APPLICATIONENERGY Power with a purpose
There’s more to solar energy than rooftop panels and solar farms. Dr Keith Bowen of Circadian Solar looks at how a combination of concentrated photovoltaics and micro- generation could provide clean, fresh water to places where it is needed most.
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n Andhra Pradesh in south central India, more than 80 per cent of hospital admissions are the result of water-borne illnesses. There’s nothing particularly special about Andhra Pradesh. More than a billion people in the world today lack access to clean drinking water and there are more people in the world’s hospitals today suffering from water-borne diseases than any other ailment.
As glaciers shrink, droughts increase, and salt-water intrusion spreads, the world's current fresh water shortage is set to worsen. The Stockholm Environment Institute says that, using only a moderate projection for climate
change, 63 per cent of the global population will live in countries of significant water stress by 2025. But treating water is a power-intensive and hence expensive business. It’s also one that can only become more costly as the price of fossil-fuelled electricity in social, political, environmental and economic terms becomes apparent.
The world needs to find ways of cleaning, desalinating and distributing water to its citizens. And it is an area for which the use of renewable energy seems particularly apt. There is, after all, an inherent contradiction in building more carbon- emitting conventional power generation specifically to counter an issue that is dramatically worsened by climate change.
On a more practical level, the lack of clean water is often correlated with an absence of or degradation of existing electricity infrastructure. If new power generation plant is to be built, or a serious refit programme is to be undertaken, then there is an opportunity to incorporate significant levels of renewable generation into the mix.
Many renewable paths However, to talk of renewable generation as a single entity is misleading. Wind and solar power – the most likely candidates for water treatment in non-coastal areas – are very different beasts. Even within the category of solar power there are a myriad technologies. And each one has distinct properties that affect where and how it can best be deployed.
Naturally, the prevailing weather conditions will be the major factor. There is no point in erecting wind turbines in an area where the wind is but an occasional occurrence. The reality is that the areas where availability of clean water is currently the most pressing issue, and the countries where it is most likely to become one, are best suited to solar power.
In particular, concentrated photovoltaics (CPV), may prove to be the likeliest candidate for water treatment. Like other solar technologies, CPV converts the power of the sunlight into usable energy. But the advanced design of its solar cells delivers far higher energy yields than standard
www.solar-pv-management.com Issue IV 2010
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