Editorial: Compromise is key to setting energy policy Mar 16, 2011 Knox News Energy crises have been a part the American landscape on and off for the past 40 years. However, it seems we have learned little, except perhaps that politicians understand they can get a lot of mileage when they complain about America's dependence on "foreign oil." Since the 1970s when gasoline prices shot up during an embargo by the Organization of Petroleum Exporting Countries, Americans have talked about decreasing their dependence on oil from other nations, especially the Middle East. (During the current crisis, OPEC has ramped up production to compensate for the loss of Libyan crude.)
The early 1970s also was the time the environmental movement was hitting its stride, so there was talk about ending dependence on fossil fuels and switching to alternative forms of energy: solar, geothermal and wind power, among others.
And speaking of alternative sources of energy, credit U.S. Sen. Lamar Alexander with leading the way. The Tennessee Republican last week became one of the first consumers in the state to purchase a 2011 Nissan Leaf electric car, encouraging the use of electric-powered vehicles.
If enough Americans made similar purchases, he said, "that would be the single best way to reduce our dependence on foreign oil."
With gasoline prices hitting an average of $3.50 per gallon nationwide last week - about $3.35 per gallon in Tennessee - Alexander's purchase was timely.
Meanwhile, those rising gasoline prices continue to capture most of the current attention. And even politicians who seriously want Americans to find alternative sources of energy acknowledge that gasoline will remain the fuel of choice in the near future.
Now, some predict that gas prices will reach $5 per gallon by the summer, and that is causing the rhetoric to rise as well. Tennessee's U.S. representatives have decried the dependence on foreign oil as well as the lack of a clear energy policy.
U.S. Rep. John J. Duncan Jr., R-Knoxville, also expressed understandable concern about people in rural areas having to drive longer distances to work. Duncan chairs the House Transportation Committee's Subcommittee on Highways and Transit.
An energy policy should include drilling in new areas and accelerating approval of nuclear power plants, Duncan said. U.S. Reps. Scott DesJarlais, of the 3rd District, and Phil Roe, of the 1st District, agreed. DeJarlais added that alternative forms of energy should be expanded, while Roe said the U.S. should boost the use of natural gas.
Duncan said he expects the new Republican majority in the House to begin pushing for an energy policy that includes more domestic production.
The discussion needs to begin anew and not disappear when gasoline prices fall. If the GOP majority can get it going, good for them. With the House in Republican hands and the Senate and White House controlled by Democrats, the current crisis might produce what has been lacking in the past.
That would be a compromise that gives Americans a clear, coherent energy policy, one that builds instead of blames and guides instead of guesses. That would be an achievement 40 years in the making.
--
Scott's Contracting
scottscontracting@gmail.com
http://www.stlouisrenewableenergy.blogspot.com
http://scottscontracting.wordpress.com
3.26.2011
Re: Compromise is key to setting energy policy
President Carter was right
--
Scott's Contracting
scottscontracting@gmail.com
http://www.stlouisrenewableenergy.blogspot.com
http://scottscontracting.wordpress.com
Coal and E.P.A. Proposes New Emission Standards for Power Plants
Adaptation to all the proposed rules constitutes an extraordinary threat to the power sector — particularly the half of U.S. electricity derived from coal-fired generation-
Is this why the Big Coal and Big Oil Firms are Lobbying to Cut the Funding for the EPA?
--
Scott's Contracting
scottscontracting@gmail.com
http://stlouisrenewableenergy.blogspot.com
http://scottscontracting.wordpress.com
- first national standard and will require all plants to come up to the standard of the cleanest of current plants
Is this why the Big Coal and Big Oil Firms are Lobbying to Cut the Funding for the EPA?
| Mar 17, 2011 | New York Times | ||
| WASHINGTON — The Environmental Protection Agency on Wednesday proposed the first national standard for emissions of mercury and other pollutants from coal-burning power plants, a rule that could lead to the early closing of a number of older plants and one that is certain to be challenged by the some utilities and Republicans in Congress. Lisa P. Jackson, the agency's administrator, said control of dozens of poisonous substances emitted by power plants was long overdue and would prevent thousands of deaths and tens of thousands of cases of disease a year. Ms. Jackson pointedly included the head of the American Lung Association and two prominent doctors in her announcement to make the point that the regulations were designed to protect public health and not to penalize the utility industry. She estimated the total annual cost of compliance at about $10 billion (This is the Same Projected Cost for New Nuclear Reactors), in line with some industry estimates (although some are much higher), and the health and environmental benefits at more than $100 billion a year. She said that households could expect to see their electric bills rise by $3 to $4 a month when the regulation was fully in force after 2015. Ms. Jackson was acting under a court-ordered deadline to produce a draft rule by Wednesday. "Today's announcement is 20 years in the making and is a significant milestone in the Clean Air Act's already unprecedented record of ensuring our children are protected from the damaging effects of toxic air pollution," she said. Ms. Jackson said that mercury and the other emissions covered by the rule damaged the nervous systems of fetuses and children, aggravated asthma and caused lifelong health damage for hundreds of thousands of Americans. She said that installing and maintaining smokestack scrubbers and other control technology would create 31,000 short-term construction jobs and 9,000 permanent utility sector jobs. Even before the formal unveiling of the rule, some utilities, business groups and Congressional Republicans cast it as the latest salvo in a regulatory war on American industry. They cited a number of recently issued E.P.A. rules, including one on industrial boilers and the first of a series of regulations covering greenhouse gases, which they argue will impose huge costs on businesses and choke off economic recovery. "E.P.A. admits the pending proposal will cost at least $10 billion, making it one of the most expensive rules in the history of the agency," a group of utilities, the Electric Reliability Coordinating Council, said in a report this week. "Adaptation to all the proposed rules constitutes an extraordinary threat to the power sector — particularly the half of U.S. electricity derived from coal-fired generation." The group questioned Ms. Jackson's assertion that the technology needed to reduce emissions of mercury, lead, arsenic, chromium and other airborne pollutants was readily available and reasonably inexpensive. The need to retrofit scores of plants in the same short period of time will tax resources and lead to delays, it said. A spokesman for the utility industry's largest trade group, the Edison Electric Institute, said it would be easier for some utilities to comply than others, particularly those that rely more heavily on nuclear power and those that have switched to natural gas for part of their generating capacity. One utility executive said compliance would not be unduly burdensome. "We know from experience that constructing this technology can be done in a reasonable time frame, especially with good advance planning," said Paul Allen, senior vice president and chief environmental officer of Constellation Energy. "And there is meaningful job creation associated with the projects." Public health advocates said utilities had delayed the rules for more than two decades with court challenges and lobbying campaigns. "If you think it's expensive to put a scrubber on a smokestack, you should see how much it costs to treat a child over a lifetime with a birth defect," said Dr. O. Marion Burton, president of the American Academy of Pediatrics, who stood with Ms. Jackson in announcing the rule. Roughly half of the nation's more than 400 coal-burning plants have some form of control technology installed, and about a third of states have set their own standards for mercury emissions. But the proposed rule issued Wednesday is the first national standard and will require all plants to come up to the standard of the cleanest of current plants. The new rules bring to a close a bitter legal and regulatory battle dating back to the passage of the 1970 Clean Air Act, which first directed the E.P.A. to identify and control major industrial sources of hazardous emissions. By 1990, however, federal regulators had still not set standards for toxic emissions from power plants, and Congress, in the face of stiff resistance from utilities and coal interests, passed legislation directing the E.P.A. to study the health effects of mercury and other emissions, and to detail the cost and effectiveness of control technologies. In 1998, the agency finally complied, delivering a comprehensive report to Congress detailing the health impact of numerous pollutants, including mercury, which by then had been linked conclusively in multiple studies to serious cognitive harm to fetuses. In December 2000, in the last days of the Clinton administration, the E.P.A. finally listed power plants as a source of hazardous air pollutants under the Clean Air Act. The Bush administration E.P.A. faced its own deadlines to devise and put into effect controls for power plant pollution. But rather than issue emissions standards in line with federal law, in 2005, top agency officials instituted a controversial cap-and-trade program for mercury, despite a warning from agency lawyers that the move would throw the issue back into the courts and almost certainly be reversed. As predicted, a coalition of states and environmentalists sued the agency, arguing that the cap-and-trade program would not limit other toxic emissions like arsenic and would allow the dirtiest power plants to pay for the right to pollute, putting nearby communities at risk. In 2008 a federal judge ruled against the E.P.A., giving the agency three years to develop standards for mercury and other pollutants. The long delay has meant that emissions of some major pollutants have grown in recent years. The E.P.A.'s most recent data shows that from 1999 to 2005, mercury emissions from power plants increased more than 8 percent, to 53 tons from 49 tons. Arsenic emissions grew even more, rising 31 percent, to 210 tons from 160 tons. The E.P.A. will take public comment on the proposed regulations for the next several months. It anticipates publishing a final rule at the end of this year or early next year. The rule would take effect fully three or four years later. | |||
--
Scott's Contracting
scottscontracting@gmail.com
http://stlouisrenewableenergy.blogspot.com
http://scottscontracting.wordpress.com
new gearless wind turbine-low to moderate wind speeds
The Innovation by Siemens could be the solution to St Louis Wind Speeds cut in Wind Speed is 3mph just what was needed for our Wind Speeds in the St Louis Area!-. I'm further researching and will post the findings in an upcoming post. Scotty
Energy Sector / Renewable Energy Division
Energy Sector / Renewable Energy Division
Siemens launches new gearless wind turbine for low to moderate wind speeds
Brussels, Belgium, 2011-Mar-14
Siemens Energy today launched a new direct drive gearless wind turbine for low to moderate wind speeds at the EWEA 2011 wind power exhibition and conference in Brussels. The core feature of the new SWT-2.3-113 wind turbine is an innovative drive concept with a compact permanent magnet generator. This type of generator is characterized by its simple, robust design, requiring no excitation power, slip rings or excitation control systems. This results in high efficiency even at low loads. With a capacity of 2.3 megawatts (MW) and a rotor diameter of 113 meters the new wind turbine is designed to maximize power production at sites with low to moderate wind speeds. The SWT-2.3-113 is fitted with the new Siemens B55 Quantum Blades. This new blade design boosts efficiency and optimizes performance. A prototype of the new machine was installed in the Netherlands in March.
Together with the SWT-2.3-113 Siemens is introducing the Quantum Blade, a new generation of rotor blades. The new blade is lighter than previous models but retains the superior strength of earlier generations. The new B55 Quantum Blade used for the new wind turbine is 55 meters long and features a redesigned tip and root section. The root section uses Siemens "flatback" profiles to minimize root leakage and provide greater lift. The blade tip has also been redesigned to minimize loads and reduce noise levels. With a noise level of only 105 decibels (dB) the SWT-2.3-113 is one of the quietest wind turbines on the market.
Together with the SWT-2.3-113 Siemens is introducing the Quantum Blade, a new generation of rotor blades. The new blade is lighter than previous models but retains the superior strength of earlier generations. The new B55 Quantum Blade used for the new wind turbine is 55 meters long and features a redesigned tip and root section. The root section uses Siemens "flatback" profiles to minimize root leakage and provide greater lift. The blade tip has also been redesigned to minimize loads and reduce noise levels. With a noise level of only 105 decibels (dB) the SWT-2.3-113 is one of the quietest wind turbines on the market.
To date, Siemens has installed and commissioned a total of five gearless SWT-3.0-101 wind turbines in Denmark and Norway. Further projects with Siemens direct drive wind turbines are planned in the U.S., Denmark and Germany. In addition to these two new wind turbines with ratings of 3 MW and 2.3 MW, further turbines are already at the planning stage. "This year we'll launch our 6-MW direct drive wind turbine, which will be particularly suitable for large offshore wind power plants," Stiesdal stated.
Wind power is part of Siemens' Environmental Portfolio. In fiscal 2010, revenue from the Portfolio totaled about EUR28 billion, making Siemens the world's largest supplier of ecofriendly technologies. In the same period, our products and solutions enabled customers to reduce their carbon dioxide (CO2) emissions by 270 million tons, an amount equal to the total annual CO2 emissions of the megacities Hong Kong, London, New York, Tokyo, Delhi and Singapore.
Further information on the SWT-2.3-113 is available at: www.siemens.com/wind
Download of this and more press photos: www.siemens.com/Renewables/pictures/ERE201103050
The Siemens Energy Sector is the world's leading supplier of a complete spectrum of products, services and solutions for the generation, transmission and distribution of power and for the extraction, conversion and transport of oil and gas. In fiscal 2010 (ended September 30), the Energy Sector had revenues of approximately EUR25.5 billion and received new orders totaling more than EUR30.1 billion and posted a profit of more than EUR3.3 billion. On September 30, 2010, the Energy Sector had a work force of more than 88,000. Further information is available at: http://www.siemens.com/energy
Reference Number: ERE201103050e
Download SWT-2.3-113 wind turbine Spec Sheet Here cut in Wind Speed is 3mph just what was needed for our Wind Speeds in the St Louis Area!
--
Scott's Contracting
scottscontracting@gmail.com
http://tlouisrenewableenergy.blogspot.com
http://scottscontracting.wordpress.com
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.
American citizens have been exposed to failures of policymakers and regulators in the past. And these failures have placed enormous financial burdens on U.S. taxpayers and have had severe consequences for our economy and national security. The top three such failures include the savings and loan fiasco, which was caused by federal deregulation policy and banking deregulation; the recent economic meltdown caused by bad or ineffective policy on derivatives and regulation; and a catastrophic failure in homeland security on September 11th 2001 due to breaches at airports that was the result of a policy of restraint despite intelligence consensus was that the risk was "high."
Policymakers from both parties are following the same path for nuclear power -- placing arbitrarily low liability caps on nuclear power plant owners and operators (known as the Price Anderson Act) and subsidizing nuclear power RD&D, financing and loan guarantees with billions of dollars that will be paid for by taxpayer outlays.
As the U.S. public knows first hand, the arbitrary low penalty caps for oil spills seemed beyond comprehension after the mammoth BP Gulf oil spill. In this case, BP didn’t fight that battle and established a $20 billion fund. The financial market places penalties on technologies that have high technical and financial risks and this benefits taxpayers and ratepayers and is actually a safeguard for public security.
Technologies that present immense health, safety and security risks should not be cushioned, but rather the exposure and risks need to be transparent with those taking the risks, bearing the subsequent costs. The way it stands now everybody -- including you, the U.S. taxpayer -- that stands to bear the brunt of these damage costs if a nuclear failure happened on U.S. shores.
The public needs to remember and note the recent failures of nuclear power regulatory oversight: 1) a nuclear whistleblower at a PA plant complained repeatedly about sleeping nuclear control room employees, only to be fired even after he proved it by releasing pictures, 2) an unanticipated containment vessel (large) hole in an Ohio reactor, and 3) conflicts of interest by NIOSH on nuclear worker compensation -- all occurring within just the last few years.
This is only one of numerous problems, in addition to reports that nuclear plants are not passing their mock security trials, and add to that even more ridiculous containment dome tests, when we all know that nuclear power plants can be compromised when their cooling towers, pumps and substations are impacted.
There is no question that Washington, DC will listen as the truth about the real risks come out about nuclear power in such horrid detail. Renewable energy again will show itself to be the safest bet, already attracting over $250 billion in global private sector investment in 2010, already installing more MWs per year in “clean and safe energy” than new nuclear power plants. And already providing electric power at lower costs than the multibillion-dollar proposed nuclear power plants on the drawing boards in the southeastern U.S. Markets, and then policy, move to the safest, most reliable, and then lowest cost technologies. That bounty will fall on high value energy efficiency and the entire portfolio of renewable energy.
Swarms of nuclear lobbyists who have put hundreds of millions of dollars into campaign coffers are now in Washington, DC. They are claiming our nuclear power plants are different. Balderdash! The Federal Energy Management Administration (FEMA) website states that 39 states are susceptible to earthquakes, a good portion of the country could be exposed to category five hurricanes and tornadoes, and that doesn’t include the forest fires, natural gas pipeline explosions and other surprises that unexpectedly confront us every year.
In the mid-1980’s Amory and Hunter Lovins published “Brittle Power” (download the PDF here), which is mandatory reading for my sustainable energy course at George Washington University. In their piece, the Lovins’ make clear that we “undervalue risk.” In the preface, former CIA Director James Woolsey agrees in spades.
Twenty five years later, the nuclear industry says “trust us” and “it can’t happen here “ and then remind us “but keep those liability caps.” But hear me out -- legislated liability caps mean nuclear is not safe. It isn’t clean, and it isn’t cheap. The technology is a very expensive way to boil water, and my next column will deal with the immense national security concerns – the other “risk” we just overlook.
What we should have learned from the Challenger Disaster and the immense loss of life in three separate incidents on September 11th - is that the unthinkable does happen , and pretending that somehow nuclear power is exempt from that rule, is irresponsible and unqualified fantasy.
Scott Sklar is President of The Stella Group, Ltd., a strategic marketing and policy firm for clean distributed energy users and companies and is an Adjunct Professor at The George Washington University teaching a multi-disciplinary sustainable energy course.
Policymakers from both parties are following the same path for nuclear power -- placing arbitrarily low liability caps on nuclear power plant owners and operators (known as the Price Anderson Act) and subsidizing nuclear power RD&D, financing and loan guarantees with billions of dollars that will be paid for by taxpayer outlays.
As the U.S. public knows first hand, the arbitrary low penalty caps for oil spills seemed beyond comprehension after the mammoth BP Gulf oil spill. In this case, BP didn’t fight that battle and established a $20 billion fund. The financial market places penalties on technologies that have high technical and financial risks and this benefits taxpayers and ratepayers and is actually a safeguard for public security.
Technologies that present immense health, safety and security risks should not be cushioned, but rather the exposure and risks need to be transparent with those taking the risks, bearing the subsequent costs. The way it stands now everybody -- including you, the U.S. taxpayer -- that stands to bear the brunt of these damage costs if a nuclear failure happened on U.S. shores.
The public needs to remember and note the recent failures of nuclear power regulatory oversight: 1) a nuclear whistleblower at a PA plant complained repeatedly about sleeping nuclear control room employees, only to be fired even after he proved it by releasing pictures, 2) an unanticipated containment vessel (large) hole in an Ohio reactor, and 3) conflicts of interest by NIOSH on nuclear worker compensation -- all occurring within just the last few years.
In March 2007, John Jasinski sends the Nuclear Regulatory Commission a letter alleging guards are sleeping throughout the nuclear plant in York County, Pa. The NRC refers the concern to plant owner Exelon and security provider Wackenhut, who denies it and blames a nuclear employee of being disgruntled. The NRC accepts the statement. On Sept. 10th WCBS in New York informs the NRC that it has a videotape of guards asleep or nodding off in a “ready room” near the nuclear reactor. A newspaper documented one of the nuclear staff who worked more than 150 hours during a 14-day period, and averaged more than 54 hours a week for more than 10 months. Finally on Sept. 21st, an NRC inspection confirms that only the 10 guards caught on tape were sleeping — one of the four shifts is implicated. On Nov. 1st Exelon terminates its contract with Wackenhut and takes over the plant’s security. Whistle-blower Kerry Beal, on leave during the investigation, is not among the Wackenhut guards rehired by Exelon. (Excerpt here.)
There is no question that Washington, DC will listen as the truth about the real risks come out about nuclear power in such horrid detail. Renewable energy again will show itself to be the safest bet, already attracting over $250 billion in global private sector investment in 2010, already installing more MWs per year in “clean and safe energy” than new nuclear power plants. And already providing electric power at lower costs than the multibillion-dollar proposed nuclear power plants on the drawing boards in the southeastern U.S. Markets, and then policy, move to the safest, most reliable, and then lowest cost technologies. That bounty will fall on high value energy efficiency and the entire portfolio of renewable energy.
Swarms of nuclear lobbyists who have put hundreds of millions of dollars into campaign coffers are now in Washington, DC. They are claiming our nuclear power plants are different. Balderdash! The Federal Energy Management Administration (FEMA) website states that 39 states are susceptible to earthquakes, a good portion of the country could be exposed to category five hurricanes and tornadoes, and that doesn’t include the forest fires, natural gas pipeline explosions and other surprises that unexpectedly confront us every year.
In the mid-1980’s Amory and Hunter Lovins published “Brittle Power” (download the PDF here), which is mandatory reading for my sustainable energy course at George Washington University. In their piece, the Lovins’ make clear that we “undervalue risk.” In the preface, former CIA Director James Woolsey agrees in spades.
Twenty five years later, the nuclear industry says “trust us” and “it can’t happen here “ and then remind us “but keep those liability caps.” But hear me out -- legislated liability caps mean nuclear is not safe. It isn’t clean, and it isn’t cheap. The technology is a very expensive way to boil water, and my next column will deal with the immense national security concerns – the other “risk” we just overlook.
What we should have learned from the Challenger Disaster and the immense loss of life in three separate incidents on September 11th - is that the unthinkable does happen , and pretending that somehow nuclear power is exempt from that rule, is irresponsible and unqualified fantasy.
Scott Sklar is President of The Stella Group, Ltd., a strategic marketing and policy firm for clean distributed energy users and companies and is an Adjunct Professor at The George Washington University teaching a multi-disciplinary sustainable energy course.
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.
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.
Subscribe to:
Posts (Atom)
Featured Post
How Two Friends Turned Abandoned CASTLE into a 4☆HOTEL | by @chateaudut...
Join us on an extraordinary journey as two lifelong friends, Francis and Benoit, turn a crumbling, centuries-old castle into a stunning 4-st...
-
Thank You for stopping by the Green Blog. If additional information in needed or you have a question let me know by posting a question or ...
-
Coalition for the Environment flat out opposes second nuclear plant | More ...
-
Convection is the movement of air in response to heat Warm air rises, cool air sinks. Because walls and windows are usually cooler than th...
