Dear Soares,

 There are many methods of utilizing solar energy.

1. By using the heat energy directly for room heating, water heating, drying and some other applications.

2. By concentrating the heat energy on to a pipe or boiler by using solar concentrators of different shapes, converting water or some other low boiling point fluids into vapours, run a turbine using the vapours and generate electricity.

3. By converting the sun light directly into electricity by using Photo-Voltaic (PV) cells etc. 

You can refer any paper or book on solar energy  utilization.

Regarding your second question about the reduction of costs, presently the cost of generation of PV electricity is on higher side compared to conventional methods of generation owing to the cost of the PV panels. But yes, as more and more technologies come in, the costs will definitely come down. One thing you have to notice is that the capital cost required is more but the running costs of PV panels are pretty low as there is no fuel cost. But there is always an element of uncertainly of availability of power. A lot of research is being done to address this problem of uncertainty and increase the reliability of energy supply.

Regarding third question, the answer is in the above para. The cost of generation in conventional methods, i.e., thermal and hydel are definitely cheaper, but you know they are exhaustible in nature. There is a need to shift to Renewable energy sources.

Dear Soares,

 There are many methods of utilizing solar energy.

1. By using the heat energy directly for room heating, water heating, drying and some other applications.

2. By concentrating the heat energy on to a pipe or boiler by using solar concentrators of different shapes, converting water or some other low boiling point fluids into vapours, run a turbine using the vapours and generate electricity.

3. By converting the sun light directly into electricity by using Photo-Voltaic (PV) cells etc. 

You can refer any paper or book on solar energy  utilization.

Regarding your second question about the reduction of costs, presently the cost of generation of PV electricity is on higher side compared to conventional methods of generation owing to the cost of the PV panels. But yes, as more and more technologies come in, the costs will definitely come down. One thing you have to notice is that the capital cost required is more but the running costs of PV panels are pretty low as there is no fuel cost. But there is always an element of uncertainly of availability of power. A lot of research is being done to address this problem of uncertainty and increase the reliability of energy supply.

Regarding third question, the answer is in the above para. The cost of generation in conventional methods, i.e., thermal and hydel are definitely cheaper, but you know they are exhaustible in nature. There is a need to shift to Renewable energy sources.

Dear Marcelo,

Your question is very general, and to be a bit blunt, sounds like: "please do my homework for me". There are many introductory texts on solar energy, both on the web and in the form of books. I recommend you start with that.

Marcelo Negri Soares,

When you are asking how the solar energy works, I assume that you want to have an idea about operating principles. The answer to that question for me is:

* The concentrations of doping atoms. The mobility and diffusion coefficient. The lifetime and diffusion length. And finally, the band gap energy. 

My point of view of the second question is that the cost of electricity depends not only on how this is produced but also of the country economy. For instance, almost 70% of electricity generated in my country is by hydroelectric power stations but the electricity price is very expensive here. This happen because of an irregular economy and expensive taxes. 

About the third question, I think hydroelectric generation is cheaper than a thermoelectric or gas station because you don't produce toxic substances into the environment or society.

Much of our wealth has been grown on our laziness. It was so much easier to burn the oil which just spilled out of California then to invent the photodiode (at that time).

Then the next laziness, is the economical one, and the power of (western) economy (which is more a dictature of the few entrepeneurs) to keep a business running, and the lack of courage of the lazy customers not to change to more reasonable (sustainable) products.

today, it is probably cheaper to build photodiodes than to dig holes for oil (or clean fukushima).. but we lazy (coward) humans  can not change stupid habits.

what is cheap?  we are cheap, our attitude is cheap..  we will pay for it, our earth will give us the change.

The most modern PV module is one which divides the light into a spectrum and use the most efficient PV material in every sub part of the spectrum. By doing this you can increase the electric efficiency above 25% and still use cheap materials.

 Think one thing to find answers- Solar means heat and you can do so many things with heat. ( Generate steam, Solar Cells, Water purification, Refrigeration, Dryers etc. ). Renewable energy sources are free but materials used for energy conversion costs much. Presently Solar equipments are cheaper than equipments of other energy because in solar energy there is no use turbines (except you generate energy with steam) like other sources use turbines.

Dear Henrik Kofoed,

Can you please give some inputs regarding the increase of efficiency in PV modules?

Hi K. Prakash Kumar,

you can start the efficiency optimisation from PV losses. I shared an article from Delf University a couple days ago, where is enhanced the PV performance. I think you take into account the information below:

1. Loss due to non-absorption of long wavelengths,

2. Loss due to thermalisation of the excess energy of photons,

3. Loss due to the total reflection,

4. Loss by incomplete absorption due to the finitethickness,

5. Loss due to recombination,

6. Loss by metal electrode coverage, shading losses,

7. Loss due to voltage factor,

8. Loss due to fill factor

I hope this information help.

Thank you and best regards,

Julián Gallego

About improving efficiency in PV modules:

http://www.sciencedaily.com/releases/2008/10/081023100536.htm

http://physics.ucsd.edu/do-the-math/2011/09/dont-be-a-pv-efficiency-snob/

Thanks gentle men,

I appreciate the information.