30 Sep, 2019

Parabolic solar cooker fabricated by the Agriculture Engineering Department at Bunda College
Southern Africa is one of the regions estimated to be most at risk from climate change and Malawi has not been spared. The climate change impact has been manifested in several ways. Most parts of the country are experiencing different types of weather related extreme events that have recently increased in their frequency of occurrence and intensity. It’s now not uncommon to see variations in rainfall patterns, floods as well a prolonged dry spells in various parts of the country.

Community consultations also confirm fears that climate change experts have had over the years. Farmers are now planting late into the growing season; rains are coming very late and ending much earlier. In some cases, the amount of rains has been very low while in some areas have experienced floods. This instead has led to food insecurity in several households particularly in the country’s vulnerable districts and causing challenges to meet several livelihood entitlements.

Climate change adaptation and vulnerability assessments show that communities in Malawi are highly vulnerable to experience different climate change risks including flooding, shorter rainfall periods, prolonged dry spells, and unpredictable onset of rainfall, drought, strong winds and hail storms.

Major impacts of these risks on agricultural production include crops drying before maturity; crop damage due to floods, soil degradation due to soil erosion, loss of soil fertility and siltation of fields, shortage of water, loss of agricultural land, destruction of infrastructures such as roads, bridges and houses, challenges to pest and weed management, reduction in yield and consequently food insecurity.

Despite efforts by the government of Malawi and its development partners to address climate change and weather variability impacts, there are still eminent gaps and challenges in terms of capacity to enhance local and national adaptation, mitigation and address the effects or challenges brought about by climate change.

It is with this background that the Lilongwe University of Agriculture and Natural Resources (LUANAR) realised that without building a strong scientific human resource, impacts of climate change in key sectors of the economy are likely to cause suffering for the majority of Malawians through food shortages and unsustainable rural and urban livelihoods. The University, therefore, saw the need to introduce several programmes with emphasis on climate smart agriculture for enhanced skills among its students.

LUANAR is implementing a lot of programmes that are focusing on promoting climate smart technologies.

Climate-smart practices would increase farm productivity and incomes, and make agriculture more resilient to climate change, while also contributing to mitigation. This section outlines a range of practices, approaches and tools aimed at increasing the resilience and productivity of agricultural production systems, while also reducing and removing emissions led by various experts at the institution.

Through the Agricultural Engineering Department LUANAR has over the years been actively involved in the development and evaluation of climate-smart engineering technologies. These technologies are designed to provide solutions to the problem of climate change so as to enhance food security. A number of technologies have been developed, tested and evaluated. Among these technologies are the Khadin for rainwater harvesting, the parabolic solar cooker for cooking using energy from the sun, the biomass briquette as fuel for cooking and biogas for cooking and power generation from waste resources.

Rainwater Harvesting – The Khadin Project
As stated earlier, due to the problem of climate change, rains have become erratic and inadequate. As a response to this, LUANAR has been involved in rainwater harvesting projects. Rainwater harvesting is the collection of rainwater for reuse on-site, rather than letting it to run-off. A very popular and ancient method of rainwater harvesting involves collecting rainwater from rooftops and storing the water in small buckets, tanks or ponds. The collected and stored water can be used for watering gardens, livestock or for any domestic uses. The amount of water collected and stored is limited by the roof area and the storage capacity.
Dr Kanthunzi recollects that over the past years, LUANAR was focusing on rooftop rainwater harvesting. However, current effort is now on developing and assessing technologies for harvesting large volumes of surface runoff water as one way of improving the water supply situation in Malawi.
He said one technology that has attracted the attention of his department is the construction of earthen embankments (or check dams) across streams and wetlands with the aim of impounding large amounts of surface runoff to let it percolate into the ground.
“These embankments are known as Khadins in India and have been successful in conserving water in areas that receive low rainfall. The embankments not only help to increase moisture in the submerged land but also prevent soil erosion. The moisture that is conserved is adequate to raise one or two crops,” said Dr Kanthunzi.
LUANAR is demonstrating and assessing the performance of the Khadin technology by constructing some Khadins across wetlands around Bunda Campus. These wetlands have been drying up and the there is hope that through the use of the Khadins, large volumes of rainwater runoff will be conserved and the local aquifers will be recharged quickly and this will eventually rejuvenate the streams and wetlands. Farmers who have currently abandoned their dimba gardens due to lack of water are expected to go back to their fields once the Khadins are in place. Based on the results from the pilot areas of the Khadin project, LUANAR plans to replicate the project to other areas where the effect of climate change is having a negative impact on the water supply in wetlands and streams. There is hope that the Khadins will provide a solution to the problem of dwindling water supply and the depletion of the water table in many areas of Malawi as a result of the problem of climate change. Even under low rainfall conditions, the Khadin may charge the soil with enough water that can support one of two crops.
Solar Parabolic Cooker
The dependence on fuelwood and charcoal for cooking is a major cause of deforestation contributing to climate change. LUANAR had been developing alternative means for cooking in order to reduce the use of fuelwood and charcoal. Recognizing that Malawi lies in the tropics where the sun is nearly always overhead, the Agricultural Engineering Department placed its focus on developing parabolic solar cookers. Solar cookers use the energy from the sun for cooking. The parabolic solar cooker is a type of solar cooker that uses a dish-like device to concentrate sunlight from a large area and focus it to a single point where a pot of pan is placed. The pot or pan converts the light into heat energy. In order to maximize the absorption of energy, the pot or pan must be painted black. Parabolic solar cookers can attain temperatures above 290°C and can be used for cooking various foods, grilling meats, frying, baking or boiling water in minutes. Although the solar cooker requires that the food preparation be done sometime before the actual meal time, it requires less hands-on time during cooking. The only task that one has to do as the cooking progresses is to rotate and tilt the solar cooker so that it is always facing the sun with the rays normal to its surface. Solar cooking is an outdoor activity that is only done during the day when the sun is brightly shining. The solar cooker is less useful in cloudy weather so that an alternative cooking source is still required in those conditions.
Realising that the majority of people who uses fuelwood and or charcoal are those who are economically disadvantaged, LUANAR, through the Agricultural Engineering Department, has been developing and testing a variety of low-tech parabolic solar cookers that are relatively inexpensive and that can be fabricated using locally available materials and resources. Commercial parabolic solar cookers use mirrored surfaces with high reflectivity to concentrate the light from the sun to the pot. In order to reduce the cost, aluminium foil, confectionery packages and any other reflecting material have been used in LUANAR’s solar cookers. Despite using these low-cost reflecting surfaces, the performance of the solar cookers has not been impaired.
Dr Kanthunzi said to further reduce the cost of the solar cookers; his department has fabricated solar cookers using waste paper, cardboard, low-grade sheet metal, bamboo baskets and sisal-reinforced concrete. A metal or wooden framework is used to support the cooker. Because solar cookers use no fuel and cost nothing to operate, their use can help reduce fuel cost, air pollution, and can also slow down the deforestation caused by the use of fuelwood and charcoal. The use of the parabolic solar cooker can considerably reduce carbon dioxide emissions and thereby offer a solution to the problem of climate change that lead to biodiversity loss and ecosystem degradation.
These are but some of the various technologies and innovations that LUANAR come up with over the years. A lot more is being done to improve the efficiency of the current innovations but also to come up with new ones. Eventually the aim is to contribute towards sustainable food security amidst issues of climate change.