Geothermal power uses the thermal energy generated and stored in the Earth to heat water, which is then used to turn a turbine of a generator, thus producing electricity. Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants. Descriptions of each:

  1. Dry steam power plants utilize a well sunk deep into the Earth to make steam from the heated ground. The steam then travels up a pipe, into a turbine, which turns a generator to produce electricity. This is the oldest type of plant used. The first one was built in 1904 in Lardarello, Italy, and is still in use today. It is also used at The Geysers, an American geothermal power plant that is the largest one of its kind in use today. (photo source)
  2. Flash steam power plants pump super heated water at high pressure up from a deep well and into the plant on the surface. Once the water is in the plant it is brought down to normal atmospheric pressure so it turns to steam that is used to turn turbines. The key is that the water is then cooled and returned down to be heated again at the bottom of the well so energy from active areas without very much water are still able to be harnessed. (photo source)
  3. Binary cycle power plants use closed loop systems of fluids which limits the emissions from the geological formation. The hot water harnessed from deep in the well is pumped into a heat exchanger where it heats the other liquid into a steam before being returned to the formation to allow it to be reheated. The secondary steam is used to operate the turbines and is also on a closed loop to limit possible emissions. (photo source)
Think you know everything there is to know about wind power? 
It may come in handy to know your wind turbine facts, as the wind energy industry is booming. Throughout the globe, the amount of turbines more than quadrupled between 2000 and 2006, with global capacity was reaching over 70,000 megawatts at the end of 2011. To put this in perspective, in the United States, where citizens are notorious for their energy consumption, a single megawatt is able to power 250 homes. European and Asian countries are in the lead with usage and reliance on wind power, and industry experts predict that at this rate, wind power will be responsible for a third of the world’s energy by 2050.
Take this quiz to test your knowledge!

Think you know everything there is to know about wind power?

It may come in handy to know your wind turbine facts, as the wind energy industry is booming. Throughout the globe, the amount of turbines more than quadrupled between 2000 and 2006, with global capacity was reaching over 70,000 megawatts at the end of 2011. To put this in perspective, in the United States, where citizens are notorious for their energy consumption, a single megawatt is able to power 250 homes. European and Asian countries are in the lead with usage and reliance on wind power, and industry experts predict that at this rate, wind power will be responsible for a third of the world’s energy by 2050.

Take this quiz to test your knowledge!

Harnessing Light’s Full Spectrum: Scientists Claim Solar Power Breakthrough

Chemists at Ohio State University say they have produced a next-generation material that not only absorbs the full spectrum of sunlight, but also make makes the electrons generated more easy to capture.
The hybrid material — a combination of electrically conductive plastic and metals like molybdenum and titanium — is the first of its kind to capture the full solar spectrum, according to Malcolm Chisholm, one of the authors of the paper describing the research, which appears in Proceedings of the National Academy of Sciences. Solar panels in use today capture only a small fraction of the energy contained in sunlight.
The material generates electricity just like other solar cell materials do: light energizes the atoms of the material, and some of the electrons in those atoms are knocked loose.
Ideally, the electrons flow out of the device as electrical current, but this is where most solar cells run into trouble. The electrons only stay loose for a tiny fraction of a second before they sink back into the atoms from which they came. The electrons must be captured during the short time they are free, and this task, called charge separation, is difficult.
In the new hybrid material, electrons remain free much longer than ever before.

Harnessing Light’s Full Spectrum: Scientists Claim Solar Power Breakthrough

Chemists at Ohio State University say they have produced a next-generation material that not only absorbs the full spectrum of sunlight, but also make makes the electrons generated more easy to capture.

The hybrid material — a combination of electrically conductive plastic and metals like molybdenum and titanium — is the first of its kind to capture the full solar spectrum, according to Malcolm Chisholm, one of the authors of the paper describing the research, which appears in Proceedings of the National Academy of Sciences. Solar panels in use today capture only a small fraction of the energy contained in sunlight.

The material generates electricity just like other solar cell materials do: light energizes the atoms of the material, and some of the electrons in those atoms are knocked loose.

Ideally, the electrons flow out of the device as electrical current, but this is where most solar cells run into trouble. The electrons only stay loose for a tiny fraction of a second before they sink back into the atoms from which they came. The electrons must be captured during the short time they are free, and this task, called charge separation, is difficult.

In the new hybrid material, electrons remain free much longer than ever before.

 
Science Shields Bats from Wind-Turbine Accidents
Researchers have developed an interactive tool that uses bat calls and local environmental conditions to help wind farms reduce bat fatalities while still running efficiently.
Bat activity depends on the time of year and a number of environmental factors, such as wind direction and speed, moon phase and air temperature, according to researchers from the U.S. Department of Agriculture’s Forest Service’s Pacific Southwest Research Station. The new tool allows users to visualize the probability of bat presence based on changes in date and weather conditions.

Using devices to detect bats’ echolocation calls, the researchers linked the presence of bats to weather conditions measured on-site. The results showed that multiple echolocation detectors were required to accurately characterize bat activity.
The study also showed that echolocation detectors placed at 72 feet and 170 feet (22 meters and 52 meters) above ground were more effective at characterizing migratory bat activity than those closer to the ground. The researchers used these findings to help build the interactive tool, which can be found on the PSW website.
"Properly deployed echolocation monitoring can be an effective way to predict bat activity and, presumably, fatalities at wind-energy facilities," Weller says. "These days, pre-construction echolocation monitoring is as common as meteorological monitoring at wind-energy facilities, so the basic building blocks for these models are available at most proposed sites."
The study authors note that bat migration patterns are still poorly understood and that further research is being conducted regarding the relationship between wind turbines and bat activity.

Science Shields Bats from Wind-Turbine Accidents

Researchers have developed an interactive tool that uses bat calls and local environmental conditions to help wind farms reduce bat fatalities while still running efficiently.

Bat activity depends on the time of year and a number of environmental factors, such as wind direction and speed, moon phase and air temperature, according to researchers from the U.S. Department of Agriculture’s Forest Service’s Pacific Southwest Research Station. The new tool allows users to visualize the probability of bat presence based on changes in date and weather conditions.

Using devices to detect bats’ echolocation calls, the researchers linked the presence of bats to weather conditions measured on-site. The results showed that multiple echolocation detectors were required to accurately characterize bat activity.

The study also showed that echolocation detectors placed at 72 feet and 170 feet (22 meters and 52 meters) above ground were more effective at characterizing migratory bat activity than those closer to the ground. The researchers used these findings to help build the interactive tool, which can be found on the PSW website.

"Properly deployed echolocation monitoring can be an effective way to predict bat activity and, presumably, fatalities at wind-energy facilities," Weller says. "These days, pre-construction echolocation monitoring is as common as meteorological monitoring at wind-energy facilities, so the basic building blocks for these models are available at most proposed sites."

The study authors note that bat migration patterns are still poorly understood and that further research is being conducted regarding the relationship between wind turbines and bat activity.

Can Floating Turbines Save Wind Power?
The best place to build the wind farms of the future is the open ocean. While the breeze can be frustratingly variable on land, if you travel just 20 miles off the coastline, the wind blows at a consistent clip of around 33 feet per second. But along most parts of the coastal United States, the ocean floor drops off quickly. That makes standard offshore turbines, the kind that are fixed to the sea bottom for stability, too expensive to be worth it. Two companies, Sway and Principle Power, are currently testing a new kind of technology to combat this problem: floating wind turbines. Principle’s turbine is called WindFloat; the company has a prototype currently working in the waters off Portugal. It sits atop a base formed by three pontoons anchored to the seafloor by cables. Its 240-ton nacelle (gear housing) turns to meet the breeze, the way a land-based turbine does. Sway’s prototype, operating in Norway, is more of a small tower. Its center of gravity lies below the structure’s center of buoyancy, which lets it stay upright even in stormy seas. With Sway, the entire tower rotates to get in the best position to capture wind. Though these prototypes are currently in Europe, the United States is keeping a close eye. The Department of Energy, which estimates that wind power could cover 20 percent of our energy needs by 2030, has contributed funding to both systems. The hope is that offshore wind power can alleviate some of the problems hampering that energy source in America now. 

Can Floating Turbines Save Wind Power?

The best place to build the wind farms of the future is the open ocean. While the breeze can be frustratingly variable on land, if you travel just 20 miles off the coastline, the wind blows at a consistent clip of around 33 feet per second. 

But along most parts of the coastal United States, the ocean floor drops off quickly. That makes standard offshore turbines, the kind that are fixed to the sea bottom for stability, too expensive to be worth it. Two companies, Sway and Principle Power, are currently testing a new kind of technology to combat this problem: floating wind turbines. 

Principle’s turbine is called WindFloat; the company has a prototype currently working in the waters off Portugal. It sits atop a base formed by three pontoons anchored to the seafloor by cables. Its 240-ton nacelle (gear housing) turns to meet the breeze, the way a land-based turbine does. 

Sway’s prototype, operating in Norway, is more of a small tower. Its center of gravity lies below the structure’s center of buoyancy, which lets it stay upright even in stormy seas. With Sway, the entire tower rotates to get in the best position to capture wind. 

Though these prototypes are currently in Europe, the United States is keeping a close eye. The Department of Energy, which estimates that wind power could cover 20 percent of our energy needs by 2030, has contributed funding to both systems. The hope is that offshore wind power can alleviate some of the problems hampering that energy source in America now. 

In Solar Power, India Begins Living Up to Its Own Ambitions
Two years ago, Indian policy makers said that by the year 2020 they would drastically increase the nation’s use of solar power from virtually nothing to 20,000 megawatts — enough electricity to power the equivalent of up to 15 million modern American homes during daylight hours when the panels are at their most productive. Many analysts said it could not be done. But, now the doubters are taking back their words.
Dozens of developers, because of aggressive government subsidies and a large drop in the global price of solar panels, are covering India’s northwestern plains — including this village of 2,000 people — with gleaming solar panels. So far, India uses only about 140 megawatts, which can provide enough power to serve a town of 50,000 people, according to the company. But analysts say that the national 20,000 megawatt goal is achievable and that India could reach those numbers even a few years before 2020.

In Solar Power, India Begins Living Up to Its Own Ambitions

Two years ago, Indian policy makers said that by the year 2020 they would drastically increase the nation’s use of solar power from virtually nothing to 20,000 megawatts — enough electricity to power the equivalent of up to 15 million modern American homes during daylight hours when the panels are at their most productive. Many analysts said it could not be done. But, now the doubters are taking back their words.

Dozens of developers, because of aggressive government subsidies and a large drop in the global price of solar panels, are covering India’s northwestern plains — including this village of 2,000 people — with gleaming solar panels. So far, India uses only about 140 megawatts, which can provide enough power to serve a town of 50,000 people, according to the company. But analysts say that the national 20,000 megawatt goal is achievable and that India could reach those numbers even a few years before 2020.

How Renewable Energy May Be Edison’s Revenge
At the start of the 20th century, inventors Thomas Alva Edison and Nikola Tesla clashed in the “war of the currents.” To highlight the dangers of his rival’s system, Edison even electrocuted an elephant. The animal died in vain; it was Tesla’s system and not Edison’s that took off. But today, helped by technological advances and the need to conserve energy, Edison may finally get his revenge.
The American inventor, who made the incandescent light bulb viable for the mass market, also built the world’s first electrical distribution system, in New York, using “direct current” electricity. DC’s disadvantage was that it couldn’t carry power beyond a few blocks. His Serbian-born rival Tesla, who at one stage worked with Edison, figured out how to send “alternating current” through transformers to enable it to step up the voltage for transmission over longer distances.
Edison was a fiercely competitive businessman. Besides staging electrocutions of animals to discredit Tesla’s competing system, he proposed AC be used to power the first execution by electric chair.
But his system was less scalable, and it was to prove one of the worst investments made by financier J. Pierpont Morgan. New York’s dominant banker installed it in his Madison Avenue home in the late 19th century, only to find it hard to control. It singed his carpets and tapestries.
So from the late 1800s, AC became the accepted form to carry electricity in mains systems. For most of the last century, the power that has reached the sockets in our homes and businesses is alternating current.
Now DC is making a comeback, becoming a promising money-spinner in renewable or high-security energy projects. From data centers to long-distance power lines and backup power supplies, direct current is proving useful in thousands of projects worldwide.
"Everyone says it’s going to take at least 50 years," says Peter Asmus, a senior analyst at Boulder, Colorado-based Pike Research, a market research and consulting firm in global clean technology. But "the role of DC will increase, and AC will decrease."
          Image: Nikola Tesla (left) and Thomas Edison (right)

How Renewable Energy May Be Edison’s Revenge

At the start of the 20th century, inventors Thomas Alva Edison and Nikola Tesla clashed in the “war of the currents.” To highlight the dangers of his rival’s system, Edison even electrocuted an elephant. The animal died in vain; it was Tesla’s system and not Edison’s that took off. But today, helped by technological advances and the need to conserve energy, Edison may finally get his revenge.

The American inventor, who made the incandescent light bulb viable for the mass market, also built the world’s first electrical distribution system, in New York, using “direct current” electricity. DC’s disadvantage was that it couldn’t carry power beyond a few blocks. His Serbian-born rival Tesla, who at one stage worked with Edison, figured out how to send “alternating current” through transformers to enable it to step up the voltage for transmission over longer distances.

Edison was a fiercely competitive businessman. Besides staging electrocutions of animals to discredit Tesla’s competing system, he proposed AC be used to power the first execution by electric chair.

But his system was less scalable, and it was to prove one of the worst investments made by financier J. Pierpont Morgan. New York’s dominant banker installed it in his Madison Avenue home in the late 19th century, only to find it hard to control. It singed his carpets and tapestries.

So from the late 1800s, AC became the accepted form to carry electricity in mains systems. For most of the last century, the power that has reached the sockets in our homes and businesses is alternating current.

Now DC is making a comeback, becoming a promising money-spinner in renewable or high-security energy projects. From data centers to long-distance power lines and backup power supplies, direct current is proving useful in thousands of projects worldwide.

"Everyone says it’s going to take at least 50 years," says Peter Asmus, a senior analyst at Boulder, Colorado-based Pike Research, a market research and consulting firm in global clean technology. But "the role of DC will increase, and AC will decrease."

          Image: Nikola Tesla (left) and Thomas Edison (right)

 
Bill Gates to Collaborate With China on Fourth-Generation Nuclear Reactor
Bill Gates recently confirmed during a talk at China’s Ministry of Science and Technology that a company in which he is a primary investor, Terrapower, will be collaborating with Chinese scientists on a next-generation nuclear reactor. It’s still in the early stages, but there are a lot of impressive superlatives being thrown around, and we have to wonder: Why not bring it Stateside, Mr. Gates?
Gates himself classified the project as in the “early stages,” and understandably so: the reactor proposed would be a Generation IV reactor, which, well, don’t exist yet. In fact, they’re not even particularly close to existing; most estimates peg the earliest construction of a Generation IV reactor at around 2030. In case you were wondering, currently active nuclear reactors are classified as Generation II or III, with first-generation reactors having been long shut down.
But we’re excited by the ambition of the project. Gates said “The idea is to be very low cost, very safe and generate very little waste,” and classified it as a traveling wave reactor. It’s a theoretical kind of reactor, under study by Terrapower that requires no enriched uranium, but actually uses depleted uranium, which means hardly any nuclear waste. They can also run for, theoretically, decades without refueling. The name comes from the idea that fission begins in a specific part of the core and moves outward, in a traveling wave.
Terrapower and the Chinese scientists will be researching the possibilities of this reactor over the next five years—good thing Terrapower falls under the umbrella of our pal Nathan Myhrvold's loaded Intellectual Ventures, because that research alone could top a billion dollars in cost.

Bill Gates to Collaborate With China on Fourth-Generation Nuclear Reactor

Bill Gates recently confirmed during a talk at China’s Ministry of Science and Technology that a company in which he is a primary investor, Terrapower, will be collaborating with Chinese scientists on a next-generation nuclear reactor. It’s still in the early stages, but there are a lot of impressive superlatives being thrown around, and we have to wonder: Why not bring it Stateside, Mr. Gates?

Gates himself classified the project as in the “early stages,” and understandably so: the reactor proposed would be a Generation IV reactor, which, well, don’t exist yet. In fact, they’re not even particularly close to existing; most estimates peg the earliest construction of a Generation IV reactor at around 2030. In case you were wondering, currently active nuclear reactors are classified as Generation II or III, with first-generation reactors having been long shut down.

But we’re excited by the ambition of the project. Gates said “The idea is to be very low cost, very safe and generate very little waste,” and classified it as a traveling wave reactor. It’s a theoretical kind of reactor, under study by Terrapower that requires no enriched uranium, but actually uses depleted uranium, which means hardly any nuclear waste. They can also run for, theoretically, decades without refueling. The name comes from the idea that fission begins in a specific part of the core and moves outward, in a traveling wave.

Terrapower and the Chinese scientists will be researching the possibilities of this reactor over the next five years—good thing Terrapower falls under the umbrella of our pal Nathan Myhrvold's loaded Intellectual Ventures, because that research alone could top a billion dollars in cost.

 Why Did a Scottish Wind Turbine Explode in High Winds?
This striking image of a wind turbine in Ardrossan, North Ayrshire, Scotland as it exploded in high winds has made headline news. The turbine was destroyed yesterday as the region was battered by winds of up to 260km/h when a ferocious Atlantic storm powered into northern parts of the UK. But what caused the explosion?
An amateur video shows the turbine head spinning on its axis and one turbine blade apparently losing its carbon composite skin before the fire starts.
It’s not yet clear what happened, but attention is likely to focus on the turbine’s ability to shut itself down in high wind. A wind turbine normally shuts down when winds reach 55 mph - but something clearly went awry in Ardrossan, perhaps causing excess current in the generator windings, which may have led to the fire.
The shutdown is normally performed by ‘feathering’ the turbine blades so they do not turn. ”In general the turbine blades will pitch out in high winds, keeping the turbines in idle mode,” confirms a spokesman for the turbine’s manufacturer, Vestas of Aarhus, Denmark.
Another source of the problem may be a fault in the turbine’s gearbox, which ensures the rotor speed is adjusted so that the generator provides electricity that matches what is required by the grid it is feeding.
The accident is now under investigation by Vestas and the wind farm’s operator, Infinis of Edinburgh, UK. Infinis says that the site has been disconnected (PDF) from the grid as a “precautionary measure” while it investigates the cause of the blaze.
That the turbine shed large pieces of flaming material will also be of some concern to people living close to such installations - and will almost certainly fuel future planning permission objections from vocal anti-wind farm groups like Country Guardian - not to mention the sheep who were grazing happily below.

 Why Did a Scottish Wind Turbine Explode in High Winds?

This striking image of a wind turbine in Ardrossan, North Ayrshire, Scotland as it exploded in high winds has made headline news. The turbine was destroyed yesterday as the region was battered by winds of up to 260km/h when a ferocious Atlantic storm powered into northern parts of the UK. But what caused the explosion?

An amateur video shows the turbine head spinning on its axis and one turbine blade apparently losing its carbon composite skin before the fire starts.

It’s not yet clear what happened, but attention is likely to focus on the turbine’s ability to shut itself down in high wind. A wind turbine normally shuts down when winds reach 55 mph - but something clearly went awry in Ardrossan, perhaps causing excess current in the generator windings, which may have led to the fire.

The shutdown is normally performed by ‘feathering’ the turbine blades so they do not turn. ”In general the turbine blades will pitch out in high winds, keeping the turbines in idle mode,” confirms a spokesman for the turbine’s manufacturer, Vestas of Aarhus, Denmark.

Another source of the problem may be a fault in the turbine’s gearbox, which ensures the rotor speed is adjusted so that the generator provides electricity that matches what is required by the grid it is feeding.

The accident is now under investigation by Vestas and the wind farm’s operator, Infinis of Edinburgh, UK. Infinis says that the site has been disconnected (PDF) from the grid as a “precautionary measure” while it investigates the cause of the blaze.

That the turbine shed large pieces of flaming material will also be of some concern to people living close to such installations - and will almost certainly fuel future planning permission objections from vocal anti-wind farm groups like Country Guardian - not to mention the sheep who were grazing happily below.