Tag Archives: agriculture

Taita Taveta County, Kenya – Biogas Partnership for Farming Communities

Taita Taveta county lies approximately 150km northeast of Mombasa and 300km southeast of Nairobi in Kenya. Residents of Wundanyi subcounty were approached in 2013 by a newly-formed NGO, Taita Biogas, to pilot new biogas installations, due to the high prevalence of cattle farming in the region. This gives ready availability for high-quality feedstock for biogas digesters in the form of cattle manure. To date, the NGO has installed over 600 household-scale biodigesters in the country, and has completed two institutional biodigesters for schools in the region, with a third under construction. These institutional-scale installations will use human and food wastes as feedstock rather than cattle wastes.

The business model for the NGO provides an opportunity for consumers who would not be able to afford a biodigester installation outright to install a system. Taita Biogas covers half of the cost of installation, and also arranges contractors to construct and commission the system. The households then pay the remaining amount for installation, usually in the region of KSh145,000 (GBP1,035). In recent years the NGO has expanded operations through partnership with the Micro Enterprise Support Project, another Kenyan NGO supporting farmers venturing into macadamia nut and French bean farming. Whilst this partnership has not been successful to date, due to MESP pulling out in 2017, a new partnership with the organisation is to be formed with additional funding, and a loan finance option provided through the MESP to members for biogas installations.

Household biodigester user Honorata Nyange cleaning utensils at her Lushangonyi home in Taita Taveta County, Kenya. Photo/Malemba Mkongo, star.co.ke

There are a range of benefits available to the farmers who have installed these biogas systems, as well as the institutional-scale digesters installed by regional schools. Households have reported a huge reduction in the amount of money and time invested in collecting firewood and purchasing charcoal, and the institutional users have reported a 50% reduction in the cost of purchasing firewood for cooking since installation of the digesters. In addition, this scheme is innovative in that householders are coordinating with the NGO to apply for regulatory permission from the Energy Commission of Kenya to bottle and sell biogas on the local market, as self-producers. Biogas sells for comparable prices to natural gas on the Kenya market (KSh200/kg (GBP1.43/kg), compared to KSh175-250 (GBP1.25-1.78/kg) for natural gas), and should regulatory permission be granted, these biogas installations have the potential to become an additional revenue stream for the farmers. Finally, household users have reported significant improvements in both cooking quality and ease of use when using biogas compared to firewood or charcoal, with a reduction in combustion residues and ease of lighting when using biogas as a fuel source.

The NGO is currently expanding its operations both on a geographical and technology-focused scale. As well as its operations in Kenya, the NGO is conducting feasibility studies for joint biogas/solar photovoltaic/solar water heater applications in Ethiopia, as well as local training workshops in partnership with an Ethiopian NGO, MCMDO-REESDE, for solar water heating technology, both in terms of installation and local construction.

Star.co.ke (2017) Taita Taveta Dumps Firewood for Biogas. Available at: https://www.the-star.co.ke/news/2018/02/12/taita-taveta-dumps-firewood-for-biogas_c1707691 [Accessed 10th March 2018]
Taita Biogas (2018) What We Do. Available at: http://biogas-taita.de/home.php [Accessed 10th March 2018]


What Could The Energy Transition Be For Thermal Energy Services in the Global South – Part 3

Following our previous post on heating, this last post will investigate other energy service needs linked notably to farming activities.


Refrigeration in developing countries in remote areas is rarely found except for specific needs like to keep vaccines for health centres. A number of possibilities exist to provide refrigeration with LPG, with passive solar, and again using ground-source heat pumps, but it seems solar PV is the most economical one. Various attempts have been made at renewable refrigeration over the past 30 years, predominantly focusing on solar collector designs, although photovoltaic vapour compression systems are the most commonly found for vaccine refrigeration. The high cost of these systems can often be justified by the importance of the application.

Larger refrigeration systems based on solar collection/kerosene/LPG power using different absorption refrigeration cycles (for example the Platen-Munters ammonia-water-hydrogen continuous diffusion absorption cycle) have been tested for ice-making in developing countries, but the lack of constant heat sources in renewably-powered systems has made reliability and efficiency a concern. Alternatives do exist to LPG-powered refrigeration in the form of solar refrigeration however, and with the current global lowering of photovoltaic and other solar components, the technology is becoming more cost-effective and viable to small entrepreneurs.


Platen-Munters absorption refrigeration system and cycle. Image – centrogalileo.it

Drying is to be found in agriculture, but not at a small scale for individual households. Tray design solar dryers can be useful for small agricultural businesses to increase productivity, and are often easy to construct from locally-sourced materials. Updraft-style solar dryers are more complex from a design perspective, requiring specific attention to be paid to air flows and moisture extraction from the heating areas.


Solar drying for chilli pepper crop in Peru, with locally-produced equipment. Image: Carlos Bertello, GIZ EnDev Peru.

Other Agricultural Uses

Milk pasteurisation is a critical issue for dairy farmers in the developing world. It has been estimated that over 50% of an average rural dairy farmer’s milk crop in Kenya will spoil before it has been sold, which has a severely detrimental effect on their livelihood and income generation. Modern pasteurisation equipment using steam boilers and batch-type pasteurisers can significantly increase output and income from a rural dairy farm in the developing world.

These steam boilers can be renewably powered, for example through biomass from animal/crop waste. Low-temperature (70-80°C) water can be substituted for steam in the pasteurisation process with only slight plant modifications, and this allows the potential for greater renewable energy use in the process, for example through flat-plate solar collector water heating, or cogeneration/recuperation from electricity generation or refrigeration equipment condensers. Whilst renewable pasteurisation technology has not been a focus of many organisations, the FAO have produced a report on the potential uses and processes for the technology, which is available here (http://www.fao.org/docrep/004/t0515e/T0515E03.htm).


Potential for novel pasteurisation technologies in the developing world, to be powered by renewable electricity from solar or biomass digesters. Image: Openideo, Sarah Rizk, Stanford University.

In conclusion of this series of three posts, there exists vast potential over the wide range of available thermal energy services for the residential, industry and commercial sectors, notably in the Global South in general, and Sub-Saharan Africa specifically. The STEPs project will specifically be working most on the services that appear most viable in the Sub-Saharan African context: cooking/heating services for household needs, and low-temperature hot water production for households. The need for sustainable cooking and household thermal energy is a pressing one, and the STEPs project, through investigating a technology-neutral approach to thermal energy services and business, hopes to address this need.

– Xavier Lemaire & Daniel Kerr – UCL