A couple of weeks ago I expressed my frustration with a competition to design a new kind of toilet for the third world, and a winning entry that looked like a physics lab with a toilet on top. That was the Gates Foundation attempting to reinvent the toilet, and while it’s an incredible piece of technology, it’s not something that’s going to go in a mud hut.
If you start with the poor and the assumption that it will go in a mud hut, you can still create amazing technologies. For evidence of that look no further than Practical Action’s new stove. They started off developing a smokeless cooker that would use fuel wood more efficiently and prevent the smoke-related illnesses that plague many families in poor countries. Along the way they realised that the stove could generate electricity at the same time. Remarkably, the Score-Stove generates electricity from sound.
The stove has a pipe attached that becomes pressurised as it heats up, causing lots of tiny pieces of metal to vibrate. These vibrations are then captured by a speaker, which feeds into an alternator. It can generate 36 watts of power, and the inventors believe it can be refined up to 50 watts – enough to provide a clean light source or charge a phone. Apparently it makes a ferocious din inside the pipe, but users only hear a humming noise while using the stove.
The stove has been tested in labs and in homes in Kenya, Bangladesh and Nepal, with development teams at a number of British universities. It works, and it can be installed in a mud hut. The challenge now is to adapt the prototypes to ensure that they can be built using only locally available materials – the true test of an appropriate technology.