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3.26.2011

Nuclear Debacle – Not Clean, Not Safe | Renewable Energy News Article

Washington, D.C., United States – The recent earthquake in Japan and subsequent loss of 10% of Japan's electric power due to failures and explosions in at least two nuclear power plants, demonstrates the frailness of relying on any "one" energy source, particularly one that holds the extremely high risk of contaminating the air and water, and could be a target for terrorist acts. 
 

Wind Turbine Trends in Recent Drivetrain Design

A Turning Moment: Trends in Torque Transfer | Special Supplement: Wind Technology Magazine Article Petten, the Netherlands -- Trends in Recent Drivetrain Design


There are well over 30 different significant manufacturers currently delivering wind turbines rated at more than 1 MW and more than 130 different models of varying capacities. However, the main differences between turbines are found in the nacelle and more particularly, in the drivetrain. By modifying the layout, manufacturers try to improve the reliability and reduce costs.


In the 'classic' layout - which is or has been used by most manufacturers - the rotor is attached to a main shaft supported by two bearings. The front bearing is closest to the rotor's centre of gravity, the second is located just before the gearbox. As an alternative, in a direct drive layout, a generator is rigidly connected to the rotor, either with or without a shaft and a direct drive concept does therefore not have a gearbox. Whereas in the classic layout normally only part a of the power passes through power electronics, with direct drive turbines usually all power generated is converted with power electronics.


To make maximum use of the wind, it has become common practice to allow the rotor speed to vary and the resulting frequency variation is compensated using power-electronics.


Wind turbines have several limitations, such as tip-speed. From a mechanical point of view, a high tip speed seems desirable as a higher rotational speed implies less torque. Gearbox architecture is determined by both torque and the rotational speed; the higher the torque, the larger the first stage of the gearbox will be; the higher the gearbox ratio, the more complex the gearbox. Thus, to make onshore turbines bigger, their rotational speed must come down (because of blade noise), increasing the torque. That means a higher gear ratio and a larger, more complicated gearbox. For offshore turbines noise is not as much of an issue so they could rotate faster - up to the point where aerodynamics limit the tip-speed.


Turbines and Their Features


Considering the current trend that is seeing a steady increase in turbine power, a number of commercially available machines are explored. However, some newer turbines or those still under development have not been included, such as the the Sinovel 3 MW, the Clipper Brittanica 10 MW and others. Nonetheless, the details of those considered does provide an overview of major design features.


Acciona AW-x/3000


Acciona follows the 'classic' design for its 3 MW turbine and has also opted to keep two main rotor bearings, whereas others in the same class combined one bearing with the gearbox. This design is aimed at reducing loads on the gearbox. Three sets of blades are available, two smaller options from LM and a larger Acciona-specific option.


Bard: Bard 5.0


The first turbine designed and built by Bard Engineering, the drivetrain was developed by Winergy. Specifically for offshore applications, given its fairly low rated wind speed (12.5 m/s) and heavy construction it may be expected to be up-rated to a higher power. The power electronics have all been placed at the bottom of the tower, reducing top-head-mass. The turbine's size and mass makes it difficult to install on a monopile. Bard Engineering has therefore developed its own tripile concept, which basically consists of three monopiles and a 490 tonne crosspiece. Combined with a dedicated installation ship, Bard aims to install a turbine in two days. (See Bard image, below, right.)


Clipper: Liberty 2.5 MW


The Liberty 2.5 MW contains a two-stage gearbox that splits the torque generated by the rotor over four medium speed axes. Each axis is then attached to its own permanent magnet generator. This allows the turbine to function at reduced capacity if a generator fails. Smaller generators are also easier


to handle and can be replaced using the on-board hoist. On the other hand, if the gearbox fails the generators do not produce any power and for many turbines the gearbox has been the biggest source of downtime. Nonetheless, other manufacturers are at least exploring multiple generators and Clipper has announced plans to build a 10 MW offshore version.


Darwind: DD115


Like the Bard 5.0, Darwind's DD115 is a 5 MW turbine that has been specifically designed for offshore. Unlike the Bard 5.0, it has a direct drive generator, which negates the need for a gearbox. There is only a single main bearing integrated into the generator and no main shaft. The generator is relatively small, possibly because Darwind uses a permanent magnet generator instead of an electrically excited system.


DeWind: DeWind 8.2


Where most variable speed turbines rely on power electronics to match grid frequency, the DeWind 8.2 2MW turbine uses two gearboxes, one of which has a variable ratio. This is used to keep the generator at a constant speed, while allowing the rotor to rotate at a variable speed. According to the manufacturer, this can actually save mass because the amount of power electronics required is far less. The variable transmission gearbox can achieve a ratio of 1:3 to 1:5.5 with hydrodynamic coupling. This design is also under consideration for the uprated Bard 5.0.


Ecotècnia (Alstom): Ecotècnia 100


Ecotècnia follows a very similar design approach to Acciona's AW-x/3000 in that it also uses a gearbox and doubly-fed, asynchronous generator. However, there are some differences. Most notably, the gearbox is claimed to be 'fully separated' from the support structure that supports the main bearings. The idea behind this is that the gearbox will then be subjected to lower, more predictable loads. (see lead image for article.)


Enercon: E-126


Enercon was the first company to successfully adopt a direct drive system, though the particular design does result in a large and fairly heavy nacelle. The Enercon 4.5 MW E-112 first prototype was built in 2002. Since then it has been upgraded to 6.0 MW. Enercon supports its rotor on a shaft. The rotating part of the generator is located in front of the main bearing (other direct drive concepts can have it at different locations). Meanwhile Enercon has moved on in their development to the E-126, which has now been rated at 7.5 MW. Interesting to see are the divided, partially steel blades on the E-126.


General Electric: GE 3.6/104 offshore


GE's 3.6 MW turbine was first introduced in 2002 as a turbine meant for offshore. The drivetrain is standard. Seven of these turbines were installed off Ireland to form the Arklow Bank wind farm, but a subsequent expansion was cancelled. More recently GE purchased ScanWind, developing a 4.5 MW offshore direct drive turbine.


Multibrid (Areva): M5000


A 5 MW offshore turbine halfway between the classic design and the direct drive employed by Enercon, on the one hand it avoids the large mass of the direct drive, on the other it still uses a gearbox, so has more moving parts. Using a tripod construction. Six Multibrid M5000s are now installed at the Alpha-Ventus offshore test site. (see image, above, left)


REpower: 3.xM and 5M


The basic layout of REpower 3.xM and 5M is standard. The 5M is designed for both offshore and onshore, while the 3.xM is only onshore. The 5M has been used in Thornton bank phase I and the Beatrice deep-offshore study. REpower is testing a 6 MW prototype turbine with the same dimensions as the 5M. So far using LM Glasfiber blades, REpower also has a joint venture with Rotec, PowerBlades for the MM92 and the 3.xM and is developing blades for the 6M.


Siemens: SWT-3.6-107


Siemens also uses the classic layout for this turbine. Since developing this turbine, Siemens has extended the rotor diameter to 120m. Siemens has also developed a 3.0 MW turbine with a direct drive generator. In numbers Siemens is the second most installed offshore wind turbine of 3 MW or more in operational wind farms, but first in terms of rated power.


Vergnet: GEV HP-1 MW


Unlike the other turbines examined here, this turbine by Vergnet is different in almost anything but the drive-train. The turbine is designed for installation without the use of separate large crane. Rather, it is its own small crane attached to the tower under construction and can assemble the tower and lift the first part of the nacelle. In this part a second crane is present that hoists up the second part of the nacelle and the two-bladed rotor. (image, right.)


Vestas: V90-3 and V112-3


The V90-3 places the gearbox directly against the rotor hub, alleviating the need for, and the mass of, a low speed shaft. However, problems occurred in the gearbox and the V90-3 was withdrawn from offshore sales in early 2007, but re-issued a year later. The new V112 reintroduced a low-speed shaft and the generator now sports permanent magnets.


WinWind: WWD-3


WinWind uses a smaller version of the Multibrid M5000 drives. The WWD-3 machines are designed for fairly benign wind sites (IEC class IIa and IIIb) and uses a small version of the Multibrid, integrated generator/gearbox drive.


Trends in Recent Drivetrain Design


Examining turbine designs reveals that pitch-to-feather with variable speed control is adopted almost universally. Nearly all turbines have three bladed, upwind rotors, though there are some exceptions. Most gearboxes for drivetrains using a generator without permanent magnets are three-stage gearboxes. Gearboxes for permanent magnet generators tend to have only two stages. Gearbox mass seems to scale nearly linear with power, while generator mass scales a bit less than linear.


However, one aspect that does not have a trend is the layout of the drive-train, which shows considerable divergence. The combination of medium speed, permanent magnet generators and low ratio gearboxes as well as variable gear ratio gearboxes and fixed speed generators are interesting alternatives to direct drive and the 'classic' drivetrains.


Wouter Engels is a researcher at the ECN centre of the Netherlands.

House Coat - Citizen Response

Citizen Comments on the House Coat project courtesy of You Tube.


3.25.2011

Most near nuclear plants not ready for emergency



CNN Poll: Most near nuclear plants not ready for emergency


Washington (CNN) – Most Americans who live within 50 miles of a nuclear power plant aren't prepared for a nuclear emergency and don't think the police, hospitals and other emergency services in their community are prepared either, according to a new national poll.

Map: How close is your home to a nuclear power plant?

But a CNN/Opinion Research Corporation survey released Friday indicates that only four in ten believe it is likely that an accident or natural disaster at the nuclear plant near them will put their family in immediate danger, and only one in seven think that is very likely to happen.

Graphic: Are you prepared?

Full poll results [pdf]

As a result, only 18 percent of people who live within 50 miles of a nuclear plant have a disaster supplies kit ready, and six in ten are not familiar with the evacuation route they would need to use if the worst happened.

Radiation: What you need to know

"Staying put may also not be a good idea – nearly six in ten believe that the police, hospitals and first responders in their area are not prepared for a nuclear emergency," says CNN Polling Director Keating Holland.

A 1982 study from Sandia National Laboratories, commissioned for the Nuclear Regulatory Commission, said the consequences of a nuclear meltdown in the United States would be catastrophic. The disaster could cause 50,000 fatalities and $314 billion in property damage. In today's money, that's $720 billion.

Cleanup: Who would pay for nuclear disaster cleanup?

Putting a number on a hypothetical scenario such as a full nuclear meltdown in the United States obviously leaves much room for guesswork. The NRC noted the age of the 1982 Sandia study, suggesting it's no longer accurate. The agency is working on a new study, said NRC spokesman Scott Burnell, but that study focuses on health impacts, not property damage.

Winfred Colbert, an energy attorney, said that in the only major disaster at a U.S. nuclear plant, the partial meltdown at Three Mile Island in 1979, the containment structure generally worked. Not much radiation is thought to have leaked into the atmosphere. The $70 million or so in evacuation, cleanup and other associated costs were easily paid for by the industry's $12.6 billion fund.

But with so many major U.S. cities so close to nuclear power plants - New York, Boston, Chicago, Washington D.C. and Philadelphia are all with a 50-mile fallout zone - it's hard to imagine a major disaster wouldn't result in damage far exceeding $12 billion.

The CNN Poll comes two weeks after a catastrophic earthquake in Japan triggered a tsunami that severely damaged a nuclear power plant, resulting in a possible meltdown of some of the reactors.

On Friday, authorities in Japan raised the prospect of a likely breach in the all-important containment vessel of the No. 3 reactor at the stricken Fukushima Daiichi nuclear power plant, a potentially ominous development in the race to prevent a large-scale release of radiation.

Traces of radioactive iodine tied to the plant have been detected as far away as Sweden and the United States. Authorities have said those levels are far below what's considered harmful to humans.

Nonetheless, the situation in Japan has caused Americans to reflect on a "what if?" scenario.

Just two months ago, California residents living near a controversial nuclear power plant grilled nuclear regulators over the reactor's safety at a public hearing. At issue was the 2008 discovery of a previously unknown earthquake fault located less than a half mile off shore from the plant.

Officials with the Nuclear Regulatory Commission and the owner of the plant, PG&E, told residents the plant could withstand the magnitude of quake that's likely to be triggered by the Shoreline Fault. A quake along the Shoreline Fault is predicted to reach magnitude 6.5, according to PG&E. The earthquake that hit Japan was a magnitude 9.0.

With PG&E wanting to extend the license, the 26-year-old Diablo Canyon plant near San Luis Obispo is likely to face more scrutiny in the aftermath of the nuclear crisis in Japan. The additional questions over the plant's safety come at a critical time for the U.S. nuclear industry.

Read more on California residents' concerns:

The NRC is reviewing applications for 19 new reactors across the country. Most of the new plants are slated for sites where reactors already exist. None are slated for California which has a moratorium on new nuclear power plants.

President Obama has proposed expanding nuclear power in the U.S. as a green energy source. In fact, the president touted Japan's push toward nuclear energy at a town hall meeting in 2009. The White House is showing no signs of backing away from nuclear energy now.

The CNN/Opinion Research Corporation survey was conducted March 18-20, with 1,012 people questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.

– CNN's Jim Acosta, Evan Glass, Ed Hornick, Paul Steinhauser and CNNMoney.com's Steve Hargreaves contributed to this report.

Filed under: CNN poll • Energy • Nuclear power • Polls


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Most near nuclear plants not ready for emergency

CNN Poll: Most near nuclear plants not ready for emergency


Washington (CNN) – Most Americans who live within 50 miles of a nuclear power plant aren't prepared for a nuclear emergency and don't think the police, hospitals and other emergency services in their community are prepared either, according to a new national poll.

Map: How close is your home to a nuclear power plant?

But a CNN/Opinion Research Corporation survey released Friday indicates that only four in ten believe it is likely that an accident or natural disaster at the nuclear plant near them will put their family in immediate danger, and only one in seven think that is very likely to happen.

Graphic: Are you prepared?

Full poll results [pdf]

As a result, only 18 percent of people who live within 50 miles of a nuclear plant have a disaster supplies kit ready, and six in ten are not familiar with the evacuation route they would need to use if the worst happened.

Radiation: What you need to know

"Staying put may also not be a good idea – nearly six in ten believe that the police, hospitals and first responders in their area are not prepared for a nuclear emergency," says CNN Polling Director Keating Holland.

A 1982 study from Sandia National Laboratories, commissioned for the Nuclear Regulatory Commission, said the consequences of a nuclear meltdown in the United States would be catastrophic. The disaster could cause 50,000 fatalities and $314 billion in property damage. In today's money, that's $720 billion.

Cleanup: Who would pay for nuclear disaster cleanup?

Putting a number on a hypothetical scenario such as a full nuclear meltdown in the United States obviously leaves much room for guesswork. The NRC noted the age of the 1982 Sandia study, suggesting it's no longer accurate. The agency is working on a new study, said NRC spokesman Scott Burnell, but that study focuses on health impacts, not property damage.

Winfred Colbert, an energy attorney, said that in the only major disaster at a U.S. nuclear plant, the partial meltdown at Three Mile Island in 1979, the containment structure generally worked. Not much radiation is thought to have leaked into the atmosphere. The $70 million or so in evacuation, cleanup and other associated costs were easily paid for by the industry's $12.6 billion fund.

But with so many major U.S. cities so close to nuclear power plants - New York, Boston, Chicago, Washington D.C. and Philadelphia are all with a 50-mile fallout zone - it's hard to imagine a major disaster wouldn't result in damage far exceeding $12 billion.

The CNN Poll comes two weeks after a catastrophic earthquake in Japan triggered a tsunami that severely damaged a nuclear power plant, resulting in a possible meltdown of some of the reactors.

On Friday, authorities in Japan raised the prospect of a likely breach in the all-important containment vessel of the No. 3 reactor at the stricken Fukushima Daiichi nuclear power plant, a potentially ominous development in the race to prevent a large-scale release of radiation.

Traces of radioactive iodine tied to the plant have been detected as far away as Sweden and the United States. Authorities have said those levels are far below what's considered harmful to humans.

Nonetheless, the situation in Japan has caused Americans to reflect on a "what if?" scenario.

Just two months ago, California residents living near a controversial nuclear power plant grilled nuclear regulators over the reactor's safety at a public hearing. At issue was the 2008 discovery of a previously unknown earthquake fault located less than a half mile off shore from the plant.

Officials with the Nuclear Regulatory Commission and the owner of the plant, PG&E, told residents the plant could withstand the magnitude of quake that's likely to be triggered by the Shoreline Fault. A quake along the Shoreline Fault is predicted to reach magnitude 6.5, according to PG&E. The earthquake that hit Japan was a magnitude 9.0.

With PG&E wanting to extend the license, the 26-year-old Diablo Canyon plant near San Luis Obispo is likely to face more scrutiny in the aftermath of the nuclear crisis in Japan. The additional questions over the plant's safety come at a critical time for the U.S. nuclear industry.

Read more on California residents' concerns:

The NRC is reviewing applications for 19 new reactors across the country. Most of the new plants are slated for sites where reactors already exist. None are slated for California which has a moratorium on new nuclear power plants.

President Obama has proposed expanding nuclear power in the U.S. as a green energy source. In fact, the president touted Japan's push toward nuclear energy at a town hall meeting in 2009. The White House is showing no signs of backing away from nuclear energy now.

The CNN/Opinion Research Corporation survey was conducted March 18-20, with 1,012 people questioned by telephone. The survey's overall sampling error is plus or minus three percentage points.

– CNN's Jim Acosta, Evan Glass, Ed Hornick, Paul Steinhauser and CNNMoney.com's Steve Hargreaves contributed to this report.



--
Scott's Contracting
scottscontracting@gmail.com
http://www.stlouisrenewableenergy.blogspot.com
http://scottscontracting.wordpress.com


Illinois senators question nuclear power experts about safety of state's reactors - WQAD

Illinois senators question nuclear power experts about safety of state's reactors - WQAD CHICAGO (AP) — U.S. Sen. Mark Kirk says the size of the evacuation zones around the six nuclear power plants in Illinois should be reviewed. Kirk and fellow U.S. Sen. Dick Durbin held a forum Friday with a panel of four nuclear experts that resembled a congressional hearing to talk about safety in Illinois in the wake of the disaster in Japan. Four of Illinois' 11 reactors are almost identical to those involved in Japan's nuclear crisis. Exelon Corp. owns the plants and says they're safe. Officials sought to assure the senators that Illinois plants are safe and have multiple layers of safeguards. Kirk and Durbin also were interested in making sure the state's stockpile of potassium iodide pills for people in evacuation zones is consistent with new 2010 census numbers.

What’s so scary about nuclear power plants? - Local / Metro - TheState.com

What’s so scary about nuclear power plants? - Local / Metro - TheState.com WASHINGTON — Nuclear radiation, invisible and insidious, gives us the creeps. Even before the Japanese nuclear crisis, Americans were bombarded with contradictory images and messages that frighten even when they try to reassure. It started with the awesome and deadly mushroom cloud rising from the atomic bomb, which led to fallout shelters and school duck-and-cover drills. The experts tell us to be logical and not to worry, that nuclear power is safer than most technologies we readily accept. But our perception of nuclear issues isn’t about logic. It’s about dread, magnified by arrogance in the nuclear industry, experts in risk and nuclear energy say. Japan Earthquake Nuclear Crisis In this image made off Japan's NTV/NNN Japan television footage, smoke ascends from the Fukushima Dai-ichi nuclear plant's Unit 3 in Okumamachi, Fukushima Prefecture, northern Japan, Monday, March 14, 2011. The second hydrogen explosion in three days rocked Japan's stricken nuclear plant Monday, sending a massive column of smoke into the air and wounding 11 workers. (AP Photo/NTV/NNN Japan) “Whereas science is about analysis, risk resides in most of us as a gut feeling,” said University of Oregon psychology professor and risk expert Paul Slovic. “Radiation really creates very strong feelings of fear— not really fear, I would say more anxiety and unease.” Thirty years ago, before the 1986 Chernobyl nuclear disaster, Slovic took four groups of people and asked them to rate 30 risks. Two groups — the League of Women Voters and college students — put nuclear power as the biggest risk, ahead of things that are deadlier, such as cars, handguns and cigarettes. Business club members ranked nuclear power as the eighth risk out of 30. Risk experts put it at 20. The only fear that Slovic has seen as comparable in his studies to nuclear power is terrorism. A Pew Research Center poll after the Japanese nuclear crisis found support for increased nuclear power melting down. Last October the American public was evenly split over expanding nuclear power; now it’s 39 percent in favor, 52 percent opposed. “Nuclear radiation carries a very powerful stigma. It has automatic negative associations: cancer, bombs, catastrophes,” said David Ropeik who teaches risk communications at Harvard University. You can’t separate personal feelings from the discussion of actual risks, said Ropeik, author of the book “How Risky Is it, Really?” But Ropeik, who has consulted for the nuclear industry, said those fears aren’t nearly as justified as other public health concerns. He worries that the public will turn to other choices, such as fossil fuels, which are linked to more death and climate change than the nuclear industry is. He cites one government study that says 24,000 Americans die each year from air pollution and another that says fossil fuel power plants are responsible for about one-seventh of that. At the same time, health researchers have not tied any U.S. deaths to 1979’s Three Mile Island accident. United Nations agencies put the death toll from Chernobyl at 4,000 to 9,000, with anti-nuclear groups contending the number is much higher. Since 2000, more than 1,300 American workers have died in coal, oil and natural gas industry accidents, according to federal records. Radiological accidents have killed no one at U.S. nuclear plants during that time, and nuclear power has one of the lowest industrial accident rates in the country, the Nuclear Energy Institute said. Ropeik calls this mismatch between statistics and feelings “a classic example of how public policy gets made — not about the numbers alone, but how we feel about them, and it ends up doing us more harm.” Alan Kolaczkowski, a retired nuclear engineer, faulted his own industry. “Those in the industry believe it is so complex it cannot be explained to the general public, so, as a result, the industry has a trust-me attitude, and that only goes so far.” Read more: http://www.thestate.com/2011/03/25/1750503/whats-so-scary-about-nuclear-power.html#ixzz1Hdz9xenP

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