use the natural convection processes of hot air, innovative approaches include a fan that runs on photovoltaic energy, moving the air inside the dryer artificially and increasing its efficiency. As opposed to conventional sun drying, solar drying usually takes place inside a closed system, protecting the commodities from outside impurities. The complexity of different types of solar dryers vary: direct, indirect, mixed or hybrid drying are the main options for different needs. Read more…

Solar Box Dryer

The solar box dryer consists of a box with a glass cover on top, inclined at an angle to allow maximum solar radiation to enter. The inner walls of the box are covered with an aluminium sheet with black coating to absorb the radiation entering through the transparent top. The products to be dried are spread on three trays made of stainless-steel wire mesh inside the box. At the lower part of the construction, a rectangular opening at the front wall allows the entrance of air, which through convection enters the box, dries the products, and leaves with the extracted moisture through a chimney made of galvanized iron sheets at the top. It has a small capacity and the drying rates are relatively slow, leading to discoloration of the products, which makes this simple technology suitable for domestic but not commercial use. Read more…

Solar Cabinet Dryer

A little bit more complex than the solar box dryer is the relatively more expensive solar cabinet dryer. It consists of two parts: a collector to heat the incoming ambient air using solar radiation and a drying chamber in which food to be dried is spread on a number of trays on different layers. Using glass wool for insulation and aluminium and galvanized iron for heat conduction, the dryer allows indirect heating, which is recommended for drying herbal products, usually sensitive to direct sunlight. In contrast to the solar box, the cabinet dryer is recommended for community use and small-scale income generating industries. Read more…

Solar Tunnel Dryer

While the above-mentioned technologies use air circulation uniquely from natural convection, the solar tunnel dryer includes a small blower running on photovoltaic energy to force air circulation through the solar collector and the drying chambers. Arranged in the form of a tunnel, dryer boxes and solar collectors capture solar energy and heat the product on the trays, while the air forced through the tunnel removes the moisture even under unfavourable conditions. These dryers are recommended for large scale drying for commercial uses. Read more…

Solar-Biomass Hybrid Cabinet Dryer

The hybrid biomass-solar version includes a biomass stove installed adjacent to the collector system of the basic solar cabinet dryer. Using a supplementary fuel as biomass can enhance the drying capacity of the simple solar cabinet dryer, allowing higher drying temperatures, recommendable for drying fish and meat products. Read more…

Actors & Innovations

Based on the technologies presented above, different innovators have developed and adapted them to local needs. Main barriers to adopt solar powered devices have been addressed, which has encouraged actors to find innovative solutions that facilitate access for all kind of end users. This section includes innovations regarding irrigation, cooling, drying and other agri-food processing technologies, and a chapter dedicated to innovative solutions for the adoption of solar-powered technologies .

Solar Powered Innovations for Irrigation

Different innovators have shown the potential of solar energy in pumping and irrigation technologies. Creative approaches span from solar hydroponic irrigation systems to low-cost pay-as-you-go models, facilitating access in regions without reliable electricity supply. The use of solar energy appeals especially to smallholder farmers in the Global South, where solar radiation is an abundant and free resource.

Solar Powered Pumps for Improved Irrigation

iDE and its partners have developed a new product category of solar powered pump for irrigation. The so-called Sunflower pump includes a highly efficient piston pump powered by an 80-watt PV panel, featuring a 40 % reduction in weight and volume while retaining its efficiency. Meant to help smallholder farmers increase their production and reduce the involved costs for labour and the use of other fuels, the technology development is however only one component of bringing the solar pump to scale. IDE has identified five key factors needed to bring a clean irrigation solution to scale, including the use of an appropriate technology, a viable business plan, an accompanying finance model, an established supply chain and marketing and educational resources. Read more…

A Hydroponic Green Farming Initiative

The Jordanian innovator ECO Consult first won the Powering Agriculture Award in 2013 for the development of an integrated hydroponic irrigation model combined with photovoltaic farming. This model not only allows the saving of energy costs but also of water resources, which are scarce in Jordan. Since 2013, the interest among farmers and households in Jordan has grown significantly with this technology promising an increase of agricultural produce and new sources of income and employment opportunities. Read more…

Low-Cost Pay-Per-Use Irrigation Using Solar Trolley Systems

In India, where water availability for irrigation depends on monsoon patterns, it is necessary to pump ground water in order to keep growing and producing, and thus generating income. Given a lack of electricity access, the most reliable energy source for pumping is diesel fuel, which has many drawbacks (environmental pollution, ever-increasing costs, among others). With the purpose of avoiding these obstacles to farmer’s economic prosperity, Claro Energy has come up with a pay-per-use irrigation service that uses a portable solar pump. Using a pre-paid card system, farmers can remotely activate affordable, convenient and on-demand pumping service with no upfront capital costs that can irrigate larger amounts of farmland during the dry season. Furthermore, the funds saved can be invested in more efficient technologies, increasing farmers’ productivity and income while decreasing GHG emissions. Read more…

Affordable, High-Performance Solar Irrigation for Smallholder Farmers

Another pay-as-you-go (PAYG) model has been adopted by the Kenyan innovator KickStart: as solar-powered irrigation technologies still remain expensive in Kenya, adopting a PAYG model allows flexible financing options, which not only make this technology affordable for poor smallholder farmers, but also increases the awareness of clean energy by mainstreaming accessibility. This turns out in a higher demand for sustainable energy, and thereby encourages financing institutions to invest in this kind of technologies, enabling the transition from rain-fed subsistence farming to year-round commercial agriculture. Transforming food and income security of smallholder farmers and broader rural communities, the PAYG model helps people lift themselves out of poverty and allows expand smallholders’ role in water management. Read more…

PV-Integrated Drip Irrigation and Fertigation Systems

As water resources are scarce in the MENA region, the inefficient use of irrigation water and fertilizers for crop production have large impacts on soil health. In order to ensure a sustainable use of water and soil, the Italian NGO Institute for University Cooperation (ICU) has supported the promotion of a solar-powered drip fertigation system in Jordan and Lebanon. This has allowed farmers to cultivate larger areas as more water is available for irrigation, and to safeguard soils from salinization, since fertilizer application becomes more efficient, which also saves the farmers money and thereby increases their income. The result has encouraged local partners onsite to invest in this promising innovation. Read more…

Scaling the Distribution of Tailored Agro-Solar Irrigation Kits to Smallholder Farmers

Only 6 percent of African arable land is under irrigation, while climate makes the majority of the continent unsuitable for rainfed cultivation. This leads to low crop yields and a generalized disconnection from the agriculture value chain. However, the few farmers who irrigate rely on expensive diesel pumps or carry the water by hand. This has led the innovator SunCulture to recognize the potential of solar-powered irrigation, and to develop the AgroSolar Irrigation Kit (ASIK), for cheaper and easier access to solar-powered irrigation. SunCulture has started training technicians, agronomists and hopes to expand the distribution partnerships across the entire continent. Read more…

Renewable Microgrids for Off-Grid Fish Hatcheries and Surrounding Communities

In Bangladesh, off-grid fish hatcheries rely extensively on diesel and kerosene to provide electricity for water pumping and lighting. Both energy sources are costly, pollute the environment and threaten the food chain and human health. The International Development Enterprises iDE have developed a business model attractive for investors to promote a clean energy solution: the implementation of solar and hybrid solar/wind micro-grids. This innovation does not only increase and enhance the productivity of the hatcheries but also provides domestic energy access, increasing the hours of lighting and allowing the use of fans and refrigerators. Read more…

Sunflower Pump: Asset-Financed Solar Irrigation Pumps for Smallholder Farmers

The PAEGC innovator Futurepump developed the SunFlower Pump, which is an easy-to-maintain solar irrigation pump, built around a simple piston pump arrangement. In collaboration with Kenya’s Equity Bank, which has made the product available to customers through consumer financing, Futurepump has established a loan system making the Sunflower Pump become cheaper and easier to access by Kenyan smallholder farmers, allowing an increase of nearly 50 % of agricultural production by irrigating their fields. Read more…

Micro-Solar Utilities for Small-Scale Irrigation

As irrigation practices in Senegal are often labour- or cost-intensive, the Earth Institute at Columbia University, partnering with the MDG Center West and Central Africa (WCA) has developed a central solar energy unit to power multiple alternate current (AC) pumps for irrigation. The proposed solution takes advantage of the benefits of solar without the high costs associated with direct current (DC) powered pumps and battery storage. Using prepaid electricity cards, small farmers can easily afford this PAYG irrigation service, resulting in higher revenues from lower costs and higher production rates. Read more…

Solar Powered Innovations for Cooling

Using the same principles of the above presented solar ice maker, creative approaches for solar cooling have been developed, allowing food preservation in regions without reliable access to electricity at affordable prices, reducing post-harvest losses and ensuring a higher food security. It also results in higher incomes and independency, and helps mitigating climate change.

ColdHubs

ColdHubs are large walk-in storage rooms for fresh vegetables which include a refrigeration system that runs on solar power. Developed by ILK Dresden and the Smallholder Foundation, this innovation can save huge amounts of perishable food (storage capacity of up to 2 tons) and works off-grid, being especially suitable for rural areas, where large amounts of food need to be stored before joining the market. Read more…

Solar Powered Innovations for Drying

Actors and innovators have adapted the above-mentioned drying technologies to the specific needs of different value chains. Using solar photovoltaic power can enhance energy efficiency and provide access to the poorest in rural areas without electricity. The use of this type of energy means lower costs for food conservation processing, leading to less post-harvest losses and higher incomes through value-adding processes.

Solar Bubble Dryer

This innovation allows safe and efficient drying conditions using solar energy: the solar bubble dryer, designed by the University of Hohenheim (Germany) and the International Rice Research Institute (IRRI). The technology consists of a 15 to 26 metres long plastic tube where the rice is laid out. The transparent upper side of the tube allows the sun’s rays to penetrate, building up heat inside and drying the product. The heat is distributed uniformly by solar-powered fans that make the air flow, removing the moisture. For optimized drying, the rice is turned regularly using a rolling bar. Being currently optimized energetically and trialled in different countries, the bubble dryer can cost between € 1,200 and € 3,400.

GrainSafeTM Dry (GSD) Development

In collaboration with the International Rice Research Institute (IRRI) and the University of Hohenheim, GrainPro, Inc. have designed the GrainSafeTM Dry (GSD). The GSD combines in-store drying with hermetic grain storage. In-store drying aims to control the relative humidity of the drying air, so that all grain layers in the deep bed reach equilibrium moisture content. This is possible as a blower that runs on solar power, pushes warm air at the bottom of the device into the grain bulk until the desired humidity level is reached. In hermetic storage the grains are enclosed in an airtight container made from material with very low oxygen permeability, protecting the grains from insects and water reabsorption. Combining the in-store dryer with the hermetic storage properties allows drying and storing food in a protected environment. Including a drying controller allows increasing energy efficiency adapting the blower speed to the relative humidity. With a capacity of 1 to 5 tons of rice, and anticipated system costs of $ 1,100, the GSD still needs to be tested and optimized before a commercial prototype can be developed. Read more…

Solar Powered Innovations for Other Agri-Food Processing Devices

The highly significant effects on income generation and poverty reduction when providing mechanical energy for food processing displays the great potential of sustainable energy systems in rural areas. The following innovations show how the adoption of renewable energy in different processing steps for food production allows substituting traditional energy sources and reducing costs while increasing efficiency. The large variety of approaches reach from aquaculture aeration systems to solar oil presses, having different kinds of effects on local society and economy.

Field Evaluation of a Passive Aeration System for Aquaculture

Aquaculture accounts for a significant percentage of the GDP of many low-income countries. By artificial aeration, the level of dissolved oxygen in the deeper water layers of the fish farm’s ponds can be increased, leading to higher fish yields and enhanced food security. However, using a conventional electrical pump for artificial aeration can become very costly. The University of Toronto and its partners have introduced a passive aeration system that only uses solar thermal energy. The technology is applied at the bottom of the pond, mixing the water and resulting in higher levels of oxygenation, an improved water quality and higher yields. Since using solar thermal energy, the system proves much more affordable than traditional ones. Read more…

Solar Agro-Processing Power Stations

The Village Infrastructure Angels (VIA) started the mission of making poverty-alleviating infrastructure affordable to everyone in 2012. As energy plays a key role in agricultural production, especially in processes like milling, introducing solar mills in rural areas through microfinancing programs has increased income and saved manual labour. VIA have deployed different types of solar mills to different countries of the Global South, improving the livelihoods of farmers, especially women, who are often involved in manual processing. Read more…

Solar-Powered Oil Press for Sesame Seeds

This solar-powered oil press allows off-grid oil extraction of sesame seed. Being a counter-seasonal crop that requires little fertilizer or pesticide inputs, sesame grows under harsh weather conditions and can promise higher income when processed appropriately. Designed by the University of Hohenheim, the solar-powered oil press for sesame seed includes a solar panel connected to a control unit which calculates the optimal operational setting dependent on seed moisture content and the current weather conditions, increasing its energetic efficiency . Although the price of the solar-powered unit reaches between € 8,000 and € 13,000, sesame, as a cash crop, allows a payback period of 4 months when the mill is run during the harvest season. Additionally, as a by-product of the oil extraction, the seed cake can be sold as animal fodder.

Innovative Solutions for the Adoption of Solar Powered Technologies

Adopting solar powered technologies in countries with low incomes can be complicated. The main barriers include the lack of financial resources or access to financing options and the missing information necessary to dare the transition to sustainable energy. Innovative approaches have been developed in order to overcome these obstacles and allow easier implementation of solar power in agri-food systems.

Private Sector Financed Community Solar Microgrids and Agricultural Accelerators

Small-scale producers from low-income agricultural communities are among the most vulnerable actors in agricultural value-chains in Guatemala. Suitable technologies, including irrigation and cooling facilities are readily available, but the lack of affordable energy or financing options to invest in clean energy are among the constraints that prevent producers from accessing them. The Universidad del Valle Guatemala (UVG), a non-for-profit secular university has partnered with Development Ventures and Greenergyze, S.A. to develop an innovative approach which aims creating access to low-cost utility companies for ‘off-grid’ agricultural communities. The so-called Community Accelerator consists of a localized photovoltaic (PV) mini-grid that will be operated by a local for-profit service provider company that also provides agribusiness service. This “utility in a box” approach is designed so that private sector financing can be used to fund the Accelerators, making this clean energy solution scalable without additional donor funding. Read more…

Case Studies

This section shows how the technologies and innovations presented above have been piloted in different environments of the Global South. Providing innovators and experts with valuable feedback and experience from local end users, these case studies also show how solar innovations can lead to increasing yields and revenues .

Case Studies of Solar Powered Technologies for Irrigation

SPIS have been adapted to all kinds of geophysical patterns, allowing agricultural practices where crop cultivation had never been successful before. The following case studies show how arid areas with access to groundwater or other water sources can benefit from SPIS making food production more effective and contributing to food security.

Solar Powered Irrigation Systems in Egypt

Egypt’s agricultural sector employs 54 percent of the country’s population. Yet, the traditionally used areas for crop cultivation close to the Nile are being replaced for living, outsourcing agriculture to the remote areas in the arid desert. Due to the geophysical conditions of the region, constant irrigation is required to keep food growing. However, as electrification for water pumping is too expensive, diesel prices are rising, and require transportation to the cultivated areas, solar water pumps are the only way to go. The initiative RaSeed (called into life by the German development programme “Agricultural Water Productivity as Adaptation to Climate Change”) aims to promote the use of PV systems, targeting farm specific optimization of drip irrigation systems (as soils are very sandy), providing high quality solar energy technology and training in Egypt. Given that most farms in Egypt are in remote desert areas, polycrystalline cells have a better cost-efficiency ratio. However, as this system does not provide a backup power source, three different and more advanced solar pump systems were made available: 1) combining solar energy with batteries for excess energy storage (battery based system ), 2) a combination of solar and diesel power (solar fuel saver system ) or 3) a variable speed drive that connects and regulates PV panels and the diesel generator. The latter is the most cost efficient and most adequate for the Egyptian agricultural sector. Read more…

Case Study Kenya – Ongata-Rongai

In some remote areas in Kenya, grid connection is not reliable enough to run irrigation systems without a back-up generator. This has led the Centre of Alternative Technologies (CAT) in Kenya to pilot a highly efficient hydroponic irrigation system running on solar power (for more information, see Tools & Technologies). Integrated with a reverse-osmosis mechanism for nutrient supply, a tracking system is used for constant feed, saving up to 50 percent of the electricity costs. The system is especially interesting for intensive farming where landholding is limited and soils have a low quality. However, capital and operational costs are high, and due to unreliable grid power supply, production losses are also at risk, as the tracking system is essential for continuous water flow. Furthermore, PV panels need to be protected against theft, and under the local conditions, lettuce is the only suitable crop. Read more…

Photovoltaic (PV) Pumping Systems for Irrigation

Despite being a technically mature technology, photovoltaic pumping systems lack widespread expansion due to the initial investment costs, especially for small-scale farmers, and the technical know-how required for installation and maintenance. However, once these problems are solved, PVP irrigation can improve agricultural production and increase employment and revenues. This article showcases the efforts made in different regions in order to help establish PVP irrigation. Read more…

Country Case Study Chile

In the 1980s, the electricity sector in Chile has gone through a process of privatisation and liberalisation. However, small and medium-size farmers have been subsidised, also when using solar water pumps, including up to 90% of investment costs. This has led farmers to form unrealistic expectations about obtaining systems at below-market rates., preventing a market-oriented dissemination of SPIS as subsidies continue. Within the scope of the existing subsidy scheme, about 1,500 solar irrigation pumps have been installed. But the standardised and limited system kits supported by Chilean government subsidies only seldom meet the exact requirements of the target farms, leading to complaints from the farmers, as their solar pump delivers too little water. They also miss the instant high pressure and water flow they are used to from grid supplied electric and diesel engine driven pumps.

Country Case Study India

Grants and subsidies for SPIS technology promotion and demonstration are provided by the Indian government and international donors. 50,000 solar powered pumping systems were installed in 2015. The government uses a combination of subsidy, credit and technical support to promote PV irrigation. An important conclusion is that technical and agronomic assistance should preferably be offered to farmers from one source (one institution) to also facilitate the introduction of PV-powered drip irrigation systems and improved irrigation techniques. In recent years, the Indian private sector started offering SPIS components, and now all main components are produced locally, creating employment in a new sector. Some manufacturers also provide farmers with turn-key solutions, which definitely contributed to better overall system efficiency and performance of the technology. Irrigation water is free of charge and water quality is good. However, groundwater level is constantly falling, which may lead to environmental problems in the near future.

Country Case Study Kenya

Within the Rural Electrification Master Plan (REMP) remote public buildings are equipped with solar PV systems. However, solar-powered irrigation receives no specific support so far. Recently, first private companies started developing the Kenyan market and installed a few hundred SPIS. The main purpose of solar water pumps in rural areas is to secure drinking and livestock water supply. These systems are often sponsored by international donors. In order to bridge grid power failures and to reduce their monthly electricity bill, a number of flower farms and tea plantations have been willing to invest in solar solutions. Although the advantages are evident, the purchase decisions in Kenya still is taken in favour of competing conventional energy systems, as the perception persists that PV is too expensive. The Kenyan company SunCulture offers the cost-effective AgroSolar Irrigation Kit, combining solar pumping technology with a highly efficient drip irrigation system that makes it cheaper and easier to start farming.

Country Case Study Morocco

The International Finance Corporation (IFC) conducted a market assessment in Morocco and identified a solar pump market poised for rapid growth in the medium term. The leading manufacturer Lorentz is leading the local SPIS market and sells about 2,000 pump/controller units per year. The Moroccan SPIS market is mainly driven by small to medium-size private farmers who produce cash crops for the local market and for export. The use of efficient irrigation systems is supported by the government through a subsidisation programme (Plan Maroc Vert). SPIS, however, are only promoted by tax incentives. Although the electrification rate of Morocco is above 95 %, most farmers want to reduce their electricity bill and go for solar power, as grid electricity for irrigation is already more expensive, leading to disconnect their electric pumps and driving the Moroccan solar pump market.

Case Studies of Solar Powered Technologies for Cooling

An increasing number of cooling technologies based on renewable energies are being used in different steps of the agricultural value chain, enhancing the economic situation of smallholder farmers in the Global South. The following case studies provide an insight to the diversity of solutions, and the benefits obtained from implementing climate-smart cooling technologies in rural environments.

SunDanzer: Solar Powered Refrigeration for Kenyan Dairy Farms

In Kenya, 85 percent of the dairy farms do not have access to refrigerated storage and transportation due to limited electrification in rural areas, leading to dramatic losses from milk spoilage. SunDanzer together with Winrock International have developed an affordable small-scale portable cooling system: the photovoltaic refrigerator (PVR) runs on solar energy and uses phase-change materials – substances capable of storing and releasing large amounts of energy – and therefore needs no battery. Additionally, the innovators have developed milk can blankets to retain the temperature during transportation. 60 solar-powered milk cooling refrigerators have been installed so far in Kenya, 2 in Rwanda. Users of SunDanzer’s refrigerators have stated that the technology has delivered many benefits, including increased financial security for households, increased food preservation, and saved time, added to household income. Read more…

Reducing Milk Spoilage through Solar-Powered Chilling

10 billion USD worth perishable food is wasted annually in India because of unreliable cold-chain supply networks. Especially in farming areas and villages, the lack of reliable electricity to run refrigeration systems is the main problem. India being the largest consumer and producer of milk in the world, Promethean Power Systems together with Hatsun Agro and Orb Energy have developed a solar milk cooling system that uses an innovative thermal energy battery pack. Charging on intermittent power sources such as solar power and/or a few hours of grid electricity, it allows changing the local food waste situation considerably. Read more…

SunChill Solar Cooling for Horticultural Preservation

An innovation designed by Rebound Technologies (United States) aims to reduce post-harvest losses and enhance food consumption quality. The first versions of the SunChill cooling system have been tested in Mozambique and after being validated, a commercialization and expansion to the market is planned. The solar off-grid refrigeration system allows to immediately cool down food during harvest and provides continued product cooling at markets or central processing facilities. SunChillTM transforms 50 °C solar thermal energy into 10 °C refrigeration, doubling shelf life and creating access to nutritional fruits and vegetables. Also, manufacturing and service-based employment, leading to additional income, is expected to increase. By the end of the project, Promethean sold over 600 units, enabling 25,000 dairy farmers to chill their milk without diesel generators to get their milk to the market safely. Read more…

Solar Milk Cooling with Insulated Milk Cans

Milk produced on small- to medium-scale farms is usually transported to milk collection facilities. The spoilage caused by bacterial growth during transportation due to warm temperatures leads to milk being refused by vendors. Furthermore, many farmers do not sell their evening milk to the collection centres, as it cannot be stored adequately overnight. Instead, they sell the milk to neighbours or use it themselves. This can increase the on-farm losses and reduce income. The solar milk cooling system developed by the University of Hohenheim (Germany) uses solar energy for ice production. The produced ice is used to cool the milk by putting it into an ice-compartment of an insulated milk can. This system allows lower temperatures during transportation and overnight storage, increasing the farms production and income. On-field implementations have taken place mostly in Tunisia (10 installed systems), Kenya (4 installed systems), and Colombia (also 4 installed systems). Read more…

Case Studies of Solar Powered Technologies for Drying

Adapting the solar dryer to meet the specific needs of every agricultural value chain, has allowed the implementation of this technology in many parts of the world under very different operational conditions. The here presented case studies are only a fraction of the possibilities of the solar dryer and showcase how the innovative drying approaches could increase product quality and thereby farmers’ incomes. With examples from different value chains from across the globe, this technology reveals a high adaptability and a great potential for livelihood improvement.

Modern Solar Drying in Afghanistan

Food drying is a very common way of preserving edibles in Afghanistan. However, the traditional drying practices, which consist of placing the food on flat grounds such as rooftops, are vulnerable against dust, dirt and insects. Therefore, the Modern Solar Drying project, in collaboration with the Afghan Bedmoschk Solar Center e.V. have adapted the Hohenheim Solar Tunnel Dryer to smaller versions, that enables farmers to test and evaluate the technology in a non-expensive way. Despite the positive outcomes of the technology, the higher end prices of the dried products will require a marketing campaign, in order to reach wealthier end-consumers and provide higher revenues to the farmers. Read more…

Coffee processing with solar dryers in Peru

Energising Development Peru promotes solar dryers among smallholder coffee farmers for the first drying period, where the humidity of the beans is reduced to around 25 percent. The dryer filters UV radiation and reduces the relative humidity of the air with constant and natural ventilation. As coffee can only be stored and exported at a lower level of humidity, a second drying phase is required to get the beans down to 12 percent humidity. For this, a second solar dryer is employed which has a capacity of 2 tonnes of coffee and is managed by farmers’ associations. The implementation of this solar dryer also provided by EnDev has increased farmers’ incomes by up to 30 percent per year. Read more…

Drying oregano with solar dryers in Peru

In Peru, in Candarave, oregano has been dried traditionally for many years. However, the residents have tried to improve their improvised driers without success. After adapting the coffee dryer (see above) to the needs of the product in order to keep its characteristic green colour despite the drying process (adjustment of level of solar radiation, degree of hydration, positioning and air flow), the quality of the product has increased notably, meeting export standards and reaching a larger market. This showcases the broad versatility EnDev’s solar dryer has, allowing its use for many different product types, reaching from fruits as pineapples and bananas to vegetables and tubers as potatoes. Read more…

Drying peaches with solar dryers in Bolivia

Especially countries with a high variety of agricultural products can profit from the adaptability of the solar dryer. Another implementation example of EnDev’s solar dryer can be found in rural Bolivia, a country with a high geographical diversity, where one third of the population relies on agriculture for their main livelihood. EnDev supports two kinds of dryers: one is completely delivered by the manufacturer and costs USD 150, the other much simpler version can be constructed by the farmer using local materials such as wood and bamboo, which also encourages the technical understanding and keeps maintenance costs low. The association AFRUCH dries fruits to make them more durable. Peaches, for example, are dried for conservation and preparation of the traditional soft drink “mocochinchi”, which consists of dried peaches boiled with cinnamon and clove. After the acquisition of the solar dryer, the association could increase their income by 60 percent over the last three years. Read more…

Drying chili peppers with solar dryers in Peru

An example of how solar dryers can be adapted to the producers’ needs could be found in Inclán, Peru, where the development of the dryer took place as a participatory process. Involving the farmers, who provided the necessary information about the product requirements, and the technical provider, which offered assistance and helped to modify the technology, the solar dryer for chili drying was developed. The main advantages were the reduced contamination of the product, which normally is dried on the ground, guaranteeing a uniform product quality, and saving enormous amounts of time. This allowed the product to enter a quality certification process and to become part of other food value chains, where the purity and adequate management of the product were required. Allowing the product to reach a higher position in the markets, the solar dryer helped generating a higher economic benefit for the Peruvian farmers of Inclán. Read more…

Case Studies of Financing Approaches for Solar-Powered Agri-Food-Processing Systems

Providing technical guidance and access to financing is a pivotal step in order to successfully implement solar-powered agri-food processing technologies. Here is one example of how agribusinesses can experience an income boost by getting access to solar electricity to power their processing systems:

Smart Grid on Main Street: Electricity and Value-Added Processing for Agricultural Goods

Most of Haiti’s population lack access to electricity and farmers often lose value of their crops due to missing infrastructure and processing equipment. The existing processing facilities are typically diesel-powered and expensive to operate, limiting farmers’ options to maximize the value of their products by processing agricultural goods. EarthSpark, a U.S.-based, non-profit organization with the mission of bringing energy access to Haiti’s unelectrified population, has developed a solar-diesel hybrid micro-grid system that will increase access to affordable, reliable electricity for value adding agricultural processing. Providing technical guidance and facilitating access to financing for local partners, EarthSPark assists agribusinesses in upgrading to efficient electric mills so the processing of breadfruit crops can be modernized. Using a pre-paid smart metering system, the project will also provide access to electricity to surrounding residents and boost agribusiness incomes. By the end of March 2017, EarthSpark had expanded the microgrid from a pilot stage with 54 connections to a town-sized, solar-powered smart grid providing power to residents and commercial clients through a total of 452 connections. Read more…

Publications & Tools

This section offers a collection of current publications and tools, which can serve as further reading about solar powered technologies in agricultural value chains. They include handbooks, reports, guides and toolboxes for visualizing the first steps before implementation.

Publications & Tools on Solar Power

Global Solar Atlas

Understanding solar resource is crucial for the development of solar energy applications. The World Bank Group have provided the Global Solar Atlas in addition to a series of global, regional and country GIS data layers and poster maps, to support the scale-up of solar power in our client countries. This work is funded by the Energy Sector Management Assistance Program (ESMAP), and is part of the initiative on Renewable Energy Resource and provides long-term averages of solar resource (global, diffuse and direct normal), the principal climate phenomena that determines solar power generation. In this Global Solar Atlas, the most reliable sources of data currently available are used to generate the solar resource estimates provided, with the objective of supporting policy development and the initial decisions along the journey of developing of solar power project. Read more…

Publications & Tools on Solar Powered Irrigation

Solar-powered pumps were first developed in the late 1970s. However, only recently the declining prices of solar panels have allowed the extensive use of this increasingly affordable clean energy solution. The benefits for regions that lack access to electricity have been proven, leading to analyses for further expansion and up-scaling measures that enable a better and sustainable livelihood.

Solar Pumping for Irrigation: Improving Livelihoods and Sustainability

Stimulating socio-economic development in agriculture can help the fight against poverty. By adopting solar-based solutions, cost-effective and environmentally sustainable energy for irrigation in areas without access to electricity can lead to an improvement of livelihoods. Key drivers behind the adoption of solar pumping technologies are a broad flexibility when it comes to designing the SPIS; taking into account target groups and the long term sustainability of markets when considering financial instruments to support solar pumping; focusing on after sales support and capacity building; assessing the direct and indirect impacts on water resources; package energy and water-efficient solutions in water-stressed areas; monitoring performance and gathering data; considering the influence of availability and cost of energy on the choice of crops grown; and the adoption of integrated approaches to programme design. The main opportunities offered by solar-powered irrigation systems for farmers are the supply of energy and improved access to water for irrigation, improved yields and increased incomes, reduction of manual work and improved expenditure of time, enhanced crop resilience and food security, more income generating opportunities by complementing staple foods with high-value crops, among others. But also governments can profit by implementing SPIS through the reduction in electricity and fuel use, subsidy savings, reduced fuel imports, creation of small businesses/employment across the value chain, improved reliability of power systems, increased agricultural economic output, and emissions reductions. Read more…

The Benefits and Risks of Solar-Powered Irrigation: An Overview

In 2015, the FAO and GIZ hosted an exploratory workshop to identify the benefits and risks of SPIS in developing countries. Representatives from regions around the globe shared their experiences and knowledge, covering a broad band of climate zones, farming systems and water usages. The results can be found in the report ‘The Benefits and Risks of Solar-Powered Irrigation: An Overview’, where the advantages of SPIS, but also the challenges of implementing this clean energy solution are collected from past experiences, allowing projections for the future. Read more…

SPIS Toolbox

Many factors determine the type of irrigation method and respective pumping system that suits an agricultural production system best. There are many possible ways of irrigating, which have certain advantages and disadvantages for each use in agriculture. The Toolbox on Solar Powered Irrigation Systems (SPIS) can help determining which method suits best which agricultural system. It includes tools for calculation of the crop water requirements, for irrigation scheduling, but also helps setting up the SPIS, making a financing plan and determining the payback time when investing, including even a maintenance guide based on useful checklists for a longer product lifetime. Once the system requirements are determined, the appropriate technologies can be incorporated and help increasing agricultural yields.

Solar-powered irrigation systems – Technology, Economy, Impacts

Although solar powered irrigation systems (SPIS) have been for long on the market, it is only now, as prices of solar panels are decreasing, that the number of users that can afford incorporating photovoltaic technologies in their agricultural equipment increases. However, most farmers in emerging economies do not know about these newly accessible technologies or simply do not dare the step towards innovative systems, as upfront investment costs seem too high to them. To overcome this knowledge gap which acts as barrier, the here presented report summarizes the main characteristics of different irrigation technologies and of SPIS, introducing the user to different ways of designing such a system, and offering an overview of the management requirements and about financial viability. The tools available in the SPIS Toolbox allow calculating beforehand the suitability of any irrigation system, and are the practical implementation of the informative chapters of the report. Read more…

Publications & Tools for Solar Powered Cooling

The refrigeration and air conditioning (RAC) sector is expected to account for 13 percent of global greenhouse gas (GHG) emissions by 2030. With an increasing importance of the sector in the Global South, and the impact caused by the use of conventional climate damaging refrigerants, research and development of low-cost climate-friendly solutions is pivotal. The RAC sector can provide different climate-smart cooling technologies affordable for costumers in the Global South and improve living standards considerably without polluting.

Ice-Making as a Productive Application in Green Mini-Grid (GMG) Systems

Productive Use (PU) activities, which refer to the utilisation of electricity for income and employment generation, can catalyse rural development and sustainable economic growth. The increasing demand for energy and the increasing household income can accelerate the success of green mini-grid (GMG) projects. The presented guide is designed to help practitioners assess whether ice-making for food preservation (in this case, fish) is an appropriate and financially viable application and provides guidance on how to operationalize ice-making PU. It is organized as a series of tools that help establish a set of best practices for off-grid electrification initiatives. The tools include: a feasibility checklist, a business model guidance, technical considerations and requirements for appropriate mini-grid sizing, a detailed financial model assessing various scenarios, and a guide on monitoring and evaluation. Read more…