APPLICATIONENERGY
photovoltaics. CPV units also have an optics system, that magnifies the power of the sun even further, and a sun-tracker unit so that the cells follow the path of the sun and are able to ‘harvest’ a larger fraction of the sun’s rays.
The result is a system that is incredibly efficient and capable of delivering far greater levels of power from a single unit than other forms of solar electricity generation. The net result is a system that has the potential to be much more cost-effective.
The high levels of efficiency of CPV also makes it suitable for micro-generation. In the developed world, micro-generation is often seen as a well- intentioned whimsy on the part of wealthy but committed environmentalists. But in the developing world, where significant proportions of the population live in off grid rural areas or in over- crowded, unplanned urban sprawl, micro- generation has immediate and obvious benefits. Like micro-finance before it, thinking small can help solve big problems.
For example, a basic micro-desalination unit – the size of an average washing machine – requires 800 watts of electricity to produce 1,000 litres a day. That’s enough for a family’s daily needs. A single CPV unit could power four of five of these machines – thus providing a cost-efficient, space- efficient and energy-efficient power source.
In another example, an individual hospital might need 100 - 200 kw to power its own water treatment facility. In the right climate that can prove to be a more robust and more reliable source of essential clean water than an inadequate water or even electricity grid.
But there are other considerations when it comes to choosing energy sources, not least of which is support and maintenance. Systems designed for a long lifecycle and minimal maintenance are ideal. The more moving parts, the more complex its underlying engineering and the more maintenance it is likely to require.
That may make it inappropriate for certain countries that could otherwise benefit. But, if you can fix a car you can fix a CPV system. So for places like India – where most small towns and many villages have a mechanic enjoying a lively trade in the repair and refurbishment of Ambassador cars and auto-rickshaws - it could be the argument that seals the deal.
Broad support
The deployment of renewable energy in general and CPV in particular can also support nascent tourist industries by powering the water treatment required by hotels, swimming pools and even golf
courses. The water consumed by these enterprises has long been an area of concern in many areas, particularly where resources are already limited. There is a greater awareness that providing luxuries should not have an unacceptable social and environmental cost, and balancing the need to attract tourist dollars to boost the local economy and ensuring the population has its basic needs met has not always been successful. But using renewable micro-generation to power water treatment can assist in this area.
But perhaps the biggest advantage of linking technologies like CPV to very specific functions such as water treatment and desalination plant is that they make perfect demonstration projects in which the benefits of renewables can be immediately seen. In an industry that needs to boost its profile, demonstrate effectiveness and encourage greater investment, this is exactly the kind of venture that developers like. It creates something of a virtuous circle where greater investment leads to greater penetration, which in turn leads to lower costs which encourages further deployment.
There is no one easy answer to the world’s water problems. And certainly CPV does not provide the complete solution. But it does tick a lot of immediate boxes, and could play a significant role in ensuring that clean, healthy water doesn’t become the preserve of the wealthy few. But more than that, it opens the door to a whole host of other renewable energy alternatives.
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www.solar-pv-management.com Issue IV 2010
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