Ashden Winners

Sky Link Innovators / Biogas for homes and institutions

Area of work:

The Waterloo Foundation
Play Video

Deforestation is ravaging rural Kenya as people strip forests for vital cooking fuel. Yet biogas, produced from animal and human waste is a viable alternative.

Sky Link is a social enterprise that builds and installs biogas plants. Sky Link also trains local technicians so that they have the skills to build biogas plants.

Over 200 domestic biogas systems installed.

Over 5,200 people benefitting.

1,100 tonnes/year reduction in CO2 emissions.

"The cook likes it, because he doesn’t have to chop the wood, the food cooks faster, and the kitchen doesn’t get smoky like before. And the children love it because their food doesn’t taste of smoke!"

Mercy Mungania, Tania School, Kenya


Kenya currently has only 1.9% forest cover, which is well below the 10% minimum recommended by the UN. Clearing land for agriculture and cutting trees for wood has led to lack of forest cover, which in turn has resulted in increased soil erosion. The rural population of Kenya continue to rely on wood for fuel despite its increasing cost, and many city dwellers use charcoal which puts even greater pressure on wood resources.

Sky Link Innovators has tackled this problem by introducing the use of biogas as a source of fuel for cooking, heating and electricity.

Cooking on a biogas stove, Tania School, Kenya.

The organisation

Sky Link Innovators was established in 2007 by two cousins, Samwel Kinoti and Agnes Marete, with George Onyango joining shortly afterwards as the third partner. It aims to develop biogas technology as a commercially viable source of energy, and to tackle the issues of deforestation, indoor air pollution and access to affordable energy. The company has grown rapidly over the last three years and now works through a small core staff and 20 contracted technicians. Sky Link’s turnover in 2009 was US$40,000 (KSH 3,240,400).

The technology

How does it work?

Biogas systems take organic material such as animal dung into an air-tight tank, where bacteria break down the material and release biogas – a mixture of mainly methane with some carbon dioxide. The biogas can be burned as a fuel, for cooking or other purposes, and the nutrient-rich residue which remains can be used as organic compost. The biogas systems used by Sky Link are fixed-dome designs, built from brick in underground pits. Sky Link installs 12 to 16 m3 size domestic systems which are designed to use mainly animal dung. Such a system requires the household to have between about three and eight cows. The gas is used mostly for cooking but can also be used to generate electricity.

Meru Prison – main digester under construction.

Sky Link also installs larger systems for institutions, ranging in size from about 30 m3 for schools to 124 m3 in Meru prison. These can also process animal dung, but the main purpose of the larger ones is to manage human sewage from latrines.

How much does it cost and how do users pay?

US$1 = KSh81 (Kenyan Shillings) [May 2010]

The cost of a 12 m3 domestic biogas system is about US$1,850 (KSh 150,000). This is a substantial amount, but can be paid back in about four years through savings on increasingly expensive fuelwood. This time can be reduced to about three years if savings made from substituting commercial fertiliser for biogas residue are included, since these amount to about US$230 (KSh 18,600) per year for a small farm.

We’re saving a lot of money by not having to buy firewood, and we don’t need so much fertiliser either; so the plant will pay for itself in about six months or so.

Mercy Mungania, Tania School.

Households buy the construction materials and provide unskilled labour. 50% of the cost of Sky Link labour is paid on signing the contract, 30% when the work is almost completed, and the remainder when the system is fully commissioned. In this way households are able to spread the cost of buying a biogas system. Sky Link does not offer any credit to customers, but offers help to households wishing to borrow money from their local Savings and Credit Society.

A typical school system costs about US$19,753 (KSh 1.6 million), and the 124 m3 plant for Meru prison cost about US$42,000 (KSh 3.4 million).

How is it manufactured, promoted and maintained?

The institutional systems are built entirely by Sky Link technicians, including sourcing materials and construction. As far as possible materials are sourced and manufactured locally, including quarry stones, clean river sand, cement, bricks, ballast, steel bars and timber. In the case of the domestic biogas plant, the customer is told what materials to buy and how to dig the pit. Sky Link makes the measurements and marks the pit outline, and the householder can work at their own pace. A technician then comes in to install the system.

I saw the biogas at my brother’s place, and thought I must have it. It’s so fast to cook with, compared to firewood, and you don’t have to stay in the kitchen the whole time, feeding the fire. You can leave a pot simmering and just get on other things.

Mary Waringa Nguku, farmer

Sky Link offers a one year guarantee on all its systems. The technician will visit a new installation every month for six months to make sure everything is running smoothly. After that, technicians can be contacted if anything goes wrong or parts need replacing.

Sky Link trains all its technicians, who in turn educate the end users on how to use the system. They also train the community leaders, who are usually contacted by Sky Link when they enter a new community to serve as informal consultants to provide introductions and sales leads, as well as give advice and support to customers.

The benefits of biogas are advertised through leaflets and brochures. Sky Link also gives live demonstrations at agricultural fairs and promotes through word of mouth.


Sky Link has installed about 200 domestic biogas systems, benefiting some 1,200 people (assuming an average household size of six). It has also installed institutional biogas systems in five schools and orphanages, benefiting about 2,500 students and one in Meru Prison, improving sanitation for 1,500 prisoners and staff. The company is currently providing consultancy services for the installation of a second prison system.

Eating lunch cooked on biogas – Tania School.

Environmental benefits

People in rural Kenya are very aware of the impacts of deforestation. Helping to avoid deforestation by reducing the use of unsustainable fuelwood (and the charcoal which is made from it) is seen as the most important environmental benefit of the biogas systems.

Biogas plants cut greenhouse gas emissions, by reducing the use of unsustainable fuelwood and (particularly for the larger plants) reducing methane emissions from poorly managed sewage disposal.

Based on typical measurements on biogas systems from elsewhere, a SkyLink domestic system probably saves about 3.5 tonnes/year of unsustainable wood or 5 tonnes/year CO2, and a school system about 10 tonnes/year wood and 15 tonnes/year CO2. From estimates made by SkyLink, the prison saves about 22 tonnes/year wood and 33 tonnes/year CO2. The savings related to reduced methane emission have not been estimated but are probably significant as the system was installed to replace a connection to the municipal sewage system, which had frequent leaks.

People can see the rivers drying out; they can see the loss of forests and they’re worried about it. So they know we need alternative sources of energy [to wood].

John Mugethe Mbugua, Sky Link Community Worker

All the biogas systems installed to date therefore save about 800 tonnes/year of wood and reduce greenhouse gas emissions by the equivalent of about 1,100 tonnes/year CO2.

Social benefits

Owners of biogas systems have a better quality of life because less time and money is spent collecting or buying firewood. Indoor air pollution from cooking with fuelwood is greatly reduced, so cooks enjoy a healthier and cleaner environment.

Managing manure with a biogas plant improves hygiene and reduces the smell. For institutions, hygienic management of human sewage is a particular advantage.

Children who would previously have spent time collecting fuelwood can now attend school more regularly. The slurry, used as a fertiliser, increases crop yield and food security for families.

There’s so much less smell now that the dung goes straight into the digester. It’s much cleaner and healthier, and that’s important, because of the patients.

Dr Thiakunu CK Mwirabua, clinic, Meru

Economic and employment benefits

Sky Link employs five people at the head office. They also work with a team of 20 field technicians who are contracted out to each project, mostly on a full-time basis. The technicians receive training from Sky Link.

There are additional income generating opportunities associated with biogas production, such as slurry-fertilised crops and fishponds. Young people trained as technicians can also earn extra income from maintaining and repairing systems in place.

Potential for growth and replication

Sky Link continues to grow, with orders for biogas systems on the rise. Forest cover is diminishing rapidly, making biogas very attractive as an alternative cooking fuel. Lack of consumer awareness and upfront costs are Sky Link’s main obstacles to growth. It plans to increase awareness through education campaigns and advertising. Sky Link is particularly keen to expand the use of biogas in schools, to cut the heavy wood use and also serve as demonstrations for the wider community. Sky Link will also be looking at other renewable energy technologies, such as wind and solar, to bring the benefits of renewable energy to as many people as possible whilst at the same time benefiting the environment.

Read More / Related posts

This site uses cookies to provide you with the best user experience. By using the Ashden website, you accept our use of cookies.

Stay up to date

Be the first to know about our latest projects and news