James A. Tyrrell, County Antrim, N. Ireland
Concentrating photovoltaics
There has been a lot of talk lately about the pros and cons of using photovoltaics on the roofs of homes in order to generate electricity. Given the amount of sunshine which Malta receives throughout the year, this would seem like an ideal solution to cut down on the use of fossil fuels for energy generation.
There are however problems, not the least of which is the cost of installation. Another problem is the efficiency of the system and whether or not the total outlay can be repaid during the typical life of the system.
It would seem therefore, that if the cost of these solar solutions could come down, coupled with an increase in efficiency and, hopefully, sensible government grants towards the costs, they may become viable.
To that end I wanted to pass on something I was reading about in the Technology Review published by MIT. The article concerns a new form of photovoltaics called concentrating photovoltaics. IBM is developing this at the moment and other firms are also working on similar ideas. Energy from the sun, although abundant, is diffused and this affects the overall efficiency of the system. The basic principle of concentrating photovoltaics is that the rays of the sun are concentrated through a lens and directed onto a solar cell.
IBM have said that using this method they can create five times more energy than in a normal system and that one square centimetre of solar cell produces as much as 230 watts of energy, which is far more efficient than anything seen before in solar technology. Compared to what is being produced today, these will be a lot cheaper since most of the unit would be comprised of cheap lenses or reflectors rather than solar cells. It also means that since less would be required, more efficient solar cells could be used.
As I said earlier, other firms are also working on this and related technology and it's only a matter of time before cheaper and more efficient home units become available.
The main problem they are facing at the moment is in regard to cooling the systems as the concentrated sunlight produces extremely high temperatures but they are working alongside engineers who specialise in cooling computer chips to try and overcome this.
Popular Stories
In Discussion
5 Comments
Post comment
Please sign in or create your Account to post comments.
James A. Tyrrell
Sep 15th 2008, 20:55
@Nigel Lawrence. C Cassar made the very points I was going to make Nigel so I thank him for that. I think the set-up you are describing was the way it used to be with these systems and as you say it was quite an outlay.
With the new reverse meter system none of this is necessary. Your system is basically feeding to the grid all the time, which you are credited for, and then you draw your power from the grid as and when you need it. I saw a documentary recently where one householder was receiving a cheque from his electricity supplier every quarter instead of him paying them!
Aldo Gatt
Sep 15th 2008, 17:42
Mr Lawrence, you are right to consider the expense of the whole setup but aren't you a tiny bit negative in your assertive statement in view of the facts presented by Mr Tyrell? If IBM's claim is correct, would that not make a massive difference, despite the initial expenses? Not to mention that the energy generation being substituted will not be decreasing in price any time soon.
C Cassar
Sep 15th 2008, 16:13
@ Nigel Lawrence - Electric power generated by voltaics is fed back into the grid system, effectively turning your meter backwards. Power is then drawn from the grid system. Batteries are not used to store the generated electricity. This is how the system work all across Europe including Germany, Austria, Italy and the UK. This allows one to feed the grid system 24 hours a day, 7 days a week (depending on weather) even when nobody is resident in a property.
Alex Ellul
Sep 15th 2008, 14:54
http://www.nanosolar.com
This URL will show why photovoltaics will be one of the world-wide electrical power providers within a few decades. Nanosolar are already manufacturing, on a large scale, PV panels that produce electricity to the grid, cheaper than oil powered systems. I will not say that this is the end of oil, but as some scientists are predicting, the era of oil is approaching is end.
Nigel Lwrence
Sep 15th 2008, 12:43
Photo voltaics alone will not provide your energy needs. On top of the costs of the panels, one has to buy the storage batteries, the charge regulators for the same and the static inveters to make the power usable. Now add the cost of this little lot together and you can see why "John public" will not be outlaying a substantial financial amount for a system which will more than likely NOT give any return to the investment.