Posted: August 14, 2013 By:

Let there be light!

Saw this story on the BBC News website recently, and it made me think about how the¬†simplest solutions are often the best. It’s also a great solution from a sustainability point of view (with the possible exception of the bleach required to stop the water going green, but hey let’s not worry about that too much) – not just in terms of being environmentally sustainable, it also ticks the social and economic sustainability boxes. In Bangladesh for example, it’s helped hundreds of people – including sari makers and rickshaw repairers – whose livelihoods depend on having sufficient light.

Essentially a Brazilian mechanic called Alfredo Moser’s had a ‘light-bulb’ moment (no pun intended) when he came up with a way of illuminating his house during the day without electricity – using nothing more than plastic bottles filled with water and a tiny bit of bleach. In the last two years his innovation has spread throughout the world. It is expected to be in one million homes by early next year.


It works using simple refraction of sunlight – take a clean empty two-litre plastic bottle, fill it with water, and add two capfuls of bleach to protect the water so it doesn’t turn green [with algae]. Next, make a circular hole in the roof with a drill or similar (don’t try this at home children) and then push the bottle upwards into the hole. Finally, just fix the bottle in place, and seal the gap around it, with polyester resin. Simples! For further details click on the link below:


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news, sustainability