From Windows to toilets: Bill Gates backs plans for a solar-powered loo for the third world

Philanthropy: Bill Gates speaks at yesterday's event, where he awarded $100,000 to CalTech for its work on a sun-powered loo for the third world

Bill Gates, the world's leading private philanthropist, is betting the future of sanitation in the third world will be solar powered.
The Microsoft co-founder handed a $100,000 (£64,000) prize to the California Institute of Technology yesterday for its work on a sun-powered toilet stall.
Mr Gates hopes self-contained unit, which recycles water and breaks down human waste into storable energy, can become a core part of his foundation's push to improve health in the developing world.
Lack of sanitation causes 1.5million children under 5 to die each year, said Mr Gates, and Western-style toilets are not the answer as they require complex sewer infrastructure and use too much water.
That's why Mr Gates is backing new inventions in toilet technology, which he says has not fundamentally changed since the invention of the flushing toilet in 1775.
'Imagine what's possible if we continue to collaborate, stimulate new investment in this sector, and apply our ingenuity in the years ahead,' Mr Gates said at his foundation's Seattle headquarters yesterday.
'Many of these innovations will not only revolutionise sanitation in the developing world, but also help transform our dependence on traditional flush toilets in wealthy nations.'
His foundation announced $3.4million (£2.2million) in funding for toilet projects, bringing total investment in its 'Reinvent the Toilet Challenge' to about $6.5million (£4.1million).
About 2.6billion people, or 40 per cent of world's population - mostly in sub-Saharan Africa and south Asia - lack access to safe sanitation, according to Mr Gates.

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Last year the Bill & Melinda Gates Foundation gave grants to eight universities and asked them to tackle the problem by creating a hygienic toilet that uses little or no water, is safe and affordable and can transform waste into energy, clean water and nutrients.
Mr Gates yesterday presented prizes to the teams which have showed the most progress, handing Caltech the first of $100,000 for its working model of a solar-powered toilet stall.
The invention uses a solar panel to produce poower for an electrochemical reactor that breaks down faeces and urine into hydrogen gas. That gas can be stored in hydrogen fuel cells to provide a back up energy source for night operation or use in low-sunlight conditions.
The revolutionary toilet's mechanism is designed to be buried beneath a conventional-looking stall and urinal set-up, which the Caltech team showed in cross-section at the Gates Foundation courtyard. Water recovered from the continuous process is pumped up again to provide water to flush the toilet.

Mr Gates, right, looks at a device that uses solar energy to treat human waste, as he tours the fair

Mr Gates also handed out prizes to Britain's Loughborough University and Canada's University of Toronto for their designs, which focus on transforming faeces into usable resources.
The software pioneer is hoping many of the universities will work together to develop the best technologies. He is aiming to get new-style toilets into use in the next two to four years.
Mr Gates's foundation is spending about $80million (£51million) a year on water, sanitation and hygiene issues, areas where it thinks it can make a marked difference in people's lives.

Walter Gibson of Bear Valley Ventures, left, holds a tray of black soldier larvae which are part of Sanitation Venture's Tiger Toilet system. Right, James McHale, vice president of engineering for American Standard Brands, uses simulated human waste to demonstrate their concept for a better seal for latrine

The $370million (£236million) in total it has committed to that area so far is still only a small slice of global funding for health, development and education provided by the foundation.
In total it has handed out, or is committed to, grants worth more than $26billion (£16.5billion) since Mr Gates started his philanthropy in 1994.
The foundation, which Gates co-chairs with his father and wife, Melinda, is the world's biggest private philanthropic organisation with an endowment worth more than $33billion (£21billion).