Gobsmacked. Yep, that’s me. ‘Why’, you ask? ‘Let me tell you’, I answer.

Because of this man: Mr Moser. Alfredo Moser. Inventor of the bottle light.

In 2002, the Brazilian mechanic had a light-bulb moment and 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.

So how does it work? Simple refraction of sunlight, explains Moser, as he fills an empty two-litre plastic bottle.

“Add two capfuls of bleach to protect the water so it doesn’t turn green [with algae]. The cleaner the bottle, the better,” he adds.

Wrapping his face in a cloth he makes a hole in a roof tile with a drill. Then, from the bottom upwards, he pushes the bottle into the newly-made hole.

“You fix the bottle in with polyester resin. Even when it rains, the roof never leaks – not one drop.”

The lamps work best with a black cap – a film case can also be used.

“An engineer came and measured the light,” he says. “It depends on how strong the sun is but it’s more or less 40 to 60 watts,” he says.

What is refraction?
  • Refraction is the bending of light, which is caused by a change in its speed
  • The speed of light is determined by the density of the substance through which it passes
  • So refraction occurs when light passes from one substance to another with a different density – e.g. from air to water
  • In the case of the “Moser lamp”, sunlight is bent by the bottle of water and spread around the room

His boss at the time suggested getting a discarded plastic bottle, filling it with water and using it as a lens to focus the sun’s rays on dry grass. That way one could start a fire, as a signal to rescuers. This idea stuck in Moser’s head – he started playing around, filling up bottles and making circles of refracted light.

Soon he had developed the lamp.

“I didn’t make any design drawings,” he says. “It’s a divine light. God gave the sun to everyone, and light is for everyone. Whoever wants it saves money. You can’t get an electric shock from it, and it doesn’t cost a penny.”

How much energy do the lamps save?
  • The plastic bottles are up-cycled in the local community, so no energy is needed to gather, shred, manufacture and ship new bottles
  • The carbon footprint of the manufacture of one incandescent bulb is 0.45kg CO2
  • A 50 Watt light bulb running for 14 hours a day for a year has a carbon footprint of nearly 200kg CO2
  • Moser lamps emit no CO2

Source: UN

“There was one man who installed the lights and within a month he had saved enough to pay for the essential things for his child, who was about to be born. Can you imagine?” he says.

Extracts taken from an article by Gibby Zobel BBC World Service, Uberaba, Brazil

So, whereas we at AquAid are not suggesting that you use your water from your water cooler for this ground breaking invention, we felt it only right that we dof our cap to the inventor. More power to you, Mr Moser!