Counting on cow dung

http://allafrica.com/stories/201207020509.html

Rwanda: Charging Your Phone With Cow Dung
By Saskia Houttuin, 30 June 2012

When one thinks of animal dung, one usually thinks: messy. Dutch research
institute TNO has developed a prototype of a socket that turns biogas heat
into electricity. Together with SNV and BoP Innovation Center, students at
Delft University of Technology visited Rwanda for TNO to test this new
prototype in people's homes. Who could have ever imagined, that one day
mobile phones would be charged with cow dung?

Students Anne Jansen (24) and Diana Alacron (32) spent six weeks in Rwanda's
countryside, where they spoke with families to understand their specific
needs when it comes to gas and electricity.

"We noticed a need for gas for cooking, but also for electricity," says
Diana. "Eighty percent of the Rwandan population has no access to
electricity." Meanwhile, according to their research, almost everyone owns a
mobile phone - both parents and their children.

Phone charging

"When people don't have electricity, they walk every three days to the city
where they leave the phones on little charging stations," explains Anne.
"This means a lot of effort, time and money is spent on charging.
Electricity would make them more independent".

The biogas socket is still in development, but after their research in
Africa, the students are confident with its development. "It's easy to
apply," says Diana. "The idea is to simply connect the socket to the cook
stove, which means no new difficult system regarding the installation."

How many cows?

Although biogas installations require refined technology, the underlying
process is quite simple. One gathers dung and urine in an underground tank
and a gas is produced. The resulting residue can be used as fertiliser for
agriculture.

So how many cows do you need to charge a phone while still having enough for
cooking and light? According to Anne, one needs 400 liters of gas for one
hour of cooking. The biogas socket will use 50 to 150 liters of biogas per
hour. In terms of dung this means a "daily minimum of thirty to forty
kilograms of cow dung, so one needs at least two cows," says Anne.

Dung etiquette

Both students were surprised to discover it was very impolite to ask how
many cows a family owned. "It's like asking in Western countries how much
people earn. But it's nice to experience these cultural differences," says
Anne. "You may prepare a lot beforehand, but you will always come across
something unexpected. Our solution was to simply count the cows in the
garden".