Bioenergy: turning a pest into energy

Water hyacinth is an aquatic plant that has become invasive in many countries across the world. But in Uganda, the University of Leeds is working with researchers from the Centre for Research in Energy and Energy Conservation (CREEC) and colleagues in India to try and solve this problem by turning a pest into a source of energy.

The plant was introduced to Africa in the 1980s and has become a serious problem on Lake Victoria, destroying fish stocks by draining oxygen from the water, clogging irrigation channels and transportation routes and providing a breeding ground for mosquitoes.

Removal of the plant is expensive, so to cover costs and make it sustainable, the team are looking at how to turn it into biogas. The aim is to create processes that are viable for both low-income countries like Uganda and middle-income countries like India. The researchers are looking at every stage of the process, from investigating new pre-treatment options, the use of different micro-organisms for anaerobic digestion, and exploring additives that can increase biogas yield. They are also examining ways to upgrade the resulting gas to a methane suitable for cooking, electricity generation, transportation and refrigeration.

Producing biogas is just one element of the BEFWAM (bioenergy, fertiliser and clean water from invasive aquatic macrophytes) project which is funded through a £1.7 million GCRF/BBSRC grant. Because the plant thrives where there is run off of fertilisers and sewage, it can be used to draw these from the water, with the waste from the biogas production then used again as fertiliser to create a sustainable cycle.

Dr Andy Ross, who leads the project from the University of Leeds, explains:

"Water hyacinth represents a new supply chain of biomass which can be used to produce bioenergy, transforming the invasive plant into a friend rather than a foe. The aquatic plant is also very efficient at removing pollutants from water bodies, providing a real win-win."

Energy at a local level

The project is one of many undertaken through the Clean Energy Research Alliance (CERA), a collaboration between researchers in Uganda, Tanzania, Congo-Brazzaville, India, Indonesia and the University of Leeds. CERA focuses on developing sustainable, community-based energy systems for low-and middle-income countries, using renewable energy sources, such as biomass.

Professor of Global Challenges, Jon Lovett, from the University of Leeds Faculty of Earth and Environment explains: “Biomass is sometimes seen as a controversial energy source, but you only get problems of sustainability when you try and replicate large-scale energy systems using biofuels. When it’s small-scale and community based, with smallholders growing their own energy needs, often with dual-use indigenous crops that supply both food and fuel or using agricultural waste – or in this case, an invasive plant - then it’s a more sustainable proposition.”

Building capacity and impact

As with all projects within CERA, the research has been designed to promote capacity building, with the majority of the research undertaken in Uganda and India. The University of Leeds acts, as Professor Lovett puts it, as ‘the technology backstop’, providing facilities and equipment for some of the experimental work.

Mary Suzan Abbo, Managing Director of CREEC, explains: “Both the UK and India have better facilities than we have in Uganda for biogas testing and we’ve been able to draw on those resources for the research. But it’s important that the technologies and processes themselves are developed locally. You can’t just import something that works well in Europe or Asia and expect it to work in the African context. That’s why the collaboration with CERA and the University of Leeds works so well – we design the projects together to produce solid and sustainable outcomes right from the start.”

CREEC – which is based at Makerere University in Kampala – focuses on the applied side of research, so they also do extensive outreach to business, industry and policymakers to ensure new technologies will be taken up within the energy infrastructure. The technologies developed for the water hyacinth project are set to be demonstrated at pilot scale in India and in Uganda, with interest already from the Ugandan Electricity Generation Company. The outputs from these pilots will be used to encourage policy makers to increase the adoption of biogas as part of the energy mix in Uganda, both using the invasive plant as a feedstock and other sources more relevant for different parts of the country.

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