Photovoltaics

11 MW Serpa solar power plant in Portugal

A solar cell, or photovoltaic cell (PV), is a device that converts light into electric current using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s.Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954.These early solar cells cost 286 USD/watt and reached efficiencies of 4.5–6%.

Solar power has great potential, but in 2008 supplied less than 0.02% of the world's total energy supply. There are many competing technologies, including fourteen types of photovoltaic cells, such as thin film, monocrystalline silicon, polycrystalline silicon, and amorphous cells, as well as multiple types of concentrating solar power. It is too early to know which technology will become dominant.

The earliest significant application of solar cells was as a back-up power source to the Vanguard I satellite in 1958, which allowed it to continue transmitting for over a year after its chemical battery was exhausted.The successful operation of solar cells on this mission was duplicated in many Soviet and American satellites, and by the late 1960s, PV had become the established source of power for them.Photovoltaics went on to play an essential part in the success of early commercial satellites such as Telstar, and they remain vital to the telecommunications infrastructure today.other

The high cost of solar cells limited terrestrial uses throughout the 1960s. This changed in the early 1970s when prices reached levels that made PV generation competitive in remote areas without grid access. Early terrestrial uses included powering telecommunication stations, off-shore oil rigs, navigational buoys and railroad crossings.These off-grid 

Building-integrated photovoltaicscover the roofs of an increasing number of homes.

The 1973 oil crisis stimulated a rapid rise in the production of PV during the 1970s and early 1980s.  Economies of scale which resulted from increasing production along with improvements in system performance brought the price of PV down from 100 USD/watt in 1971 to 7 USD/watt in 1985.  Steadily falling oil prices during the early 1980s led to a reduction in funding for photovoltaic R&D and a discontinuation of the tax credits associated with the Energy Tax Act of 1978. These factors moderated growth to approximately 15% per year from 1984 through 1996. Since the mid-1990s, leadership in the PV sector has shifted from the US to Japan and Europe. Between 1992 and 1994 Japan increased R&D funding, established net metering guidelines, and introduced a subsidy program to encourage the installation of residential PV systems. As a result, PV installations in the country climbed from 31.2 MW in 1994 to 318 MW in 1999, and worldwide production growth increased to 30% in the late 1990s.

Germany became the leading PV market worldwide since revising its Feed-in tariff system as part of the Renewable Energy Sources Act. Installed PV capacity has risen from 100 MW in 2000 to approximately 4,150 MW at the end of 2007. After 2007, Spain became the largest PV market after adopting a similar feed-in tariff structure in 2004, installing almost half of the photovoltaics (45%) in the world, in 2008, while France, Italy, South Korea and the U.S. have seen rapid growth recently due to various incentive programs and local market conditions. The power output of domestic photovoltaic devices is usually described in kilowatt-peak (kWp) units, as most are from 1 to 10 kW.

Concentrating photovoltaics are another new method of electricity generation from the sun. Concentrating photovoltaics (CPV) systems employ sunlight concentrated onto photovoltaic surfaces for the purpose of electrical power production. Solar concentrators of all varieties may be used, and these are often mounted on a solar tracker in order to keep the focal point upon the cell as the Sun moves across the sky. Tracking is not required for concentrations of less than 2 to 5, but does increase flat panel photovoltaic output by up to 20% in winter, and up to 50% in summer.

Experimental Solar Power

Concentrating photovoltaics in Catalonia, Spain.

Asolar updraft tower (also known as a solar chimney or solar tower) consists of a large greenhouse that funnels into a central tower. As sunlight shines on the greenhouse, the air inside is heated, and expands. The expanding air flows toward the central tower, where a turbine converts the air flow into electricity. A 50 kW prototype was constructed in Ciudad Real, Spain and operated for eight years before decommissioning in 1989.

Thermoelectric, or "thermovoltaic" devices convert a temperature difference between dissimilar materials into an electric current. First proposed as a method to store solar energy by solar pioneer Mouchout in the 1800s,thermoelectrics reemerged in the Soviet Union during the 1930s. Under the direction of Soviet scientistAbram Ioffe a concentrating system was used to thermoelectrically generate power for a 1 hp engine.Thermogenerators were later used in the US space program as an energy conversion technology for powering deep space missions such asCassini,Galileo and  Vking. Research in this area is focused on raising the efficiency of these devices from 7–8% to 15–20%.

Finally,Space-based solar power is a theoretical design for the collection of solar power in space, for use on Earth. SBSP differs from the usual method of solar power collection in that the solar panels used to collect the energy would reside on a satellite in orbit, often referred to as a solar power satellite (SPS), rather than on Earth's surface. In space, collection of the Sun's energy is unaffected by the day/night cycle, weather, seasons, or the filtering effect of Earth's atmospheric gases. Average solar energy per unit area outside Earth's atmosphere is on the order of ten times that available on Earth's surface. However, there is no shortage of energy reaching the surface. The amount of solar energy reaching the surface of the planet each year is about twice the amount of energy that will be obtained forever from coal, oil, natural gas, and mined Uranium, combined, even usingbreeder reactors.

Development, Deployment and Economics

Beginning with the surge incoal use which accompanied theIndustrial Revolution, energy consumption has steadily transitioned from wood and biomass tofossil fuels. The early development of solar technologies starting in the 1860s was driven by an expectation that coal would soon become scarce. However development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum.

The1973 oil embargo and1979 energy crisis caused a reorganization of energy policies around the world and brought renewed attention to developing solar technologies.Deployment strategies focused on incentive programs such as the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan. Other efforts included the formation of research facilities in the US (SERI, nowNREL), Japan (NEDO), andGermany (Fraunhofer Institute for Solar Energy Systems ISE).

Between 1970 and 1983 photovoltaic installations grew rapidly, but falling oil prices in the early 1980s moderated the growth of PV from 1984 to 1996. Since 1997, PV development has accelerated due to supply issues with oil and natural gas, global warming concerns (seeKyoto Protocol), and the improving economic position of PV relative to other energy technologies. Photovoltaic production growth has averaged 40% per year since 2000 and installed capacity reached 10.6 GW at the end of 2007,and 14.73 GW in 2008.Since 2006 it has been economical for investors to install photovoltaics for free in return for a long termpower purchase agreement. 50% of commercial systems were installed in this manner in 2007 and it is expected that 90% will by 2009. Nellis Air Force Base is receiving photoelectric power for about 2.2 ¢/kWh and grid power for 9 ¢/kWh.

Commercial concentrating solar thermal power (CSP) plants were first developed in the 1980s. CSP plants such asSEGS project in the United States have alevelized energy cost (LEC) of 12–14 ¢/kWh.The 11 MWPS10 power tower in Spain, completed in late 2005, is Europe's first commercial CSP system, and a total capacity of 300 MW is expected to be installed in the same area by 2013.

<><><><><><><><>

< />

Largest Concentrating Solar Thermal Power Stations

Capacity (MW)	Technology type	Name	Country	Location	Notes
354	parabolic trough	Solar Energy Generating Systems	USA	Mojave desert California	Collection of 9 units
64	parabolic trough	Nevada Solar One	USA	Las Vegas, Nevada
50	parabolic trough	Andasol 1	Spain	Granada	Completed November 2008
20	solar power tower	PS20 solar power tower	Spain	Seville	Completed April 2009
11	solar power tower	PS10 solar power tower	Spain	Seville	Europe's first commercial solar tower

Average insolation showing land area (small black dots) required to replace the world primary energy supply with solar electricity. 18 TW is 568 Exajoule (EJ) per year. Insolation for most people is from 150 to 300 W/m² or 3.5 to 7.0 kWh/m²/day.

Solar installations in recent years have also largely begun to expand into residential areas, with governments offering incentive programs to make "green" energy a more economically viable option. In Canada the RESOP (Renewable Energy Standard Offer Program), introduced in 2006,and updated in 2009 with the passage of the Green Energy Act, allows residential homeowners in Ontario with solar panel installations to sell the energy they produce back to the grid (i.e., the government) at 42¢/kWh, while drawing power from the grid at an average rate of 6¢/kWh (see feed-in tariff).The program is designed to help promote the government's green agenda and lower the strain often placed on the energy grid at peak hours. In March, 2009 the proposed FIT was increased to 80¢/kWh for small, roof-top systems (≤10 kW).

Photovoltaics are 85 times as efficient as growing corn for ethanol. On a 300 feet (91 m) by 300 feet (1 hectare) plot of land enough ethanol can be produced to drive a car 30,000 miles (48,000 km) per year or 2,500,000 miles (4,020,000 km) by covering the same land with photo cells. The deserts of the South Western United States could produce sufficient electricity to fulfill all of the electrical needs of the United States, and could use electrolysis to produce Hydrogen from water to power aircraft.

<><><><><><><><><>World's largest photovoltaic (PV) power plants

Name of PV power plant	Country	DC Peak Power (MW)	GW·h /year	Capacity factor	Notes
Olmedilla Photovoltaic Park	Spain	60	85	0.16	Completed September 2008
Puertollano Photovoltaic Park	Spain	50			2008
Moura photovoltaic power station	Portugal	46	93	0.16	Completed December 2008
Waldpolenz Solar Park	Germany	40	40	0.11	550,000 First Solar thin-film CdTe modules. Completed December 2008
Arnedo Solar Plant	Spain	34			Completed October 2008
Merida/Don Alvaro Solar Park	Spain	30			Completed September 2008
Planta Solar La Magascona & La Magasquila	Spain	30
Planta Solar Ose de la Vega	Spain	30
Planta Fotovoltaico Casas de Los Pinos	Spain	28
SinAn power plant	Korea	24	33		Completed October 2008

EPIA notes that photovoltaics provides a secure, reliable return on investment, with modules typically lasting 25 to 40 years and with a payback on investment of between 8 to 12 years.

Each of these financial incentives is aimed at increasing demand for solar photovoltaics such that they can become competitive with onventional methods of energy production. Another innovative way to increase demand is to harness the green purchasing power of academic institutions (universities and colleges). This has been shown to be potentially quite influential in catalyzing a positive spiral-effect in renewables globally.

Solar energy is not available at night, making energy storage an important issue in order to provide the continuous availability of Both wind power and solar power are intermittent energy sources, meaning that all available output must be taken when it is available and either stored forwhen it can be used, or transported, over transmission lines, towhere it can be used. Wind power and solar power tend to be somewhat complementary, as there tends to be more wind in the winter and more sun in the summer, but on days with no sun and no wind the difference needs to be made up in some manner.The Institute for Solar Energy Supply Technology of the University of Kassel pilot-tested a combined power plant linking solar, wind, biogas and  hydrostorage to provide load-following power around the clock, entirely from renewable sources.energy.

Solar energy can be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems. The Solar Two used this method of energy storage, allowing it to store enough heat in its 68 m³ storage tank to provide full output of 10 MWe for about 40 minutes, with an efficiency of about 99%.

Off-grid PV systems have traditionally used rechargeable batteries to store excess electricity. With grid-tied systems, excess electricity can be sent to the transmission grid. Net metering programs give

Seasonal variation of the output of the solar panels at AT&T Park in San Francisco.

these systems a credit for the electricity they deliver to the grid. This credit offsets electricity provided from the grid when the system cannot meet demand, effectively using the grid as a storage mechanism. Credits are normally rolled over month to month and any remaining surplus settled annually.

Pumped-storage hydroelectricity stores energy in the form of water pumped when surplus electricity is available, from a lower elevation reservoir to a higher elevation one. The energy is recovered when demand is high by releasing the water: the pump becomes a turbine, and the motor a hydroelectric power generator.

U.S. DOE Solar Energy Technologies Programs

System Integration of Solar Technologies

The U.S. Department of Energy (DOE) Solar Energy Technologies Program (SETP or Solar Program) is making significant investments in grid-integration technologies. SETP is also coordinating with all stakeholders to accelerate the integration of renewable technologies. As solar technologies provide a larger part of the U.S. electricity supply, it is becoming increasingly important that they be integrated seamlessly into the nation's electric power grid. This will require new ways of thinking about how the country generates and distributes electricity and new technologies that make it simple, safe, and reliable for solar electricity to feed into the grid. The Systems Integration subprogram focuses on breaking down the regulatory, technical, and economic barriers to integrate solar electricity into the electric grid. The subprogram accomplishes this by working with utilities and the solar industry to develop technologies and strategies. Systems Integration efforts encompass the following research and development activities: Solar System Technology Development Advanced Systems Integration System Testing and Demonstrations Renewable Energy System Analysis Solar Resource Assessment Codes, Standards and Regulatory Implementation.

Systems integration is one of the four subprograms within the DOE Solar Program. Along with Photovoltaics, Concentrating Solar Power, and Market Transformation, the SETP subprograms focus on accelerating the advancement of solar energy technologies to make solar electricity cost competitive with conventional forms of electricity.

Concentrating Solar Power

Concentrating solar power (CSP) technologies use mirrors to reflect and concentrate sunlight onto receivers that collect the solar energy and convert it to heat. This thermal energy can then be used to produce electricity via a steam turbine or heat engine driving a generator.

The U.S. Department of Energy (DOE) is ramping up its CSP research, development, and deployment efforts, leveraging both industry partners and the national laboratories. DOE's goals include increasing the use of CSP in the United States, making CSP competitive in the intermediate power market by 2015, and developing advanced technologies that will reduce systems and storage costs, enabling CSP to be competitive in the baseload power market by 2020.

DOE plans to achieve these goals through cost-shared contracts with industry, advanced research at its national laboratories, and collaboration with other government agencies to remove barriers to deploying the technology.

Within the CSP subprogram, research and development activities focus on the following areas:

• Linear Concentrator Systems
• Dish/Engine Systems
• Power Tower Systems
• Thermal Storage
• Advanced Components and Systems

You can also learn more about thebasics of CSP operations within the main technology areas.

Concentrating solar power technologies can generate electricity at relatively low cost and deliver power during periods of peak demand. In addition, integration with low-cost thermal storage adds significant value to the energy delivered from CSP plants. The public is becoming more familiar with the availability, benefits, and economic feasibility of CSP. And researchers are continuing to discover ways to reduce costs and improve efficiencies. Consequently, many utilities are including concentrating solar power in their power-generation portfolio, helping our nation reduce its dependence on fossil fuels.

CSP is one of four subprograms within the Solar Energy Technologies Program (SETP), along with Photovoltaics, Market Transformation, and Systems Integration. The SETP subprograms focus on accelerating the advancement of solar energy technologies to make solar electricity more cost competitive with conventional forms of electricity.

Photovoltaics

The U.S. Department of Energy (DOE) Solar Energy Technologies Program (SETP or the Solar Program) is aggressively funding a diverse set ofphotovoltaic (PV) technologiesthat have potential application in a range of markets.

Through its primary research and development (R&D) efforts, the PV subprogram's goal is for PV technology to achieve grid parity by 2015. Achieving this goal will lead to rapid and significant growth of solar electricity in the United States.

To reach this goal, DOE is investing in approaches across the development pipeline—from basic cell technologies to manufacturing scaleup to total system development—that demonstrate progress toward minimizing the effective life-cycle cost of solar energy. In addition, DOE is partnering with national laboratories, start-up companies, universities, and integrated industry teams.

The PV subprogram's R&D activities are divided into the following three categories:

• New Devices and Processes—These research and development activities address the development of novel PV devices or processes with potentially significant performance or cost advantages.
• Prototype Design and Pilot Production—These R&D activities emphasize development of PV prototype components or systems produced at pilot-scale with demonstrated cost, reliability, or performance advantages.
• Systems Development and Manufacturing—These R&D activities focus on PV components and systems that are ready for mass production and capable of delivering energy at target costs.

In support of its R&D efforts, SETP developed technology roadmaps that identify key needs in various solar technologies. The roadmaps were created by the Solar Program in collaboration with its partners from national laboratories, universities, and private industry.

Although electricity from PV systems is still more expensive than electricity from the utility grid, demand from PV technology systems has the potential to expand rapidly and become a significant part of the national energy supply, as additional advancements are made and grid parity is reached.

Photovoltaics is one of the four subprograms within the Solar Program. Along with Concentrating Solar Power, Systems Integration, and Market Transformation, the SETP subprograms focus on accelerating the advancement of solar energy technologies to make solar electricity cost competitive with conventional forms of electricity.

System Integration of Solar Technologies

The U.S. Department of Energy (DOE) Solar Energy Technologies Program (SETP or Solar Program) promotes the commercialization of solar technologies by addressing non-technical issues that act as barriers to the adoption of solar energy technologies. DOE's Market Transformation effort identifies and prioritizes significant barriers beyond traditional "cost" issues and develops specific activities and external partnerships to address those barriers.

The Solar Program identified the following market barriers to widespread dissemination of solar technologies:

• A shortage of information about solar technologies and little consumer awareness
• Insufficient product standards
• Inconsistent interconnection, net metering, and utility rate structures and practices for solar systems
• Inadequate codes and complex and expensive permitting procedures
• Inconsistent and insufficient state and local financial incentives and other market drivers
• A lack of flexible, sophisticated, and proven financing mechanisms
• Limited education for and insufficient numbers of trained and experienced personnel and services.

DOE is successfully addressing these market barriers through the following market transformation activities.

• Solar America Cities provides financial and technical assistance to cities committed to the widespread adoption of solar energy technologies.
• Solar America Showcases provides technical assistance to large-scale solar installations in high-visibility locations.
• Solar America Board for Codes and Standards involves the creation of a collaborative board of experts who formally gather and prioritize input from solar photovoltaic stakeholders (e.g., policymakers, manufacturers, installers), resulting in coordinated recommendations to organizations establishing codes and standards for existing and new solar technologies.
• State Technical Outreach provides information and tools to state governments and energy agencies developing state solar energy programs.
• Utility Technical Outreach provides information and tools to utilities to assist them in developing utility solar energy programs.
• Builder Technical Outreach provides information to builders wanting to incorporate solar energy technologies into their building practices.
• Workforce Education, Training, and Development provides resources to educators, professionals, and prospective students seeking education and training in solar energy technologies.

Solar Power

Get this box

Latest Solar Projects and Technologies

Heathrow Airport Gets Green Makeover 

BAAis trying to upgrade its airport terminal Heathrow East by investing to an amount of £1 billion and naming it as Terminal 2. This new terminal would be designed by Foster + Partners and developed by Ferrovial Agroman and Laing O’Rourke’s joint partnership company HETCo. This terminal will house around twenty million passengers every year that chose Star Alliance airlines. 

Plastics That Convert Light To Electricity

We all are familiar with the positive impact of alternative energy on our environment. Now researchers are trying to improve upon the existing alternative energy technology. As far as solar energy is concerned they are trying to make solar panels cheap and people friendly. Normally the solar panels are quite bulky and difficult to fit in on existing architecture. Therefore scientists all over the world are focusing on developing organic solar cells. They could be inexpensive and look like thin films. 


Solar Forest Cools and Charges Electric Cars

Imagine a parking lot that keeps your car cool and charges it while you do whatever you need to do after parking your car. That’s what the new solar forest designed by designer Neville Mars aims to achieve. Electric-powered automobiles are a great way of reducing pollution levels but the main hurdle in the way of them becoming mainstream vehicles is long duration of time they need to recharge. Even to cover small distance you need to recharge your vehicle for hours. One solution is to speed up the recharging process, and another is recharging the cars while they stand unused, like in a parking lot. 


SunCatcher Power System Ready For Commercial Production

Stirling Energy Systems (SES) and Tessera Solar worked jointly and have come out with their precious device called SunCatchers(TM). They exhibited their four newly designed solar power collection dishes at Sandia National Laboratories’ National Solar Thermal Test Facility (NSTTF). SunCatchers are the new dishes that will be utilized on commercial-scale by 2010. Chuck Andraka, who is the lead Sandia project engineer, shares his enthusiasm about SunCatchers, "The four new dishes are the next-generation models of the original SunCatcher system. Six first-generation SunCatchers built over the past several years at the NSTTF have been producing up to 150KW of grid-ready electrical power during the day. Every part of the new system has been upgraded to allow for a high rate of production and cost reduction." 


Solar Lanterns for Sub-Saharan Africans

When one lives in a developed country it becomes hard to visualize that how people manage in those parts of the world where electricity is still a distant dream. Residents of the village Ahire, Maharashtra in India claimed that people didn’t want to marry their daughters in their village due to lack of electricity. Now the government has installed solar panels in the village and the residents are having electricity for the first time. Similarly someone is thinking about people living in Sub-Saharan Africa, which is said to be the least electrified region in the world. To a rational mind the task seems daunting. The mind will think about infrastructure, finance, technical know-how, professionals etc. But an imaginative mind will think of bypassing all this and think about reality and what works without the essentials. A Kansas State University student is doing such kind of thinking. He is combining engineering and nature to design a more affordable and more sustainable lighting source for those souls living without electricity. 


UAVs to be Powered by Dye-sensitized Solar Cells

The progress is being steadily made in the field of alternative energy. Though we have not hit the bull’s eye yet but still the search is on. Scientists and researchers all over the world are spending sleepless nights on their projects to find an all-pervasive alternative to fossil fuels. How can we utilize the alternative energy technology for unmanned aerial vehicles (UAVs) When we think about the unmanned aerial vehicles (UAVs) we think of saving human resource, undoubtedly the most precious resource of any nation. But UAVs have some drawbacks too. They can’t fly to the far and distant places because after traveling certain distance an aircraft needs refueling. And here we face the disadvantage of UAVs. They can’t refuel. But if they utilize solar energy they can travel more and work more effectively in enemy’s territory. The Air Force is thinking of using Dye-sensitized solar cells (DSSCs) for unmanned aerial vehicles (UAVs) in future. Then they can fly for a longer duration of time without refueling. 


The Solar Powered Barn

Your barn has always been a good source of energy. Up till now it has been due to the fact that you store all your wood in the barn. But now you can have a barn that not only preserves your wood for winter it also produces solar energy -- enough to meet the energy requirements of the barn and in some cases the access energy can also be sold. Barns are normally constructed at places that have no electricity supply but have a great need for power, for many barns have wood-processing machines and even small offices, and running them off generators can be pretty expensive and polluting.


Highly Adaptable Solar Cells

There are two things that prevent solar cells from entering the mainstream: their prohibitive cost, and their inadaptability. Even if people can somehow overcome the cost barrier, the havoc they allegedly wreck upon buildings and houses keeps many people away from switching to non-fossil-fuel power generation, and besides, sunshine is never uniform. It varies with location, it fluctuates with the movement of the sun, and it increases and decreases in intensity as the weather changes. To justify cost and effort, people need something more stable, more dependable, and more sustainable.


Solar Power Tiles for your Rooftop

Just imagine your neighborhood mason fitting your roof tiles and these same tiles producing dependable solar energy for your house or office – you no longer need to hire scientists and alternative energy nerds for a simple roof job, and the cost is no longer a bottleneck. A technology catches on when it is easier to implement and efficient to use. With Solé tiles, constructing roofs that produce solar energy without becoming cumbersome and expensive eye-sores is soon going to become a reality.

 
First Hybrid Solar Power Station

Weizmann Institute created a milestone in the field of alternative energy in association with AORA. AORA is a leading Israeli solar energy technology company. It launched the world's first hybrid solar thermal power station at Kibbutz Samar in southern Israel. During the inaugural launch of the powerhouse, guests from other countries such as Spain, Switzerland, Austria, Chile and Australia were also present. Yehoshua Fried, who is the chief executive officer of the AORA, thanked American investor Meir Reiss and Canadian Director of Corporation and Consultant to Management, Zev Rosenzweig, for believing in his dream.

 
Transparent Electronics: A Solar Energy Breakthrough

 Not even in our wildest dreams have we anticipated that while we are simply looking out the window enjoying the outside view our windows can simultaneously produce energy for our household needs! Not only windows but the facade of the house, too, might be harnessing the power of solar energy. This might be our future domestic power supply scenario. This can be possible with the help of transparent solar cells. These solar cells can increase the surface area to produce energy.

18JUN
New Generation of Solar Devices with Trapped Sunlight

What a wonderful age we are living in! We hear about so many possibilities in the field of alternative energy. Scientists all over the world are thinking about alternatives to fossil fuel. On every scale be it large or small progress is being made. Here the researchers are inspired by the Greek legend Dionysius' ear. Dionysius erected a cave. It was shaped like an ellipse. Dionysius’ purpose was to hear the words whispered by a prisoner in one of the foci of the cave. Some of the present day science day museums are following the same features where two people standing the extreme ends of a room can hear each other’s whisper. This feature motivated physicists Roberto De Luca and Aniello Fedullo, both of the University of Salerno in Italy, to design sunlight traps. They are using two elliptical mirrors, with one collecting sunlight and another (they named it zozzaroid) focusing sunlight back to the vertex of previous one and into the blackbody. Here they are using mirror for steam generation.

14JUN
Flexible Solar Powered Rooftop Shingles

Researchers at Pacific Northwest National Laboratory (PNNL) in Richland have developed flexible solar panels that could be installed on roofs like shingles. This technology was originally used to protect flat panel televisions from dampness. They used to cover television screen with transparent, thin films that acted as barriers. These transparent thin film barriers are now becoming the basis for flexible solar panels that would be installed on roofs like shingles. These flexible rooftop solar panels are known as building-integrated photovoltaics, or BIPVs. They could replace today's boxy solar panels. We all know that current solar panels are made with rigid glass or silicon and mounted on thick metal frames. If we compare present solar panels and flexible solar shingles we will find the later ones less expensive to install than current panels and made to last 25 years.

12JUN
Light-driven Nanomotor

 How we see things around us without noticing it! We know the peculiar habit of the sunflower. How it moves with the movement of the sun everyday. But if we want to move anything with the help of sunlight we are not as lucky as the sunflower is. We first have to convert sunlight into heat or electricity and then convert any of this into mechanical energy. Scientists are trying to imitate the action of the sunflower at nanoscale right now. It is no less than a miracle but scientists are the greatest magicians on this earth. Coming generations will reap the benefits of their hard work. A team of the University of Florida chemists is trying a new mechanism to transform light straight into motion – albeit at a very, very, very tiny scale.

09JUN
Lasers Make Solar Cells Competitive

 For centuries we have been using fossil fuels for industrial and domestic purposes. Most of us consider fossil fuels cheap. But now we are realizing the "real" costs of using fossil fuels. It is destroying our environment and making us pay in other terms. Another problem we are facing is, what were luxuries for the previous generation have become the necessities for current generation. We are using lots of gadgets such as computers, cell phones, iPhones and kitchen and home appliances. They all run on electricity. It is now clear that most of us will be driving electric cars in future. So the problem will be compounded by our growing energy needs. According to the newest forecast from the World Energy Council (WEC) global electricity requirements will double in the next 40 years. At the same time, we know that prices for the dwindling resources of petroleum and natural gas are mounting.

07JUN
Solar Powered Wi-Fi Bus Stops

 What a delightful combination for environmentalists! While you are waiting for your bus to arrive you can happily stay in touch with the cyber world. San Francisco bus stops produce solar electricity and offer Wi-Fi connectivity too. By 2013, San Francisco is planning to have 1100 such solar-powered bus shelters put in throughout the city. This project can act as a catalyst for other states and even countries to follow. They have taken care of the bus stops at the grass root level too. They have used recycled materials to develop these bus stops. The bus stops’ roofs will have solar panels. The underutilized energy of these bus shelters will be directed back to the grids.

05JUN
Solar Powered Surveillance Aircraft

Bye Aerospace Inc. (Denver, Colorado), is collaborating with thin film PV manufacturer Ascent Solar. This is not one of those tie ups taking place everyday. The echo of this tie up will be heard for a long time in the alternative energy scenario. Ascent Solar is providing necessary solar energy technology to Bye Aerospace to develop a hybrid unmanned aerial vehicle (H-UAV). The aerial vehicle is named as Silent Sentinel. This aircraft will be stored using electric power, thin film solar photovoltaics (PV) and some additional technologies to enhance its low emissions, quiet operations and endurance. Bye Aerospace will also utilize a Williams International FJ33 turbofan engine for primary propulsion. Silent Sentinel would be a robust, long-range UAV that would integrate various clean-energy features.

02JUN
Molten Salt Solar Plant

If you happen to travel to Las Vegas, you can come across a tall tower surrounded by around 1,800 mirrors. Mirrors size may be equivalent to a billboard. Don’t confuse it with a futuristic movie set. It is an alternative energy power plant committed to produce clean and green energy in desert areas. The project could be completed by 2013. It might utilize an array of 15,000 heliostats to direct sunlight to a solar collecting tower. The solar collector might be at a height of 600 feet. Twenty five feet wide mirrors can also be utilized to direct sunlight to the tower.

30MAY
New Solar Stadium in Taiwan

 It’s official now. Taiwan will hold the World Games 2009 in July. This international sporting event will include games like korfball, billiards, dragon boat racing and women’s tug-of-war. But why are we discussing World Games 2009 in an alternative energy spectrum? Actually Taiwan can boast of Asia's first fully solar-powered stadium. The stadium gives a dragon-like impression if you happen to view it from the sky. In their culture dragon is associated with good fortune. If you happen to spot the dragon scales, look carefully again. These dragon scales are actually 8,844 solar panels. These solar panels are enough to meet the stadium’s energy needs. The roof covers an area of 14,155m2 . They can produce about 1.14 gigawatt hours of electricity every year. This amount of electricity is enough to power 80% of the stadium’s surrounding neighborhood when it’s not in use. The stadium has 3,300 lights and two giant TV screens.

23MAY
Solaren Corp. to Launch Solar Panels into Orbit

We keep hearing about harnessing the solar power from space. Some call it tall claims and some dismiss it as too costly an affair or pie in the sky. But it seems that in near future harvesting solar energy from space is becoming a reality. Pacific Gas & Electric Company (PG&E) from San Francisco is in the energy sector for decades. They have produced power from atomic energy, natural gas and water. Now PG&E has gone ahead and collaborated with Manhattan Beach start-up called Solaren Corporation. But what put this deal apart from others? Actually Solaren Corporation aims to launch a series of giant solar collectors into orbit 23,000 miles above Fresno. They will beam the energy to earth in the form of radio waves. Now PG&E has finalized a contract with Solaren to buy the power on one condition if they can make the technology work.