Solar is the Latin word for sun — a powerful source of energy that can be used to heat, cool, and light our homes and businesses. That's because more energy from the sun falls on the earth in one hour than is used by everyone in the world in one year. A variety of technologies convert sunlight to usable energy for buildings. The most commonly used solar technologies for homes and businesses are solar water heating, passive solar design for space heating and cooling, and solar photovoltaics for electricity. [Source: U.S. Department of Energy]

Businesses and industry also use these technologies to diversify their energy sources, improve efficiency, and save money. Solar photovoltaic and concentrating solar power technologies are also being used by developers and utilities to produce electricity on a massive scale to power cities and small towns. By some reckonings if it was possible to cover a 100-by-100 mile square area with photovoltaic panels (electricity-producing solar penels) they panels would cover just 0.3 percent of the United States but supply enough power for the entire country.

The main types of solar power are: 1) Concentrating solar power, technologies that harness heat from the sun to provide electricity for large power stations; 2) Passive solar technology, technologies that harness heat from the sun to warm our homes and businesses in winter; 3 Solar photovoltaic technology, technologies that convert sunlight directly into electricity to power homes and businesses; 4) Solar water heating, technologies that harness heat from the sun to provide hot water for homes and businesses; and 5) Solar process heat, technologies that use solar energy to heat or cool commercial and industrial buildings. The National Renewable Energy Laboratory (NREL) conducts research in the following solar technologies: 1) Concentrating solar power research; 2) Photovoltaic (solar cell) research; 3) Solar process heating and cooling; and 4) Solar water heating

Total global energy consumption is around 16 terawatts (16 trillion watts). Each day around 120,000 terawatts of energy from the sun reaches the Earth. The main problems with harvesting solar energy as an electricity source is collecting it efficiently and storing it when there is no sunlight. Some of the earliest solar technology was developed by NASA to power spacecraft. One of the biggest challenges today its developing battery systems that can effectively store energy. [Source: George Johnson, National Geographic, September 2009]

“The Economist described the solar energy industry as being in its adolescent stage: “no longer a child to be coddled, pampered, but not yet able to pay its way.” Only about six gigawatts of solar cells were sold in 2009. As it stands “there would be no significant market for solar cells were it not for government subsidies. Some analyst think solar will relay take off until after the potential of wind power has plateaued sometime around 2025.

Solar Energy Costs and Inefficiencies

Solar energy remains expensive. According to 2010 calculations by the International Energy Agency power from photovoltaic systems cost between $200 and $600 a megawatt, compared to $50 and $70 a megawatt for onshore wind power and even lower for fossil fuels. A typical utility-scale instillation produces only a fifth of its maximum capacity due to clouds, night time, dirty panels and so on. To replace a one-gigawatt ocal plant running at 70 percent capacity would require about half of all the cells worldwide in 2009.

“But there is no doubt the market is growing. According to Bloomberg New Energy Finance, a research firm. The demand for solar energy increased from 1.7 gigawatts un 2006 to an estimated 10,5 gigawatts in 2010. The growth has largely been fueled by the policy in Germany in which a guaranteed price is promised for solar power making it profitable for people to invest in it. [Source: Bloomberg]

“New generation solar energy systems produces electricity at a cost of about 20 cents 30 cents per kilowatt hour, compared several dollars two decades ago. If cells could be developed that absorbs 50 percent of the energy of the sun, the cost could be reduced to 2 cents a kilowatt hour. Coal, natural gas, wind and nuclear cost between 5 and 7 cents a kilowatt hour.

“The key to making the solar energy industry grow is government subsidies and regulations, Among the most successful have been the “fed-in tariffs: used in Germany and Spain in which power companies are required to buy solar energy from power plants and home that produce it at a premium price.

Concentrating Solar Power

Many power plants today use fossil fuels as a heat source to boil water. The steam from the boiling water spins a large turbine, which drives a generator to produce electricity. However, a new generation of power plants with concentrating solar power systems uses the sun as a heat source. The three main types of concentrating solar power systems are: linear concentrator, dish/engine, and power tower systems.[Source: U.S. Department of Energy]

Linear concentrator systems collect the sun's energy using long rectangular, curved (U-shaped) mirrors. The mirrors are tilted toward the sun, focusing sunlight on tubes (or receivers) that run the length of the mirrors. The reflected sunlight heats a fluid flowing through the tubes. The hot fluid then is used to boil water in a conventional steam-turbine generator to produce electricity. There are two major types of linear concentrator systems: parabolic trough systems, where receiver tubes are positioned along the focal line of each parabolic mirror; and linear Fresnel reflector systems, where one receiver tube is positioned above several mirrors to allow the mirrors greater mobility in tracking the sun. [Source: U.S. Department of Energy]

A dish/engine system uses a mirrored dish similar to a very large satellite dish, although to minimize costs, the mirrored dish is usually composed of many smaller flat mirrors formed into a dish shape. The dish-shaped surface directs and concentrates sunlight onto a thermal receiver, which absorbs and collects the heat and transfers it to the engine generator. The most common type of heat engine used today in dish/engine systems is the Stirling engine. This system uses the fluid heated by the receiver to move pistons and create mechanical power. The mechanical power is then used to run a generator or alternator to produce electricity.

A power tower system uses a large field of flat, sun-tracking mirrors known as heliostats to focus and concentrate sunlight onto a receiver on the top of a tower. A heat-transfer fluid heated in the receiver is used to generate steam, which, in turn, is used in a conventional turbine generator to produce electricity. Some power towers use water/steam as the heat-transfer fluid. Other advanced designs are experimenting with molten nitrate salt because of its superior heat-transfer and energy-storage capabilities. The energy-storage capability, or thermal storage, allows the system to continue to dispatch electricity during cloudy weather or at night.

Concentrating Solar Plants

Thermal solar power plants consist of covering acres of desert with mirrors that focuses intense sunlight on a fluid, heating it enough to make steam, which turns a turbine and generates electricity. The process is more efficient than similar cells in that a great percentage sunlight is converted into electricity but it requires a lot of land and because large expanse of land are usually far from where energy is need long transmission cables. [Source: U.S. Department of Energy]

Solar thermal uses mirrors to concentrate heat, produce steam and drive a turbine, Plants using such technology can theocratically be built on a scale similar to that of a gas-fired power station, of a few hundred megawatts,, Sch plants require big investment, more planning and permissions and infrastructure such as transmission lines, Such plants can produce a lot of power. One proposed by Brightsource Energy that has been approved for the Mojave desert in California will produce more power than all the photovoltaic cells install in the United States in 2009.

One such plant — Nevada Solar One, completed near Las Vegas by the Spanish firm Acciona in 2007 — uses 182,000 parabolic mirrors, covering 250 acres, to focus light on long black steel tubes with a hear transfer fluid that reaches temperatures of 750 degrees F. The plant produces 64 megawatts of electricity, enough to power 14,000 homes, at a price of 15 to 20 cents per kilowatt hour, compared to 7 cents per kilowatt hour for electricity from a coal-powered plant. One advantages with thermal solar plants is that they produces electricity at a peak in the middle of the day when demand is the high. Disadvantages other than clouds are environmental concerns about covering large tracks of desert with mirrors and lack of electricity infrastructure in the middle of the desert and distance from places that need the power.

More sophisticated plants using “power towers” flanked by thousands of mirrors that pivot to focus light are being built on Spain. Algeria and Morocco and are planned for Israel, Mexico, China, South Africa and Egypt.

Passive Solar

Step outside on a hot and sunny summer day, and you'll feel the power of solar heat and light. Today, many buildings are designed to take advantage of this natural resource through the use of passive solar heating and daylighting. The south side of a building always receives the most sunlight. Therefore, buildings designed for passive solar heating usually have large, south-facing windows. Materials that absorb and store the sun's heat can be built into the sunlit floors and walls. The floors and walls will then heat up during the day and slowly release heat at night, when the heat is needed most. This passive solar design feature is called direct gain. [Source: U.S. Department of Energy]

Other passive solar heating design features include sunspaces and trombe walls. A sunspace (which is much like a greenhouse) is built on the south side of a building. As sunlight passes through glass or other glazing, it warms the sunspace. Proper ventilation allows the heat to circulate into the building. On the other hand, a trombe wall is a very thick, south-facing wall, which is painted black and made of a material that absorbs a lot of heat. A pane of glass or plastic glazing, installed a few inches in front of the wall, helps hold in the heat. The wall heats up slowly during the day. Then as it cools gradually during the night, it gives off its heat inside the building.

Many of the passive solar heating design features also provide daylighting. Daylighting is simply the use of natural sunlight to brighten up a building's interior. To lighten up north-facing rooms and upper levels, a clerestory — a row of windows near the peak of the roof — is often used along with an open floor plan inside that allows the light to bounce throughout the building.

Of course, too much solar heating and daylighting can be a problem during the hot summer months. Fortunately, there are many design features that help keep passive solar buildings cool in the summer. For instance, overhangs can be designed to shade windows when the sun is high in the summer. Sunspaces can be closed off from the rest of the building. And a building can be designed to use fresh-air ventilation in the summer.

Solar Hot Water

The shallow water of a lake is usually warmer than the deep water. That's because the sunlight can heat the lake bottom in the shallow areas, which in turn, heats the water. It's nature's way of solar water heating. The sun can be used in basically the same way to heat water used in buildings and swimming pools. [Source: U.S. Department of Energy]

Most solar water heating systems for buildings have two main parts: a solar collector and a storage tank. The most common collector is called a flat-plate collector. Mounted on the roof, it consists of a thin, flat, rectangular box with a transparent cover that faces the sun. Small tubes run through the box and carry the fluid — either water or other fluid, such as an antifreeze solution — to be heated. The tubes are attached to an absorber plate, which is painted black to absorb the heat. As heat builds up in the collector, it heats the fluid passing through the tubes. The storage tank then holds the hot liquid. It can be just a modified water heater, but it is usually larger and very well-insulated. Systems that use fluids other than water usually heat the water by passing it through a coil of tubing in the tank, which is full of hot fluid.

Solar water heating systems can be either active or passive, but the most common are active systems. Active systems rely on pumps to move the liquid between the collector and the storage tank, while passive systems rely on gravity and the tendency for water to naturally circulate as it is heated. Swimming pool systems are simpler. The pool's filter pump is used to pump the water through a solar collector, which is usually made of black plastic or rubber. And of course, the pool stores the hot water.

Solar water-heating systems are designed to provide large quantities of hot water for nonresidential buildings. A typical system includes solar collectors that work along with a pump, heat exchanger, and/or one or more large storage tanks. The two main types of solar collectors used for nonresidential buildings — an evacuated-tube collector and a linear concentrator — can operate at high temperatures with high efficiency. An evacuated-tube collector is a set of many double-walled, glass tubes and reflectors to heat the fluid inside the tubes. A vacuum between the two walls insulates the inner tube, retaining the heat. Linear concentrators use long, rectangular, curved (U-shaped) mirrors tilted to focus sunlight on tubes that run along the length of the mirrors. The concentrated sunlight heats the fluid within the tubes.

Space cooling can be accomplished using thermally activated cooling systems (TACS) driven by solar energy. Because of a high initial cost, TACS are not widespread. The two systems currently in operation are solar absorption systems and solar desiccant systems. Solar absorption systems use thermal energy to evaporate a refrigerant fluid to cool the air. In contrast, solar desiccant systems use thermal energy to regenerate dessicants that dry the air, thereby cooling the air. These systems also work well with evaporative coolers (also called "swamp coolers") in more humid climates.

Chinese Solar Water Heaters

China is a leader in the manufacturing and sale of solar water heaters — relatively unsophisticated, mattress-size, stainless steel devices that use the sun rays to heat water and cost about $220. Used for household purposes such as showering. washing dishes and washing, the device consists of an angled row of cola-colored glass tubes that absorb heat from the sun. The most common models are filled with cold water. As the solar heater is heated, the water rises into an insulated tank where it can remain hot for days. [Source: David Pierson, Los Angeles Times, September 2009]

“Models produced by Dezhou-based China Himi Solar Energy Group cost between $190 and $2,250 and work even when temperatures are below zero and the skies are filled with clouds or smog. Unlike solar panels that use expensive technology to produce electricity the solar water heaters consist of a row of sunlight-capturing glass pipes angled below an insulated water tank. Sunlight travels freely through the glass, generating heat that is trapped in a central pipe where the heat is transmitted to water. The secret to operating in cold temperature is the vacuum separating the inner tube with its energy-trapping coating from an outer tube.

“In Rizhao, a seaside city in Shandong Province with 2.8 million people, 99 percent of the households use solar water heaters. The devices used there have improved so much over the years some don’t need direct sunlight and function on cloudy or smoggy days. Advanced models have electrical water heaters that switch on during frigid cold days.

“As of 2009 more than 30 million homes in China had solar water heaters, accounting for two thirds of the world’s solar water heating energy and preventing more than 20 million tons of carbon dioxide from entering the atmosphere. Christopher Flavin of the Washington-based Worldwatch Institute told the Los Angeles Times, “China absolutely dominates the global market and they have done it relatively quietly and without a lot of fanfare. It’s an interesting example of their ability to take technology that was developed elsewhere and adapt it to their market on a scale no one had conceived of.”

“The heating of water typically accounts for a quarter of the energy used in a building. The use of water heaters is so high in Rizhao because the local government there requires solar water heaters to be installed in all homes and subsidizes their cost. For many families that installed the devices it was the first time they ever had reliable hot water. In Dezhou, another city known for energy conservation, 90 percent of the household and streets are lit with solar-powered lights.

“The solar water heater market in China is very competitive. More than 5,000 companies manufacture water heaters there. The president of Gold Giant, one of 150 manufacturers in Rishao, told the Los Angeles Times, “The market is huge but the competition is fearsome.” Another water heater maker has had success with the slogan that his water heater will “take the feathers off a chicken.” The largest in China, Himin Solar Energy Group, got a $50 million investment from Goldman Sachs. Some are looking for export market abroad. The American market, where people use an average of 400 liters of water daily, will be difficult to crack because the heaters don’t heat that much water.

Solar Process Heat

Commercial and industrial buildings may use the same solar technologies — photovoltaics, passive heating, daylighting, and water heating — that are used for residential buildings. These nonresidential buildings can also use solar energy technologies that would be impractical for a home. These technologies include ventilation air preheating, solar process heating, and solar cooling. [Source: U.S. Department of Energy]

Many large buildings need ventilated air to maintain indoor air quality. In cold climates, heating this air can use large amounts of energy. But a solar ventilation system can preheat the air, saving both energy and money. This type of system typically uses a transpired collector, which consists of a thin, black metal panel mounted on a south-facing wall to absorb the sun's heat. Air passes through the many small holes in the panel. A space behind the perforated wall allows the air streams from the holes to mix together. The heated air is then sucked out from the top of the space into the ventilation system.

Solar Photovoltaic Technology

Solar cells, also called photovoltaic (PV) cells by scientists, convert sunlight directly into electricity. PV gets its name from the process of converting light (photons) to electricity (voltage), which is called the PV effect. The PV effect was discovered in 1954, when scientists at Bell Telephone discovered that silicon (an element found in sand) created an electric charge when exposed to sunlight. Soon solar cells were being used to power space satellites and smaller items like calculators and watches. Today, thousands of people power their homes and businesses with individual solar PV systems. Utility companies are also using PV technology for large power stations. [Source: U.S. Department of Energy]

Photovoltaic solar cells work by using sunlight to stimulate atoms to release electrons and thus creating electricity. Currently, the best photovoltaic system converts about 33 percent of the incoming light to electricity. Scientists at the University of California have developed technology for making solar cells that may boost efficiency to 56 percent. The advantage with photovoltaic cells is that can be put near where the power is needed on a roof top or some other such place. Conventional crystalline-silicon photovoltaics are difficult to mass produce.

Solar panels used to power homes and businesses are typically made from solar cells combined into modules that hold about 40 cells. A typical home will use about 10 to 20 solar panels to power the home. The panels are mounted at a fixed angle facing south, or they can be mounted on a tracking device that follows the sun, allowing them to capture the most sunlight. Many solar panels combined together to create one system is called a solar array. For large electric utility or industrial applications, hundreds of solar arrays are interconnected to form a large utility-scale PV system.

Thin Film Solar Cells and Third-generation Solar Cells

Traditional solar cells are made from relatively heavy and inflexible silicon plates. Second-generation solar cells are called thin-film solar cells because they are made from amorphous silicon or nonsilicon materials such as cadmium telluride. Thin film solar cells use layers of semiconductor materials only a few micrometers thick. Because of their flexibility, thin film solar cells can double as rooftop shingles and tiles, building facades, or the glazing for skylights. [Sources: Newsweek, Time, U.S. Department of Energy]

Thin film solar cells utilize cheaper and more flexible cells. While they generate roughly half the power of traditional silicon cells, are easier to make. They begin as thin sheets of plastic that are coated with chemicals such indium, gallium and diselenide that help turn sunlight into electricity. They use less silicon than conventional cells or none at all because they are less efficient than conventional cells they are best used in deserts or areas with a lot of sun. Cells made by the company First Solar use cadmium telluride and cost less than a dollar to make. The technology could be undermined by cheaper price for conceptional silicon cells or more efficient thin films.

Third-generation solar cells are being made from variety of new materials besides silicon, including solar inks using conventional printing press technologies, solar dyes, and conductive plastics. Some new solar cells use plastic lenses or mirrors to concentrate sunlight onto a very small piece of high efficiency PV material. The PV material is more expensive, but because so little is needed, these systems are becoming cost effective for use by utilities and industry. However, because the lenses must be pointed at the sun, the use of concentrating collectors is limited to the sunniest parts of the country.

Advances in Solar Photovoltaic Cell Production

The silicon wafers that absorb sunlight and turn it into electric current can run upwards of $130 a pound because of a complex fabrication process that involves melting silicon, letting it crystallize into large ingots, and cutting it into thin wafers. Current solar cell production methods require expensive equipment and special conditions. High-purity solid silicon is needed and the silicon molecules are turned into gas through a vacuum-based process. Massachusetts-based 1366 Technologies simplifies things by repeatedly skimming the solid “skin” off the top of a pool of molten silicon. Mechanical engineer Frank van Mierlo, 1366's CEO, says this method should cut the cost of photovoltaic wafers by two-thirds. “Ideally, we could produce electricity with solar at the same price you can produce electricity with coal.”[Source: Yomiuri Shimbun, February 9, 2011; Discover, February 16, 2012]

“In February 2011, the Yomiuri Shimbun reported: “A team of researchers succeeded in producing solar power generation cells by heating glass plates coated with liquid silicon, a significant improvement over conventional methods.The Japan Advanced Institute of Science and Technology team, headed by Prof. Tatsuya Shimoda, announced. The new method makes it possible to produce solar cells at a much lower cost than conventional means. It also can be used to create multilayer solar cells, which were previously difficult to produce. Shimoda said the new method makes it theoretically possible to significantly improve solar cell performance. The team hopes to put the method into practical use in about five years. [Source: Yomiuri Shimbun, February 9, 2011]

“Focusing its attention on liquid silicon, Shimoda's team coated glass plates with polysilane--a silicon-based solution--and used heat from electric heaters to create silicon films on the plates' surface. This process was repeated three times.The team eventually succeeded in producing a solar cell with three silicon layers, each with different characteristics, by mixing boron and other materials with polysilane.While the new cells can only generate about 20 percent the power of conventional models, the team said it was possible to increase cell performance using higher precision silicon layers.

Solar Power Policy and Investments

In the 1970s the administration of liberal U.S. President Jimmy Carter offered generous subsidies to purchasers of solar panels. Those subsidies were taken down by conservative president Ronald Reagan with conservatives calling solar energy a liberal pipe dream and a waste of taxpayer money.

“But the subsidies were key to getting the solar industry up and going. In October 2011, The Economist reported: “By pushing the price of panels down, subsidies have created possibilities that were not there before. In some sunny parts of America, and elsewhere, people who can afford the upfront costs of solar panels on their roofs can now get electricity from them more cheaply than they can get it down the wires from a power station. Solar panels with battery back-up can now compete with diesel generators for many off-grid applications in developing countries’such as powering mobile-phone masts, which are spreading like unsubsidised wildfire through much of the world. [Source: The Economist, October 15, 2011]

“In December 2011, Google announced that it would spend $94 million to develop four solar farms serving Sacramento, California. The project is expected to provide energy for 13,000 U.S. homes. A few months earlier Google said it would help homeowners purchase solar systems. AP reported: “Google says it will invest $75 million to help 3,000 homeowners install solar panels on their roofs. The plans allow homeowners to install a $30,000 solar electricity system on their house for little or no money up front. Instead, customers pay a monthly fee that is the same or less than what they would otherwise be paying their local utility for power. Google will own the panels, and get paid over time by customers who purchase the electricity the panels produce. This is the latest a string of investments Google has made in renewable energy, now totaling $850 million.” [Source: Jonathan Fahey, AP, September 27, 2011]

Generous Subsidies and the German Solar Power Industry

Michael Birnbaum and Anthony Faiola wrote in the Washington Post: “In December 2011 alone, Germany installed nearly as much solar capacity as the United States has in total, fueled by the subsidies that solar companies admit sometimes made it possible not to worry whether there was sufficient demand in a given area for the power they would produce. Germany’s hardscrabble East turned old Communist-era military bases into power plants. Some solar companies became experts at digging up unexploded munitions to make way for fields of photovoltaic panels. “It was a very easy business model. You only had to secure a piece of land, and you had to find an investor,” said Richard von Hehn, the head of business development at Gehrlicher Solar, a company based in central Germany. [Source: Michael Birnbaum and Anthony Faiola, Washington Post, March 18, 2012]

“The subsidies for renewable energy cost German consumers about $14 a month for a family of four. Companies that generate renewable energy get a guaranteed above-market rate for 20 years. Though solar energy supplied 3.1 percent of Germany’s electricity needs in 2011 — hampered in part by the country’s famously dreary weather — the industry consumed closer to half of the overall renewable subsidies, which also support other energy sources such as wind and biomass.

“The mass production of solar panels in China — driven in large part by Europeans clamoring to buy them — means that some forms of solar installation cost half what they did three years ago. Germany nearly doubled its capacity in 2010, and last year, installations grew even faster, as the industry workforce swelled to 130,000.

Problems for Solar Power

Nicole Dyer wrote in Discover magazine: The solar industry was off to a hot start January 2010 as manufacturers worldwide were churning out photovoltaic panels in record numbers. But by summer the boom in supply had given way to a spectacular bust in demand. Start-up Solyndra very publicly defaulted on a $535 million Department of Energy (DOE) loan in August, joining two other American solar-energy ventures in bankruptcy. Solyndra officials and a handful of politicians blamed cutthroat prices in China, coupled with declining demand in cash-strapped Europe, which represents 80 percent of the world’s solar market. [Source: Nicole Dyer, Discover, January-February 2012]

“But the truth is more complicated. China’s outsize solar subsidies may make it harder for American solar companies to compete, but they have also helped drive down the cost of solar panels by 30 percent since 2010. The problem is that declining prices have done little to solve solar energy’s efficiency problem. Most photovoltaic panels on the market today convert less than 14 percent of the energy in sunlight into electricity, a number that has barely budged since the 1980s.

“Low efficiency drives up all the infrastructure costs associated with photovoltaics, making it hard for even low-cost panels to compete with fossil fuels. “Everything scales with efficiency,” says physicist Ramamoorthy Ramesh, program manager for the SunShot Initiative, a doe program that aims to make solar energy cost-competitive with fossil fuels by 2020. “The number of panels you need at 20 percent is essentially half of what you need at 10 percent, so you can make do with fewer panels.”

“Fewer panels working harder would reduce land-use issues, decrease the cost of installation, and make solar power more cost-competitive. The lesson of Solyndra, then, is not to dump solar subsidies, as some politicians have suggested, but to redirect that money into R & D, where it will spur innovation — the true solution to solar’s demand woes.

Solar Power Polluters

Some companies associated with with the solar industry that are supposedly to be helping the environment are notorious polluters. The Luoyamg Zhonggui High-Technology, for example, which operates on the Yellow River in Henan Province, is a major producer polysilicon, a material widely used in solar panels around the world and a major supplier for Suntech, a company founded by one of China’s richest men. The byproduct of polysilicon production is silicon tetrachloride, a highly toxic substance that is loaded on to dump trucks and dumped in corn fields in villages near the factory. [Source: New York Times]

“Polysilicon is an essential component for solar technology but is tricky to produce. It requires large amounts of energy to make, the smallest amounts of impurities can ruin a batch and for every ton of polysilicon that is produced four tons of silicon tetrachloride is created.

“In the last few years increased demand for polysilicon has caused the price of the material to jump from $20 a kilogram to $300 kilogram. As the price has risen a number of Chinese companies — supported with venture capital and low-interest loans from the government — have sprung up to meet the demand. The factories require sophisticated technology to make the polysilicon and are supposed to recycle the water they use. The Chinese are racing full bore ahead making polysilicon factories even though they haven’t worked out the trickier elements of making the stuff and disposing of the waste materials.

“More than 20 new polysilicon factories have opened or are being built. Their capacity is 80,000 to 100,000 tons — more than double the 40,000 tons produced in the entire world today. The problem with this is that these factories will also produce tons of silicon tetrachloride and there are few regulations or punishments to keep it from being irresponsibly dumped by the factories. Tests of fields where the silicon tetrachloride has been dumped show high levels of chlorine and hydrochloric acid which poison the soil and prevent crops from growing.

Wasteful Solar Subsidies

In October 2011, The Economist reported: “The rush to subsidise solar power over the past decade has been massively wasteful and squalidly political. Nowhere is this more obvious than in the sorry saga of Solyndra, a Californian maker of novel tubular solar panels down the maw of which the Obama administration shovelled $535m in the hope of “green jobs” and photo ops. It got instead mismanagement, bankruptcy and scandal. The money wasted on Solyndra, though, is as nothing compared to the tens of billions of euros squandered on solar panels in Germany. So little electricity do these panels produce under its cloudy northern skies that the emissions from a single large coal-fired power station are enough to nullify all the benefits that their carbon-free contribution might bring. The green jobs they, too, were meant to bring are largely, though not entirely, in China. [Source: The Economist, October 15, 2011]

“Fixating on solar power, which is still a more expensive way to generate electricity than most, has delivered little by way of emissions reductions for the subsidy buck, and left governments paying through the nose for whatever the industry can ship, rather than encouraging true innovation. Europe's solar subsidies have proved not just expensive, but also unreliable. As so often happens with such regimes, their excessive generosity has led to a glut of output, and their cost has risen, leading governments to cut rates. Capacity will probably shrink as a result, discouraging innovation. A high price on carbon, set in such a way that investors could count on it lasting for decades, would have created a more stable business environment and thus, over the long run, brought about more innovation in clean energy.

Cutbacks in Subsidies Through the Solar Industry into a Tailspin

Government subsidies have helped make Germany a world leader in solar technology were suddenly cut. Michael Birnbaum and Anthony Faiola wrote in the Washington Post, “These and cuts elsewhere in Europe threw the solar industry into crisis just short of its ultimate goal: a price to generate solar energy that is no higher than fossil-fuel counterparts. [Source: Michael Birnbaum and Anthony Faiola, Washington Post, March 18, 2012]

“Across Europe, governments are slashing public spending to cut their deficits, and green-energy subsidies are a target, too, even as solar power accelerates in the United States, helped by sympathetic federal policies and an increase in subsidies that came as part of the federal stimulus program.

“German policymakers cut once-generous subsidies as high as 29 percent to 15 percent. Britain and Italy have made similar moves, and Spain abandoned its subsidies altogether. Advocates say that in sunny regions, solar energy is within several years of becoming cost-competitive with fossil-fuel power — if solar companies can stay in business in the meantime.

“While many concede that the subsidies have become overly generous at a time when solar panels have dropped dramatically in price, they insist that governments are reneging on their pledges to go green and argue that the rollbacks are happening too abruptly. Some question whether countries will still be able to boost renewable energy’s share of the power supply in 2020 to their goals of 20 percent in Britain and 35 percent in Germany.

“This whole development has been made possible by Germany and a few other European countries,” Richard Schlicht, the head of Geosol Germany, a solar power company, told the Washington Post Solar power “is becoming cheap only through mass production. And this has happened only through creating the demand. To stop it now makes no sense.”

“Alternative-energy experts suggest that with the solar panels’ declining prices, subsidy cuts are not only acceptable, but to be expected. Though they criticize governments for offering woefully short notice, they suggest the cuts are inevitable as the solar industry becomes more competitive with fossil-fuel energy production. “Everybody knows we can’t go the way we’ve been going,” said Miranda Schreurs, the director of the Environmental Policy Research Center at the Free University of Berlin and a government adviser. “It’ll break the bank.”

German Solar Firms Go Bust After Subsidies Dropped

After the subsidies were lowered several solar companies declared bankruptcy. Others said they would give up on Europe and focus on developing countries, where poor infrastructure makes solar panels that work off the grid a cost-effective competitor to diesel generators. Sarah Marsh and Christoph Steitz of Reuters wrote: “Subsidies, or so-called feed-in tariffs, through which operators of solar panels receive a guaranteed price for the electricity they generate, made Germany the world's largest solar market and had created 150,000 jobs by 2010. But over the past two years, Germany has sharply reduced the tariffs, and a recent proposal to limit subsidies for new solar installations may seal the industry's fate.

“Now, German solar companies are either laying off staff or putting them on reduced working hours. The contrast with the broader economy is stark. Overall, German unemployment has steadily declined in recent years as Europe's biggest economy outperforms its rivals in Europe. Since the end of last year, roughly 5,000 companies involved in the solar business have shut up shop, shedding about 20,000 jobs, according to German solar industry group BSW. [Source: Sarah Marsh and Christoph Steitz, Reuters, December 14, 2011]

“Berlin-based Solon, Germany's first solar energy company to go public, filed for insolvency, becoming Germany's biggest casualty so far. SMA Solar, Germany's top solar group, said it would lay off up to 1,000 temporary workers, citing weak demand for its invertors, a vital piece of equipment in solar systems.

Better Solar Subsidies

According toThe Economist: There is much that governments can do to encourage such progress in the future without repeating the mistakes of the past. They should limit the grounds on which people can object to neighbours' solar installations through the planning process. They should remove subsidies for technologies that compete with solar. In India, which has lots of sun and lots of back-up generators burning subsidised diesel, that could be a game changer in itself. Above all they must fix a price of carbon that gives innovators the confidence that competing with fossil fuels for the long term will be a rewarding, and perhaps hugely profitable, undertaking. If politics prevent them from setting a substantial carbon price, they might consider requiring utilities to have a carbon-free component to their generating portfolios, as happens in many American states. But that needs to be open to all carbon-free technologies, not just the ones that the politicians like, so that the most efficient can prosper. [Source:The Economist, October 15, 2011]

“In the long run, there is little reason to doubt that a great deal of the world's energy will come from solar systems. The sun is hugely powerful — it delivers more energy in an hour than humankind uses in a year — and unlike fossil fuels it will never run out. The application of new materials science and nanotechnology offers the possibility of cost reductions much larger than can be imagined in windpower or hydropower, in biomass or in nuclear power. But massive subsidies are not the way to build the business.

Solar Plane

Reuters reported: “A solar energy plane landed in Morocco completing the world's first intercontinental flight powered by the sun to show the potential for pollution-free air travel. The Solar Impulse took off from Madrid at and landed at Rabat's international airport after a 19-hour flight. Shortly before Swiss pilot Bertrand Piccard landed in Rabat's airport, the project's co-founder and pilot, Andre Borschberg, said the aircraft has proved its sustainability. "The aircraft can now fly day and night. It's quite a show ... It's a technology we can trust," he told reporters. [Source: Reuters, June 5, 2012]

“The Solar Impulse project began in 2003 with a 10-year budget of 90 million euros ($112.18 million) and has involved engineers from Schindler, the Swiss elevator manufacturer, as well as research aid from Belgian chemical group Solvay....The aircraft crossed the Gibraltar Strait separating Africa and Europe at one of its narrowest points. The flight is crucial for the project's developers because it would help improve the organization of a world tour planned in 2013.

“The plane, which requires 12,000 solar cells, embarked on its first flight in April 2010 and completed a 26-hour flight, a record flying time for a solar-powered aircraft, three months later.It made its first international flight last month when it completed a 13-hour trip from the western Swiss town of Payern to Brussels.

“With an average flying speed of 44 mph (70 kilometers per hour), Solar Impulse is not an immediate threat to commercial jets, which can easily cruise at more than 10 times the speed. The typical commercial jet can make the flight from Madrid to Rabat in a little more than an hour.

Image Sources: U.S. Department of Energy; Wikimedia Commons

Text Sources: New York Times, Washington Post, Los Angeles Times, Times of London, The Guardian, National Geographic, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Wall Street Journal, The Atlantic Monthly, The Economist, Global Viewpoint (Christian Science Monitor), Foreign Policy, U.S. Department of Energy, Wikipedia, BBC, CNN, NBC News, Fox News and various books and other publications.

Last updated August 2012

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