Walking out of the kitchen we went round the back of the house to see the digester itself. It no longer stood alone in the middle of a muddy plot of land but was surrounded by green leafy vegetables and banana plants.
In addition to producing cleaner fuel, biogas digesters provide a source of rich, organic bioslurry that can be used to improve soil structure, soil fertility and crop yields. Applying bioslurry to crops is more effective than using raw manure because the digestion process increases the availability of nutrients.
Feeding the digester
Holding a bucket in one hand and a shovel in the other, Pastor Julius led us round to his cow shed. He filled the bucket full of cow manure and led us back to the digester where he poured it into the mixing chamber, followed by a bucket of water. He explained that he leaves the manure in the mixing chamber for a couple of hours to let the sunshine heat it up, before returning and allowing it to flow into the digester.
Pre-heating the manure like this helps the digester to maintain a warmer temperature which, in turn, speeds up the digestion process. Combining this with feeding the digester each day ensures that the family has a constant and reliable supply of biogas fuel for cooking.
Pastor Julius has covered his digester with a protective structure made of transparent plastic (the type of plastic used to make greenhouses). This helps to maintain a higher temperature inside the digester and protects it from being damaged by the sun, birds or animals. Digesters can also be covered by a tin roof, straw thatch or a concrete dome.
As we walked back towards the kitchen, we saw the pipe that carries biogas from the digester to the two-ring stove Marsha placed her saucepans on earlier.
Reflecting on our conversations I was so encouraged. The construction of the digester has not only resulted in greater yields of nutritious crops, a sustainable supply of cooking fuel and cleaner air in the kitchen, it has also enhanced the relationship between husband and wife. What a great example of biogas technology unlocking sustainable energy for abundant life!
CREATIVenergie is committed to unlocking sustainable energy for abundant life. The team works with local and international partners to find solutions to energy problems. Join one of their interactive webinars to find out more: www.biogas.eventbrite.co.uk
Bitesize Energy Exchange
Across sub-Saharan Africa, solar panels and biogas digesters provide clean and sustainable electricity and cooking fuel for people whose homes are not connected to national electricity or gas grids.
However, many families are unable to afford their own solar panels or digesters, excluding them from the opportunities and benefits that clean sources of energy bring. At the same time, some of their neighbours have more energy than they need: more solar power is generated than is consumed during the day; biogas systems continually produce gas and the excess is wasted.
After winning an Energy Catalyst award in 2019, CREATIVenergie and several international partners are working to develop a system that will allow the fair distribution of clean energy supplies.
Starting in Uganda, Tanzania and Rwanda, their Bitesize Energy Exchange (BEE) project aims to develop technologies to allow excess solar power and biogas fuel to be packaged, distributed and traded in small quantities.
For example, surplus solar power can be used to charge portable batteries. These batteries can then be rented from an energy hub and later returned for recharging. Excess biogas can be packaged into safe, portable containers.
This will increase access to reliable supplies of affordable, clean energy for low-income families who are not able to generate energy for themselves.