Analysis

Biogas technology development in Malawi

Deforestation is one of the chronic environmental challenges haunting sustainable development in Malawi. Despite multiple efforts exerted by various state and non-state actors to address the challenge, deforestation continues to reveal its ugly face. Although contributing factors are numerous and complex, the country’s over-dependence on firewood and charcoal for domestic cooking combined with inadequate alternatives is to blame.

Obviously, the effect of unreliable and unaffordable hydro-electric power supply cannot be overemphasised.  Recognising the critical role that renewable and alternative energy innovations can play, various players are promoting alternative energy technologies including efficient cook stoves, solar cookers, briquettes, gel fuels and biogas. This article focuses on the development of biogas technology in Malawi.

Biogas is a combustible mixture of gases (mainly methane and carbon dioxide) produced from decomposition of organic wastes. The gas can be collected and used as fuel for cooking, lighting, and also for running refrigerators and engines. Thus, the adoption of biogas technology can contribute towards the reduction of deforestation through reduced dependence on fuelwood.  This, in turn, would enhance the country’s capacity to address climate change through reduced direct emission of more potent greenhouse gases such as methane and increased sequestration of carbon dioxide by trees.

Additionally, biogas technology can lead to improved respiratory health and general quality of lives for women and children due to a cleaner cooking environment, reduced workload, and increased savings on time and money.  Waste management and agricultural productivity can also be improved as a result of biogas technology. Further, the development and promotion of biogas within the energy sector can propel the establishment of new enterprises thereby creating a whole range of opportunities for jobs and small and medium enterprises both in urban and rural areas.

The potential multiple benefits offered by the biogas technology aroused the interest of many Malawians from as early as the 1970s. However, it was not until the early 1990s that organised efforts were made by private companies, government departments, academic institutions and organisations to demonstrate and disseminate the technology at community and industrial level. Despite concerted efforts, industrial attempts to commission a large scale biogas plant at Dwangwa failed. The dissemination of household or village-sized biogas plants also faced drawbacks that suffocated the technology in Malawi.

According to a study by the Environmental Affairs Department in 2003, lack of local expertise, awareness and high initial investment costs of the technology are some of the barriers to growth of biogas technology in Malawi.

The high cost of initial capital investment relates to the two digester designs which have been promoted in Malawi, namely, the fixed dome and the floating drum. The fixed dome digester comprises an underground brick and reinforced concrete tank with a closed and immovable dome-shaped top in which gas is collected. In the floating drum digester, however, the gas is stored in an inverted metallic drum which floats either directly on the fermentation slurry or into a water jacket of its own.

Construction of both these designs requires a considerable amount of cement, burnt bricks and a skilled builder. The advantage of these designs is that they are durable and have low maintenance requirements and a long lifespan, if well-constructed. The high material and labour requirements, however, translate into high initial capital investment which is often unaffordable to an average Malawian household.

As a result, most of the few biogas digesters available in the country were built with funds from development partners rather than individual households or communities themselves. This has constrained the adoption, development and sustainability of biogas technology in Malawi, which builds a strong case for the promotion of low cost alternative biogas digester designs such as the Tubular Polyethylene Biogas Digester.


The Author is studying for Masters in Environmental Science at the University of Malawi, Chancellor College, but writing in his personal capacity.

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