Where long the shadows of the wind had rolled, Green wheat was yielding to the change assigned; And as by some vast magic undivined The world was turning slowly into gold. Like nothing that was ever bought or sold It waited there, the body and the mind; And with a mighty meaning of a kind That tells the more the more it is not told. So in a land where all days are not fair, Fair days went on till on another day A thousand golden sheaves were lying there, Shining and still, but not for long to stay— As if a thousand girls with golden hair Might rise from where they slept and go away. —Edwin Arlington Robinson |
November 5, 2005
"The Sheaves"
"Noisy turbine annoys neighbours"
Windflow Technology is shutting down its Gebbies Pass [500kW] wind turbine each night because of noise concerns. ...categories: wind power, wind energy, wind turbines
The turbine looms over a ridgeline above photographer Julie Riley's McQueens Valley property.
Ms Riley, who objected unsuccessfully to the project at its resource consent hearing on the basis of noise and landscape values, said the turbine was much louder than expected.
Windflow was not able to stick to its resource consent, and people 3km from the wind turbine could hear it whenever it was running, she said.
"They said it would be quieter than 30 decibels and we would only be able to hear it 3 per cent of the time.
"They would have had a lot more people complaining at the resource consent hearing if people down the valley knew they were going to be affected.
"We are hearing it almost 100 per cent of the time when it is running," Ms Riley said.
Two noises were emanating from the site, just more than 1km from her house.
"Two hydraulic pumps run all the time. I can hear those at night," she said.
"When they have the blades going it is terrible. It sounds like 'grind, grind, grind'. It obliterates the bird sounds and all the nature sounds that we have all come here for."
Wind turbines require high maintenance
It's not just the gearbox. You've got 40 tons of rotor blades turning and changing pitch, attached to a 70-ton nacelle which turns on top of a 250-foot-high tower to catch the wind. A mechanical challenge in any environment to be sure.
The following is from John Galambos, "Brooklyn wind turbine performance over 12 years," presented at New Zealand Wind Energy Association Conference, 31 August 2005. Remember that this single turbine near Wellington (N.Z.) is a demonstration installation, with all the money necessary thrown at it to keep it going. Since most of the financial benefits in the U.S. disappear after a few years (6 years for accelerated depreciation, 10 years for production tax credit), the more likely scenario for most facilities is abandonment, as with many of those in Altamont Pass, California, and the sad specimens at South Point, Hawaii.
TECHNICAL ISSUES DURING OPERATION
Years 1 and 2
Gearbox oil issues with build up of black gunge
Part of skylight roof section vanished during 1994 storm
- oil type changed
Slip coupling operating too frequently, required replacement
- 38.5 m/s 10-sec average
- Estimated 45m/s 3-sec gust, turbine rated for 70m/s 3-sec gust
- Anemometer cup vanished (years 5 and 11 also)
Blackening of gearbox oil
- High wind shutdown changed from 25 to 22 m/s
Years 3 and 4
Blade inspections revealed gel coat failures
Tower to foundation ring flange-to-flange bolts started failing
- Appear to relate to damage from thrown stones
Numerous minor factory technical upgrades continued
- Managed by monitoring and change out
Yaw drive issues, noisy
- Driven by Service Bulletins not issues on site
Years 5 to 9
- motors and worm drive gears replaced
Pitch accumulator leaking - replacement with production loss
Controller required Y2k modifications
Yaw drive gearboxes replaced
Ongoing issues relating to EMC
Gearbox low speed shaft stiffener fitted
- Susceptible to strong local FM radio transmission
About year 10
- Factory modification for high winds
- Internal expansion sleeve to hollow shaft
- Too late, damage done, gearbox would require replacement before long.
Gearbox high speed shaft bearing failed at 9+ years
Weather mast guy hardware failed
- Noisy gearbox operation
- Before original gearbox was replaced
Gearbox replaced at 10 years
- Repair can have safety implications
Years 11 and 12
- Refurbished unit, "as new", with warranty
- Shaft end floats outside maintenance tolerances when delivered
- Bearing replaced after 3 months
- Gearbox replaced again after 13 months
- Condition monitoring trials unsuccessful
Nose cone replaced
Tower section joining bolts corroded
- Disintegrating
Pitch linkage connections failed,
- Replaced at 11 years
Yaw ring and yaw gears failed
- Rods damaged and replaced
Other
- Long outage
- No local parts
- Numerous control card replacements/updates to Service bulletins
- Included fans to control cards, oil filtering etc
- Communications issues at times – not turbine related
- Distribution disturbances have tripped the turbine
- Some misc contactor failures, replacement repairs, consumables etc.
categories: wind power, wind energy, wind farms, wind turbines
"Wind Powers American Dream"
Wind Powers American Dreamcategories: wind power, wind energy, Vermont, Judith Miller
by Judith Miller
Washington, DC -- I have just spent two weeks embedded with the president of the American Wind Energy Association and cannot convey strongly enough the urgent need for massive wind power development in this country.
Randall Switscher took me with him to see site after site that was either totally lacking industrial development or mostly wasted with low-grade agriculture.
"These people desperately need our help," Randy told me. "We need to bring them into the 21st century, get some investment going there."
Randy's model is the transformation of Nigeria by the presence of foreign oil companies who built schools, hospitals, banks, and communication infrastructure. Nigeria now rivals Sweden in measures of equality and health, he says.
During a retreat in the lovely unspoiled mountains of Vermont, I met Keith Dewley, a college-educated architect. He told me how grateful he is to Mr. Switscher for providing a beacon of hope to Vermonters. It is now normal for a Vermont child to hope to go to college, and that is directly a result of the activity of wind developers from outside, he told me.
Keith's interest verges on the artisitic. "What I learned in college was that aesthetics are about social constructs, about what we expect from our lives. Are we defined by hayfields strewn with rotting manure and mountains left to grow wild without any consideration of financial development needs? When I look up, I want to see the future!"
There are, of course, some holdouts who fear the changes Randy represents. Others selfishly want to preserve a system they have benefited from, however backward. Randy admits that the campaign to win their hearts and minds will be long and hard.
"We may not ever convince some of them," he says. "But we're going in there anyway, because that's our duty as world citizens. Sooner or later they'll have to get used to it. Our mission is bigger than any one of us."
Keith Dewley's daughter Hilary, a proud sophomore at the University of Vermont, echoed the enthusiasm of her elders. "The ancient Egyptians built pyramids as monuments to their beliefs. That's what wind turbines are -- just knowing they're there we can feel better going about our business."
Progress wouldn't be possible without a strong government commitment. I am currently embedded with an analyst in Goldman Sachs and will be writing soon about why massive profits are necessary to guarantee the success of wind power development.
November 3, 2005
Wind power facts
categories: wind power, wind energy, wind farms, wind turbines, environment, environmentalism, Vermont
High cost, low benefit
categories: wind power, wind energy, wind farms, wind turbines
The gearbox: wind power's Achilles' heel
This month's Windpower Monthly examines a little-known twist in the "mature technology" of large-scale wind turbines:
Gearboxes have been failing in wind turbines since the early 1990s. Barely a turbine make has escaped. Six years ago the problem reached epidemic proportions, culminating in a massive series failure of gearboxes in NEG Micon machines. At the time, the NEG Micon brand was the most sold wind turbine in the world. The disaster brought the company to its knees as it struggled to retrofit well over one thousand machines. It has since been taken over by Vestas, the world's largest wind turbine manufacturer. Vestas is still grappling with the aftermath of the gearbox catastrophe.
The wind power industry and its component suppliers now believe that such major series failure of gearboxes is a thing of the past. Today's far larger and more sophisticated turbines, they say, are safe from mistakes encountered in early phases of technology development.
Bigger turbines, however, are proving to be far from immune to gearbox failure, as Windpower Monthly reports in its November issue. ...
The wind industry's gearbox problem has for years been shrouded in secrecy. While blame for the failures has been spread far and wide, questions outnumber the answers by far. At Windpower Monthly we set ourselves the task of finding out the true scale of the problem. Why is it that gearboxes in wind turbines have so massively failed? What is the solution? ...
The good news is that understanding of the highly complex loads that gearboxes -- and particularly their bearings -- are subject to is being helped by a new industry willingness to co-operate and face up to the challenges of wind power's rapid technological evolution. But only time will tell whether a definitive solution has been found -- and whether it will stay the course as wind turbines get ever bigger and more demanding of engineering ingenuity.
categories: wind power, wind energy, wind turbines