Pioneering the Use of Solar Tunnels by Farmer Associations for Agricultural Processing in Northern Mozambique

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Smallholder farmers in northern Mozambique depend on stored dried agricultural produce for their nourishment and income. To dry their produce, they spread cereals and vegetables on the ground under the sun. This traditional method is dependent on weather conditions and results in products with a short storage life as they deteriorate quickly. As a result, this approach impacts negatively on food security and livelihoods. Solar drying tunnels can provide an alternative solution for farmers to reduce post-harvest losses, avoid malnourishment and stabilise sources of income. The drying is faster and results in a higher quality product than traditional methods. This project was implemented in the districts of Ancuabe, Pemba Metuge, Meluco, Quissanga and Macomía in Cabo Delgado Province. A feasibility survey established that of 300 smallholder farmers, 235 were active in six farmers’ associations and over half of these were women. The size of the households ranged from five to eight members, with more than four children per household of school age but with only one or two enrolled in basic education.

Technology, Operations & Maintenance

As part of this project six solar tunnel dryers for food preservation were built in cooperation with the six existing local farmers’ associations. The tunnels are 3.5m wide, 5m long and 2m high. They are made of locally available bamboo, iron rods, PVC joints, rope and imported UV plastic film. The tunnels are protected from moisture from the soil by having concrete flooring and they feature elevated wooden surfaces for drying. The solar tunnels were located adjacent to the premises of the farmers’ associations. These sites were chosen, among other reasons, because they would be far from the reach of wildlife. The members of the associations, as well as some local builders and carpenters, received training on solar tunnels, their construction and maintenance. The associations oversaw the construction of the tunnels. The solar dryers are mostly used for cereals (maize and rice), cassava and vegetables (cowpea beans) between March and October. These products are usually stored for six months, in sacks and pots. Around 75% of these products are for self- consumption and the remaining quantities are sold at market.

Delivery Model & Financial Management

The tunnels are owned by the farmers’ associations, who manage, service and repair them. The sharing of the benefits and obligations that derive from the solar tunnels was stipulated during the project’s implementation. A schedule was established to enable around fifty households to dry their products in each tunnel. Each participating household uses the dryer about four times per month. As payment, the households contribute approximately 1kg of dried products per drying session. The revenue from the sale of these products is used for the maintenance of the solar tunnels. Additionally, the tunnels are rented out to users from outside the association. In addition to technical capacity-building, as part of the project eighteen female entrepreneurs received training in nutrition, food processing, drying, storage and micro/small business development. These women are now responsible for managing the solar tunnels. Moreover, 300 members of the associations were trained in small business management during weekly meetings. The project was implemented within the framework of ADPP’s small-scale farmers’ clubs programme, which had been running for over seven years at the time of the project implementation, with support from the EU, AECID and their own funds.

Environmental Issues

Solar tunnel dryers offer certain co-benefits in addition to their positive impact on food security and livelihoods. They reduce unintended food waste and avoid dependence on fossil fuels. Numerous factors, such as the type and quantity of dried produce and the alternative drying method that is replaced, influence the total extent of the mitigation benefit.

Social Issues

The local population was involved in the project preparation, which also aimed to raise awareness about the potential of passive solar energy technologies. In interviews, women highlighted the benefits of the solar dryers. The women can perform other tasks while their produce is in the dryer instead of spending time surveying their produce, spread on the ground, to ensure it is not eaten by birds or chicken; they also no longer have to gather up the produce in event of changes in the weather (rain, wind or dust). The solar dryers also allow farmers to dry more produce in less time.

Results & Impact

As a result of the project, harvest losses have been significantly reduced and local food security has increased. Up to 2,250 individuals from the farmers’ associations benefited directly from using the tunnels, plus an unquantified number of external users. Monitoring via semi-structured interviews across the six farmers’ associations targeted revealed that the introduction of solar dryers reduced post-harvest losses. Moreover, marketing was improved because users agreed the joint sale of their products at better prices. Data regarding changes in income generation was not collected; one barrier being that these farmers do not usually quantify their incomes and expenditure. Preliminary data on quantities dried and sold, as well as prices, indicated that the price for tomatoes is the highest, leading to around 80% being destined for sale rather than for self-consumption. In the case of kale, however, the price and quantities dried are relatively high, but the quantity sold is low. This may indicate a preference of households for the self-consumption of this product. As a result of the project, a number of users planned to build new dryers, which are seen as a potential business opportunity for local entrepreneurs. Moreover, users showed interest in further improving the storage conditions of dried products to prevent infestation by insects.


This low-cost technology, together with the local availability of materials and potential for capacity-building, makes this post- harvest food processing concept replicable in comparable contexts. The implementing partners are well positioned to apply the experience elsewhere in Mozambique and in other countries. Humana has been active in sub-Saharan Africa since 1987, while ADPP is a local development NGO that has implemented over 60 projects across the provinces of Mozambique. Reliance on existing farmer networks, proximity to a relatively large market (Pemba) and the identification of specific demand via a pre-feasibility study proved to be key to the economic sustainability of this initiative. The main constraint in replicating the project is the initial capital investment required.

Lessons learned

The joint consideration of food security and income generation requirements proved useful. More attention should be paid to aligning demand for dried produce with the production of suitable crops for processing in the solar tunnel dryers. The introduction of new crops may be needed if the sale of surplus is pursued as an objective. The availability and sourcing of materials was an issue for this project and should be considered in future similar projects. Sourcing the plastic remains a problem in the target district and was a potential challenge in terms of delays in the maintenance of the tunnels. It is anticipated that the demand created will eventually lead to the local availability of this material for both new construction and for repairs. The project concept and lessons learned were shared in Mozambique among agricultural students, governmental representatives, NGOs and farmer organisations. Farmers from the communities surrounding the project area showed interest in installing similar solar tunnel dryers. The scaling-up of the project had been planned.

Projects with same technology

Energy Efficiency and Renewable Energy for Food Drying Processing in Rural Agricultural Cooperatives

To strengthen the fruit exporting sector in Burkina Faso and Eritrea through the introduction of solar based energy efficiency measures and quality improvement technologies