Sustainablog

This blog will cover some news items related to Sustainability: Corporate Social Responsibility, Stewardship, Environmental management, etc.

14.6.06

Giant Wind Turbines


Thanks to Norbert for this one................



Content:

Giant Wind Turbines by Kevin Bullis
Floating wind farms placed far offshore could lead to affordable electricity -- without cluttering the view.

http://www.technologyreview.com/read_article.aspx?id=16801
Tuesday, May 09, 2006

Giant Wind Turbines
Floating wind farms placed far offshore could lead to affordable electricity -- without cluttering the view.

By Kevin Bullis

Huge turbines mounted on floating platforms could make wind power competitive with fossil-fuel-generated electricity. These advanced wind turbines, which are in development, could be situated far from the shore, too, avoiding battles with onshore residents who object to the presence of large wind farms.

GE has announced a $27 million partnership with the U.S. Department of Energy to develop 5-7 megawatt turbines by 2009, each of which could power well over 1,000 homes. Supplanting the company's current 3.6 megawatt turbines, these giant energy factories should make wind power more economical, since the major cost of building and installing offshore wind farms does not depend primarily on a turbine's size, but on the number of them that need to be erected. By 2015, GE could have even bigger, 10-megawatt turbines, according to Jim Lyons, leader of advanced technology for GE's wind energy business.

[For images and illustrations of wind turbines, click here.]  
Description Text
Wind turbines compared with the Washington Monument in Washington DC. The new GE turbine would be shorter but have a larger rotor diameter (140 meters) than an experimental five-megawatt turbine.

Image courtesy of Stephen Connors, MIT

Copyright Technology Review 2006


Description text
The Horns Rev Wind Farm in Denmark, rated to produce 160 megawatts, is situated in water just 10-15 meters deep, compared with 50-100 meters made possible with the "tension-leg" technology now used by the petroleum industry.

Image courtesy of Paul Sclavounos, MIT

Copyright Technology Review 2006

Description text
Three different designs for floating wind turbines.

Image courtesy of Paul Sclavounos, MIT

Copyright Technology Review 2006

Making the turbines larger, however, comes with technical challenges. The new turbines will be mounted to towers rising 90 to 95 meters and will have rotors measuring 140 meters in diameter. Imagine a structure larger than a football field rotating at a leisurely ten to twelve revolutions per minute. To decrease the weight of the massive rotor blades and tower, GE plans to use composite fibers, as well as alternatives to the weighty gearboxes now used to transfer energy from the rotor to the electrical generator.

The new turbines will also need to be more reliable than their onshore counterparts, because maintenance will be far more difficult and expensive. GE is developing new ways to deal with the extreme battering the turbines will receive from the wind.

Today's turbines compensate for changes in wind speed by actively turning their blades to catch less wind. The new turbines will adapt to gusts by using sensor-based technology that will quickly angle the blades out of the wind to reduce the wear and tear on the turbine. These sensors could include basic accelerometers, embedded fiber-optic sensors that detect shape changes in the blades in response to gusts, and forward-looking, laser-based "radar" that allows the turbine to anticipate wind-speed changes.


None of these technological advances will make a difference, however, if erecting monstrous turbines is blocked by shoreline residents who see them as visual pollution. A potential solution is floating platforms that allow the turbines to be located farther out in the sea -- and out of sight. Current projects locate wind turbines in waters less than 20 meters deep. Going farther out on the continental shelf, which extends several hundred kilometers from the U.S. East Coast, would mean locating them at depths up to 50 meters, which is probably too deep to build towers or trusses that support turbines standing on the sea floor, at least at an affordable cost.

MIT researchers recently demonstrated the feasibility of "tension-leg" platforms, a technology that oil companies have recently adopted for deep-water rigs. The wind turbines and towers would be assembled at a shipyard and placed on top of large floating cylinders (see images). The canisters would be ballasted on the bottom with high-density concrete to keep the structure from tipping over, and the whole turbine assembly would be tugged out to sea.

There, four steel cables would be attached to the platform, anchoring it to the sea floor. First, though, some water would be allowed into the cylinder, causing the structure to sink more into the water. Once the cables are attached, the water is pumped back out again, allowing the turbine to rise, tightening the cables, and preventing the turbine from bobbing up and down, yet allowing some lateral movement that would help cushion the impact of storm waves on the tower. (The blades themselves would be high enough to avoid even waves from hurricanes.) The cable tension can be adjusted for different weather conditions, says Paul Sclavounos, professor of mechanical engineering and naval architecture at MIT.

Based on wind-speed measurements, researchers at MIT, led by Stephen Connors, director of the Analysis Group for Regional Electricity Alternatives, calculated that large turbines located far offshore could ultimately cost less per power generated than either land-based turbines or near-offshore ones, even factoring in extra costs, such as much longer underground electricity transmission cables. The upside: much more fast and steady wind, which would allow the turbines to generate power at 50 percent capacity on average throughout the year, compared with 30 percent or less with on-land turbines.

Offshore wind farms could also have the advantage of being close to big cities, unlike wind farms in remote areas, which require significant power grid upgrades to transport the power to places where it's needed. "I personally see this as the endgame," says GE's Lyons. "We'll see gigawatt-scale projects delivering clean energy to the East Coast.

But making the technology cheap enough to be feasible will not be easy. "You've got to push all the buttons to get the costs down," Lyons says. Using a combination of far-offshore and land-based farms, however, one day it may be possible to provide 20 percent of U.S. energy from wind, he says.



Some comments from our community... [An inconvenient truth? Eco-friendly energy is expensive and impractical ]


Two replies to an earlier mailing...

----- Forwarded by Jean-Francois Barsoum/Markham/IBM on 13/06/2006 17:07 -----
Jean-Francois,

I am going to argue with this article.

There are bladeless wind turbines which are quite small and don't run the risk of ripping off your house in high winds.  Furthermore, installing wind or solar on the ground or on a pole mount is another option.

I recently installed a 3.328 KW solar system on my roof.  In merely two weeks time, it has generated enough electricity to meet my needs and still push 121 KWh back onto the grid.  During the winter, the system won't fair quite as well but overall the system is sized to meet 100% of my needs (a bit over 400 KWh per month).  That means an electrical bill of $0 forever.  The system cost me about $30,000 retail.  After rebates from the local utility company plus federal tax credits, the actual cost will be about $10,000.  The payback period is about 12 years.  Likely much shorter if/when energy costs continue to go up.

Anyone being quoted a $70,000 system to meet only half their electrical needs needs to get some new quotes.  Or make some SERIOUS energy efficiency improvements to their house.

I am glad to talk more about this with anyone who might be interested.

Thanks,

Steve

Steve Bauhs
IBM Sales and Distribution Division
Americas Software Marketing

----- Forwarded by Jean-Francois Barsoum/Markham/IBM on 13/06/2006 17:07 -----

Jean-Francois, I can't argue with the numbers, although I think they reflect a backward's look at energy costs that were (and still are) artificially low.  I attended a talk by a Dutch architect who has been building energy-efficient homes for about 10 years.  Total energy consumption is 70% less than comparable 'traditional' homes, at about 16% higher capital cost.  The homeowner is not asked to make a choice between improved sustainability or upgraded broadloom - they buy the package or go elsewhere.  The technologies used are 'off the shelf'.  The benefit to the consumer is predictability - they are much less affected by increased energy costs.

I also agree that utilities need to be major players, but at a distributed level.  I think it makes a lot of sense for homeowners to generate electricity and still be grid connected.  If the utilities charged you for the actual cost of peak load energy, a solar panel that delivers just enough power to reduce the peak load requirements becomes economically feasible.  In fact, the utilities would be better off paying you to install the solar panel than to build another power plant that only runs a small fraction of the day.  The Dutch architect includes solar power in his designs, but only to supplement grid power (no batteries required, thank you).  


Community-based solutions also make sense.  Where you live, are there any areas where a common 'heat-sink' could be used for ground-source heating/cooling?  There can be economies of scale, but each has a 'sweet spot'.  Twice as big may be better, but 10 times as big might be worse.

       Regards, Norbert
 



Jean-Francois Barsoum/Markham/IBM@IBMCA

06/08/2006 02:24 PM

To
cc
Subject
An inconvenient truth? Eco-friendly energy is expensive and impractical






Thanks to Laurie for sending this one... I can vouch for (some of) the truth of this article. A solar panel system to cover 1/2 my monthly electricity needs would cost US$70,000; wind generators are not allowed in my (urban) municipality (too ugly, perhaps); we're on a bedrock, so geothermal is impossible, or at the very least, impractical. But as Laurie pointed out, through our efforts, perhaps we can change the equation and make the technology pay off in a shorter amount of time...

And by the way, there is also a big difference between individuals using those technologies and utilities exploiting them on a grander scale. That's why, if it is ever going to take off in any significant way, the "green energy" movement will likely have to move from local, personal action to broad, government/utility supported actions.

The price of going green
Ross Clark
1175 words
29 April 2006
The Spectator
34 36
English
(c) The Spectator (1828) Limited 2006

PROPERTY - Ross Clark says that eco-friendly energy is expensive and impractical

The world's ugliest boiler is attached to the side of my house. It is a slab of grey metal from which protrudes a short exhaust pipe, just at the right height to blast the hat off anyone who happens to be walking to the front door at the wrong time. Worse, it covers the garden with a petrochemical fug, and with oil prices rising rapidly it is costing me more than £1,000 a year to keep my tank full. If anybody had an incentive to turn to 'green' energy it is me.

If I could replace my heating system with one of Dave Cameron's windmills and a few solar panels, believe me I would.

But I am not getting very far at the moment in my search for a green form of energy for my home. There has been no shortage of architectural awards doled out to 'eco-friendly' homes; there is no end to the websites that promise to help me cut my carbon emissions and exploit 'free energy' from the sun or the wind. It is just that when it comes to keeping yourself warm, none of them seems quite able to do the job. Inasmuch as they save you energy at all, it is usually at such a high installation cost that you will be lucky still to be alive when your home improvements recoup their costs. Take double glazing: the government is so convinced of the merits of having two panes of glass instead of one that it is now illegal to replace a window with single glazing. Yet according to BRE, the formerly government-owned Building Research Establishment, it could take up to 100 years for a double-glazed window to repay its cost in fuel savings. And if it is the environment you are interested in saving, forget it: the double-glazing industry is a huge consumer of uPVC, an oil-based plastic which is horribly toxic to produce and to dispose of.

For about £1,500 plus VAT, you can, like Dave Cameron, have a windmill installed on your roof, allowing you to make use of entirely free energy. But don't get too excited: unless you live a fairly monkish existence it is unlikely to meet your energy needs.

According to Windsave, a Scottish-based company which manufactures the devices, you can count on your windmill producing at least 500 kilowatt-hours of electricity every year. But that is only enough to keep a onebar electric fire going for 20 days — equivalent to a whopping £30 worth of electricity.

At this rate it would take the windmill about 50 years to recover its costs. My own household already consumes about 4,000 kilowatthours of electricity a year — and that is just on lights, cookers, computers and so on, not on heating the house. Nor is it possible to save energy by moving to a windier area: irritatingly, Windsave's windmills have to go into auto-shutdown in strong winds in order to prevent them pulling the side off your house.

Never mind, that still leaves solar panels.

The government is so keen to encourage us to collect free energy from the sun that it is offering homeowners grants of £400 to install solar panels. However, that is not going to cover the cost of installing such a device. I have found a company called the Green Shop willing to install a solar hot-water system in my home for £2,830 plus VAT. But I am warned that I will still need a boiler as the solar panels will not produce enough energy to fill my hot-water cylinder in the winter.

And what would I save in any case? In summer I supply my house with hot water using an immersion heater timed to make use of off-peak electricity. Last summer it cost me just £20. At this rate it would take more than 100 years for my investment in solar panels to pay off — by which time I wonder whether the panels would still be working at all.

The other option is to do what the Queen and Elton John have both done: install a geothermal pump in my house. This is, in effect, a refrigerator in reverse, exploiting latent heat within the soil. Water would be pumped through pipes laid beneath my house, where the soil is at a fairly constant 10infinityC. The water would then be pumped into my house and compressed, in the process of which it would heat up and discharge warmth into my living-room.

Although fairly standard in North America, there aren't many homes with geothermal pumps in Britain. But I did find Nicholas Ray, an architect who has incorporated geothermal pumps in two new houses he is building in the yard of his offices in Cambridge. The first sight was not promising: his office windows, and several surrounding buildings, were covered with a tarpaulin spattered with muddy clay; sinking a 40-metre deep borehole is a pretty messy business. Installing a geothermal pump was easier for the Queen, apparently: she was able to install a system exploiting the heat contained within the water of the lake in the grounds of Buckingham Palace. Elton John, too, had an easier time: if you have an acre or more of garden you can install the pipework for your geothermal pump at a relatively shallow depth, it being the length of pipe which matters. It is only those of us with small gardens who have to drill deep.

The mess is not the only objection to installing a geothermal pump. Although heat extracted from the ground comes free, the pump requires a considerable quantity of electricity to pump water around the circuit.

In fact, admits Ray, the system won't help the occupants of his new houses save any money compared with what they would pay to heat them with a conventional heating system fired by a condensing boiler. In other words, I would never recoup the £2,000 it would cost to drill a borehole; unless, that is, oil prices rise faster than electricity prices.

I am not wholly put off. If I can transfer a little bit of pollution from my own garden to a distant power station, there is some benefit to me. I have asked an American company to conduct a feasibility study into installing a geothermal pump. But I am unconvinced that green energy is yet at the stage at which it provides a practical option for people other than the well-off. It is certainly not about saving money. It is really about assuaging middleclass guilt and having a few toys to show off to your friends. As for helping the environment, there is a rather more straightforward way and one which is guaranteed to save money: switch your central heating off and invest in a £30 sweater from Marks & Spencer.

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