Dryland Bioenergy

Over 630 million people in sub-Saharan Africa have no access to electricity, on a continent in which an estimated 75 % of the population is rural. Demand for electricity is predicted to double between now and 2030, and this critical energy gap is holding back economic development.

Current solutions have focused on fossil fuels, hydropower and solar power. However a major source of renewable energy could be provided by dedicated bioenergy crops capable of thriving in semi-arid climates.

Succulent plants which show the exceptionally water-use-efficient mode of photosynthesis known as Crassulacean acid metabolism (CAM) have a huge potential for bioenergy production. These crops could be cultivated on marginal, abandoned agricultural land and produce a viable energy yield through the process of advanced anaerobic digestion (AAD). By targeting marginal or degraded land, these bioenergy crops would avoid competition with the better-quality land required for food crops - and with as much as 50% of the African continent classified as dryland, there are plentiful opportunities for utilization of abandoned land.

Although a persuasive theoretical case can be made for succulent plants as a bioenergy resource for the semi-arid regions of Africa, there is a dearth of relevant information to demonstrate the practical feasibility of utilizing this resource.

The Dryland Bioenergy interdisciplinary team is led by three members of academic staff from different departments working closely with a local renewable energy company, Tropical Power Ltd.

The principal objectives of this programme are:

• to demonstrate the suitability of CAM plants as a feedstock for AAD by comparison of laboratory and field studies with plants cultivated on a trial plot in Kenya;
• to produce a bioreactor design with greatly enhanced efficiency for AAD (targeting a 10- to -30-fold improvement on conventional AD) that is cheaper to build at scale; and
• to produce Africa-wide and country-level assessments of AAD implementation potential based on environmental and social criteria, involving participatory community-level assessments of the barriers and opportunities for implementation and uptake.
  

With an estimated 800 million people in sub-Saharan Africa still dependent on firewood and charcoal as their primary source of energy for cooking and heating, even the generation of modest amounts of biogas would bring enormous benefits, both in terms of health and reducing the pressure on the remaining vegetation as a source of fuel.

We believe this would facilitate a transformation in the agriculture-energy nexus in many parts of Africa by providing a source of renewable energy to smallholders and rural communities who lack access to grid electricity.