We can be happy about any kWh produced in the current situation with solar systems. The solar energy is free of any costs and free of CO2 emissions. Producing energy, heating or cooling does not need as much steel and concrete as big wind turbines need. Some solar systems even are nearly free of maintenance.
Powered by Sun there are mainly two different systems:
A - Thermal systems for cooling and heating, even producing electrical energy
B - PV / Photo Voltaic systems for producing electrical energy
A - Thermal systems for cooling and heating, producing electrical energy
Solar thermal energy (STE) is a form of energy and a technology for harnessing solar energy to generate thermal energy or electrical energy for use in industry, and in the residential and commercial sectors. https://en.wikipedia.org/wiki/Solar_thermal_energy. In Solar Thermal Technology collectors in several designs are used as flat and vacuum tube collectors – not to be confused with flat PV modules, which are an array of interconnected PV cells) and even other designs as parabolic trough designs (in German language : Flachkollektoren, Vaccumröhrenkollektoren und Parabolrinnenkollektoren).
All solar collectors convert the solar radiation into heat for hot water, heating and solar cooling – or for electricity. Flat solar thermal collectors are very easy to mount, but by their simple construction do have high heat losses. Solar vacuum tubes collectors work as a thermos, inside the heat is stored. They need less space as flat collectors and have a higher efficiency (page 12, Bauen + Wohnen, Solarenergie, Beilage Landsberger Kreisbote).
Costs and Return on investment (ROI) in Solar Thermal Systems
When considering costs not only the higher efficiency is reducing the costs, solar thermal collectors need less space than PV systems: There are less costs of surfaces and the far more expensive substructure foundation and the mounting frames.
In 2014 costs were about a third part of the costs of PV systems, therefore collector systems seem as well a good base for businesses. “It is just that there are clear priorities of what provides the best return on your investment and what most reduces the need for burning fuel, and…” The following link is an independent hint. We in Royal Network & Production Alliance do not have to do anything with that company: http://www.solarconsultants.com/thermalpvcomp.php
Saving electricity: The solar tubes collector technology saves enormous percentages of electricity - compared with lower percentages if produced by Gas and Oil or even lower percentages if the electricity is produced by PV. One example: In solar thermal cooling, the overall efficiency of refrigeration is 50-55 % if OPC collectors (manufacturer AMK-SOLAC Systems AG http://www.amk-solac.com/index.php?lang=en
in conjunction with a chilling engine, with an efficiency of 0,75 % are used. If compressor refrigeration is generated by means of electricity based on gas and oil, the comparable overall efficiency is only 15 %.
In Doha / Qatar and in many other countries – even in Norwege - self-cleaning vacuum solar tubes collectors have been installed
The system built in Doha in Hamad Bin Khalifa University is a long experienced, powerful and very intelligent Solar System of vacuum solar tubes collectors. It works there now four years without any errors, free of regular maintenance. Based on a unique and highly awarded technology it has proven in operation and is stronger against high temperature, sand storms and sea water influences as corrosion than other solar thermal products especially flat plate collectors. These do not any damage to humans or animals / birds.
In Doha / Qatar - Powered by solar parabolic collectors
The Agricultural project in Qatar Sahara Forest Project aims to convert desert areas into nourishing agricultural lands with greenhouses for cultivating vegetables and fields for wheat - powered by solar parabolic collectors and by PV modules. The agricultural project is about to expand to Jordan. http://www.wiwo.de/technologie/umwelt/innovationen-katars-wueste-soll-millionen-menschen-ernaehren/8418300.html and http://saharaforestproject.com/concept/technologies.html
Solar thermal power plants with mirror systems loose precision and can be very critical
Solar thermal collector systems are harmless and seem to be a very good choice – when not combined with deadly mirror systems as in plants with solar towers, in solar plants with dish-design and Fresnel systems. All these latter systems work with mirror systems and can be very critical - unless there is no protection for humans doing maintenance and birds. Furthermore these systems seem to loose their precision over the years and each single mirror must be readjusted. They work quite ok under laboratory conditions, in practice and real conditions they seemingly not have proven in the longer run.
Solar thermal towers in Solar Thermal power plants producing electricity with mirror systems
In these often huge Solar thermal power plants with mirror systems sun’s energy is intensified by mirror systems: “Power towers (also known as ‘central tower’ power plants or heliostat power plants) capture and focus the sun’s thermal energy with thousands of tracking mirrors (called heliostats) in roughly a 2 square mile field. A tower resides in the centre of the heliostat field. The heliostats focus concentrated sunlight on a receiver, which sits on top of the tower. Within the receiver, the concentrated sunlight heats molten salt to over 1,000 degree Fahrenheit – 538 degree Celsius). The heated molten salt then flows into a thermal storage tank where it is stored, maintaining 98 % thermal efficiency, and eventually pumped to a steam generator. The steam drives a standard turbine to generate electricity” https://en.wikipedia.org/wiki/Solar_thermal_energy. Due to an oral information many plants had to be rebuilt because the salt crystallized in the pipes. Then the pipes are no longer usable.
Thermal energy at higher temperatures can be converted more efficiently to electricity and can be more cheaply stored for later use. The first commercial power plant was built in Spain 2007, named PW10 with a capacity of 11 MW. I was informed years ago, that in Spain huge damage was done to the nature, forests devastated. Since then a number of plants have been proposed and built on a number of countries as Spain, Germany, US, Turkey, China, India… https://en.wikipedia.org/wiki/Solar_thermal_energy
Ivanpah Solar Power Facility: In 2014 in the Mojave desert in California the world’s largest solar thermal plant started operation. It is mentioned in https://en.wikipedia.org/wiki/Solar_thermal_energy to generate 392 MW from 3 towers. Google is one of the minor investors (because of Google’s diversification into the energy market). 347.000 mirrors reflect and concentrate the suns’ rays onto 3 solar towers. In 3 140m high towers water is heated. Then the thermal energy is changed into electric energy by steam turbines from German Siemens company. The Ivanpah Solar Power Facility plant is constructed next to a nature reserve and has very bad and deadly effects on birds and animals. A Compliance-document writes about this awful effects: http://docketpublic.energy.ca.gov/PublicDocuments/07-AFC-05C/TN201443_20131217T074835_ISEGS_November_2013_MCR.pdf
Dish-designs in Solar thermal power plants
Dish-designs to convert thermal energy into electrical energy: Here a parabolic solar dish concentrates the sun’s rays on the heating element of a stirling engine https://en.wikipedia.org/wiki/Solar_thermal_energy
Fresnel Technologies in Solar thermal power plants and also in conjunction with PV cells
Fresnel Technologies are mirror systems, further developments of parabolic trough designs - not only used in solar thermal systems but as well in other solar power plants powered by PV cells.
“A linear Fresnel reflector power plant uses series of long, narrow, shallow-curvature (or even flat) mirrors” (mirror-stripes, as in the principle of a Fresnel-lense) “to focus light onto one or more linear receivers positioned above the mirrors. On top of the receiver, a small parabolic mirror can be attached for further focusing the light. These systems seem to offer lower overall costs by sharing a receiver between several mirrors (as compared with trough and dish concepts, while still using the simple line-focus geometry with one axis for tracking…. This is similar to trough design (and different from central towers and dishes with dual axis)….Rival single axis technologies include the relatively new linear Fresnel reflector (LFR) and compact LFR (CLFR) technologies.” https://en.wikipedia.org/wiki/Solar_thermal_energy
B – PV/Photo Voltaic Systems
We received in 2013 an information from a businessman in Bahrain and in 2014 from a German in China: From there PV will or is already flooding the markets at extremely low prices. As you know, success here is not about PV itself, but about the technologically most advanced applications connected to it, as solar street lighting or others. In Russia and in Turkey they are about to establish huge plants to produce energy by PV to serve own and foreign markets. Worldwide scientists work to increase the efficiency of the solar cells. A higher efficiency thus is reducing the costs of PV surfaces and the more expensive substructure foundation and the mounting frame. In Germany less and less PV roofs – from manufacturers here - are installed. Banks invest a lot rarer, because the margins are getting narrower and narrower. Here PV systems already can be leased. As I was informed: If only one module is affected – the whole array of modules has to be replaced. Of course, there are corrosion and sun proof applications of advanced technological systems – in conjunction with PV cells – working stable and reliable under harsh and hot conditions.
Photovoltaic solar cells and systems are mostly based on Silicon
A solar cell, or photovoltaic cell (PV) converts light into electric current using the photoelectric effect. Researchers created the silicon cell in 1954 https://en.wikipedia.org/wiki/Solar_thermal_energy
Most PV cells are based on silicon – these semiconductor until now is the most used material, but there are other base materials as well.
The whole process can be easily followed in QSTec’s website. Due to this website and in this case Polysilicon is produced, melted down and reshaped to make ingots. These vary in size and length. Then they are sliced into ultra thin wafers. “Solar cells are made from wafers and convert the energy from sunlight into electricity in what is known the photovoltaic effect. Solar cells are the building blocks of solar modules. Solar modules (also known as solar panels) are comprised by interconnected clusters of solar cells. These cells are generally protected by an aluminium housing and glass. Modules are installed in singularly or together in arrays for a wide range of residential and commercial power generation applications.” http://www.qstec.com/products/solar-value-chain-qstec
SolarWorldAG claimed a new PV technology (in end of 2014) with a solar cell with an efficiency with 21.7 %. No manufacturers of crystalline silicon have done it so far. The increase at industrially produced cells is 10 %. In the laboratory, certainly higher increases are possible. A higher efficiency is reducing the costs of PV surfaces and the more expensive substructure foundation and the mounting frame http://green.wiwo.de/wirkungsgrad-rekord-solarworld-setzt-auf-neue-fotovoltaik-technologie/
A planned solar energy producing PV plant is built with Germans, QSTec is a Joint Venture between Qatar Foundation, Qatar Solar, SolarWorld AG and Qatar Development Bank.
PV solar cells or solar thermal systems: The hotter it is - the lower the efficiency
Photovoltaic systems with solar cells – compared to solar thermal systems with several forms of collectors - are worse applicable to hot climate. With increasing heat, solar cells loose efficiency.
New solar cells: The higher the efficiency of a solar cell, the cheaper the current.
The efficiency of a solar cell indicates how many percent of the solar radiation converts into electrical energy. Thus many teams of scientists work world wide to increase the efficiency of the solar cells and to invent new solar cells, not based on silicon:
Solar Cell with Rare Earth Erbium
Fraunhofer Institut in Freiburg / Germany developed solar cells, which not only can convert the light but also the heat of the sun’s rays into energy. The infrared rays of sun’s heat give their energy to Erbium atoms. However Erbium is one of the Rare Earths, since there is then the resource problem.
http://green.wiwo.de/innovation-solarzellen-produzieren-strom-jetzt-auch-aus-waerme/
Perowskit solar cells
High power Perowskit solar cells with an efficiency of 20,1 % developed (article from17.11.2014) in Southern Korea. These cells were already certified in October 2014. A Perowskit cell was discovered in 2009. These cells will be very cheap, since Perowskites are available in masses. To manufacture such solar cells only very small amounts of the material are necessary. Solar power thus would be the cheapest power source - mentions the article. To date records only have arisen in the laboratory – the next step would be the manufacturing of efficient modules, stable and reliable. However the cell decomposes most rapidly when exposed to moisture.
Researchers hoped that the cells might be printed on glass, steel, plastic and other materials as parts of facades. This meanwhile has turned out as impossible, as I was informed http://green.wiwo.de/durchbruch-billig-solarzelle-erreicht-20-prozent-wirkungsgrad/
Concentrator solar cells
consist of more than 30 electro-optically active layers, which are produced in a complicated process. They are not made from silicon, like most cells – but from compounds – the so-called VII semiconductors, elements from the third and fifth group of the periodic table of the elements, such as gallium, arsenic, indium and http://green.wiwo.de/wirkungsgrad-forscher-knacken-weltrekord-bei-solar/. Solar cells working with other technologies are said to have a far higher efficiency than PV cells.
Fresnel Technologies
These are mirror systems, further developments of parabolic trough designs - not only used in Solar thermal systems but as well in conjunction with PV cells https://en.wikipedia.org/wiki/Solar_thermal_energy
Solar cooling - Solar thermal or PV systems? Qatar
In Qatar two types of PV solar cells are tested in QSTEC Qatar Science and Technology Park to produce electrical energy for the stadiums. Due to their technology PV cells are better or worse applicable to hot climate, since with increasing heat solar cells loose efficiency. Before the decision to invest more into solar cells manufacturing Qatar tests the available technologies of solar cells: The test area has 35,000 sqm and costs have been 20 millions US $. Besides electrical energy from solar cells, Qatar used already solar thermal systems. Solar thermal vacuum tube collectors are installed since 2011 in different complexes of male and female student dorms in Doha at Hamad Bin Khalifa University in the area of Qatar Foundation. Solar thermal parabolic collectors work since 2012 (?) in the Sahara Forest Project.
Solar cooling - Solar thermal or PV systems? Qatar / Stadiums
21 Aug 2015: Due to an article in WiWoGreen the cool climate in winter in the stadiums for Worldcup 2022 will be achieved by a refined system from German company Krantz TKT Aachen: Each seat is equipped with sophisticated air conditioning – from 3 openings flows cold air that is guided in that way, that the air envelops the viewers – creating a micro climate to each person. The immense power consumption will be partially produced in the future in solar power plants. If from solar thermal power plants or PV solar cells power plants seems to be tested. Electricity from the sun is very useful since Qatar has 2075 - 2225 kW / square meter. Twice as much as in Germany: We’re expecting a 1000 hours of sunshine a year and the sunlight comprises everywhere 1 kW / square meter, so that we come to an annualized basis to approximately 1000 kWh. With the new cooling system 15 degrees less are claimed, counted in summer with 40 degrees Celsius out-side temperature. It’s mentioned, that the Qatari winter as well seems to be hot – thus viewers might appreciate cooling in winter as well. But in Doha around 17 degrees in December are not rare, thus a solution combining cooling and heating by the same systems should be taken into consideration. This seems or is already discussed in Qatar. The stadium Jassim-bin-Hamad is equipped with the sophisticated cooling technology. Now German Krantz TKT hopes for orders also for the remaining stadiums. http://green.wiwo.de/katars-wm-stadien-klimatisiertes-feld-dank-solarstrom
20 Oct 2016: The stadium al Al Gharrafa Stadium or Thani bin Jassim Stadium will see a friendly match between two football giants in 13 Dec 2016 http://www.qatarairways.com/global/en/press-release.page?pr_id=pressrelease_fcbvsalahli.
I.e. the energy balance/ eco audit of the system can be known already in beginning of 2017!
