Rampant use of fossil fuels resulting in environmental pollution has necessitated the exploration of renewable energy sources. Sustainable development goal 7 stipulates the need for affordable, clean energy to meet human and industrial needs. Abundance of organic waste, in developing economies, makes methane from biogas a major source of renewable energy. The main limitation being that the raw biogas contains carbon dioxide, hydrogen sulfide and other unwanted gases, therefore it requires purification to remove non-methane components. However, existing biogas purification and upgrading systems are relatively expensive and require sophisticated technology and skills to operate them, hence they are unaffordable especially in many developing economies. Besides, these technologies are mainly applicable to large scale systems and are unsuitable for the small-scale systems mostly found in developing economies. This review critically evaluates the potential of low-cost biogas purification materials such as iron rich soils, activated carbon from solid waste, waste iron fillings, and biomass ash for use in household and small-scale biogas plants. These materials have demonstrated considerable performance achieving the following removal efficiencies; clay (90 %); iron-rich New Zealand Brown soil (93.8 %); commercial steel wool (95 %); and compost (80 %).

Hi Kang'Ethe Muchiri Brian,

Your project is very interesting and clearly valuable for rural energy access. I recently published a paper in Applied Sciences where we analyzed hybrid renewable systems combining biogas generators, PV panels, batteries, and the grid to improve power reliability in rural areas of Spain. One of the studied scenarios focused on the integration of a biogas generator as a core energy source.

Although our work is not directly focused on purification methods, it may help you in:

• Sizing energy components based on load profiles and meteorological data,
• Evaluating cost and reliability of small-scale biogas-based hybrid systems,
• Comparing different configurations (e.g., biogas-only, biogas+PV, or full hybrid with storage and grid),
• And assessing the techno-economic feasibility of rural setups like the one you're developing.

Here’s the open-access paper in case it’s useful: Article Hybrid Energy Solutions for Enhancing Rural Power Reliabilit...

Feel free to reach out if you want to discuss anything related to our case study!

Best regards