As the name suggests, concentrated solar power uses mirrors to concentrate the sun's energy onto one point. Let's explore more...

Concentrated solar is fundamentally different from the solar photovoltaic (PV) power in that it uses the sun’s heat to generate electricity whereas concentrated solar often uses a solar-thermal method.

How Concentrated Solar Works: Mirrors surround a central tower, concentrating the sun's energy in one spot.

Solar PV cells rely on the sunlight being converted directly to electricity while CSP focus the sunlight using reflectors to generate heat that is used to run a steam engine and drive an electric generator [3].

This is the same way power is generated in a fossil fuel thermal plant – using the sun’s heat instead of heat from burning fossil fuels.

What Are The Different Types of Concentrating Solar Power Systems

There are three main types of CSP system;
1. Parabolic Trough Systems
2. Power Tower Systems
3. Parabolic Dish Systems

How Parabolic Trough CSP Systems Work

Parabolic troughs use reflective material to focus sunlight onto a focal point – a receiver pipe [5].

parabolic trough solar
Parabolic trough: The sun is focused on a central pipe.

The receiver pipe contains fluid which transfers the heat to boil water and turn generator turbines.

The parabolic trough design allows the sun’s heat to be focused to between 30 and 100 times its normal intensity [6].

A collector field is made up of an array of multiple parabolic troughs arranged in parallel along a north-south axis [4].




How Parabolic Trough Solar Panels Track The Sun

In order to maximize output, the troughs are setup with sun trackers to move about a north-south axis as the sun spans the sky from east to west [4].

This is necessary because the trough has been designed to direct all the sunlight onto the receiver pipe - therefore the angles at which the sunlight hits the trough need to be the same throughout the day.

A heat transfer fluid (HTF) runs through the receiver pipe. Oil is commonly used at the HTF but molten salt is also used frequently [2].

The main characteristics of these fluids are that they can retain high temperatures without turning into gas.

This hot fluid is channeled through a system of pipes where it heats water and generates steam, which is routed to run a steam powered turbine that drives an electric generator [5].

Some advanced systems have energy storage systems that allow the storage of hot fluid for use after the sun sets while other systems have fossil fuel or natural gas powered backup systems [4].

Parabolic trough systems are the oldest and thus most common CSP systems in use today with early developments of about 354 MW which were installed between 1984 and 1991 in the Mojave Desert in California [5].

How Concentrated Solar Towers Work

Concentrated solar towers work on the same principle as the parabolic trough system:

  1. Sunlight is manipulated to heat fluid
  2. Which generates steam.
  3. The steam powers an electricity generation power plant (see below).

The difference between solar towers and parabolic trough systems

The main difference between the tower and parabolic trough systems is the way the sun is reflected.

Solar tower systems use an array of mirrors, known as heliostats, which have been programmed to track the sun’s motion [4].

These heliostats focus and concentrate the sunlight on a central tower mounted receiver. Unlike the Parabolic trough which increases the sun’s intensity about 100 times, the tower system causes the sunlight to hit the receiver at about 1,500 times the normal intensity of the sun [6].

In 2009, a 20MW solar tower plant went online in Seville, Spain [7]. According to reports the tower systems will be developed to generate between 50MW and 200MW each in the near future [4].

 
 

How Parabolic Dish Solar Power Systems Work

The parabolic or solar dish systems focus and concentrate the sun’s intensity in a manner amplifies it up to 2000 times [6].

This high intensity makes it the most efficient system attaining a sun-to-grid conversion rate of 31.5% [7].

The parabolic dish system is made up of a solar concentrator, which is a dish, and a power conversion unit.

The power conversion unit is made up of a heat engine mounted on a receiver [4].

The Dish is mounted on a two-axis system that is programmed to follow the sun throughout the day because the concentrator has to get the most out of the sun in order to maximize the heat delivered at its focal point where the power conversion unit is located [4].

The receiver, which is part of the power conversion unit and lies between the engine and the dish, is made up of a series of tubes that carry a cooling fluid.

This system is conventionally smaller than the solar tower and parabolic trough systems. Nevertheless, what it lacks in size, it makes up for in power generation.

What heat transfer fluid is used in Concentrated Solar Photovoltaic Systems (CSPs)?

Most systems use either helium or hydrogen as the heat transfer fluid. The fluid absorbs the heat directed at the power conversion unit by the dish and transfers it in controlled amounts to the heat engine where it is converted to electricity [6].

Stirling or Brayson Cycle engines are the preferred choice of power conversion engines used in these systems [4].

The Future of CSP

It is natural that CSP would be compared to solar PV when assessing the future of the technology because they are both solar powered systems. There are three main factors considered when power utilities are debating on which renewable energy technology to generate electricity from. They are [8]

i. Competitive energy Cost
ii. Ancillary Services
iii. Delivery Upon Demand

Leading researchers argue that CSP is in a position to perform better than solar PV in all the three categories [9] especially since the inexpensive thermal storage offered by CSP systems allow for better delivery of energy upon demand [9].

Nevertheless, the recent drops in PV prices of between 30% and 40% have rocked the boat enough for investors to trust more in PV technology [11].

The bottom line is that the CSP technology still lags far behind PV as far as market penetration is concerned.

As a result, market growth surveys and projections continue to indicate that the technology will take a long time to catch up with solar PV.

CSP system installations are expected to reach about 10.8 GW and PV systems to reach 45.2 GW by 2014 while the two systems reported 0.29 GW and 7.0 GW in 2009 respectively [10].

This shows that the market growth prospects of CSP systems are much faster than PV since CSP systems are expected to increase 37 times while PV will increase about 6.5 times. Other factors such as availability of land for CSP systems may limit the developments, but only time can tell.

 
 
 




Article References

[1]. Solar Energy At Home – Types of Solar Energy: http://www.solar-energy-at-home.com/types-of-solar-energy.html

[2]. U.S. Department of Energy, Argonne National Laboratory – Solar Energy Systems; Primer on Solar Energy: http://web.anl.gov/solar/primer/primer4.html

[3]. How Stuff Works – How Solar Thermal Power Works: http://science.howstuffworks.com/environmental/green-tech/energy-production/solar-thermal-power.htm

[4]. Solar PACES, Solar Power And Chemical Energy Systems – CSP How It Works: http://www.solarpaces.org/CSP_Technology/csp_technology.htm

[5]. The Energy Blog – About Parabolic Trough Solar: http://thefraserdomain.typepad.com/energy/2005/09/about_parabolic.html

[6]. How Stuff Works – Solar Thermal Systems: http://science.howstuffworks.com/environmental/green-tech/energy-production/solar-thermal-power1.htm

[7]. Environmental and Energy Study Institute – Concentrated Solar Power Fact Sheet: http://www.circleofblue.org/waternews/wp-content/uploads/2010/09/csp_factsheet_083109.pdf

[8]. Renewable Energy World – CSP – PV Pricing… The Ongoing Price War: http://www.renewableenergyworld.com/rea/partner/first-conferences/news/article/2011/06/csp-pv-pricing-the-ongoing-price-war

[9]. Advantages Of Solar Energy – The Future Shape of Concentrating Solar Power (CSP): http://advantagessolarenergy.info/the-future-shape-of-concentrating-solar-power-csp/

[10]. Examiner – Market Growth for PV Solar vs. CSP: Which is Fastest: http://www.examiner.com/article/market-growth-for-pv-solar-vs-csp-which-is-fastest

[11]. Renewable Green Energy Power – Solar Energy Facts – Concentrated Solar Power (CSP) Vs Photovoltaic Panels (PV): http://www.renewablegreenenergypower.com/solar-energy-facts-concentrated-solar-power-csp-vs-photovoltaic-pv-panels/

 
 

If you own a printer, from time to time you'll run out of ink.

Instead of throwing the cartridge out, see if there are any services in your area for toner cartridge recycling - services are available in most areas nowadays.

Recycling toner cartridges isn't something you do every day, but it's important!

By recycling, you'll probably save yourself some money on your new toner cartridge, you'll avoid adding a heap of concentrated toxins into landfill, and you'll avoid the emissions and waste by-products required for manufacturing a new cartridge.




Why Recycle Printer Toner Cartridges?

Where To Go?

Many printer retailers will offer their own scheme of discounts to people with old cartridges, then they'll get the printer cartridges remanufactured.

Some companies will offer a straight buy-back scheme - where you can drop your used toner cartridge into the shop and they'll give you cash.

If your retailer or manufacturer doesn't have a toner cartridge recycling scheme, you can still recycle through other-brand or generic local printer shops. They'll often accept most brands of cartridge, clean them up and refill the ink, then on-sell them.

Price - Buying a High Yield Toner Cartridge

Because it saves you money, recycling toner cartridges is generally a no-brainer.

There is a cost however. You'll need to spend a little more upfront to buy a high yield toner cartridge - one that is going to survive being refilled and cleaned over and again.

Cheap toner is available, so forking out a little more to begin with is a decision that requires weighing up the short term cost with long term monetary and environmental benefits.

Tips for Toner Cartridge Recycling




 

When it's time to upgrade your computer, it's important to take a little effort to find a good computer disposal and recycling service.

Many areas will have a national computer recyling day, sometimes also called an E-day, where people can drop off old computers and peripehrals for recycling. The old computers are then picked up by a local computer recycler and disposed of appropriately.

The computers can be taken apart and many parts can be used in other systems, or sent on to a specialized computer recyling service center to be broken down and reconstitued.




Why bother with Proper Computer Disposal & Recycling?

Computers contain a myriad of chemicals and toxins, which, if not recycled, generally end up in landfill. Once in landfill, these chemicals leach into the soil and have the potential to contaminate nearby land, vegetation, and waterways.

Some of the common toxic chemicals found in computers and computer parts include high levels of heavy metals such as lead (mainly in CRT monitor glass), mercury, phosphorus, and beryllium.

What can be recycled?

You'll need to check with your local computer recycling service, but below is a list of equipment that most will accept and dispose of appropriately.

Tips for Computer Recycling

The easiest way to go is to keep your ears open for local computer disposal events where you can bring your e-waste to a certain location and a recycling service will take it off your hands.

If you're concerned about just how eco friendly or trustworthy the recycler is, do a little due dilligence:




There are many benefits of wind energy, but also problems. We'll explore these below.

People and Animals

Wind turbines impact people and animal that live in close proximity to wind farms.

The wildlife most likely to be adversely affected by wind farms are birds and bats, who are susceptible to things such as disturbance, habitat loss and collisions.




There have been a number of high profile wind farms that have been delayed and/or cancelled due to environmental concerns, including:

According to the Royal Society for the Protection of Birds, “if wind farms are located away from major migration routes and important feeding, breeding, and roosting areas of at-risk bird species, it is likely that they will have minimal impacts” [3].

In order to minimize these risks it is essential that a thorough study of the area, including an environmental impact assessment, is conducted before planning the building of wind farms.

 

Common Complaints About Wind Farms

The most common complaint is that wind farms are an eye-sore, and a blight on the natural landscape and scenery.

Residents living near wind farms also have both psychological and physiological complaints.

Some complain of not being able to sleep due to turbine noise, and psychological issues due to the low decibel sound and vibration that the turbines produce.

The Canadian and American wind energy associations requested an expert panel review the situation and investigate. The resulting document, Wind Turbine Sound and Health Effects [4] determined the following:

 

In order to alleviate some of these issues the best plan should be to educate the residents about the impact of the wind farm.

 
 

When undertaking the development of a wind farm, planners should also take into consideration the number of residents in the area, and should consider finding areas that are less densely populated to construct wind farms.

In addition, new technological developments, and methods to reduce wildlife mortality should be prioritized, to make this clean, green energy source that much greener.




Wind Energy Jobs

The United State department of energy reports, “According to the American Wind Energy Association, employment in the wind industry’s manufacturing sector has increased from 2,500 jobs in 2004 to 20,000 in 2010, with an estimated additional 14,000 manufacturing jobs planned.”[1]

Positive impact through reduced emissions

One of the most important factors in using wind energy is that it does not have the negative environmental impact that fossil fuels do. Wind energy, unlike fossil fuels, does not produce greenhouse gases, the discharge of particles and other pollutants into the atmosphere, or cause liquid or solid wastes to be discharged into water and/or soil [2].

Between the savings on energy costs for consumers that can be realized by the use of wind energy, and the increased number of employed individuals, the benefit to economies are substantial.

 
 

Article References

[1] U.S. Department of Energy. Wind and Water Program. Wind Energy Benefits

[2] Wind Energy, The Facts. Environmental Benefits

[3] Royal Society for the Protection of Birds. Wind Farms

[4] Wind Turbine Sound and Health Effects: An Expert Panel Review

[5] Renewable Energy World. Wind energy outlook 2012: An uncertain forecast. Retrieved from http://www.renewableenergyworld.com/rea/news/article/2011/12/wind-energy-outlook-2012-an-uncertain-forecast?page=2

[6] Save Our Sound: http://www.saveoursound.org/

 

Below is a table of wind powered energy plants around the world. The table is listed from largest to smallest. In the right hand column you'll see whether it's an onshore plant or offshore.

Wind Power Plant NameLocationInstalled CapacityType 
Gansu JiuquanChina5,160Onshore[1]
Inner Mongolia EastChina4,211Onshore[1]
HeibeiChina4,160Onshore[1]
JilinChina3,915Onshore[1]
Inner Mongolia WestChina3,460Onshore[1]
JiangsuChina1,800Onshore[1]
Alta Wind Energy CenterUSA1,550Onshore[2]
Jaisalmer Wind ParkIndia1064Onshore[3]
Alta Wind Energy CenterCalifornia, United States1020Onshore[4]
Roscoe Wind FarmUSA781.5Onshore[5]
Horse Hollow Wind Energy CenterUSA735.5Onshore[5]
Capricorn Ridge Wind FarmUSA662.5Onshore[5]
Fowler Ridge Wind FarmUSA599.8Onshore[5]
Sweetwater Wind FarmUSA585.3Onshore[5]
Buffalo Gap Wind FarmUSA523.3Onshore[3]
Dabancheng Wind FarmChina500Onshore[5]
Meadow Lake Wind FarmUSA500Onshore[5]
Panther Creek Wind FarmUSA458Onshore[5]
Walney Wind FarmUnited Kingdom367.2Offshore[6]
Whitelee Wind FarmScotland322Onshore[9]
Thanet Offshore Wind ProjectUnited Kingdom300Offshore[7]
Fântânele-Cogealac Wind FarmRomaina300Onshore[5]
Hallett GroupSouth Australia, Australia298Onshore[5]
Lake Bonney Wind Farm 1, 2 & 3South Australia278Onshore[5]
Horns Rev IIDenmark209Offshore[5]
Rødsand IIDenmark207Offshore[5]
Melancthon EcoPower CentreOntario, Canada200Onshore[10]
Wolfe Island Wind ProjectOntario, Canada197.8Onshore[11]
Lynn and Inner DowsingUnited Kingdom194Offshore[5]
Waubra Wind FarmVictoria, Australia192Onshore[5]
Prince Wind Energy ProjectOntario, Canada189Onshore[12]
Enbridge Ontario Wind FarmOntario, Canada181 [5]
Robin Rigg (Solway Firth)United Kingdom180Offshore[5]
Gunfleet SandsUnited Kingdom172Offshore[5]
Nysted (Rødsand I)Denmark166Offshore[5]
OrmondeUnited Kingdom150Offshore[5]
Centennial Wind Power FacilitySaskatchewan, Canada149Onshore[13]
Capital Wind FarmNew South Wales, Australia140.7Onshore[8]
Woolnorth Wind FarmTasmania, Australia140 [5]
St. Joseph Wind FarmManitoba, Canada138 [5]
Portland GroupVictoria, Australia132Onshore[5]
Jardin d'Eole Wind FarmQuebec, Canada127 [5]
Bear Mountain Wind ParkBritish Columbia, Canada120 [5]
Port Alma Wind FarmOntario, Canada101 [5]
Chatham Wind FarmOntario, Canada101 [5]
Anse-à-Valleau Wind FarmQuebec, Canada100 [5]
Caribou Wind ParkNew Brunswick, Canada99 [5]
Erie Shores Wind FarmOntario, Canada99 [5]
St. Leon Wind FarmManitoba, Canada99 [5]
Kent Hills Wind FarmNew Brunswick, Canada96 [5]
Altamont Pass Wind FarmUSA  [5]

 

 

Sources
[1] http://www.gwec.net/index.php?id=125
[2] http://www.oces.com/projects.html
[3] http://en.wikipedia.org/wiki/List_of_onshore_wind_farms
[4] http://en.wikipedia.org/wiki/Alta_Wind_Energy_Center
[5] http://en.wikipedia.org/wiki/Wind_farm
[6] http://www.dongenergy.com/walney/Pages/index.aspx
[7] http://www.vattenfall.co.uk/en/thanet-offshore-wind-farm.htm
[8] http://www.infigenenergy.com/rpv.html
[9] http://www.whiteleewindfarm.co.uk/about_windfarm?nav
[10] http://www.transalta.com/facilities/plants-operation/melancthon
[11] http://www.transalta.com/wolfeisland
[12] http://www.canwea.ca/images/uploads/File/Case_studies/CanWEA_Brookfield_EN.pdf
[13] http://www.canwea.ca/farms/wind-farms_e.php

If you see a solar panel, the chances are it's made of monocrystalline solar cells. They are by far the most widely used solar photovoltaic technology.

This article looks in detail at how monocrystalline solar panels work. If you're looking for a simple explanation of solar photovoltaics, you may wish to read the article on how solar panels work.

monocrystalline solar
Most solar panels on the market are monocrystalline.

Monocrystalline cells were first developed in 1955 [1]. They conduct and convert the sun’s energy to produce electricity.

When sunlight hits the silicon semiconductor, enough energy is absorbed from the light to knock electrons loose, allowing them to flow freely.




 

Monocrystalline vs Polycrystalline Solar Panels

Crystalline silicon solar cells derive their name from the way they are made. The difference between monocrystalline and polycrystalline solar panels is that monocrystalline cells are cut into thin wafers from a singular continuous crystal that has been grown for this purpose. Polycrystalline cells are made by melting the silicon material and pouring it into a mould [1].

The uniformity of a single crystal cell gives it an even deep blue colour throughout. It also makes it more efficient than the polycrystalline solar modules whose surface is jumbled with various shades of blue [1].

Apart from the crystal growth phase, their is little difference between the construction of mono- and polycrystalline solar cells.

The cells are usually laminated using tempered glass on the front and plastic on the back. These are joined using a clear adhesive and then the module is framed with aluminium. Single crystal modules are usually smaller in size per watt than their polycrystalline counterparts [1].

 
 

Why is silicon used in solar cells?

The atomic structure of silicon makes it one of the ideal elements for this kind of solar cell. The silicon atom has 14 electrons and its structure is such that its outermost electron shell contains only four electrons. In order to be stable, this shell needs to have eight electrons.

In its normal state or pure form, each silicon atom attaches itself to four other silicon atoms to form a stable silicon crystal [2].

In the silicon crystal’s pure state, there are very few free electrons available for carrying the electric current. In order to alter their electrical conductivity, other elements are introduced to the silicon as useful impurities in a process known as Doping [2].

 

Doping of silicon semiconductors for use in solar cells

Doping is the formation of P-Type and N-Type semiconductors by the introduction of foreign atoms into the regular crystal lattice of silicon or germanium in order to change their electrical properties [3].

As mentioned above, electricity is generated when free electrons are directed to carry a current within the cell’s electric field [2].

When the silicon atoms share their electrons, they can attain equilibrium easily because each atom needs four electrons and each can give four electrons.

The elements used in doping however, either have 5 or 3 electrons that they can share which are also known as valence electrons [3].

 

When elements with five valence electrons are introduced to the silicon crystals, the normal sharing of electrons begins, but the fifth electron remains unattached or unbound [2]. This unbound electron can easily be dislodged from the atomic shell when energy is introduced to the crystal causing it to be negatively charged.

This makes the crystal an N-Type semiconductor where the “N” stands for negative [2].

Some of the elements with 5 valence electrons include phosphorus, antimony and arsenic; phosphorus is the most commonly used element in crystalline solar cells.

On the other hand, when elements with three valence electrons such as boron, aluminium and gallium are introduced, there is a deficiency of electrons and instead, holes are formed [3].

This means that the crystal will carry a positive charge because it needs extra electrons to fill the hole left thus making it a P-Type Semiconductor where the “P” stands for positive. The holes move around seeking to be filled just as the free electrons move around ‘looking’ for holes to fill [2].

The P-Type and N-Type silicon semiconductors are combined to make the solar cell. When in contact, these two semiconductors generate the electric field which is necessary for electricity to flow in the solar cell [2].

The extra or free electrons in the N side are attracted to fill the holes in the P side. Unfortunately, at the point of contact, also called the junction of the two semiconductors, the electrons and holes mix to form a barrier preventing the electrons on the N side from crossing to the P side.

This barrier becomes an electric field separating the two sides when equilibrium is reached and acts as a diode allowing the flow of electrons in one direction, from the P-type semiconductor to the N-type [2].

 
 

Electricity generation at cell level

All that is needed for the electricity to be generated is the flow of electrons through a path provided within the electric field. However, we have seen that the flow of electrons has been localized and limited by the electric field which acts as a barrier between the cells. Nevertheless, this flow can be achieved when sunlight hits the solar cell.

The sun’s rays carry their energy in form of photons. Each photon usually has enough energy to dislodge one electron when it hits the solar cell [2].

In freeing one electron, it automatically causes a hole to be freed simultaneously. Due to the barrier’s disposition to allow the flow of electrons to the N-side only, the freed electron – if within the range of the electric field – will be sent to the N-Type semiconductor while the hole is sent to the P-Type.

Since this motion does not restore balance, the electron that was just displaced will seek to return to the P-Side so that neutrality is restored. Since the electron cannot cross back to the P Side from the N-Side via the barrier between the semiconductors, an external current path is built to allow this electron to return to the P – Side.

While the electrons flow through the external current path, we can make use of its energy to power electrical appliances [2].

 

Crystalline silicon solar cell efficiency

One of the major subjects of research into crystalline silicon solar cells is their efficiency. It's widely believed that the absolute limit is that 25% of the solar energy that hits a crystalline cell can be converted to electricity [2].

Researchers are hard at work to reach this efficiency with some companies like Sunpower and Sanyo achieving high efficiencies of up to 24% [4].

The wide spectrum of sun light wavelengths is responsible for the loss of about 70% of the energy that hits the solar cell [2].

The light from the sun has different wave lengths which we see as different colours. The different wavelengths also differ in energy content; some have more energy than the solar cell needs to produce electricity while others have less energy.

The crystalline silicon cell needs about 1.1 eV (Electron Volts) of energy to release an electron in the semiconductor; any energy that is more or less than this simply goes through the cell with no effect [2]. This energy used to release the electron is unique for each material and is known as the material’s band gap.

The band gap also determines the voltage of the cell. If the band gap is low, the voltage is also low. Therefore, although using a material that has a low band gap can increase the current of the cell, it lowers the cell’s voltage. Since Power is the product of current and voltage, the power output of the cell cannot be improved in this way. The optimal band gap for a solar cell made from one material has thus been found to be 1.4 eV so as to balance the effect of the current and voltage [2].

 
 

The Future of Monocrystalline Silicon Solar Cells

Having been in the market for more than 50 years, silicon solar cells are approaching if not passing their peak potential.

As such, extensive research has gone into improving the efficiency and lowering production costs of these systems.

Now, new technology is hitting the market. The introduction of thin film solar modules, for example, has attracted a lot of attention.

Market forces in countries like the U.S. have made it unprofitable for many companies to continue manufacturing the traditional silicon solar cells with companies like GE opting to shift its resources to manufacture thin film solar modules while it closes down its silicon crystalline solar cell plants [5].

This closure of firms has greatly been caused by the fact that manufacturing the traditional solar panels is a lot cheaper in other countries such as China, which is why some American companies are shifting production to the oriental super power [5].

The main difference between the traditional silicon cells is in the materials used to make them. The modifications that go into silicon for use in solar cells make it very expensive [1].

New construction methods and materials are much cheaper and although the efficiencies of the new technologies are much lower with thin film efficiencies ranging from 4% – 12% [6], there is still a lot of room for improvement in the new systems.

Multi-junction solar modules, which combine up to four different elements in their construction, have even surpassed the maximum efficiency of crystalline silicon modules with Spectrolab achieving 41.9% efficiency in the NREL Lab Test [4] while a commercial subsidiary of Boeing set a practical record of 39.2% [4].

 
 




Article References

[1] Wholesale Solar – Three Photovoltaic Technologies: , Polycrystalline and thin film: http://www.wholesalesolar.com/Information-SolarFolder/celltypes.html

[2] The Solar Plan – Converting Photons to Electrons: http://www.thesolarplan.com/articles/how-do-solar-panels-work.html

[3] Hyper physics – Doping of Semiconductors: http://hyperphysics.phy-astr.gsu.edu/hbase/solids/dope.html

[4] The Green World Investor – Efficiency of Solar Cells Made From Silicon (, Multicrystalline), Thin Film (CIGS, CIS, aSi, CdTe, CZTS) and Multijunction: http://www.greenworldinvestor.com/2011/04/17/efficiency-of-solar-cells-made-of-siliconmulticrystalline-thin-film-cigscisasicdtecztsmultijunction/

[5] The Environmental News Service – Modern Solar Technologies Shading Out Silicon Solar Panels: http://www.ens-newswire.com/ens/nov2009/2009-11-10-094.html

[6] Civic Solar – Thin Film vs. Crystalline Silicon PV Modules: http://www.civicsolar.com/resource/thin-film-vs-crystalline-silicon-pv-modules

A solar module is an individual solar panel - consisting of multiple solar cells, wiring, a frame, and glass.

The term solar module is often confused with solar array - a solar array is a group of solar modules (panels) which are connected to the same system.

If a roof has seven solar panels, then the roof has an array containing seven solar modules.

A solar array is a group of solar panels wired together.

The terms solar array and solar module are often confused. An array consists of multiple solar modules (solar panels).

A setup of eleven solar panels connected to the same inverter is described as a solar array containing eleven solar modules.

 




Producing electricity with solar is most efficient when panels are directly facing the sun, however there is no single, global best angle for solar panels to be installed.

Calculating the optimal angle depends on the latitude of the location where they're being installed.

According to military and government OEM solutions provider Ok Solar, for a house situated at 0-15° latitude, the best angle for solar panels is 15°. For houses situated at 25-30°, add 5° to local latitude, for 30-35° add 10° to local latitude, for 35-40° add 15° to local latitude, and for houses situated at more than 40° add 20° to local latitude [1].

The best angle for your location will also change between summer and winter, when the sun is higher or lower in the sky in your location.

Once you've calculated what is the best angle for your solar panels, you've got a few options for how to acheive it.

You can get static framing made to measure to suit the optimal angle.

Going for your optimal winter angle will make your year-round production more consistent, but having a sub-optimal summer angle will mean you're not using your panels to full capacity in the summer.

A better option for static panels is to get solar panel frames that are adjustable, so you can raise the angle during winter and lower it during summer.

Solar tracker systems are a more expensive but effective option for ensuring your solar panels have the best angle all day long, every day of the year. Solar trackers constantly change the tilt of your panels to face the sun and follow it through the day.

Installing solar on your roof is useful as not only does it take advantage of unused space, but you can also make use of the roof's pitch to achieve an optimal angle. Panels can be directly installed to the roof, or spacers can be used to adjust the angle.

For ground mounted panels, installation at the correct angle will yield around a 15% increase against panels installed flat [2].




From Einstein to space shuttles, to modern breakthroughs... the history of solar is an interesting one.

Below we'll walk through a brief history of solar energy as it has developed throughout the years, starting back in 1767!

If you want to know more about solar, check out these articles:

1767, First Solar Collector

In the year 1767 a Swiss scientist named Horace-Benedict de Saussure created the first solar collector - an insulated box covered with three layers of glass to absorb heat energy. Saussure's box became widely known as the first solar oven, reaching temperatures of 230 degrees fahrenheit.

1839, Photovolataic Effect Defined

In 1839 a major milestone in the evolution of solar energy happened with the defining of the photovoltaic effect. A French scientist by the name Edmond Becquerel discovered this using two electrodes placed in an electrolyte. After exposing it to the light, electricity increased.

1873, Photo Conductivity of Selenium

In 1873, Willoughby Smith discovered photoconductivity of a material known as selenium. The discovery was to be further extended in 1876 when the same man discovered that selenium produces solar energy. Attempts were made to construct solar cells using selenium. The cell did not work out well but an important lesson was learned - that solid could convert light into electricity without heat or moving parts. The discovery laid a strong base for future developments in the history of solar power.

1883-1891 First Solar Cells Invented

During this time several inventions were made that contributed to the evolution of solar energy use. First in 1893 the first solar cell was introduced. The cell was to be wrapped with selenium wafers. Later in 1887 there was the discovery of the ultraviolet ray capacity to cause a spark jump between two electrodes. This was done by Heinrich Hertz. Later, in 1891 the first solar heater was created.

1908, Copper Collector

In 1908 William J. Baileys invented a copper collector which was constructed using copper coils and boxes. The copper collector was an improvement of the earlier done collector but the only difference was the use of copper insulation. The improvements of the invention are being used to manufacture today's equipments.

1916, Photoelectric Effect

With Albert Einstein publishing a paper on photoelectric effect in 1905 still there was no experimental evidence about it. In 1916 a scientist known as Robert Millikan evidenced the photoelectric effect experimentally.

1947, Solar Becomes Popular in the US

Following the Second World War, solar power equipment started being popular among many people in the USA. There was a huge demand of solar energy equipment.

1958, Solar Power In Space

Solar power was used to power space exploration equipment such as satellites and space stations. This was the first commercial use of solar energy.

1959-1970, Efficiency of Solar Cells and Cost

During the period between 1959 and 1970 there was major discussion about the efficiency of solar cells and reduction of costs. Up to that time the efficiency of the solar cells was only 14% and was not comparable to the high cost of producing cells. However in the 1970's, Exxon Corporation designed an efficient solar panel which was less costly to manufacture. This was a major milestone in the history of solar energy.

1977 Governments Embrace Solar Energy

In 1977 the US government embraced the use of solar energy by launching the Solar Energy Research Institute. Other governments across the world soon followed.

1981, Solar Powered Aircraft

In 1981, Paul Macready produced the first solar powered aircraft. The aircraft used more than 1600 cells, placed on its wings. The aircraft flew from France to England.

1982, First Solar Powered Cars

In the year 1982 there was the development of the first solar powered cars in Australia.

1986-1999 Solar Power Plants

Evolution of large scale solar energy plants with advancement being made in each phase. By the year 1999 the largest plant was developed producing more than 20 kilowatts.

1999, Breakthroughs in Solar Cell Efficiency

The most efficient solar cell was developed, with a photovoltaic efficiency of 36 percent.

2008, Subsidy Reduction in Spain

Due to the global financial crisis in the year 2008, the Spanish government reduced subsidies on ongoing solar power production in the country. This had a negative effect on the industry across the world.

2010, Evergreen Solar and Solyndra Fail

Two leading solar companies failed. This was due to lack of market for their high technology produced products

2012, Record Breaking Solar Plants

The past few years have seen enormous investment in utility-scale solar plants, with records for the largest frequently being broken. As of 2012, the history's largest solar energy plant is the Golmud Solar Park in China, with an installed capacity of 200 megawatts. This is arguably surpassed by India's Gujarat Solar Park, a collection of solar farms scattered around the Gujarat region, boasting a combined installed capacity of 605 megawatts.




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