Dubai Too Hot for Solar Panels?

Dubai solar projects...

Knowing a little about the relevant temperature issues would prevent being shocked when first encountering them.

So that was post 10,272 if I count backwards?

Thanks for that information.

Logically, can you know about a subject before first encountering it?

Jus' askin'

English Rose I am glad you chimed in as I was wondering if it was only me!

I mean look at all these excellent, detailed and thoughtful posts which attempt to share knowledge for the benefit of the community. Then look at the one post that sticks out "like a sore thumb"....totally pointless....

Sorry I missed this but I am a NON-Engineer and thanks for actually explaining your thought process (voted for your answer as well!).

There is always lots of talk about how solar is wonderful and perfect for places with lots of sun, such as deserts but there has been very little talk outside of Solar Green Tech Circles that there are significant limitations as well.

What shocked me is 1) that it's not so simple so it depends on the materials used to optimize for the Dubai heat and more recently 2) the Dubai official being quoted would say solar is not suitable for Dubai given there are solutions.

Some progress on the desert dust front:

A chemicals spin-out from the University of Leeds Chamelic, that is in the business of making high-tech poymer coatings, may have just come out with a much more market-ready solution for utility-scale solar.

Chamelic has developed an ultra thin surface treatment that can just be applied to the routine wash, that can repel dust for up to 8 weeks.

Independent measurements found that 100% of the light was still reflected back from the mirrors after application. In simulated harsh desert conditions, with temperatures of 30 degrees Centigrade, in dust storms with wind speeds of between 20 and 40 miles an hour, untreated mirror surfaces lost over 9% of production. Chamelic solution, in a water base, lost less than 2%, and in an alcohol base, lost less than 1%.

http://www.greenprophet.com/2012/01/chamelic-invents-answer-for-desert-solar-dust/

I'll drink to that!

'In simulated harsh desert conditions, with temperatures of 30 degrees Centigrade'

30 degrees Centigrade is not harsh desert conditions. I'm sitting in Australia with out air-con at 40 deg C and that still is harsh but livable.

45-50 deg maybe.

I believe it is PV (Photo Voltaic) Solar Power Project that is being referred to here. Gulf Countries witness very high temperatures in summers - as high as 60 Degress Celsius (in the desert) at times.

There are various PV Technologies (Crystalline) and performance of some of them gets impacted at higher temperatures due to inferior temperature coefficient. However there are other technologies (Thin film) which have better temperature coefficient and the performance does not degrade with rise in temperature.

Good point.

The solar cells used in spacecraft are based on germanium, not silicon, and withstand the extreme environment of space - and are more efficient in converting EM radiation into electricity. Of course, for now the germanium PV cells are more expensive. Perhaps with large volume production the cost would drop enough that they would be cost-competetive.

solar power production is based on p/n junction. This is generally less than a micron from surface of the silicon and is the place holes and electrons are in equal concentration so one can convert photon to electron and move this electron to battery . p/n junction is balancing of molar concentration of boron and phosphor and non of the two element will disappears in desert temperature. We use computer which get hotter than desert temperature and provide fan to cool it down. All quality test is done using thermal test at upper end to 150oC and desert is not at that temperature.

The problem may be of the material which is used to produce cell or localized design fault and heat is stored some place in the panel and may be the cause

All thanks very much,

So not only are PVs at the mercy of if it is sunny or not but in the brightest areas (such as the desert) if the right materials are not chosen the process isn't efficient.

That is something that quite frankly you don't see much discussion about.

I am always going back to Geothermal as a possible answer to our energy needs.

What about solid oxide fuel cell.

Days are not far away people around globe will carry MEMS based fuel cell to charge cell phone, tablet and computer

Ceramic based solid oxide fuel cell is very common now in close enviornment moving palet in warehouses around USA

For stable voltage it is very common in use for hospital to computer related activities

and lsit goes on

Switch to solar thermal; perfect for your harsh conditions.

.....if the right materials are not chosen the process isn't efficient.

The PV process just isn't efficient. At elevated temperatures it is even less efficient. No surprises there. Engineer and dimension systems accordingly.

Just wait until you find out 'the reality' of geothermal in Dubai

At the merci sounds so painfully :-)

solar modules are semi conductor based photo diodes. Like any diode, temperature shows up in their equation which determines the shape of the diode.

so yes, it is true that solar panels decrease their efficiency at higher temperature. The standard test is done at 25 deg Celsisus cell temperature. At this temperature the power rating is established. Effectively in a desert climate of say 5o degrees C the panel will be at maybe 75deg C. So 50 degrees above standart test conditions.

Depending on the technology the degree to which they are affected is different. In solar this is expressed by he temperature coefficients, which for crystalline silicon (the mainstream solar modul) is about 0.4%\degC and for amorphous silicon for example about 0.2%\degC. This percentage number is how much it will be below the labeled standart efficiency.

so if you get let's assume a crystalline panel in summer in the desert, it will have a maximum power output at of about 20% less than what it would do at the same illumination in Europe in winter.

however, this is a secondary issue and taken care off in the simulation programs to predict how much energy you get per year. The More important aspect is that the gulf countries get a lot of sunshine per square meter and year. This translates in a higher kWh energy yield per panel installed than in northern climates. Even with the temperature losses, a panel installed in. The gulf countries still produces about twice the energy per year as the same panel, let's say in Germany.

clearing however really is more important here than in climates with regular rain. Even on that subject though, it is not like a little dust puts the module at zero efficiency. In reality the energy yield slowly decreases with the amount of dust building up. So you just need a routine cleaning with at frequency that optimizes your cost/earnings ratio.

the Arabian countries have a great solar potential. The task here is to get them to change their perspective after generations have been accustomed to almost free and readily available oil.

Hi Tompa - nice post.

Just a thought on the dust (and sand). I wonder how much the problem is dust and sand settling and obscuring the panels and how much is the loss of efficiency through lowering of incidental light because the surfaces of the panels is highly scratched?

One of the other posters mentioned the high winds seen in sand storms. I would think a lot of damage would be done.

I'm sure it's not a show-stopper, but it will have an effect.

Ask me again in a couple of years, as I am currently working in that region on solar and surely will get the problematic first hand.

I doubt there will be much in terms of scratches damaging the modules. In the end it is a glass surface like your car windows and I havn't headed people complaining about their windshield or windows being all scratched.

the reduction in efficiency due to dust having settled in the panels will be a definite issue. I used to work in Spain, where the dust never settled as thick sticky layers, so basically, after a while there was pretty much an equilibrium between dust being blown on and off. The losses were small as we still got very good performance ratios on these plants (the performance ratio is the actual energy yield compared to the theoretical energy yield). My experiences in the middle east are that the dust here is different. It sticks to my car like concrete. So it will definitely be another story here and I doubt a solar plant can be efficient without cleaning here.