Altprofits

Solar Energy

Introduction

Solar Energy - How it works

Applications of Solar Energy

Data and Statistics 

Solar Energy Status and Trends 

Solar Energy Projects & Companies

Solar Energy - Research Efforts

Solar Energy - Barriers

Introduction

Solar is one of the fastest growing alternative energy resources today. This introduction provides a brief overview of the industry’s classification.

There are two primary forms in which energy from the sun is being derived currently: Solar photovoltaics (PV) and solar thermal. Solar PV uses the light energy from the sun to generate electricity while solar thermal uses the heat from the sunlight to generate heat energy or to generate electricity.

The contribution of solar PV to world electricity generation is only about 0.25% (with an installed capacity of about 15 GW, 2008 data). The contribution to solar CSP (concentrated solar power), the form of solar thermal used for electricity generation, is less than 0.01% (with an installed capacity of only about 0.5 GW worldwide, 2008 data).

Solar Energy - How it works

Technology

The solar energy technology can be broadly classified as follows:

1. Solar Photovoltaic
   1. Crystalline
      1. Monocrystalline
      2. Polycrystalline
   2. Thin-film
      1. CdTe (Cadmium Telluride)
      2. CIGS (Copper Indium Gallium Selenium)/CIS (Copper Indium Selenium)
      3. CIS (Copper Indium Diselenide)
      4. Amorphous Silicon (a-Si)
   3. Concentrating Photovoltaic
2. Solar Thermal
   1. Distributed Solar Thermal
      1. Flat-plate Collectors
      2. Evacuated Heat-pipe Tubes
   2. Centralised Solar Thermal
      1. Concentrating Solar Thermal
         1. Parabolic Trough Collectors
         2. Dish/Engine Systems
         3. Power Towers
         4. Hybrid Systems / Integrated Solar Combined Cycle
         5. Linear Fresnel

Solar Photovoltaic (PV)

Using solar photovoltaic, sunlight is converted into electricity. Solar photovoltaic uses photovoltaic (PV) cells usually in the form of panels, also called solar panels.

Solar PV can be used either as stand-alone systems that are off the grid or as large systems that are connected to the electricity grid. Typical system size varies from 50 watt (W) to 1 kilowatt (kW) for stand-alone systems with battery storage and small water pumping systems; from 500 W to 5 kW for roof-top grid connected systems and larger water pumping systems; and from 10 kW to megawatts for grid-connected ground-based systems and larger building integrated systems.

Solar PV - Crystalline Silicon PV Cells

The majority of PV cells produced today use crystalline silicon (c-Si) as its light absorbing semiconductor. The c-Si technology originally was developed for the semiconductor industry to produce PV cells for integrated circuits and microchips. These PV cells have energy conversion efficiency between 11 percent and 16 percent. The energy conversion efficiency of a solar cell is the percentage of sunlight converted by the cell into electricity. While the efficiency of c-Si is high, it absorbs light poorly and requires many layers to perform efficiently in solar applications.

The two types of crystalline silicon technology used to produce PV cells are mono and multi-crystalline (also called poly-crystalline). Mono-crystalline technology uses thin wafers sliced from a single, pure crystal silicon ingot. With multi-crystalline or polycrystalline technology, silicon crystals are cast into a block and then sliced into wafers.

Multi-crystalline silicon is not as pure as mono-crystalline and therefore produces lower-quality wafers. However, it is significantly less expensive.

Solar PV – Thin Film Solar Cells

The high demand for crystalline silicon PV cells has outstripped production causing the prices to rise. As a result, a number of PV cell manufacturers have begun using less expensive semiconductor materials including amorphous silicon (a-Si), cadmium telluride (CdTe), copper indium diselenide (CIS) or copper indium gallium selenide (CIGS). These materials are good light absorbers and are fairly thin.

They are known as thin-film because they are deposited in very thin layers on stainless steel, glass or a flexible substrate. The thickness of the film is less than 1 micron. Like c-Si, thin-film PV cells are combined into modules and laminated to protect them from the elements. They are less expensive than c-Si, but only have a demonstrated energy conversion efficiency of approximately 8 %. The advantage of thin-film technology is that it can be applied over large areas, providing more opportunity to generate electricity in cloudy conditions.

The shortage of crystalline silicon has led to an increased use of thin-film PV cells. Just a few years ago, they were virtually unheard of. Today, they make up approximately 30 percent of the market. (Aug 2008 data) Thin-film solar panels are made differently compared to silicon panels. The most common process used to make them is chemical vapor deposition. Gases react inside a chamber to form a condensate that settles uniformly onto a substrate.

Solar PV - Concentrating Photovoltaic

Concentrating photovoltaic systems use lenses or mirrors to concentrate sunlight onto high-efficiency solar cells. These solar cells are typically more expensive than conventional cells used for photovoltaic systems. The concentration of sunlight decreases the required cell area while increasing the cell efficiency. This technology has potential for solar cell efficiencies greater than 40 percent. The high cost of advanced, high-efficiency solar cells requires concentrated sunlight for the system to achieve a cost-effective comparison with other solar alternatives. Therefore tracking systems are usually installed to take advantage of every hour of available sunlight.

Solar Thermal

Solar thermal is a rather straightforward application of solar energy. In this, solar energy is used to either directly provide heat energy (as in the case of solar water heaters), or the heat is used to heat liquids into steam, which is then used to drive turbines to produce electricity.

The principles of concentrating direct sunlight into useful thermal energy are very basic. The basic engineering technologies for converting thermal energy into electricity have been commercially demonstrated for over two decades.

Solar Thermal Collectors

A solar thermal collector is a solar collector specifically intended to collect heat: that is, to absorb sunlight to provide heat. Although the term may be applied to simple panels used for heating such appliances as solar water heaters, it is usually used to denote more complex installations – typically for concentrating solar thermal systems.

1. Solar Thermal
   1. Distributed Solar Thermal
      1. Flat-plate Collectors
      2. Evacuated Heat-pipe Tubes
   2. Centralised Solar Thermal
      1. Concentrating Solar Thermal
         1. Parabolic Trough Collectors
         2. Dish/Engine Systems
         3. Power Towers
         4. Hybrid Systems / Integrated Solar Combined Cycle
         5. Linear Fresnel

Distributed Solar Thermal

The solar thermal concept can be used in a distributed manner, on rooftops and to generate small amounts of energy. Distributed solar thermal is normally used for heating (eg. Solar water heaters) and drying purposes (eg. drying of wet raw materials and other industrial feedstock), than for electricity generation.

These distributed solar thermal systems use solar thermal panels. These solar thermal panels can be classified as flat-plate solar collectors or evacuated tube solar collectors.

Flat-Plate Solar Collectors

These are durable, weatherproof boxes which contain a dark absorber plate located under a transparent cover. They are still the most common type of collector used for water heating in many countries despite being inferior to evacuated tube collectors in many ways.

Evacuated Heat Pipe Tubes

These are designed such that convection and heat loss are eliminated, whereas flat-plate solar panels contain an air gap between absorber and cover plate which allows heat loss to occur. Further, thermal heat pipe systems are capable of limiting the maximum working temperature, where as flat-plate systems have no internal method of limiting heat buildup which can cause system failure. Finally, evacuated heat pipe systems are lightweight, easy to install and require minimal maintenance. Flat-plate systems, on the other hand, are difficult to install and maintain, and must be completely replaced if one part of the system stops working.

Centralized Solar Thermal

Unlike the distributed use of solar thermal panels to directly capture the heat energy from the sunlight, centralized solar thermal technology concentrates the sunlight and generates electricity from the heat thus captured.

Concentrating Solar Thermal

Concentrating solar is a technology that concentrates solar energy to heat liquids into steam, which is then used to drive turbines to produce electricity. Since concentrating solar uses existing generators, piping and mirrors, the production costs are much lower than PV solar and don’t require special production facilities.

The equipments used to collect the heat energy of the sun are called concentrated solar thermal collectors.

Solar Thermal Collectors

Concentrating solar collectors use mirrored surfaces to concentrate solar energy on an absorber tube that contains a fluid – are able to produce yet more high temperatures (300º C/570°F).

As a result of their size and expense, they are scarcely used on residential applications, and are used in large projects and electrical generation. The following are the types of collectors used for concentrated solar thermal: 

1. Parabolic Trough Collectors - These collectors combine a curved mirror, shaped like a parabola to maximize the amount of sunlight collected, with an absorber tube embedded along the center of the mirror. The absorber tube is filled with oil or other fluid that can easily be heated. When sunlight hits these collectors, the mirrors focus it on the tube, heating the fluid inside. This hot fluid is then used to boil water and produce steam in a connected device and the steam is transferred to a generator that can produce electricity. A large array of connected parabolic trough collectors is needed to provide enough power for a generator.
2. Dish/Engine Systems - These systems use an array of mirrors, arranged in the shape of a dish, to concentrate sunlight onto a receiver placed at the focal point of the dish. The heat produced by these systems is transferred to a heat engine which converts the heat into mechanical energy. This energy then drives a generator to produce electricity.
3. Power Towers - Power Tower systems use a circular array of mirrors that track the sunlight and concentrate it on a receiver, placed at the top of a central tower at the focal point of the array. In much the same way as parabolic trough collectors, heat produced by the receiver is used to create steam which then powers a generator.
4. Linear Fresnel - Linear Fresnel reflectors differ from other concentrated solar power (CSP) technologies in that their long, low mirrors reflect sunlight onto a single, horizontal tubular receiver, whereas other CSPs require multiple receivers. Linear Fresnel reflectors also require fewer acres because more mirrors can be squeezed onto a smaller parcel of land. And significantly, they can produce high temperatures, which lead to a more efficient conversion of sunlight into electricity.
5. Hybrid Systems / ISCC –Hybrid systems combine power towers with natural gas power generators currently used at many power plants, creating a system that can continuously generate electricity, even when the sun isn't shining. Hybrid systems are not usually considered a separate category in concentrating solar thermal. 

Applications of Solar Energy

The Photovoltaic technology can be used in several types of applications:

Grid-connected domestic systems

This is the most popular type of solar PV system for homes and businesses in developed areas. Connection to the local electricity network allows any excess power produced to feed the electricity grid and to sell it to the utility. Electricity is then imported from the network when there is no sun.  An inverter is used to convert the direct current power produced by the system to alternative power for running normal electrical equipments.

Grid-Connected power plants

These systems, also grid-connected, produce a large quantity of photovoltaic electricity in a single point. The size of these plants range from several hundred kilowatts to several megawatts. Some of these applications are located on large industrial buildings such as airport terminals or railways stations. This type of large application makes use of already available space and compensates a part of the electricity produced by these energy-intensive consumers.

 Off-grid systems for rural electrification

Where no mains electricity is available, the system is connected to a battery via a charge controller. An inverter can be used to provide AC power, enabling the use of normal electrical appliances. Typical off-grid applications are used to bring access to electricity to remote areas (mountain huts, developing countries). Rural electrification means either small solar home system covering basic electricity needs in a single household, or larger solar mini-grids, which provide enough power for several homes.

Off-grid industrial applications

Uses for solar electricity for remote applications are very frequent in the telecommunications field, especially to link remote rural areas to the rest of the country. Repeater stations for mobile telephones powered by PV or hybrid systems also have a large potential. Other applications include traffic signals, marine navigation aids, security phones, remote lighting, highway signs and waste water treatment plants. These applications are cost competitive today as they enable to bring power in areas far away from electric mains, avoiding the high cost of installing cabled networks.

Consumer goods

Photovoltaic cells are used in many daily electrical appliances, including watches, calculators, toys, battery chargers, professional sun roofs for automobiles. Other applications include power for services such as water sprinklers, road signs, lighting and phone boxes.

Data and Statistics 

 Solar Energy Status and Trends  

 Solar PV Status and Trends

 Data for Solar Energy (PV) Worldwide

Global Solar PV – Total Installed Capacity by Year 

The above table shows a significant increase of solar PV capacity worldwide, with the capacity more than doubling for the period 2007-12, with a CAGR of about 19%.

World Photovoltaic Installations in 2007 – by Installed Capacity

(Total installation in 2007 = 2826 MW)

Source: SolarBuzz ( www.solarbuzz.com )

From the chart above, it is clear that just two countries – Germany and Spain – constitute 70% of the solar PV installed capacity in 2007. The primary reason for these countries to achieve dominating position is their respective incentive programs for solar energy. Both the countries set attractive Feed-in-Tariffs (the price paid by a distributor of power to a producer of power) for solar energy producers, thus encouraging significant investments in solar energy.

Global Installed Capacity and Annual Percentage Increase of Solar PV Power

                                                                                                           All capacity data in MW

               Source: IEA, PV Trends 2008

Solar PV Current and Future Energy Contribution in Global Electricity Supply 

Current Contribution of Solar Energy to Global Electricity Demand 

The approximate contribution of solar energy to total electricity consumption is about 0.25% (2007).

As an industry, it is forecast that solar photovoltaics (including modules, system components, and installation) will grow from a $20.3 billion industry in 2007 to $74 billion by 2017. Annual installations were just shy of 3 GW worldwide in 2007 and were 5.95 GW in 2008.

Future Contribution of Solar Energy to Global Electricity Demand

Some key future trends in the context of solar energy contribution to electricity demand can be obtained from an analysis done by EPIA/Greenpeace.

The key results of the EPIA/Greenpeace scenario show that, even from a relatively low baseline, solar electricity has the potential to make a major contribution to both future global electricity supply and the mitigation of climate change.

This analysis was done for two different scenarios: a) Advanced, b) Moderate

EPIA/Greenpeace Analysis - Advanced Scenario

This scenario is based on the assumption that continuing and additional market support mechanisms will lead to a dynamic expansion of worldwide solar PV installed capacity.

Source: Greenpeace / EPIA Report, 2008

Source: Greenpeace / EPIA Report, 2008 

EPIA/Greenpeace Analysis - Moderate Scenario

This scenario envisages the development of PV against the background of a lower level of political commitment.

Source: Greenpeace / EPIA Report, 2008

1. The EPIA/Greenpeace Advanced Scenario shows that by the year 2030, PV systems could be generating approximately 2,600 TWh of electricity around the world. This means that by 2030 solar PV will contribute about 15% of the world’s energy consumption.
2. The capacity of annually installed solar PV power systems would reach 281 GW by 2030. About 60% of this would be in the grid-connected market, mainly in industrialised countries.
3. Although the key markets are currently located mainly in the industrialised world, a global shift will result in a significant share – about 20% or an annual market of 56 GW – being taken by the developing world for rural electrification in 2030. Since system sizes are much smaller, and the population density greater, this means that up to 3.2 billion people in developing countries would by then be using solar PV electricity. This would represent a major breakthrough for the technology from its present emerging status.

Solar Thermal Status and Trends 

The Solar Thermal Industry

The energy contribution from the solar thermal plants has been a much smaller one so far, when compared to the solar PV plants.

However, a note is in order. In some ways, it can be said that the solar thermal industry’s has been vastly underestimated because so far the data that have been considered are only the energy output of the concentrating solar plants (CSP). The contributions from the end-use markets such as solar water heaters, solar house heating systems and the like have not been captured while calculating the total contribution of solar thermal segment to the worldwide energy output.

There have been studies that indicate that, with suitable assumptions about the use of distributed solar thermal for heating and drying applications, the solar thermal energy’s total installed capacity worldwide would be far higher than that of solar PV (in the order of 80 GW for thermal vs 12-14 GW for PV). However, because these are not official estimates, for this report we too consider only the energy capacities and output of concentrating solar power (CSP) segment of the solar thermal industry.

Solar Thermal Trends

Worldwide Installed Concentrated Solar Power Plants Capacity – 2000-2008

           Source: Earth Policy Institute, 2008

Notes for the above table:

1. The numbers are only for concentrated solar power plants, and do not include solar thermal energy used for water heaters, solar heating of buildings and solar architectural design.
2. The projection for 2012 has been arrived at using some proposed solar thermal power plants that are likely to come online in the next few years.

 Solar Thermal Trends - USA

1. In the US, the home market has been the major buyer of solar thermal collectors, with almost 90% of all solar collector shipments (by area of collector) bought by this segment (2006 data).
2. In the US, most of the market in 2005 was dominated by low temperature collectors, mainly for heating water in swimming pools. (2006)
3. The industry remained highly concentrated, with 92 percent of sales made by the 5 largest companies. (2006)

Trends in the Various CSP Technologies

Among the five technologies (viz Power Towers, Parabolic Trough, Dish Engine, Linear Fresnel & ISCC), parabolic trough technology's decades of proven operation is expected to keep it in good stead for the next few years, but the technology's head start could start diminishing as the potential of central receiver and other technologies are realized at a commercial scale, according to some studies. In about 3 years’ time (by end of 2010), it is expected that the real potential of the other three main technologies – Power Towers, Dish Engine, and Linear Fresnel – will be much more clear.

Concetrating solar power (CSP) is a proven technology with over 500 MW of installed capacity working worldwide, for many years. In the US alone, over 350 MW of CSP has been commercially operating in the Mojave desert since the 1980s.

Currently (as of 2009), most of the CSP power generation is done using the established parabolic trough technology. Several emerging technologies that promise higher conversion efficiencies and cost-competitive generation have been demonstrated on a smaller scale. These technologies, such as point-focusing power towers and line-focusing Fresnel reflectors, may extend the ability of CSP to provide baseload power in addition to peak load.

Commercial scale CSP technology was first developed in the wake of the oil shock of the 1970s. The largest plants constructed in this period were the nine Solar Electricity Generating Systems (SEGS) in the Mojave desert in California, built from 1984 to 1991 by Luz International. Post 1970s, the growth of CSP remained low and was restricted to mostly small pilot projects of 5 MW or less.

For nearly two decades, no new large-scale, grid-tied CSP plants were built anywhere in the world. However, in the last few years, there has been renewed interest in CSP world over. In addition to the USA, where a couple of medium sized CSP plants have started coming online since 2006, CSP has started gaining ground in Europe as well. In 2008, the first European commercial CSP plant, the 50-MW Andasol 1 project, was completed in Granada, Spain.

The current worldwide installed capacity of CSP is 502 MW (as of Mar 2009), of which 410 MW are in the US.

In the US alone, a further 8500 MW of CSP capacity is scheduled for installation by 2014. Approximately 40% of this capacity is expected to utilize parabolic trough technology, and the remainder is expected to use LFR, power tower and dish technologies.

Outside of the US, Spain is the leader in the CSP market with 1037 MW of capacity currently under construction and an additional 6000 MW of projects in the pipeline. Spain’s attraction to CSP technology has been spurred by government incentives, including the Spanish Royal Decree, which calls for 500 MW of CSP by 2010.

Other regions with plans for CSP development include the Middle East, North Africa, and Australia. In the Middle East, 325 MW of CSP capacity are being planned in countries such as Israel, Egypt, Algeria, Abu Dhabi, and Morocco. 

Distributed Solar Thermal

Solar thermal has been used in households and industries for water heating and drying. These systems typically use flat plate or evacuated type solar thermal collectors. Authentic data for the total capacity / area installed for solar thermal is not available on a global basis. However, based on news and trends, it is clear that distributed solar thermal is gaining ground in a lot of developing and underdeveloped countries owing to its ease of installation and cost savings associated with it. The growth is especially rapid in countries such as India that have large regions that get high sunlight throughout the year.

Solar Energy Projects & Companies

Top Proposed Solar Thermal Energy Projects Worldwide (as of June 2008)

Solar Energy - Research Efforts

New Developments in the Solar Industry

 A number of technological and product innovations are taking place in the solar energy industry. Some of the recent and emerging trends in solar energy are provided below:

1.  Concentrated Solar PV (CPV) - This mechanism for focusing light on small areas of photovoltaic material could make solar power in residential and commercial applications cheaper than electricity from the grid in most markets in the next few years. CPV is not exactly a new technology, but its deployment has been so far in very limited domains, and there have been no large commercial deployment of this technology. 

1. Nano-size Carbon Molecules Dubbed Buckyballs: Silicon-based solar cells represent 92% of today's photovoltaic market, but some producers are betting on different, much cheaper materials for the future. One is a conductive polymer salted with nano-size carbon molecules dubbed buckyballs. Which when applied a very thin coating of the buckyball mixture on a plastic film produce a solar cell that topped 5% efficiency - the best yet for an organic solar cell. The cost of these solar cells would be a fraction that of their silicon cousins, so a homeowner could buy five or ten times the surface area and still save money.
2. Dye Sensitized Thin-Film Solar Panels - A different type of thin-film solar panels is made using a light-absorbing dye. The anode is made from a glass plate coated with a conductive layer and a layer of titanium dioxide. The plate is then dipped into a dye which bonds to the surface of the titanium dioxide molecules. The cathode is made from a plate coated with a conductive layer and an iodine electrolyte. Both plates are joined and the edges sealed to help prevent the electrolyte leaking out. Light photons that are absorbed by the dye molecules create free electrons that cross over to the titanium dioxide, where they move up to the conductive layer on the anode. Meanwhile, the dye gains an electron from the iodine electrolyte, which later recovers it from one of the returning electrons at the cathode.
3. Organic Solar Coatings are under development at companies such as General Electric Co. (GE) and IBM (IBM). Organic solar cells are also the focus of multi-million $ research efforts in Europe.
4. Thin-film Solar Cells: The basic technology has been around for decades, but Silicon Valley–based Nanosolar created the manufacturing technology that could make that promise a reality. PowerSheet solar cells are made with printing-press-style machines that set down a layer of solar-absorbing nano-ink onto metal sheets as thin as aluminum foil, so the panels can be made for about a tenth of what current panels cost and at a rate of several hundred feet per minute.
5. Dish Technology: The Stirling dish technology converts thermal energy to electricity by using a mirror array to focus the sun’s rays on the receiver end of a Stirling engine. Each panel tracks azimuth and elevation to keep the sun’s rays focused at greatest intensity possible. This is almost twice as efficient as other solar technologies. A 20-year purchase agreement between Southern California Edison and Stirling Energy Systems signed in 2005, Inc. will result in 20,000+ dish array, covering 4,500 acres, and capable of generating 500 MW -- more electricity than all other present U.S. solar projects combined.
6. Transparent Electronics: Oregon State University (OSU) and HP’s Xtreme Energetics are working together on transparent transistors and optoelectronics technology. This technology converts sunlight to electricity at twice the efficiency and half the cost of traditional solar panels. HP has funded some of OSU’s research in advanced materials, collaborated with the university to invent transparent transistor technology, and is now making that technology available worldwide through its intellectual property licensing group.
7. PowerCube Makes Solar Energy Installation Simple  - The PowerCube makes deployable renewable energy simple by integrating the latest solar energy, power storage and power management technology. It is engineered for home use, emergency response, construction, and any other remote power needs. It’s large size (72 x 124 x 50 inches) enables it to produce 600 watts of solar power. (Jul 2008)
8. Aussie Hybrid Panel Could Halve Solar Cost - Scientists have invented a new breed of solar panel which generates electricity and hot water at the same time – and could halve the cost of going solar. Household roofs would be kitted out with rows of mini-troughs, made of mirrors, if the project gets off the ground. (Sep 2008)
9. Solar Panels That Can be Applied to Windows and Canopies - A thin polymer photovoltaic layer called Powerglass can be applied to windows, canopies and roofs to turn them into mini power plants to supply electricity. Huge high rise buildings have much more surface area in the form of windows than they do on top of their roughs. This means that Powerglass is poised to be an attractive idea and potentially can increase the use of solar panels dramatically. (2005)
10. 3-D Solar Panels - Unique three-dimensional solar cells that capture nearly all of the light that strikes them could boost the efficiency of photovoltaic (PV) systems while reducing their size, weight and mechanical complexity. The new 3D solar cells capture photons from sunlight using an array of miniature “tower” structures that resemble high-rise buildings in a city street grid. The cells could find near-term applications for powering spacecraft, and by enabling efficiency improvements in photovoltaic coating materials, could also change the way solar cells are designed for a broad range of applications.
11.  String Ribbon Approach to Manufacturing Solar Panels - Reducing the cost of solar power requires slashing the cost of manufacturing the silicon wafers on which solar cells are built. A technique first proposed in the 1980s by Professor Emanuel M. Sachs is doing just that by doubling the number of wafers made per pound of expensive silicon. Making silicon wafers currently accounts for 45 percent of that total cost. The conventional way to make silicon wafers is to cast a solid brick of silicon and then slice it into wafers. But slicing makes dust, and in this case the dust is expensive silicon, no longer pure enough to be recycled. So Sachs came up with an approach that does away with slicing. Instead of making bricks, his String Ribbon process makes long sheets of silicon just the thickness of a wafer. No slicing, no waste. In 1994, Evergreen Solar, Inc., began manufacturing crystalline silicon PV modules using the String Ribbon approach.
12. Companies such as Sharp have been working on breakthrough technologies to incorporate advanced surface texturing processes for manufacturing solar panels. These technologies result in panels that have increased light absorption and overall efficiencies.
13. Enerize Corporation of Florida has claimed a major breakthrough in improving the performance of photovoltaic module with transparent polymers to replace glass. The photovoltaic module designs use proprietary polymer protective coating materials to replace conventional glass can increase conversion efficiency by more than 20%, due to high transparency and concentration of incoming light, while providing resistance to degradation by UV and ionizing radiation, lower cost, reduced weight, and improved mechanical strength. (May 2008)
14. Photoelectrochemical (PEC) PV Cells - Unlike other PV cells that use solid crystal layers to absorb light, PEC cells are liquid. They absorb light with a dye sensitizer and use it to create electrical current in a nanocrystalline titanium dioxide semiconductor layer. The cells are encased in a carbon layer on the back and are contained in glass on both sides. A number of companies are developing this technology and they could be introduced commercially in the near future. These cells are expected to compete by significantly reducing the cost of PV cells. (Aug 2008)

 Solar Energy - Barriers

 Problems and Barriers for Solar PV

1. Raw material supply bottlenecks, manufacturing inefficiencies, the need for scale in order to achieve manufacturing economies and the difficulty in manufacturing low-cost-high-efficiency solar panels are the key problems faced by the suppliers in the solar PV industry
2. The high cost of solar PV, in the form of its high capital cost, is the biggest problem faced by the consumers of solar PV technology

Case Studies

First Solar (USA)

www.firstsolar.com

First Solar's ramp up in manufacturing has been integral to driving deep reductions in the cost of its modules. Between 2004 and 2008, First Solar's manufacturing costs declined from approximately $3.00 per watt to less than $1.00 per watt, the first company to break a benchmark long considered the "holy grail" of the solar industry.

The First Solar story began in Ohio with innovative technology, a small dedicated team of scientists and engineers, and a vision of a future powered by clean renewable electricity.

Today, First Solar is the world leader in manufacturing photovoltaic (PV) modules with an advanced thin film semiconductor process that greatly reduces the cost of producing solar modules.

eSolar (USA)

www.esolar.com

Unlike many other solar energy startups in the USA that focus on solar PV, eSolar focusses on solar thermal.

eSolar has developed a solar thermal power plant technology. eSolar’s modular, scalable power plant architecture enables custom built facilities with generating capacities of 46 MW to 500 MW and energy prices that are competitive with fossil fuels. eSolar systems provide competitive energy prices even at the 46 MW level, and can expand generation capacity to over 500 MW.

eSolar constructs power plants using a tiered delivery model. The power plants are structured on a 46 MW base unit, called a “power module” with each unit consisting of sixteen modules of thermal receivers and dual north-south heliostat fields. Each module is a complete power plant, consisting of several thermal receiver towers, each with a field of heliostat mirrors, and a central power block with steam turbine and generator. Modules can be replicated as many times as necessary to fit specific power requirements.

The Solar Office - Doxford, Near Sunderland (UK)

The Solar Office in the Doxford International Business Park is located near Sunderland in the north east of England. It was the first speculatively constructed office building to be built specifically to incorporate solar PV panels. The resulting solar façade is the largest ever constructed in Europe. It is one of the few such projects to adopt a holistic energy strategy. The 73-kilowatt PV system uses monocrystalline square cells. Over the first two years, the PV array has generated some 113,000 kilowatt hours of energy per year, comparable with the design prediction.