Back to contents

ENERGIA News Issue 3, July 1997

Why Women Adopt Solar Dryers

Jane Okalebo and Mark Hankins

This paper has been adapted from an article by Jane Okalebo and Mark Hankins entitled “Shining Examples” which appeared in the UNEP journal Way Beyond, volume 1 issue 3, 1997. We are grateful to UNEP for permission to use this material.

One of the questions that often puzzles energy planners is why some technologies seem more acceptable to people than others. For example, why have solar photo-voltaics and solar dryers been so successful in East Africa while the uptake of solar cookers has lagged far behind, often in the same communities? What lies behind a community's decision to accept or reject a particular technology?

One answer is that the priorities of the local people are different from the objectives of the donors, who often seem more interested in research than results. The key lies in income and benefits to the rural consumer. Renewable energy technologies will only be taken up if the users can make money or some other tangible benefit from them. Solar drying has always been vital in East Africa because it made economic sense. Modern solar drying technologies are being taken up in villages in Uganda and Kenya because they offer massive potential cash/flow benefits for Africans who rely on agriculture for their income. In particular, women are reaping the benefits of this new technology.

Traditional solar drying

Solar drying has always been an integral part of the African economy although it is not counted as part of the national energy flow because women and rural people are never surveyed by the planners who are mostly city dwelling men. The process of solar crop drying removes moisture from crops to prevent spoilage and facilitate storage. Kenya still looses 30-40% of her agricultural produce through such post harvest losses.

Traditionally, most crop produce was solar dried in order to preserve it. Pulses and grains were left in the field until they were partially dry and then harvested. After they were harvested, crops such as maize, beans, sorghum and millet were spread out on mats or in woven baskets and left out in the sun. Each morning at sunrise they were taken out of the store and then returned at sunset. An attendant took in the crops if it rained and scared off birds, goats and other predators. Such drying techniques reduced the moisture content of the crop by between 10% and 12% and enabled farmers to store it in granaries for consumption in the dry season before the next harvest or to sell in times of scarcity and need.

Fishermen along the shore of Lake Victoria split open their catch and dried the fish in the sun to preserve them. They could then be transported inland for sale and consumption. Animal skins were staked on rectangular frames to sun-dry. Other less exotic uses of solar drying include drying (and sterilising) clothes, plates and cutlery, drying firewood and producing a distinctive cloth made out of wattle bark and worn by Kikuyu women.

East African agribusiness also depends upon solar drying. For example, the coffee industry relies on solar heat to dry coffee beans which are then roasted and ground. The flowers of pyrethrum, a natural insecticide grown in Kenya, are dried in the sun after harvesting. In other words, there is nothing new about solar drying in Africa.

Modern solar drying

Traditional solar drying methods have disadvantages. Crops left out to dry in the sun are vulnerable to rain and pests and need an attendant to guard them. Lack of control over the drying process can result in under- or over-drying and consequent loss of overall quality. And solar drying can also change the colour, texture and taste of the produce, and leach out vitamins A, D and E.

In the late 1970's and 80's food technologists came up with two new ways to tackle these drawbacks: direct and indirect solar dryers.

The direct solar dryer is a closed, insulated box in which both solar collection and drying take place. Solar radiation passes through transparent glass or plastic into the drying compartment where it heats agricultural produce on racks, carrying moisture away through vents at the top of the compartment. The indirect solar dryer has a flat plate collector and a separate drying chamber. The air is preheated in the flat plate collector and rises to the drying chamber to dry the agricultural produce. Because of the way it stores heat, the indirect dryer is more efficient than the direct dryer.

But somehow these new technologies did not easily penetrate into the rural economy. They were designed by scientists in research laboratories and they stayed there. In the absence of a system of delivering viable technologies to the intended end-users, important findings have remained hidden away in workshop proceedings, books and manuals.

Success story

There have however, been some cases in which the market has taken up solar technology and by promoting this, it has also promoted income generating opportunities for rural populations. Experience, particularly in Kenya and Uganda, shows that the private sector may be better at introducing solar dryers than research institutions.

One such story began when a FAO/UNDP post-harvest programme at Kawanda Research Station in Uganda recommended small scale solar dryers for long-term storage and household consumption of fruit and vegetables. However, it soon found that rural groups were more interested in solar dryers for income generation than for food security.

In 1992, the Fruits of the Nile company was formed to exploit this commercial interest by linking rural producers with the market for dried fruit in Europe. It continued the work of developing and promoting small scale dryers with women's groups and businesses. For an investment of $100, a group becomes a supplier of the company and receives a simple improved solar dryer with instructions for its use. Within three years more than fifty groups had taken up the technology. In 1995, the company exported more than 40 tonnes of dried fruit.

The dried pineapples, bananas and mangoes produced by the rural women's groups are transported to a central collection point in Kampala. Produce is inspected to ensure that it meets quality standards for colour, aroma and moisture content before it is air freighted to a marketing group in the United Kingdom.

An example of such a group is the Matinyani Women's Development Group, where Geraldine Roberts has been working. The Matinyani Women's Development Group uses solar dryers to dry mangoes. In thirteen weeks each of the women in the group earned 6.000 Kshs to supplement their income. Fruit was sold to Nairobi and Mombasa and 3 tonnes were shipped last season. Demand is high and there are export orders for one tonne of dried mangoes a day to London. The mangoes have been tested in London, Brussels and Tokyo and have been recommended as the best in the world as dried mangoes from the Philippines contain sulphur dioxide.

Business has expanded so rapidly that the women's groups are starting to worry about their dependence upon Fruits of the Nile company and its ability to serve them adequately as dried fruit production increases. Not only are the women's groups generating significant incomes for themselves, the original food security concerns are also being addressed because, when they are not drying for profit, the women are drying vegetables and fruits for home storage and consumption.

The obvious conclusion is that the successful introduction of modern solar dryers depends upon their ability to generate income for their users. People are less interested in green house gas emissions and desertification than they are in more immediate things such as their own standard of living, whether the technology works and is reliable and whether it will enable them to send their children to a school or buy a cassette recorder. No matter how good it looks on drawing boards in the North, any solar technology which fails to address these needs is unlikely to be adopted in the South.

Jane Okalebo and Mark Hankins work with Energy Alternatives Africa. EAA is based in Kenya and is involved in awareness raising, training, networking, consulting and project design and management. EAA promotes the utilisation of all types of renewable energy. For more information on the experiences described above, or information about EAA, please contact Jane Okalebo or Mark Hankins through:
Way Beyond, International Centre 3rd Floor, J.H. van ‘t Hoff Institute, Building ‘B’, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands; Tel. +31.20.5256268, Fax +31.20.6258843, Email waybeyond@unep.frw.uva.nl