@ Priyankar. Current commercial available solar cells do not convert heat into electricity. However, PVT (photovoltaic solar thermal) hybrid systems present a more efficient way of utilizing incident solar radiation. Generally, when solar panels become very hot, their efficiency decreases. In order to improve the performance of solar cell, it may be necessary to cool them to their normal operating temperatures using a thermal system. You can then use the thermal system for heating purposes and no energy is lost ( in theory).

You can get more infor on PVT system studies from this publication from my group; http://ac.els-cdn.com/S0960148114001207/1-s2.0-S0960148114001207-main.pdf?_tid=bbe027f6-d305-11e3-8c8b-00000aab0f02&acdnat=1399150913_212ad394add532c8fe1075e4c6caa09e

The only reliable and proven way to store solar energy currently is using batteries. Another interesting idea will be to have a very world wide electrical grid just like we have a world wide fiber optics cable network for internet. That way you know, the sun is always shining somewhere and using demand side management, there is a possibility of stabilizing energy supply.

I agree that there is a huge potential for rooftop PV systems. There is a lot of space on skyscrapers, stadiums, parking lots etc. We can also use roofing shingles for our homes and windows can also generate huge amounts of energy.

As per my opinion - Cost (affordable to middle tier people) is a major botteneck currently which is reducing in its own pace and we can expect a change soon

The storage capacity is lacking..

Look at the german experience on renewables. 25% of green energy is possible today, but lessons need to be learned.

The solar business was spoiled by the politics who were misleaded by the greedy investors. It is recovering slowly..

None of the problem is at technological level.. it is only a human decision making question and organisation.

Going above the levels reached in Germany, is still not really a technological problem, but again a "will" problem.

To find out who will profit the most, and to sit then at the right place.. these are the only problems..

lukas

The answer is very simple. Solar energy is not a concentrated form of energy, so that you just harvest it and use it. It is a very diluted form of energy (as it is spread over a large area) and hence you must have some mechanism to concentrate it (may be by using multiple solar panels situated on various points over a large area and connected to a central facility of storage).

Yes, we have been developing and using solar energy for a long time and also we have achieved a reasonable generation but still there are certain limits like cost of generation and quality of power , the large scale use of solar energy is an issue.

Cost, cost and cost!!!

A lot of research is needed to make the solar cell more efficient to capture more and more solar energy in a short time. Second and most important limiting facor is the area required to install the solar panels in the city area where the cost of space is too high. For solving this we can install them outside the city and then carry the electric power from this site to the consumer's site.

The solar power is available only for 5 hours of the day. So if we generate the power during this time and consume it during the day time only, so no storage is required. This is mainly beneficial for the industries. A strong political willingness is required to do this.

There are a number of barriers to the large scale adoption of solar energy. Just like any other form of energy, you need to understand the value chain of solar energy from generation, through transmission up-to distribution.

Solar energy integration into the grid or the concept of smart grids presents both opportunities and challenges but the main problem lies with the current utilities who still want to maintain their monopoly over the grid. Adoption of solar energy on a large scale threaten the very existence of traditional grid from coal/oil producers and the transport sector who may be forced to cancel many years of contracts. These oil moguls are not going to allow that to happen without a fight. They have done everything to campaign against renewable energy mandates in states like Michigan and they have succeeded, but just for now .

The rest of the technological challenges can be overcome with time. Its normal for government to provide subsidies for any new technologies and this has been the case with oil and nuclear energy at some time. Advanced test-beds are already under way to test the viability of the smart grid and storage (http://www.renewableenergyworld.com/rea/news/article/2014/04/nice-grid-offers-a-glimpse-into-the-future-for-solar-pv-plus-energy-storage?cmpid=SolarNL-2014-04-29).

In short, the bottleneck is mainly due to lack of awareness on the general public coupled with aggressive propaganda by the proponents of the current grid and everyone in their chain of supply. This is out of fear for their own existence. The technology is now mature (net metering, feed-in tariffs, demand-side management, etc) for integration into any country's energy mix, one step at a time and this is inevitable. Solar panels are now available for way than less than $0.65/W and the total BoS reduction are now substaintial

Are there any technical challenges? off-course they are, just like with ant new technologies but whatever, the really challenges are, they are less serious than space exploration and we are still going into space.

For those who are misinformed, there is enough space (land and roof for most countries) for PV systems installtion and yes improvements in cell efficiency will greatly reduce this area. The cost is comparative enough for now.

I agree that it is both cost and politics that hinders adoption of solar power. But in my country Nigeria government has shown tremendous interest but need to move further by way of subsidizing for people

Thought I could share some interesting article on renewable energy affordability and how some communities have taken a proactive role to embrace this energy of the future.

http://www.renewableenergyworld.com/rea/news/article/2014/05/the-time-for-wind-and-solar-energy-is-now?cmpid=WNL-Friday-May2-2014

http://www.renewableenergyworld.com/rea/blog/post/2014/04/how-solar-is-cutting-grid-costs?cmpid=WNL-Friday-May2-2014

http://www.renewableenergyworld.com/rea/news/article/2014/05/uk-set-to-lead-utility-scale-solar-market-in-2014?cmpid=WNL-Friday-May2-2014

http://www.renewableenergyworld.com/rea/news/article/2014/05/hokkaido-is-the-new-solar-capital-of-japan?cmpid=WNL-Friday-May2-2014

A good question and good number of wise answer. Can I add one more question? Can I store/convert solar energy as well as solar thermal energy simultaneously into electricity (.....I don't know whether solar panels convert heat into electricity...I dont know)? any answer

@Dr Mrudul, good idea..........how about solar panel roofing of factories.........it will save roofing cost....no land purchase needed. how about that?

@Jephius...special thanks

@ Priyankar. Current commercial available solar cells do not convert heat into electricity. However, PVT (photovoltaic solar thermal) hybrid systems present a more efficient way of utilizing incident solar radiation. Generally, when solar panels become very hot, their efficiency decreases. In order to improve the performance of solar cell, it may be necessary to cool them to their normal operating temperatures using a thermal system. You can then use the thermal system for heating purposes and no energy is lost ( in theory).

You can get more infor on PVT system studies from this publication from my group; http://ac.els-cdn.com/S0960148114001207/1-s2.0-S0960148114001207-main.pdf?_tid=bbe027f6-d305-11e3-8c8b-00000aab0f02&acdnat=1399150913_212ad394add532c8fe1075e4c6caa09e

The only reliable and proven way to store solar energy currently is using batteries. Another interesting idea will be to have a very world wide electrical grid just like we have a world wide fiber optics cable network for internet. That way you know, the sun is always shining somewhere and using demand side management, there is a possibility of stabilizing energy supply.

I agree that there is a huge potential for rooftop PV systems. There is a lot of space on skyscrapers, stadiums, parking lots etc. We can also use roofing shingles for our homes and windows can also generate huge amounts of energy.

@Jephius, worldwide electricity is a very nice idea, infact places like Africa and Asia will have much potential to earn money by this.

@Jephius, can carbon-chips be used instead of silicon-chips in SPV?

@Jephius, just read your paper...a good work indeed. It is said PVCs can only utilize a small band of solar wavelength into electricity, then why not the glass cover of the panels are made of a particular color?

solar cell panels have a variety of limits such as solar spectrum wideness with narrow absorption of material, photon and carrier scattering and etc.; then solar energy either can not be absorbed in a cell with limited thickness or the created carriers can't be taken out of the cell. you should consider solar intensity and the incidence angle variation during a day and different seasons. Also, solar panels installation has its own challenges where in a matrix grid of cells you should optimize serial currents of columns and parallel voltages of the rows. However, solar energy, as a clean energy resource, should be studied more and more. At last I should mention that these are only some instances of this green energy problems.

Yes, We have been developing and using solar energy for a long time. But the large scale use of solar energy is still not possible due to its low efficiency and still comparatively high cost. The other technical problems that we need to address before it can support a large proportion of human power need is its grid integration and related issues like power quality.

@Harish. I am not sure if your generalization is accurate. Solar energy is surely gaining ground. Currently the USA have more than 10 GW of installed solar PV generation (both utility scale and distributed generation). This excludes the concentrated solar power plants. The cost ($/W) for systems have droped by half. You can access more data from http://www.nrel.gov/docs/fy13osti/56776.pdf.

Globally, we have more than 100 GW installed of which 30 GW is connected to the grid. You can find an update in this article; http://www.renewableenergyworld.com/rea/news/article/2013/02/100-gw-of-solar-pv-now-installed-in-the-world-today.

So yes, solar can be used and is being used on a large scale all over the world including Germany, Japan, USA, Spain etc and all the technical problems related to grid interconnection are well known. National codes and standards such as the IEEE 1547 series for distributed generation grid interconnect have long been documented and are continually being revised.

Efficiency is not a big issue on system performance. It only adds balance of system cost (BoS) and costs due to additional panels and land/roof area. Besides, most coal fired power plants are still around 33% efficient or less. Check the efficiency of nuclear, natural gas etc and you will realize that despite centuries of using these technologies, they are still very inefficient. Hydro is the only efficient way of generating energy.

@Priyankar. Its true Africa and the middle east have the greatest potential for Solar projects but political stability is a major challenge. Investors need a stable environment to ensure their interests are protected.

Currently there are no commercial carbon solar cells. However, there is ongoing research which is promising printable, flexible and cheaper all carbon solar cell. see http://www.technologyreview.com/news/506901/all-carbon-solar-cells-will-mean-cheap-and-flexible-solar-panels/. Carbon nano-tubes solar cells have long been demonstrated in the lab.

Storage.

If you could convert sunshine into liquid fuel, you could use it when the sun wasn't out, you could pipe it to dark places, into the city and factories, and you could refuel electric cars in a few minutes, making them practical. If you had pumped water storage,decent batteries or supercapacitors, you could have many of the same benefits.

Otherwise, we'll still need base load generators (coal and nuclear), and peaking generators (gas).

@James. I totally agree with you when it comes to base load, renewables, Solar, Wind and Tidal in particular are not yet mature enough for that yet, but they can reduce the amount of fossil and nuclear fuels and thus pollution if integrated into the grid.

Hopefully we will get a break-through soon when it comes to storage technologies.

Interesting article

http://www.renewableenergyworld.com/rea/news/article/2014/05/fukushima-japan-rebuilding-communities-with-solar-commits-to-a-100-percent-renewable-energy-by-2040?cmpid=WNL-Wednesday-May21-2014

http://www.renewableenergyworld.com/rea/news/article/2014/05/why-new-nuclear-technology-hurts-the-case-for-renewables?cmpid=WNL-Wednesday-May21-2014

Use of solar PV enery especially for domestic use is gaining momentum in India. But the present constraint is that it needs storage battery for its storage and utilisation. The life of the battery is normally 4-5 years and its periodic replacement is expensive. If we are able to supply the electric power captured to the grid directly, it will facilitate discarding the storage battery. I hope this would happen in the future and there would be a wide-spread use of PVC .

Challenges such as low efficiency and relatively high operational costs are still a stumbling block to large scale operation of solar panels. Issues such as cleaning and dusting the panels also comes with large costs, and reduce the shiny surface of the panels, ... thereby affecting their efficiency and ultimately the power produced. It will still take some time (probably a decade or more) before solar, wind and/or tidal energy generation becomes of age - i.e. large scale efficient and cost effective (green) energy production.

Good luck, I hope this helps.

Responses here seem to be for huge scale projects... And that is NOT where Solar matters most....

Think about recharging cellphones in remote areas.... once you can do that, it is logical to expand to tablets, PCs, wireless devices, home appliances, etc....

Think about water desalinization and pumping.. a little bit of power - in the right place - is extremely important in this...

Think about local power generation - versus use. A little power locally can do a lot. LED type lighting is getting BETTER - every 18 months or so... When you don't need transmission lines (which burn about 7.5% of the power they transport in the US, alone) - it means a more efficient use...

Think about how the current Grid is used for political and economic control... This can be very adverse in a lot of counties... In the old days, the British used to use a salt control and rationing strategy to control Colonial India. We do need to free ourselves from control mechanisms by authoritative politicians and eco-bureaucrats...

Think about the ability to make fertilizer in small batches - in remote locations. This is a really, really big issue...

Large scale is not automatically more efficient or more effective. That's 1900's political speak...

Think instead of the idea: enough power when it's needed.

--jr

I totally agree with you Jerry. However this requires a total change of mindset among most of us who thing that centralized is better than distributed generation.

Centralized is PERFECT in many situations... You can't easily have a hydroelectric damn in your backyard, for example...

BUT... Solar and Wind power are EXCELLENT for supplemental, remote, low power, and other applications...

Jephias is absolutely right about the need for a culture / mindset change..

In addition to some previous bottlenecks explained by the scientists, the payback period of PV cell investment is long like 8-10 years because of high cost of PV panels today. This case cause the negative effect specially on home applications of PV panels even in zones having enough solar radiation.

Serdar:

From a "Utility" point of view, your comments may be on target.

From the consumer or user's viewpoint, the story may be different.   From this viewpoint, each application is different...   If a user is a "long way" from the electric grid - then stranded connections DO make the cost of regular grid power VERY EXPENSIVE...  so Solar is much CHEAPER than a grid hookup...

If you have a good location, then Solar can SUPPLEMENT grid power..   so that you burn LESS energy at the power plant - by having good solar power systems at the consumer's location...

Transmission lines burn an average of 7.5% of all power move over the tlines.. this is completely wasted - as far as the user is concerned.

High solar panel costs is NOT the impediment to seeing solar panels used everywhere..   it is the HIGH COST of a minimal installation - and the high cost of inverters/installation.. 

If you could HOOK UP just ONE PANEL - and use it to OFFSET the power from YOUR REFRIGERATOR alone...  then the "utility" promoted equations simply DO NOT HOLD SWAY...    

As it is now...   tthe "COST OF PANELS" problem is MUCH LIKE having to buy a 15 passenger Bus in order to drive around.    Instead of an efficeint car or taking the public transit.   

COST of Solar Panels - is just not the problem at all..   It is a distraction from how people actually use panels and what they use power for....  

Couple of years back, space requirements for solar PV projects was the big concern. Since the solar PV plant is installed on rooftop, it don’t require extra space. Mostly rooftop space remains unutilized and solar is the best way to monetize your rooftop space. Read article titled "Why Rooftop Solar PV Plant Is So Good For You?" for more information http://greencleanguide.com/2013/12/11/why-rooftop-solar-pv-plant-is-so-good-for-you/

good article...

The DIFFICULT part in the US - is to (a) hook up small arrays to the grid in a SAFE and CHEAP fashion; (b) competing against a low cost infrastructure - that is both reliable and 24 hrs/day operable...

I think..   there is some research that could look at solar power viability - versus grid tie power/cost...    factors include Power Line quality (ie, Phase dropouts and low voltage instances).

Direct solar use - for water heating/purification - is also a great topic...