A Brazilian mechanic has invented a way of lighting his house during the day without relying on electricity.
Alfredo Moser has been using plastic bottles filled up with water and a splash of bleach to illuminate3 dark rooms since 2002 and now the idea has now spread across the world.
It is predicted that his lighting system, which works using refraction of sunlight, will be fitted in over a million homes by the end of this year.
The secret of the liquid which fills normal plastic drinks bottles that are often thrown away, is two capfuls of bleach added to water, which stops it turning green with algae4 when exposed to sunlight.
Mr Moser drills a hole in a roof tile and then pushes the filled bottle in from below, keeping the bottle in place with polyester resin5（聚酯树脂）, which waterproofs6 the 'window' in his roof.
He told Outlook on the BBC World Service that depending on the strength of sunlight, the light filling his home is the equivalent of between 40 and 60 watts7.
The mechanic came up with the idea for his 'Moser light' during one of the frequent blackouts inBrazilin 2002.
He said only factories had power in his home city of Uberaba, in southernBrazilduring the energy shortage.
It was his boss that suggested using a plastic bottle filled with water as a lens to focus the sun's rays on dry grass to light fires in case of an emergency and Mr Moser developed the concept into his light.
He told BBC World Service: '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.'
Mr Moser earned a few dollars installing the lights in his local super market and neighbours' houses but his invention has not made him a wealthy man.
He said: '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?'
Carmelinda his wife said her husband has always been handy at home and have made tables and chairs.
Illac Angelo Diaz, executive director of the MyShelter Foundation in thePhilippinesalso admires Mr Moser's ingenuity8.
The charity uses recycled materials to build houses and has plenty of bottle donations, which it fills with mud to build walls and water to create windows.
It now incorporates water bottles in roofs since learning of the Moser method and also trains local people to do the same in order to earn a small living.
Moser lamps have reportedly been fitted in over 140,000 homes in the Philippineswhere a quarter of the population live in poverty, as well as in 15 other countries, includingArgentina, IndiaandFiji.
Mr Diaz believes over one million people have installed Moser lights in 2013 and credits the mechanic with transforming people's lives.
'Whether or not he gets the Nobel Prize, we want him to know that there are a great number of people who admire what he is doing,' he said.
Mr Moser told the BBC he never imagined his invention would have such an impact but said it gives him goose bumps if he thinks how many people are using Moser lights.