Sustainable Energy Use in Fruit and Vegetable Value Chains

Introduction

Fruit and vegetables provide important nutrients and vitamins and are essential for human health. As labour-intensive high-value crops, they are not always available for all income classes. However, producing within the sector has a great income generating potential, which increases purchasing power and in turn the demand.

In food-insecure countries, the sector has become an important source of employment and additional income generation. Cultivation of fruit and vegetables in developing countries has shown to have a positive impact on the food and nutrition security (FNS), as it provides healthy and nutritious food, rich in vitamins, increases incomes and purchasing power for high-value crops. There is a plausible correlation between the development of the fruit and vegetable value chain and food security. Especially post-harvest activities offer more opportunities to add value, which are increasingly carried out at the source, rather than at the end-market destination. This allows the diversification of local markets with good quality and high-value products which increases farmers’ incomes significantly.

Women are often the main producers of food and vegetable value chains. Hence, supporting the fruits and vegetables value chains improves their status and confidence. As they usually use the generated income to invest in education and family health, horticultural activities show to have also potential for increasing social capital.

As a labour-intensive activity, producing within the fruit and agriculture value chain has a comparative advantage under conditions where arable land is scarce, and labour is abundant. Recent trends show that peri-urban areas are increasingly involved in post-harvest activities particularly, which require, due to international standards and growing competition on the global market, higher skilled labour.

Applying renewable energy within the different steps of the fruit and vegetable value chain can reduce production costs and increase efficiency, which has a positive impact on economic development.

Women selling tomatoes at a tomato market in Ghana (GIZ/Kayser).

Production

The fruit and vegetable value chain begins where these commodities are grown. Fruits, vegetables, and crops in general need different kinds of resource inputs. The soil they grow on provides organic matter, which requires water for nutrient absorption and transport within the organism. Ensuring water availability for efficient nutrient supply by irrigating can improve agricultural yields by up to 400 percent.

However, moving water from the source to the field requires mechanical energy. Using renewable energy to power pumping and irrigation systems can not only reduce greenhouse gas emissions, but also lower the costs of buying diesel or kerosene fuels and thereby increase the sources of income for large and small-scale farmers.

In addition, regions that are off-grid or without reliable access to electricity due to constant blackouts can benefit from renewable energies by gaining more constant energy supply. If efficient irrigation methods like drip irrigation are implemented, valuable water resources can be saved and crops can be planted on more land, leading to an extra source of income. The additional vegetated land cover will furthermore allow the protection of the increasingly threatened soil resources, enhancing resilience against soil erosion through the binding capacity of roots.

The risks associated with nutrient losses due to erosion, for example caused by flood irrigation, have led the company Waste Stitching in India to develop a system of recycling blackwater (wastewater containing faeces and urine) and greywater (streams without faecal contamination) from households for production of market-quality compost. This can be applied and serve as a soil fertilizer for exotic vegetables, and further enabling women agri-entrepreneurs to have better quality crops and extended crop season. Read more…

Conservation

After harvest, fruits and vegetables need to go through certain processes until they can be consumed: processing, packaging, transportation and marketing. Along these steps, post-harvest losses may occur. FAO estimates that 30 to 40 percent of all food production is lost before it reaches the market. Measures like cooling or processing can considerably reduce these losses. However, investing in such measures can be expensive and work-intensive, especially for small farms, for which it is essential to reduce losses. Using renewable energies can lower costs and save emissions.

Cooling

Creative approaches and innovations in the cooling field span from solar photovoltaic systems to biogas-powered models, facilitating access to cooling in rural areas without grid-access. The use of climate-smart systems for cooling leads to fewer post-harvest losses, higher food security and lower costs for food preservation. It can also result in higher incomes and independency and helps mitigating climate change.

SunChill Solar Cooling for Horticultural Preservation

A cooling innovation that aims reducing post-harvest losses and enhance food consumption quality is 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. The innovation is also expected to create manufacturing and service-based employment. By the end of the project, Promethean sold over 600 units, enabling 25,000 dairy farmers to chill their milk without diesel generators and to get their milk to the market safely. Read more…

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 Smallholders Foundation, this innovation can save huge amounts of perishable food (storage capacity of up to 2 tons) and can be used off-grid, being especially suitable for rural areas, where large amounts of food need to be stored before joining the market. Read more…

Drying

Another measure for preservation is drying. Drying food has been practiced for centuries, using traditional methods such as open-air drying. However, replacing them with modern solar drying technologies can improve the process and allow to dry larger amounts in shorter time. This not only increases the produce quality but also farmers’ revenues, supporting income generation. By promoting food-processing technologies like solar dryers, food quality is higher, guaranteeing export suitability for different types of food throughout the different regions, improving incomes and food security of small-scale farmers in remote areas.

Perishable products like fruits, vegetables, tubers or even meat and fish can be saved from spoilage by using the energy of the sun. Especially in countries where industrial technologies for conservation are not available, simple solutions like solar drying hold high potential. As opposed to conventional sun drying, solar drying usually takes place inside a closed system, protecting the commodities from outside impurities. Different types of solar dryers can be of a variable complexity: direct, indirect, mixed or hybrid drying are the main options for different needs.

Processing

Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Especially within the fruit and vegetable value chains, processing can allow long-term food preservation, allowing the final products to reach markets beyond the freshness radius, and thus improving farmers’ incomes and reducing food waste.

Involving a broad variety of processes, it is a value-adding step in the agricultural value chain, which requires high energetic inputs and contributes to a significant percentage (5 to 10 percent) of global greenhouse gas (GHG) emissions. Improving energy efficiency by introducing more efficient technologies and optimizing processing steps along the value chain may help reduce the global warming potential (GWP) of the food industry, which is considerable.

Adopting processing technologies that run on renewable energy allows independency from fuel price fluctuations and may save financial resources in the long-term and thus, improve producers’ livelihoods. The 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.

Solar-Powered Oil Press for Sesame Seed

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. Read more…

Tomato Processing by Solar Energy

By adding value to agricultural raw products, these can not only be sold at higher prices, but also acquire new qualities that ease conservation, transportation, and thereby become more marketable. The Tigray Agricultural Marketing Promotion Agency (TAMPA) started in April 2014 in collaboration with the Sustainable Land Management Program (GIZ SLMP) the promotion of micro and small enterprises for tomato processing using renewable energy. The target groups were cooperatives of tomato farmers producing in remote areas without access to electrical power. The processing site can be built by the farmers, as construction material is available onsite or further provided by the GIZ SLM Program. Consisting of a solar reflector for tomato processing, a solar panel, an inverter and acid batteries for further processing steps, the whole project allows packing processed tomatoes in sealed bags. This case study shows how the Ethiopian tomato production of small-scale enterprises can increase its revenues by using a solar processing plant for tomato products. Read more…