Summary

This document provides a comprehensive overview of different renewable energy sources like solar, wind, and geothermal energy. It explains how these sources work and discusses their applications and environmental benefits. The text highlights the growing importance of renewable energy.

Full Transcript

RENEWABLE ENERGY [VIDEO] Renewable Energy 01 The action never stops at the FedEx regional sort facility (Einrichtung). Located at Oakland International Airport in California, it's the shipping giant's hub (Zentrum) for the Pacific region. 1,700 workers and a stat...

RENEWABLE ENERGY [VIDEO] Renewable Energy 01 The action never stops at the FedEx regional sort facility (Einrichtung). Located at Oakland International Airport in California, it's the shipping giant's hub (Zentrum) for the Pacific region. 1,700 workers and a state-of-the-art conveyor (Förderband) system sort about 85 million packages per year.... To meet these electricity demands, FedEx decided to build its own power plant (Kraftwerk). It's silent, has no moving parts and it's located conveniently (praktischerweise) on the roof. Taking advantage of abundant (reichlich) sunshine and 81,000 square feet of unused roof space, FedEx hired Sharp Solar to design this photovoltaic electricity system in 2005. Today it supplies 80 percent of the facility's peak (Spitzen) electricity needs. When sunlight strikes (treffen) each of the silicon cells, it excites (anregen) electrons which are knocked (schlagen) free to form an electric current (Strom). Metal contact points carry the current away and complete the circuit (Stromkreis). Typically, 40 solar cells make up a module. Several modules are combined into an array (Feld).... And that's it. In a split second, sunlight is converted into electricity, enough to power the beehive (Bienenstock) of activity below. What kind of environmental benefit can one rooftop (Dach) bring? Over its 25-year guaranteed life, this one will offset (kompensieren) 10,800 tonnes of carbon dioxide (Kohlendioxid). That's the equivalent (Pendant) of removing 2,100 cars from the road. In an economy burdened (belasten) by the cost of increasingly scarce (knapp) oil and natural gas and a planet already feeling the impact of fossil fuel (fossiler Brennstoff) driven climate change, the technological revolution of our time is renewable energy. Sunlight, wind, water, geothermal heat and plant biomass are all essentially limitless (grenzenlos) resources. And they're all proven technologies that work right here, right now. The Sun provides the Earth with unfathomable (unergründlich) amounts of energy. In one hour, the Earth receives more energy from the Sun than the entire human race uses in a year. With current technology, photovoltaic panels covering 10,000 square miles or about ten percent of the land area of Nevada could provide all of the electricity used by the United States. Although photovoltaics - converting the sun's light to electricity - was not discovered until the 20th century, solar thermal - harnessing (nutzen) the sun's heat - is an ancient practice. Perhaps the earliest use of solar thermal technology was the south-facing (nach Süden gerichtet) home. Ancient cultures, including the Anasazi Indians of the American Southwest, designed their buildings to face south to maximise heat from the Sun which stays low in the southern sky during winter. In the summer when the Sun is high in the sky, the cliff face (Klippenwand) that extended over the building provided cooling shade. It's still a common design today. Two millennia (Jahrtausend) later, the 19th century equivalent of this technology was born: the rooftop solar water heater, which traps (einfangen) the sun's rays (Strahl) in a glass collector, and rapidly heats up water inside insulated (isoliert) glass pipes. At the turn of the 20th century, 30 percent of the homes in Pasadena California used solar water heaters. The same concept is used today to cheaply provide hot water to millions, even in cold cloudy climates. Renewable Energy 02 Solar thermal energy can also cheaply produce electricity. Giant solar power plants, like this one in California's Mojave Desert, don't use photovoltaic panels to convert light into electricity. Instead, mirrors focus solar rays onto a thin absorber tube (Absorptionsröhre) that runs along the mirror's focal point (Brennpunkt). Inside the tube is synthetic oil which is blasted with intense heat. … The superheated oil boils water into steam which turns turbines. The oil then re-circulates through the closed-loop system (geschlossenes Kreislaufsystem). In hot, dry areas solar thermal plants generate serious megawatts at a price lower than typical grid power (Stromnetz). In fact, solar thermal plants occupying (besetzen) that same ten percent section of Nevada could also supply all of the United States electrical needs. RENEWABLE ENERGY [VIDEO] Meanwhile, photovoltaic technology is surging ahead (vorpreschen) into its second century. It's come a long way since 1904 when Albert Einstein first proved that light was composed of tiny packets of energy known as photons which could be converted to electricity. Photovoltaic cells got their first big break (Chance) in the 1950s thanks to the Space Race (Wettlauf ins All). … The U.S. Space Program solar powered satellites on the other hand proved an instant success. Photovoltaic panels still power nearly all satellites in space probes (Raumsonde) within the solar system. In this sense, the 21st century lifestyle - from global positioning to global communication - is completely dependent on solar energy. The U.S. Coast Guard (Küstenwache) became one of the first earth-based users of photovoltaics powering its remote (entfernt) buoys (Boje) and weather stations with solar panels wired to batteries. In the 1970s and 80s, solar panels performed heroically during one of the worst droughts (Dürre) to hit Africa. Solar power was used to pump water from 40 feet below the parched (augetrocknet) ground saving many lives. For those already connected to the power grid photovoltaics are becoming more and more viable (rentable).... For the time being photovoltaic panels are still expensive, making solar electricity two to five times the cost of typical grid power. But grid-connected homeowners can sell excess (überschüssig) peak-hour (Spitzenzeit) electricity back to the power company at a premium (mit einem Aufpreis). Up until now the primary cost of solar cells has been the ultra-pure silicon needed for the photovoltaic reaction. But more than one company wants to change that. … Rather than silicon, Nanosolar in Palo Alto, California, uses a combination of semiconducting (halbleitend) elements.... So thin that the absorbing material is assembled (zusammensetzen) on the nano-scale, then literally (buchstäblich) printed on to a foil (Folie) substrate (Trägermaterial) as a photovoltaic ink.... Thin film solar panels as well as their silicon counterparts can be built right into a building's surface such as a roof, window glass or in the near future, paint. So-called "building integrated photovoltaics" will drive down the cost of solar electricity even further. The Sun's heat also gives rise to the invisible (unsichtbar) powerful force known as the wind. And in the future of energy, wind is a force to be reckoned with (ernstzunehmende Größe). Renewable Energy 03 Tucked (verstaut) among the rolling hills (Hügellandschaft) of central New York is the Fenner Wind Project, owned by Enel North America. Though not the world's biggest wind-power project, it represents the new thinking in wind energy. Bigger, smarter (klug) and fewer wind turbines, eliminating (beseitigen) the need for dozens of smaller turbines. Fenner is composed of 20 wind turbines built and maintained (warten) by GE (General Electric) Energy. Each stands 215 feet tall, has a rotor, 218 feet in diameter (Durchmesser), a bit longer than the wing span (Flügelspannweite) of a 747 and produces 1,.5 megawatts of electricity. Converting wind to electricity begins as the wind flows over the rotor's airfoil-shaped (geformt wie eine Tragfläche) blades (Schaufel). The combination of lift (heben) and drag (ziehen) causes the blades to rotate.... That tremendous torque (Drehmoment) is put to work inside the turbine's power plant 200 feet above the ground.... From the generator the electric current travels down the tower to underground transmission lines (Leitung) and into the power grid. The main challenge for wind power is the fact that the wind is not blowing at all sites (Standort) at all times. The solution is to diversify (aufteilen) the locations of wind turbines and guide (leiten) the turbines to the wind. Computer controls can turn the entire turbine up to 360 degrees to catch the prevailing (vorherrschend) wind. These controls also direct individual blades to pitch (kippen) into optimum wind position. … Technicians are needed to perform maintenance on the turbine and to change a light bulb (Glühbirne) on occasion (Gelegenheit). Those with a fear of heights need not apply. Clusters (Ansammlung) of wind turbines are often called a wind farm. And in the case of Fenner, New York, it really is a farm. The land is owned by local farmers like Donna Griffin. For landowners going green is a good way to make some green (Geld verdienen).... From New York to North Dakota, American farm lands and badlands (Ödland) are turning into windswept (windumtost) power plants. Farming and wind power have a long history together. In fact it was on the farm that wind power saw most of its advances (Forschritt). The famous Dutch tower mills introduced about 1390 saw many RENEWABLE ENERGY [VIDEO] innovations over the centuries including leading edge (Anströmkante) airfoil sections on its light wooden blades which dramatically improved the art of aerodynamic lift. These pre-industrial dynamos (Energieerzeuger) were mainly used for drainage (Entwässerung) and grinding (mahlen) grain into flour (Mehl). In the late 19th and early 20th centuries, small windmills on American farms were the first to employ (verwenden) a large number of light, efficient steel blades which produced significant torque even in low winds. Some of these machines were also the first to convert wind to electricity. The new era of wind technology began in the early 1980s when Zond Systems began putting 50 kilowatt wind turbines, tiny by today's standards, in the hills of Tehachapi, California.... The company also implemented variable speed turbines which allowed the rotors to accelerate (beschleunigen) and generate additional energy during a violent gust of wind (Windstoß). Advances such as these along with smarter computer controls and lighter, cheaper and more aerodynamic rotor designs, have made the cost of wind-powered electricity competitive with that of natural gas and even coal. Wind power is experiencing exponential growth. Several European nations will soon be getting 20 percent or more of their electricity through wind. In June of 2006, the U.S. Department of Energy announced it would also aim for a target of 20 percent. As engineers continue to make wind turbines more resilient (robust) and cost-efficient, you can expect them to get even bigger. As always, the bigger the rotor, the more energy that can be captured. Some of the biggest turbines are reaping (ernten) the massive wind harvest on the oceans. Wind is certainly a hot technology. But so is this: geothermal energy, hot enough to power a small nation. Renewable Energy 04 A small island nation ringed with volcanoes and perched (niedergelassen) just below the Arctic Circle (nördlicher Polarkreis) has emerged (hervortreten) as a world leader in renewable energy. By tapping (anzapfen) into their bounty (Fülle) of fire and water, the people of Iceland have become nearly energy independent. Abundant rainfall and glacial runoff (Gletscherwasser) provide hydro-electric power which represents 80 percent of nation's electricity. This water also seeps (sickern) into underground aquifers (Wasserschicht) and runs head-on (frontal) into magma-heated rock which sits close to the surface in Iceland. This collision results in geysers (Geysir), fumaroles (Fumarole), smoke events and the renewable source known as geothermal energy. Icelanders have used geothermal hot water for washing clothes and bathing for hundreds of years but it wasn't until the mid-20th century that engineers began tapping the resource on a scale large enough to replace costly imported fossil fuels.... Geothermal water brings heating and hot water to 93 percent of the nation's homes. Geothermal steam generates 17 percent of Iceland's electricity. All told (alles in allem), geothermal provides over 50 percent of Iceland's total energy needs. The Nesjavellir power plant is a dual use (doppelter Verwendungszweck) facility. It taps geothermal energy to provide electricity as well as hot water. Both end products begin here in one of 15 bore holes (Bohrloch) drilled as far as 6,000 feet below the surface. The bore hole's well (Schacht) is encased (ummanteln) in cement to a depth of about 2,000 feet. Below that, the well is lined with perforated metal to let in steam and hot water which rush (eilen) toward the surface under great pressure.... The mixture of steam and hot water is sent to the separation module. From here, the water and steam take separate paths. The steam heads for the demister (Abscheider) to remove moisture (Feuchtigkeit) that could damage the turbines. Excess water vapour (Dampf) is vented (ablassen) into the air along with trace amounts of other greenhouse gases. Over a year, this power plant will release 12,000 tonnes of greenhouse gases, what a coal-fired plant releases in 5 days.... The steam turns one of four turbines at a rate of 3,000 rpm (revolutions per minute). The turbines combine to generate a 120 megawatts of electricity which is sent on to Reykjavik. Nesjavellir is a high temperature geothermal zone meaning the water below the surface is hot enough to dissolve (auflösen) sulphur and other corrosive (ätzend) minerals. For this reason it can't be used directly in the population's heating system. Instead the power plant uses the geothermal water to heat cold, fresh water pumped in from a nearby aquifer. In the first stage of heating the water, excess steam from the electricity producing turbines is used to bring the cold water up to 125 degrees.... Inside the heat exchanger, the geothermal brine (Lake) rapidly brings the fresh water to its 187 degree RENEWABLE ENERGY [VIDEO] target temperature. The now scalding (brühend heiß) fresh water is pumped into the pipeline as it climbs uphill. After providing hot water and space heating (Raumheizung), this geothermal life line has enough heat left over to melt snow on the winter sidewalks (Gehsteig) as it passes under the streets. It also allows hundreds of greenhouses to grow fresh fruits and vegetables. Even the geothermal brine finds other uses. Unique in the world of power plants, the effluent (Abwasser) from one Icelandic geothermal plant actually provides the warm mineral-rich waters of the Blue Lagoon, a hugely popular spa. The Icelandic government has set an ambitious (ehrgeizig) long-term goal: convert all the nation's cars and even its fishing fleet to run on clean-burning hydrogen produced by geothermal and hydropower. If that day comes, all of Iceland's energy needs will be met with renewables. Iceland is far from the only place on Earth with rich geothermal resources. Generally where there's volcanic activity, there is geothermal energy. One study estimates that $865 million people in volcanic regions from Japan to Idaho could get their electricity through geothermal. That's 17 percent of the world's population. But there's another form of geothermal energy, less exotic, yet very affective that any homeowner can tap into. It's known as ground source geothermal (Erdreichwärme). Nearly everywhere on Earth, about eight feet below the surface, the air is a steady cool temperature between 50 and 75 degrees. To capture that air, a trench (Graben) is dug below the building and tubing (Rohrleitung) laid in. An antifreeze (Gefrierschutz) liquid, circulated by a small electric pump passes through the tubes. In the summer, the liquid carries heat out of the building and mild temperatures in. In the winter, the warmer ground air heats the liquid which flows into the colder building. It's in effect an underground heat exchanger (Wärmeaustauscher). As the prices of heating oil and natural gas continue to go up, more people will start to look down. And like all renewable energy sources, geothermal will be there, waiting. Renewable technology clearly has what it takes to power the grid and heat our homes, but what will it have to say about the future of the automobile? From ethanol crops to electric cars, it's a heated debate. Renewable Energy 05 At first glance (Blick), it's a typical auto repair shop (Autowerkstatt). But Lovecraft Bio-Fuels in Los Angeles is hardly typical. Give them three hours and a few hundred dollars and they'll convert your diesel car to run on one hundred percent all-American vegetable oil. Petroleum, which accounts for (verantwortlich sein für) 30 percent of the world's energy use, is growing scarcer every day. So it's not surprising to see customers lining up (anstellen) to switch (wechseln) to another kind of oil, one that's renewable. For many diesels, the conversion process simply requires adding a special high-flow filter and a heat exchanger which uses coolant (Kühlflüssigkeit), heated by the engine to raise the vegetable oil to the right temperature. The best fuel is actually used vegetable oil since the frying (Braten) process has cooked out any embedded (eingeschlossen) water.... That's because the restaurant avoids its usual oil disposal fee (Entsorgungsgebühr) and the driver gets free fuel. Of course new vegetable oil works just about as well. While the idea of running a car on cooking oil may hold a certain comic (lustig) appeal (Eindruck), vegetable oil fuel is part of the solution to a deadly serious problem. Nearly 20 percent of the world's global warming greenhouse gases come directly from automobiles. In addition to being renewable, biofuels from vegetable oil to biodiesel to ethanol have at least two environmental benefits over gasoline. They release fewer and less toxic (giftig) emissions and more importantly, their carbon emissions can potentially be offset by the carbon taken out of the atmosphere when the biofuel was a plant. Biodiesel, which is made from a plant's fatty oils and ethanol, an alcohol fuel distilled (destillieren) from a plant's sugars, are the hot biofuels of the moment. But they're also straight out of early automotive history. Rudolf Diesel built his engine to run on peanut oil. Henry Ford designed the Model T to run on ethanol.... Each new discovery of cheap domestic oil pushed these early biofuels to the margins RENEWABLE ENERGY [VIDEO] (Rand).... In the US, the most talked-about ethanol feedstock (Rohstoff) is corn grain. The corn grain ethanol yields (abwerfen) only slightly more energy than the amount of fossil fuels needed to harvest and distil it.... By contrast, the sugar cane (Rohrzucker) ethanol used in Brazil yields eight units of energy for every unit of fossil energy put in. Not only is the feedstock bursting (platzend) with fermentable sugars, but the rest of the plant is burnt cleanly to power the fermenting (Gärung) and distilling. The result is a major reduction in carbon emissions and dirt cheap ethanol for Brazilian drivers. At the National Renewable Energy laboratory in Golden Colorado, researchers aim to hit similar levels of efficiency by extracting sugars from the entire plant, which includes the so-called cellulosic biomass. Corn farmers will be happy to know that one of the more promising crops is corn stover (Maisstroh).... The hard part is converting the tough cellulose fibres (Faser) into sugars using bioengineered (genmanipuliert) enzymes. But the payoff (Lohn) could be tremendous.... The tall prairie grass known as switchgrass (Rutenhirse) may prove an even more powerful biofuel crop. Biofuels aren't the only way for renewable energy to clean up the automobile. There's also the power grid. This is a plug-in hybrid (Kombination). Like other hybrids, it runs on a gasoline engine, has an electric motor, powered in part by the momentum of braking (Bremsen). But Felix Craver and the California Car's Initiative have taken these already fuel efficient cars - in this case a Toyota Prius - a step further. They've beefed up (aufmotzen) the battery pack and converted it to run on electricity taken straight from any 120-volt outlet (Steckdose).... The gasoline is used only as a range extension (Reichweitenerweiterung) fuel. Under 35 mph, not a drop is used. Above that speed, the gas and electric motors combine for an average of 100 miles per gallon.... Cars that get 100 miles per gallon and more will be necessary if the world's farmlands are to grow fuel as well as food. With current mpg (miles per gallon) standards, there is simply not enough acreage (Ackerland) to supplant (ersetzen) the world's oil habit without endangering (gefährden) its food supplies. In 2006, the brilliantly simple plug-in prototypes greatly impressed senators and representatives (Vertreter) from both sides of the aisle (von beiden politischen Lagern). Of course electricity today is generated largely by fossil fuels but plug-in proponents (Verfechter) envision (sich ausmalen) an increasingly green power grid to charge the car's battery and cellulosic biofuels to fill the tank.... While biofuels and plug-in hybrids surge ahead (nach vorne drängen), a new wave of renewable technology is coming in with the tide (Gezeiten). Renewable Energy 06 Despite (trotz) the fact that the oceans cover 70 percent of the planet's surface, we've only begun to tap them directly as an energy source. But these marine powerhouses (Kraftwerk) may one day unlock (freischalten) the door to clean, limitless energy. Hydro-electric power was the great renewable energy source of the 20th century and it will continue to provide gigawatts of power. But with most of the world's rivers already dammed (gestaut) the future of hydropower will come from the sea. Of the various technologies to capture the ocean's energy, a tidal barrage (Gezeitensperre) is the closest in design to traditional hydropower. The barrage is essentially a dam, collecting water from high tide (Flut) until there's sufficient potential energy for power generation then forcing (zwingen) the water through turbines, when released during low tide (Ebbe). The world's largest and oldest tidal barrage, at La Rance, France, began producing power in 1966. Today it still powers 240,000 homes. A more recent technology known as tidal stream power uses propeller-like turbines to capture the kinetic energy of underwater currents (Strom).... Much of the work is taking place in the British Isles where companies such as Marine Current Turbines are thinking big, sinking massive pilings (Pfahlwerk) into the ocean floor and letting the turbines do their work. Wave power is an even newer technology. Yet it may hold the most promise of all since wave power can be captured anywhere on the ocean. In this design a 450 foot chain of pipes, connected by hinged (klappbar) joints (Gelenk), sits semi-submerged (halb eingetaucht) on the ocean. Each motion of the waves is resisted (abfangen) by hydraulic rams (Ramme) located in the hinges (Gelenk). This action pumps high pressure oil through hydraulic motors which drive electrical generators. Electrical transmission lines also keep the floating power plant tethered (anbinden) to the ocean floor. A Scottish company, Ocean Power Delivery, has installed a successful 2.5 megawatt wave farm off the coast of RENEWABLE ENERGY [VIDEO] Portugal. A wave farm, occupying less than a half a square mile of ocean would generate 30 megawatts of power or enough for 20,000 British homes. 472 square miles of ocean could power each of the United Kingdom's 24.5 million households. Each region of the Earth has its own renewable resources. From the vast (gewaltig) wind potential of North Dakota to the solar mother load that waits in the Sahara. When you put them all together, one thing becomes clear. Renewable energy offers a solution to global problems.... The technology works but a renewable future also requires political will (Wille) and a new way of thinking, in which a farm harvests wind, a harvest yields fuel and a rooftop becomes a power plant.

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