Northeast winds

Hi everyone, sorry for disappearing for so long, I was in China for half of the holidays, and I couldn’t access wordpress when I got the chance to use the com. So, thanks very much, szeyuan and chia for doing so much on the Singapore issue. I’ve got a few more scraps of info here… not very arranged, I’m sorry to say.

Okay, so since Chia and szeyuan have found alot, i shall just add some not-so-complete pieces of info.

There’s this video by Nantional Geographic about the Singapore flyer, http://video.nationalgeographic.com/video/player/news/space-technology-news/singapore-flyer-apvin.html. It mentions that “the island city’s wind gusts were a challenge for designers”. Hmm, somehow it seems that at the height of the singapore flyer, there are high gusts of wind, althougth it is mentioned in the video that these could come out of nowhere. So it seems that at high altitude singapore has high winds, but these do not seem to be consistent enough to be harnessed effectively.

According to http://www.actapress.com/PaperInfo.aspx?PaperID=25020&reason=500, The School of Electrical and Electronic Engineering at Singapore Polytechnic has installed a solar-wind hybrid power station in Singapore mainly for educational and research purposes. This 21 kW capacity power station generates electricity from solar and wind at 230V and 50Hz frequency. A complete state-of-art data acquisition system is installed at the station to monitor various parameters. The parameters include ambient temperature, solar radiation, humidity, charging current, battery bank voltage (maximum and minimum battery voltage), voltage of individual cells, kWh consumed by the load and Inverter output voltage and current. In this paper, a detailed description of the power station and analysis of the readings obtained for various parameters are illustrated. This is the abstract of the report “Configuration of a Solar-Wind Hybrid Power System in Singapore”. The rest of the report is unavailable online. It seems to show that wind energy is being tested in singapore, even if only for research purposes.

This is also apparent from http://www2.ntu.edu.sg/ENewsreader/Campus+News+and+Events/astar+news.htm, where centres by the Agency for Science, Technology and Research will focus on developing alternative energy technologies such as solar, wind and fuel cells. This also shows how Singapore is looking into the use of wind energy.

Regarding Singapore’s sutability for harnessing of wind power, Mr Lim Swee Say, current minister for the environment commented that “Unlike other countries, we are unable to tap on renewable sources of energy…to reduce our dependency on fossil fuels. We do not have the natural endowments to tap hydropower or geothermal energy. Even solar and wind energy present little scope due to our cloudy skies and slow wind speeds.” in his speech at The Handover of CCP4 to Senoko Power and Award of ISO 14001 at Senoko Power Station in 2004, as taken from http://app.env.gov.sg/view.asp?id=CDS1396.

So, it seems that Singapore indeed does not have the currently required resources to harness wind energy as a large-scale replacement for fossil fuels. How about other types, or small scaled wind-energy harnessing?

1. As seen from http://limjunying.wordpress.com/2008/05/30/nano-vent-skin-of-micro-wind-turbines/, quoting from www.nanoventskin.blogspot.com, a building covered in nano vent skin invovles capturing light energy and using micro wind tubines to harness wind energy, which will also absorb carbon dioxide. Just by looking at this directly, it may be suitable for Singapore as it makes use of sunlight, which is abundant in sunny singapor. Also from the picture below, we can see that the building is constructed among many trees, which shows it may not need large areas to work, which might be a useful feature in Singapore’s case.

2. Instead of adopting windmills or wind farms that harness wind energy directly, it may be more practical in Singapor’s case to adopt a method which works another way, and adapts wind energy as well. As put by www.urbanwindenergy.co.uk, harnessing wind does not necessarily mean putting up a wind turbine. Harnessing wind energy is all about finding a replacement for fossil fuels. In households, much energy is used in creating a comfortable indoor environment or climate, due to singapore’s hot and humid climate. Energy is used for fans and aircons, which are on for practically the whole day.

According to the Architectural Science Review published in 2007, as taken from http://goliath.ecnext.com/coms2/gi_0199-6987610/Applying-natural-ventilation-for-thermal.html, by applying natural ventilation effectively, comfortable indoor environments can be created without the use of aircons, but with an effective ventilation system. This may help in reducing the use of fans and aircons in residential and office buildings. Effectively, energy can be saved this way. Although the website has removed all graphics from the online version of the report, this concept brought up is an interesting one. Instead of only appyling ‘cures’ to a ‘problem’, we can also work on ‘preventative measures’ that will help in the long run. This concept also allows for more explorations into how wind energy can be harnessed or used in ways that do not need large areas of land. Wind may not need to be used to generate electricity, but can be directed so that it will discourage the use of electricity.

Okay, that’s all for now. I’ll compile in another post soon.

Posted by Jenny, 26 June

A windy day in Singapore

haha, yep there’s really lil stuff posted regarding Singapore and wind energy but Chia2 information is really good and useful (: a round of applause for chia2! (: welll done ! ^-^

here’s what i found on the what Singapore has to offer regarding this area.

Basically in 2006,

“ Vestas Wind Systems, the world’s top wind turbine maker, plans to establish a research base in Singapore to meet Asia’s growing appetite for clean, cheap and inexhaustible energy supplies, an executive said in local media on Friday.

The Denmark-based company will invest up to 500 million Singapore dollars (322 million US dollars) over the next 10 years to set up the wind technology research and development centre, said Thorbjorn Rasmussen, Vestas Asia Pacific president. “  – from http://www.monstersandcritics.com/news/energywatch/renewables/news/article_1206165.php/Denmark-based_firm_convinced_of_wind_energys_future_in_Asia

Hence, this shows about the wind technology research that would be on-going in Singapore in years  to come. Hence this highlights a probability and possibility to which how wind energy would probably have a chance in the energy production in Singapore in the future with the technology aided by the research centre to look into this area.

 And recently this year at around January 2008, from http://asiacleantech.wordpress.com/2008/01/16/siemens-to-set-up-wind-energy-centre-in-singapore/ which although is a wordpressjournal, but it gives an article from The Straits Time newspaper regarding how Siemens would be setting up a wind centre in Singapore. Here are snippets of the newspaper article:

” January 16, 2008 (Straits Times) – In the latest in a spate of alternative energy-related investments in Singapore by foreign companies, Siemens will open a new regional sales office to promote its wind energy technologies. The German industrial giant announced the new initiative at a conference as it kicked off its 100th anniversary celebrations at the Victoria Concert Hall yesterday. “

“The wind energy centre, which will be based at the Siemens Centre building in MacPherson Road, will initially have just a ‘handful of staff’, said Siemens country manager Hans-Dieter Bott. Siemens will ‘build it up over time’ and hire more staff as business grows, he added.

And he is confident it will grow as countries around the world look for new sources of energy to power their economies.

Globally, he said, the ‘booming’ market for wind energy has grown from a multimillion- euro market to a multibillion-euro one within a ’short time’.

And while the Republic itself is unlikely to be installing any wind generators, it is a ’strategic’ location that is well linked to both the key wind energy research centres in Denmark and regional wind energy markets such as Australia and South Korea.”

From the above, we can also see the possibilties and opportunities that would arise with the setting up of the wind centre in Singapore (where Siemens promote its wind technologies) . It mentions how Singapore is a ’strategic’ location that is well-linked to key wind research centres and regional wind energy market. Note that it mentions that Singapore is however probably unlikely to be installing wind generators.

From the above two sources, it mentions about companies to be setting up wind centres in Singapore, hence this gives a sort of probability and clues to which which way Singapore would be heading in the renewables with regards to the wind sector, which is in areas of research technology and possibly future energy production using wind energy (well, with the promoting of wind technologies, possibly). Although this would probably not happen in the near future, but it highlights the areas in which Singapore is progressing in the wind sector.

szeyuan (:

Wind energy–singapore?

Heh, when i m categorizing this post, i had to click on the “show all categories” thing, since Singapore info is soo little and rarely used. Thx to those who have posted anything abt it!

here’s some bits of info found here and there.

http://www.nccc.gov.sg/renewables/Others.shtm thinks that Wind turbines are usually designed to operate at a minimal wind speed in order to generate electricity. Singapore does not have abundant winds except near coastal areas or at some off-shore islands. This could reduce the performance of wind turbines and hence the viability of wind as a renewable resource for Singapore.

http://www.nuspa.org/cms/?q=node/38 also thinks that Solar and wind energy is basically land-intensive, therefore it may not be a feasible solution for land-scarce Singapore. However, small scale electricity and energy production is reasonable and beneficial.

but!

http://www.technologystudent.com/energy1/wind8.htm says that Although wind turbines can be very tall each takes up only a small plot of land. This means that the land below can still be used. This is especially the case in agricultural areas as farming can still continue.

Wind turbines are available in a range of sizes which means a vast range of people and businesses can use them. Single households to small towns and villages can make good use of range of wind turbines available today.

Wind turbines have a role to play in both the developed and third world. (very vague, i know)

however, still in that very same website:

Large wind farms are needed to provide entire communities with enough electricity. For example, the largest single turbine available today can only provide enough electricity for 475 homes, when running at full capacity. How many would be needed for a town of 100 000 people?

oh well.

http://www1.eere.energy.gov/windandhydro/wind_ad.html mentions that Wind power must compete with conventional generation sources on a cost basis. Depending on how energetic a wind site is, the wind farm may or may not be cost competitive. Even though the cost of wind power has decreased dramatically in the past 10 years, the technology requires a higher initial investment than fossil-fueled generators. (Therefore the COST may deter Singapore in using wind energy?)

Wind resource development may compete with other uses for the land and those alternative uses may be more highly valued than electricity generation. (This i think is one of the best points given. true, even if u think that wind energy is impt, but feels that the space can be used for something more impt, esp in s;pore that has so limited space…)

Good thing is, Wind energy is one of the lowest-priced renewable energy technologies available today, costing between 4 and 6 cents per kilowatt-hour, depending upon the wind resource and project financing of the particular project.

yay!

but wait! regarding costs, this is what http://environment.newarchaeology.com/wind_energy.php has to say. The debate over costs is never clear cut and both sides will massage figures for their own benefit. The truth is that in the UK, wind energy is more expensive than Combined cycle gas turbines and cheaper than hydroelectricity. The initial start-up costs of turbines are expensive, but the running costs are minimal in comparison to most other forms of energy generation. This is because the ‘fuel’ (the wind) is a free resource. In addition, pro-turbine groups will point out that the real cost of gas (and coal) power generators should include the cost to the environment of global warming. This is hard to quantify, so be vary wary about all figures. (In other words we can’t fully trust if wind energy is really quite cheap or quite expensive)

And there’s this problem with wind’s varying speeds, or sometimes lack of it. The wind doesn’t blow all the time What do we do on still evenings? Sit in the dark? This is an emotive argument with some merit.
Variable generation can only supply up to 10% or 20% of
peak demand, without having to make any significant changes to the grid. However, nobody is really sure how to deal with a figure larger than 20% at present.

Also about use of space here: Both sides argue about the ecological impact of wind farms. Pro-wind campaigners point out that only 1 percent of a farms ground surface actually gets built on, so natural wilderness or crop and livestock farming can continue around the bases of the turbines. However, no studies have been conducted on the effects on livestock of living beneath turbines. (Furthermore, Singapore can’t really spare space for farming…are there other things we can do under a wind turbine? Since land is a scarce resource here, land use has to be planned carefully.)

The potential effects on birds is often cited as an issue, but in the UK, the The Royal Society for the Protection of Birds (RSPB) supports the increased use of wind power, “as long as wind farms are sited, designed and managed so they do not harm birds or their habitats”. (singapore has limited sites to choose from though, as we only have few good sites for wind energy. but hopefully one day, part of our energy can be from nice, clean renewable energy.)

The arguments about the health problems are not to be dismissed lightly. Symptoms such as headaches, nausea, sleeplessness and
depression have all been attributed to low frequency emissions from wind turbines. Medical experts are best placed to conduct more research. Most turbines are placed far away from human habitation so the issue rarely arises at present. (this is even more important. Singapore is quite urbanised everywhere, even wikipedia states so, except in Bukit Timah nature reserve and reclaimed land still undergoing the process of being developed. Hard to find somewhere far enough from people so as not to suffer from ill health!)

And if anyone notices, i purposely did not put out the arguments about how Wind turbines spoil the scenery. See, the world is really dying, and if nothing is done about it we won’t have any beautiful scenery left to protect. In my opinion (other opinions are gladly accepted too tho! we’ll like to hear everyone’s views as far as possible), wind turbines can go a long way in helping to save the environment, but by rejecting using wind turbines we might be able to stare at the landscape for a couple more years…then the poor Earth dies on us. And anyway whenever i see a picture with a nice landscape and wind turbines, i think of how beautiful it is, since it’s helping us to save the environment. There’s also a very interesting effect when u see how nature interacts with man-made stuff.

There. My two-cents worth.

chia2

Post compiled information into the Pages

harlo everybody! as you know, last time i created pages, which can be found at the header on top. (you would be able to see the pages’ names when ur cursor goes over them)

Yup, so i think once one has compiled finish, be it that it has been edited or not, we can put our compiled information into the pages. Then, we can edit from there, which would make it more formal and not so messy, as it would be just one page alone for one research question, minus all the other blog entries (:

to put the stuff into the page, you can just click to the page you are suppose to put ur info, then click ‘edit’. yep, then you can add stuff from there. (:

sze yuan ^-^

Using of Wind Energy in Denmark (COMPILED)

hey all, here’s the compiled set of “Using of Wind Energy in Denmark”…please help me edit parts which require so…thanks a lot! (:

(2) 19% of Denmark’s total energy production is energy converted from wind energy by its wind turbines. This category looks into:

a) How electricity is harnessed using wind power, i.e. the methods etc in Denmark

b) Where is this 19% energy converted from wind energy used, e.g. domestically, in industries, recreational, just to increase/take over some part of Denmark’s energy production etc.

c) What is the most popular method used in Denmark if there are more than one methods used. Basically, facts of wind energy specific to Denmark.

Features of Denmark that allows for wind power generation

Denmark has relatively modest average wind speeds in the range of 4,9 to 5,6 m/s measured at 10 m height. Onshore wind resources are highest in the Western part of the country, and on the Eastern islands with coastlines facing South or West. The country has very large offshore wind resources, and large areas of sea territory with a shallow water depth of 5 to 15 m, where generating wind power is most feasible. These sites offer higher wind speeds, in the range of roughly 8,5 to 9 m/s at 50 m height. 

Using of Wind Energy in Denmark: Past, Current, Future

In the 1980s, most of the electricity production in Denmark was based on coal and the acidification of forests and lakes by acid rain was predominant n the environmental debate. Early Danish wind turbine development was thus a far cry from simultaneous government sponsored research programmes on very large machines in Germany, USA, Sweden, the UK, or Canada. In the end, improved versions of the classical, three-bladed upwind design from the Gedser wind turbine appeared as the commercial winner of this wild competition, but admittedly not without a number of wreckages, mechanical, and financial.

Denmark has, within the last 20 years, invested more in wind energy than any other European country. This is consistent with Denmark’s long tradition of using wind as an energy source. The main objective of investing in wind energy in 1976 was to make Denmark less dependent on imported energy supply. One of the main drawbacks of wind energy is that electricity can only be produced where there is wind. In Denmark this problem was avoided by connecting the private wind turbines to the national grid, allowing fluctuations to average out and so provide a constant supply.

Today wind power provides 20% of Danish electricity consumption. Within a few years, the wind power industry has grown to become a significant industrial sector providing huge benefits for exports and employment. From single turbines at the beginning, wind power generation plants are now used and the Danish wind power industry is at the leading edge in an ever more competitive global market.

As Denmark’s future energy supply faces numerous challenges and has become subject to unstable international conditions, offshore wind now has a key role to play. Offshore wind power can contribute significantly to achieving the EU goals of a 21 percent share of renewable electricity by 2010, halting global warming and reducing Denmark’s dependence on coal, oil and gas.

In Denmark’s energy strategy for 2025, their government expects to see a significant increase in the use of renewable energy in the years to come. The market-based expansion of this sector will be brought about through incentive schemes and investment in physical infrastructure as well as research, development and demonstration. With higher oil prices and high CO₂ allowance prices, a significant proportion of the renewable energy expansion would be expected to be delivered by large, offshore wind farms. At sea, wind resources are better and suitable sites are more readily available to enable these large projects to operate in harmony with the surrounding environment.

In Denmark, as offshore Wind farms impact on their natural surroundings, it is essential to ensure that conditions in unique marine areas are not detrimentally affected. Spatial planning when identifying potential locations for offshore wind farms, taking into account grid connection routes and other areas of interests, must ensure that future offshore wind farms are established in suitable areas in such a way that substantial adverse environmental impacts can be avoided or diminished.

One of the challenges Denmark face is to assess the cumulative effects from multiple offshore wind farms to arrive at optimal site selection. Thus a committee on future offshore wind farms is currently updating the Danish action plan from 1997 to use the experience and learning gained to date in order to identify appropriate locations and at the same time to minimize visual disturbances and the effects on animal species such as marine birds and mammals.

Wind Generation in Denmark: The methods and machines

1) Modern Wind Turbines

Denmark has (in 2003) around 3,000 MW wind power, which is supplied by approximately 5,500 wind turbines. Individuals and cooperatives own around 80% of the capacity.

Avedøre Holme, Denmark: The picture shows the Avedøre Wind Farm, just 5 kilometres from the city centre of Copenhagen, Denmark. The 12 Bonus 300 kW wind turbines, (and one 1,000 kW power company test wind turbine) are located next to a 250 MW coal-fired power plant. (Photograph Søren Krohn, © 1997 DWIA)

 

  2) Large Onshore Wind Farms

Rejsby Hede wind farm consist of 40 turbines from Bonus Energy each of 600 kW. The turbines were erected in 1995 near Tønder in southern Jutland. Totalling 24 MW it was the largest wind farm in Denmark at the time.
Today the largest onshore wind farm in Denmark is Syltholm on the southern island Lolland. The farm consist of 35 NEG Micon 750 kW turbines i.e. a total capacity of 26,25 MW.

 

3) Multi-Megawatt Wind Turbines

NEG Micon 2 MW: The prototype of the NEG Micon 2 MW turbine was commissioned in August 1999. It has a 72 m (236 ft.) rotor diameter. In this case (Hagesholm, Denmark) it is mounted on a 68 m tower. In the background you see the foundations for two sister machines. The turbine is intended for offshore applications.

From the outside it resembles the 1500 kW NEG Micon machine so much, that you’d have to see the turbine in its stopped state (with the blades pitched out of the wind) in order to notice the difference: The rotor blades are pitchable, since the machine has active stall power control, whereas its 1500 kW cousin has passive stall power control.

 

4) Megawatt-Sized Wind Turbines

Nordex 2,5 MW: The prototype of the Nordex 2,5 MW turbine was commissioned in the spring of 2000. The rotor diameter of the wind turbine is 80 m. The image shows the prototype at Grevenbroich, Germany, which has a 80 m tower. The turbine has pitch power control. (Photo © 2000 Nordex)

Pitch Controlled Wind Turbines

On a pitch controlled wind turbine the turbine’s electronic controller checks the power output of the turbine several times per second. When the power output becomes too high, it sends an order to the blade pitch mechanism which immediately pitches (turns) the rotor blades slightly out of the wind. Conversely, the blades are turned back into the wind whenever the wind drops again.

The rotor blades thus have to be able to turn around their longitudinal axis (to pitch) as shown in the picture. During normal operation the blades will pitch a fraction of a degree at a time – and the rotor will be turning at the same time.

Designing a pitch controlled wind turbine requires some clever engineering to make sure that the rotor blades pitch exactly the amount required. On a pitch controlled wind turbine, the computer will generally pitch the blades a few degrees every time the wind changes in order to keep the rotor blades at the optimum angle in order to maximise output for all wind speeds. The pitch mechanism is usually operated using hydraulics. 

 

The Future for Megawatt-Sized Turbines: The megawatt market really took off in 1998. Since then, it has been clear that the market trend is towards bigger projects with bigger wind turbines. Megawatt-sized machines will be ideal for offshore applications, and for areas where space for siting is scarce, so that a megawatt machine will exploit the local wind resources better.

5) Offshore Wind Turbines: Offshore wind energy is a promising application of wind power, particularly in countries with high population density, and difficulties in finding suitable sites on land. Construction costs are higher at sea, but energy production is also higher. The largest offshore wind farms in Denmark are Horns Rev by the west coast of Jutland and Nysted close to Lolland – 160 and 158 MW respectively. The Danish energy plan, Energi21, from 1996 set up a target for 4,000 MW offshore wind power in 2030. These 4,000 MW are expected to produce 13.5 TWh per year equivalent to 40% of the Danish electricity consumption.

Nysted Offshore Wind Farm: The most recent large offshore farm is Nysted Offshore Wind Farm at Rødsand built in 2003. The wind farm is located app. 10 km south of the town of Nysted on Lolland and consists of 8 rows with 9 turbines each. The total power of the 72 wind turbines each of 2.3 MW thus reaches 165,5 MW. The annual electricity production of the wind farm is 600GWh, enough to supply 145,000 (Danish) households. The wind turbine towers are about 70 m tall, and the rotor blades 41 m long. The picture is from the initial phase of the installation.

Horns Rev – Denmark’s Largest Wind Farm: The largest wind farm in Denmark is the offshore wind farm of Horns Rev, which was completed in 2002. It is situated in the North Sea, 14-20 km off the coast of Jutland. With its 80 Vestas 2MW turbine, the wind farm has a total capacity of 160 MW. That makes it the largest offshore wind farm in the world today (2003). The farm supplies the equivalent of 150,000 (Danish) households. The larger production compared to Nysted is due to better wind conditions.

Aerodynamic Improvement Devices

A number of technologies known from the aircraft industry are increasingly being applied to improve the performance of wind turbine rotors.

One example is vortex generators, which are small fins, often only about 0.01 metre (0.4 inch) tall, which are fitted to the surface of aircraft wings. The fins are alternately slightly skewed a few degrees to the right and the left. The fins create a thin current of turbulent air on the surface of the wings. The spacing of the fins is very accurate to ensure that the turbulent layer automatically dissolves at the back edge of the wing.

Curiously, this creation of minute turbulence prevents the aircraft wing from stalling at low wind speeds. Wind turbine blades are prone to stalling even at low wind speeds close to the root of the blade where the profiles are thick. Consequently, on some of the newest rotor blades you may find a stretch of one metre or so along the backside of the blade (near the root) equipped with a number of vortex generators. (Picture © LM Glasfiber A/S).

How things work?

1) Wind Turbine Generators

The wind turbine generator converts mechanical energy to electrical energy. Wind turbine generators are a bit unusual, compared to other generating units attached to the electrical grid. One reason is that the generator has to work with a power source (the wind turbine rotor), which supplies very fluctuating mechanical power (torque).

Generating Voltage (tension): On large wind turbines (above 100-150 kW) the voltage (tension) generated by the turbine is usually 690 V three-phase alternating current (AC). The current is subsequently sent through a transformer next to the wind turbine (or inside the tower) to raise the voltage to somewhere between 10,000 and 30,000 volts, depending on the standard in the local electrical grid. Large manufacturers will supply both 50 Hz wind turbine models (for the electrical grids in most of the world) and 60 Hz models (for the electrical grid in America).

Cooling System:  Generators need cooling while they work. On most turbines this is accomplished by encapsulating the generator in a duct, using a large fan for air cooling, but a few manufacturers use water cooled generators. Water cooled generators may be built more compactly, which also gives some electrical efficiency advantages, but they require a radiator in the nacelle to get rid of the heat from the liquid cooling system.

Starting and Stopping the Generator: If you connected (or disconnected) a large wind turbine generator to the grid by flicking an ordinary switch, you would be quite likely to damage both the generator, the gearbox and the current in the grid in the neighbourhood.

Design Choices in Generators and Grid Connection: Wind turbines may be designed with either synchronous or asynchronous generators, and with various forms of direct or indirect grid connection of the generator. Direct grid connection mean that the generator is connected directly to the (usually 3-phase) alternating current grid.

Indirect grid connection means that the current from the turbine passes through a series of electric devices which adjust the current to match that of the grid. With an asynchronous generator this occurs automatically.

To find out more about how the size of wind turbines could affect certain areas and the reasons for choosing different sizes of turbines, you could visit: http://www.windpower.org/en/tour/wtrb/size.htm

2) Rotor Aerodynamics

Rotor blades for large wind turbines are always twisted. Seen from the rotor blade, the wind will be coming from a much steeper angle (more from the general wind direction in the landscape), as you move towards the root of the blade, and the centre of the rotor. A rotor blade will stop giving lift, if the blade is hit at an angle of attack that is too steep. Therefore, the rotor blade has to be twisted, so as to achieve an optimal angle of attack throughout the length of the blade. However, in the case of stall controlled wind turbines in particular, it is important that the blade is built so that it will stall gradually from the blade root and outwards at high wind speeds.

3) The Wind Turbine Yaw Mechanism

The wind turbine yaw mechanism is used to turn the wind turbine rotor against the wind. The wind turbine is said to have a yaw error, if the rotor is not perpendicular to the wind. A yaw error implies that a lower share of the energy in the wind will be running through the rotor area.

4) Aerodynamics of Wind Turbines: Lift

The rotor consisting of the rotor blades and the hub are placed upwind of the tower and the nacelle on most modern wind turbines. This is primarily done because the air current behind the tower is very irregular (turbulent). Modern wind turbines borrow technologies known from aeroplanes and helicopters, plus a few advanced tricks of their own, because wind turbines actually work in a very different environment with changing wind speeds and changing wind directions. The reason why an aeroplane can fly is that the air sliding along the upper surface of the wing will move faster than on the lower surface.

This means that the pressure will be lowest on the upper surface. This creates the lift, i.e. the force pulling upwards that enables the plane to fly.

The lift is perpendicular to the direction of the wind. The lift phenomenon has been well known for centuries to people who do roofing work: They know from experience that roof material on the lee side of the roof (the side not facing the wind) is torn off quickly, if the roofing material is not properly attached to its substructure.

Sources:

http://www.energyquest.ca.gov/story/chapter16.html

http://www.renewableenergyworld.com/rea/news/infocus/story?id=46749

http://www.managenergy.net/download/opet_gp/summaries/_s023p_gpr_ntua-on-wind-denmark.htm

http://www.windpower.org/en/pictures/modern.htm

 posted by szeyuan

Using of Wind Energy in Denmark

Using of Wind Energy in Denmark

This publication describes the Danish experiences with offshore wind power and discusses the challenges of environmental issues that Denmark has had to address in relation to the two large-scale demonstration offshore wind farms Horns Rev and Nysted since 1999.

05 December 2006

Denmark to Increase Wind Power to 50% by 2025, Mostly Offshore

Preface: The Power Source for the Future – Flemming Hansen, Minister for Transport and Energy, and Connie Hedegaard, Minister for the Environment [Denmark] 

Our future energy supply faces numerous challenges and has become subject to unstable international conditions. To meet these challenges, offshore wind has a key role to play. Offshore windpower can contribute significantly to achieving the EU goals of a 21 percent share of renewable electricity by 2010, halting global warming and reducing our dependence on coal, oil and gas.

We have come a long way since the 1980s, when most electricity production was based on coal and when the acidification of forests and lakes by acid rain was the predominant theme in the environmental debate. Today wind power provides 20% of Danish electricity consumption.

Within a few years, the wind power industry has grown to become a significant industrial sector providing huge benefits for exports and employment. We are now talking about windpower generation plants rather than single turbines, and the Danish wind power industry is at the leading edge in an ever more competitive global market.

In the energy strategy for 2025 the Government expects to see a significant increase in the use of renewable energy in the years to come. The market-based expansion of this sector will be brought about through incentive schemes and investment in physical infrastructure as well as research-, development- and demonstration. With higher oil prices and high CO₂ allowance prices we expect that a significant proportion of the renewable energy expansion will be delivered by large, offshore wind farms. At sea, wind resources are better and suitable sites are more readily available to enable these large projects to operate in harmony with the surrounding environment.

We are therefore very pleased that the Danish environmental monitoring program on large scale offshore wind power has received a positive evaluation by the International Advisory Panel of Experts on Marine Ecology.To sustain public acceptance and provide continued protection to vulnerable coastal and marine habitats, it is important to build upon the positive experience gained so far with the use of marine spatial planning instruments. 

Offshore Wind farms impact on their natural surroundings and it is essential to ensure that conditions in unique marine areas are not detrimentally affected. Spatial planning when identifying potential locations for off shore wind farms — taking into account grid connection routes and other areas of interests — must ensure that future offshore wind farms are established in suitable areas in such a way that substantial adverse environmental impacts can be avoided or diminished. One of the challenges we face is to assess the cumulative effects from multiple offshore wind farms to arrive at optimal site selection.
Thus a committee on future offshore wind farms is currently updating the Danish action plan from 1997 to use the experience and learning gained to date in order to identify appropriate locations and at the same time to minimize visual disturbances and the effects on animal species such as marine birds and mammals.

from: http://www.renewableenergyworld.com/rea/news/infocus/story?id=46749

Denmark has relatively modest average wind speeds in the range of 4,9 to 5,6 m/s measured at 10 m height. Onshore wind resources are highest in the Western part of the country, and on the Eastern islands with coastlines facing South or West. The country has very large offshore wind resources, and large areas of sea territory with a shallow water depth of 5 to 15 m, where siting is most feasible. These sites offer higher wind speeds, in the range of roughly 8,5 to 9 m/s at 50 m height. 

from: http://www.managenergy.net/download/opet_gp/summaries/_s023p_gpr_ntua-on-wind-denmark.htm

posted by szeyuan

 

Abt the Singapore part

Regarding the part that Jenny has been forced to do (i pity you, jenny. tt’s the hardest one yet the most important too…)

You can find that Cynt’s compiling (it’s coherent, my dear. Not messy like you think.) actually covers some parts of the Singapore one. Like the part where there’s an analysis about Singapore and wind energy.

Let’s find out more abt S’pore and wind energy, kae? And add some of your views and comments about the article or the singapore and wind energy topic for easier analysis!

chia2

p.s. Jenny’s at China now, and won’t be back til holiday’s over, so we’ll have to help her as a group!

and cynt! u forgot to give ur compiled stuff a category. I just helped you to give it one le.

Wind energy–The general stuff :D Finally compiled

Actually it has been compiled for a while…i was hoping to make it more organized…oh well

Made mini sub titles for easier reference. Edit the stuff anyway u want if it isn’t coherent to you.

Chia2

Renewable Energy

Energy has been part of our day to day living. We use energy in almost every aspect of our lives. Appliances, equipments and machines in our houses and workplaces require energy to work. But many sources of these energy are not necessarily eco-friendly; some are even detrimental to the environment. For example, coal and fossil power plants causes an increase in air pollution; Nuclear power plants have a danger of a meltdown. However, there are safe sources of energy—renewable energy, gifts from nature. Generally, renewable energy is energy that occurs naturally and is abundant in nature.

Examples of these renewable energies:

· Solar Energy – This comes from the light from the sun. Depending on the type of process used the sunlight can be converted into electricity.

· Wind Energy – To take advantage of this energy man created wind mills and turbines that convert wind into electricity.

· Geothermal Energy – This form of energy utilizes the heat from earth itself

· Other renewable energy sources are tidal power from seas and oceans, and biomass from garbage

Our group is focusing on the topic of Wind Energy for our Physics SIA 2008; therefore we shall start by introducing what is Wind energy.

Definitions of wind energy

Wind energy is actually a form of solar energy. As the sun’s rays heat the Earth’s surface, there is a temperature difference between land, water and air, due to their different propensities to absorb heat. Temperature differences that exist between the equator and the Earth’s poles causes wind, as hot air rises replaced by cooler air. Therefore wind can be thought of as the circulatory system of planet, distributing energy from warmer areas to cooler areas. Wind flow harvested by modern wind turbines can be used to generate electricity.

Wind energy is the kinetic energy that is present in moving air. The amount of energy depends mainly on wind speed, but is also affected slightly by the density of the air, which is determined by the air temperature, barometric pressure, and altitude. The kinetic energy present in wind motion that can be converted to mechanical energy for driving pumps, mills, and electric power generators. Wind power is produced in large-scale wind farms connected to electrical grids, as well as in individual turbines for providing electricity to isolated locations. Since wind energy is a renewable energy, it is plentiful, renewable, widely distributed, clean, and reduces greenhouse gas emissions when it displaces fossil-fuel-derived electricity.

One of the main drawbacks of wind energy is that electricity can only be produced where there is wind. Electricity produced from wind energy is currently not only environmentally friendly but also competitive in price to conventionally generated electricity.”

Utility-scale wind farms produce electricity at about 4.5 ¢/kWh, making wind power competitive with fossil-fuel-generated electricity. These economics are made possible by a federal production tax credit of 1 ¢/kWh. Though wind is an intermittent resource (wind speeds varies), It can be easily integrated into the existing supply mix. Most analysts agree technological improvements & economies of scale in wind turbine production reduce cost.

The intermittency of wind seldom creates insurmountable problems when using wind power to supply up to roughly 10% of total electrical demand but using of wind energy still presents challenges, drawbacks and environmental problems that are not yet fully solved when wind is to be used for a larger fraction of demand.

Wind power is the conversion of wind energy into useful form, such as electricity, using wind turbines. In windmills, wind energy is directly used to crush grain or to pump water. At the end of 2007, worldwide capacity of wind-powered generators was 94.1 gigawatts.^[1] Although wind currently produces just over 1% of world-wide electricity use,^[2] it accounts for approximately 19% of electricity production in Denmark, 9% in Spain and Portugal, and 6% in Germany and the Republic of Ireland (2007 data). Globally, wind power generation increased more than fivefold between 2000 and 2007.^[1]

Wind power is produced in large scale wind farms connected to electrical grids, as well as in individual turbines for providing electricity to isolated locations.

Best Wind-site farms

For any wind turbine, the power and energy output increases dramatically as the wind speed increases. Therefore, the most cost-effective wind turbines are located in the windiest areas. Wind speed is affected by the local terrain and increases with height above the ground, so wind turbines are usually mounted on tall towers.

As there are complaints about how Wind turbines can alter the aesthetic character of pristine wilderness areas in northern New England and New York, some of the best wind sites are located along mountain ridges. However, considering the environmental and health benefits of using pollution-free wind power, environmentally-minded citizens should seek to identify as many suitable wind sites as possible.

Some have also raised serious concerns about noise from wind turbines and impacts on migratory bird species. However, current technology has allowed noise from wind turbines to be no louder than that of background noises, and a significant greater number of birds actually die as road-kill, etc. than from wind turbines.

History of Wind energy

People have relied on wind energy since thousands of years ago. Ancient Persians used wind energy to pump water before the birth of Christ. The world was explored by wind-driven ships long before engines were invented. Much more recently, in the 1920s, over a million wind turbines pumped water and provided electricity to farms in North America. Using windmills to grind grain is also an example of early uses of wind energy, and one closer to our time. The current interest in wind energy was started by the need to develop clean, sustainable energy systems that can be relied on for the long-term future. Modern aerodynamics and engineering have improved wind turbines. They now provide reliable, cost-effective, pollution-free energy for individual, community, and national applications.

The earliest historical reference describes a windmill used to power an organ in the 1st century AD.^[4] Windmills were used extensively in Northwestern Europe to grind flour beginning in the 1180s, and many Dutch windmills still exist.^[5]

In the United States, the development of the “water-pumping windmill” was the major factor in allowing the farming and ranching of vast areas of North America, which were otherwise devoid of readily accessible water. They contributed to the expansion of rail transport systems throughout the world, by pumping water from wells to supply the needs of the steam locomotives of those early times.^[6]

The multi-bladed wind turbine atop a lattice tower made of wood or steel was, for many years, a fixture of the landscape throughout rural America.

The modern wind turbine was developed beginning in the 1980s, although designs are still under development.

How can wind energy be used?

Wind mills convert the kinetic energy in the wind into mechanical power that can be used for specific tasks (grind grain or pump water) or a generator can convert it to electricity to power homes, businesses and schools.

· Wind energy can be used for transportation, water pumping, and grinding.

· Windmills– mechanical power to grind wheat or pump water vs. Wind turbines– generate electricity.

· Windmills that were used to grind grain are an example of early uses of wind energy. Modern uses of wind energy include generation of electricity and pumping water. Current wind energy machines are called “wind turbine generators“, “wind pumps”, or more generally, “wind turbines“.

Harvesting wind energy—wind turbines

· There are sizes from small-scale home systems of 5-15 kilowatts to utility scale systems ranging in size from 300-1000 kilowatts.

· They are usually mounted on a tower approximately 160 feet high to take advantage of the higher wind speeds and allow the blades to rotate without interference

· There are vertical-axis wind turbines, though most have airfoil-type blades that rotate around a horizontal-axis.

· Wind turbines turn in moving air and power an electric generator that supplies an electric current. A wind turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.

· Wind turbines are often grouped together into a single wind power plant, also known as a wind farm, and generate bulk electrical power. Electricity from these turbines is fed into a utility grid and distributed to customers, just as with conventional power plants.

· Wind turbines are available in a variety of sizes, and therefore power ratings. The largest machine has blades that span more than the length of a football field, stands 20 building stories high, and produces enough electricity to power 1,400 homes. A small home-sized wind machine has rotors between 8 and 25 feet in diameter and stands upwards of 30 feet and can supply the power needs of an all-electric home or small business. Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping.

· Blowing wind spins the blades on a wind turbine — just like a large toy pinwheel. This device is called a wind turbine and not a windmill. A windmill grinds or mills grain, or is used to pump water.

· The blades of the turbine are attached to a hub that is mounted on a turning shaft. The shaft goes through a gear transmission box where the turning speed is increased. The transmission is attached to a high speed shaft which turns a generator that makes electricity.

· If the wind gets too high, the turbine has a brake that will keep the blades from turning too fast and being damaged.

· A single smaller wind turbine can be used to power a home or a school. The small turbine on makes enough energy for a house. In the picture, the children at this Iowa school are playing beneath a wind turbine that makes enough electricity to power their entire school.

· In order for a wind turbine to work efficiently, wind speeds usually must be above 12 to 14 miles per hour. Wind has to be this speed to turn the turbines fast enough to generate electricity. The turbines usually produce about 50 to 300 kilowatts of electricity each. A kilowatt is 1,000 watts (kilo means 1,000). You can light ten 100 watt light bulbs with 1,000 watts. So, a 300 kilowatt (300,000 watts) wind turbine could light up 3,000 light bulbs that use 100 watts!

Horizontal-axis wind turbines

An example of a horizontal-axis wind turbine variety is the traditional farm windmills used for pumping water. It includes blade/rotor, converts energy in wind to rotational shaft energy; a drive train usually including a gearbox and generator; a tower that supports the rotor and drive train and other equipment, including controls, electrical cables, ground support equipment, and interconnection equipment.

Vertical-axis wind turbines

Vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor. Blades of this variety are designed like the wings of an airplane that create lift when exposed to the force of the wind, propelling blades around in a circular motion. The wind turbine rotor typically consists of 2/3 blades attached to a hub. A rotating shaft from the rotor feeds into a gearbox assembly and then into the generator, converting mechanical motion of the shaft into electricity. When wind change direction, the yaw system lets wind turbine pivot, letting rotor spins in a plane perpendicular to the wind.

Finally, some stuff that i have found

Wind Energy Fact vs. Fiction:

Myth: Wind generators are too loud, often to the point of being dangerous to people’s hearing.

Fact: In reality, today’s wind generators are no louder than the normal background noise we experience when we are at home. In fact, with most models, it is nearly impossible to tell the difference between the wind generator and a tree blowing in the wind.

Myth: Wind generators need very high wind speeds to be effective.

Fact: Today’s wind generators need as little as 7 mph to start generating electricity. And, they are fully operational and profitable with as little as 10-12 mph average wind speeds.

Myth: My neighbors will never allow me to install a wind generator.

Fact: Despite popular belief, when given the true facts about wind generators, neighbors, zoning boards, etc, are much less likely to be against the installation of a wind generator that you might think.

Like all renewable energy, understanding the truth of wind energy is vital to understanding the financial and ecological benefits of using these systems yourself.

http://www.siliconsolar.com/wind-energy-products.php 18 May, 2008

Tt’s all. Post quick! Today’s the day we set to finish compiling!

cept for Jenny’s part. We’ll need to analyse together o.o

Oh, Thanks to everyone for working together and being prompt to my emails

chia2

The pros and cons of wind energy

Hello all peoples!

In this post, i will be investigating the pros and cons of wind energy in both Denmark and Singapore as well as the reasons behind it and a comparison.

Firstly, the pros and cons of the use of wind energy in Denmark because of the people of denmark’s opinion on Wind energy in their country. Afterall, the people are the one who have to put up with it! Hey, hear it from the horses’ mouth!

Note: Public attitude surveys of wind power are of a very varied quality.

Renewable energy sources have more credibility with the public than non-renewables such as fossil fuels and nuclear power. In the USA a national opinion survey (Breglio, 1995) showed that 42 % of the Americans believe that renewable energy sources like solar, wind, geothermal, biofuels, and hydroelectric should be the highest priority for continued federal funding of energy research and development. Fossil fuels and nuclear energy, which are the energy sources generating the most energy in the USA come in last by 7 and 9 per cent.

In Denmark the same questions were posed (Holdningsundersøgelse, 1993). Here the attitude towards renewable energy sources was also positive. A representative group of Danes were asked if renewables should have a higher priority in national energy policy. According to this questionnaire four out of five Danes think that renewable energy sources should have a higher priority. Only 9 per cent disagree.

There is no doubt that renewable energy today is considered a full grown source of energy generation. Behind the term renewable energy is however a variety of different generation techniques. It is therefore interesting to investigate whether wind energy in particular also enjoys broad public support. A Canadian questionnaire asked a representative group of Canadians if they would like to see their provincial power utility give a high priority to wind generated electricity in their province (Omnibus Report, 1995). According to this survey 79 per cent of the Canadians believe that wind generated electricity should have a high utility priority in Canada. The same tendency can be seen in the Danish survey (Holdningsundersøgelse, 1993).

The Danes were asked if Denmark should aim for a higher utilisation of wind power. 82 per cent of the population was in favour of more wind power. A survey made in the Netherlands showed the same pattern. 80% of the Dutch population were in favour of wind energy, 5% opposed it, and 15% were neutral (Gipe, 1995). The same result were found in the UK (Simon, 1996). From 1990 to 1996 thirteen research studies have been made in the UK and across surveys also eight out of ten supports wind power. So, in general both renewable energy and wind power in particular is vested with more credibility than non-renewables such as fossil fuels and nuclear power.

The acceptance of spinning turbines is higher than that of idle ones not generating power, shows both American and Swedish studies. A paper (Wolsink and Sprengers, 1993) investigating the noise problem in Denmark, the Netherlands, and Germany shows, that the annoyance caused by wind turbine noise affects very few people and the level of annoyance is hardly related to the actual sound level of specific turbines.

Instead the annoyance is related to other causes such as negative feeling towards the wind turbines. The Danish survey showed, that those in favour of renewables and wind power in general are more positive about local turbines, they find them less noisy and less intrusive to the landscape (Gipe, 1995).

Even though it seems that the individual perception of noise and visual impact is determined by other factors than the actual noise level and the number of turbines erected, this does not mean, that noise problems and visual effects should be treated superficially.

The Denmark’s Nay sayer:

-renewable energy cannot solve our energy problems

-wind turbines are unreliable and dependent on the wind

-wind energy is expensive

-wind turbines spoil the scenery

-wind turbines are noisy

The Denmark’s yes-sayer

 -renewable energy is very much an alternative to other energy sources

-the climate change theory must be taken seriously

-wind energy is limitless unlike fossil fuels

-wind energy is none polluting

-wind energy is safe

The distance to the nearest turbine has no effect on people’s attitudes towards wind turbines in general. This indicates that people living close to wind turbines do not consider noise and visual impact to be significant problems. As a matter of fact people living closer to the nearest wind turbine than 500 meters tend to be more positive about wind turbines than people sited further away from the turbines.

Much the same pattern was identified when attitudes towards wind turbines in general were cross tabulated with the number of visible turbines from the residence of the respondents. Again, no clear pattern could be detected. But people who could see between 20 and 29 turbines tended to be more positive about wind energy than people being able to see only a smaller number of turbines. Again, this indicates that the number of actual wind turbines in the local environment has no negative influence on people’s attitude towards wind energy. In Denmark there is even a tradition for wind co-operatives, where a group of people share a wind power plant.

http://www.windpower.org/media(485,1033)/public_attitudes_towards_wind_power.pdf

Some general pros and cons of use of wind energy in Denmark.

1) It takes up very little space on their land area.

The proposed annual average energy consumption of 19 gigawatts by the year 2050 corresponds to solar energy collecting panels (in use only 50 percent of the time) with an area of roughly 180 square kilometers and a windmill swept area of about 150 square kilometers. These (vertical) areas constitute less than 1 percent of the total land area.

2) It is economically feasible.

The project has been shown to be economically feasible according to estimates of the cost of various alternatives during the 25-year depreciation period adopted. However, the initial cost per energy unit produced is higher than that for most of the alternatives, so that action is not expected to be taken immediately as a result of purely private initiative. In a public economic evaluation, other factors must be considered in addition to the cost of energy per kilowatt-hour.

3) Increases employment rate

At present, Denmark has over 10 percent of its labor force out of employment and a substantial deficit on its balance of payments, so that an early start on the solar and wind energy project, based on national industry, would have additional payoffs compared with energy systems based on imported technology or imported fuels. Several factories that are now being closed down as a result of the economic crisis could be adapted to the production of parts for solar or wind power systems, and the building industry, badly hit by unemployment, would receive legitimate work.

4) Provide a better alternative than fossil fuels like coal.

Last year, wind driven turbines produced less than 0.1 percent of America’s electricity supply -compared to 52 percent generated from coal, according to the U.S. Department of Energy. One reason that wind energy has lagged so far behind is the perception is that wind farms are more expensive to build and operate than coal fired power plants.

Also, compared to Denmark and Singapore: Wind turbines are usually designed to operate at a minimal wind speed in order to generate electricity. Singapore does not have abundant winds except near coastal areas or at some off-shore islands. This could reduce the performance of wind turbines and hence the viability of wind as a renewable resource for Singapore.

Unlike Denmark, Singapore has too little wind energy to be converted into energy we can actually use daily. It can only provide for only a very little portion of Singapore’s energy that is being used up.

Another factor is the price of setting up a wind turbine in SIngapore. although it can be used for quite a long time, but the energy it generates from the limited amount of wind in Singapore is simply not worth the cost of building the turbines. Moreover, Denmark has a larger amount of land than Singapore, so there is space for many wind turbines. Singapore has very scarce land and the cost of the land and turbines is very expensive and is not as feasible as in Denmark.

The above are probably some of the reasons why Singapore has not set up a wind turbine to generate electricity for the country.

And finally, a general table.

Pros

	Safe
	Inexhaustible
	Free

Cons

	Wind speed is variable and unreliable
	Wind farms are typically located in high, exposed, rural locations, where they can be seen as eyesores
	Often noisy, although modern turbines are quieter than their predecessors
	Wildlife habitats can be disrupted and there is a risk of birds getting caught in the blades
	Off-shore wind farms go some way to solving these problems, but they are expensive to build and maintain. It is cheaper to put more coal into an existing power station than to build a new wind farm

http://www.sciencemag.org/cgi/content/abstract/189/4199/255

http://www.wind-power.net/cheaperthancoal.htm

http://www.ieee.org/web/emergingtech/discourses/windpower/overview.html

Cynthia:)

 

While stagnant blogs do not breed mozzies, this blog happens to be our SIA…

so…just to inform anyone who comes, i have started to collate info for part 1), the general info one.

Will greatly appreciate it if u have found any new material for (1) and wishes to post it, pls send it to my hotmail account too!

so there.

Choir concert’s coming! invite ur friends too!

chia2.

The pages

hey all! i’ve uploaded pages (they are at the header bottom; they can be seen if you place ur mouse on top of the text beside the one ‘blog’), where we can house all our collated information for each category there (:

posted by sze yuan on 5/4/08

About wind energy

by the way,  jenny, i found more information about wind energy being a solar energy…it’s somewhere written at the “Understanding the Wind Resource” of the article i found (:

Wind Power

Wind energy has been harnessed for thousands of years to perform useful work for humans. Humans have used wind power for transportation, water pumping, and grinding since the time of the ancient Egyptians. In the late 19th century, the Danes began harnessing wind to generate electricity using wind turbines.

People often use the terms windmill and wind turbine interchangeably. However, windmills harness the wind for mechanical power to grind wheat or pump water, while wind turbines use the wind to generate electricity.

Today, modern wind turbines efficiently convert the force of moving air into electricity using modern design principles and high-tech materials. Wind turbines come in many different sizes from small-scale home systems of 5 kilowatts to 15 kilowatts, to utility scale systems ranging in size from 300 kilowatts to 1,000 kilowatts. To take advantage of higher wind speeds and to allow the blades to rotate without interference, wind turbines are mounted on the top of a tower typically 160 feet high. Although there has been some experimentation with vertical-axis wind turbines, most wind turbines have airfoil-type blades that rotate around a horizontal-axis. The blades are designed like the wing of an airplane creating lift when exposed to the force of the wind, which propels the blades around in a circular motion. The wind turbine rotor typically consists of two or three blades attached to a hub. A rotating shaft from the rotor feeds into a gearbox assembly and then into the generator, which converts the mechanical motion of the shaft into electricity. As the wind changes direction, the yaw system allows the wind turbine to pivot so that the rotor spins in a plane perpendicular to the wind.

Understanding the Wind Resource

Ultimately, wind is a form of solar energy. The sun’s rays heat the Earth’s surface creating temperature differences between the land, water, and air, given their different propensities to absorb heat. This phenomena, in conjunction with the temperature differences that exist between the equator and the EarthÕs poles, creates wind as hot air rises, expands, becomes less dense, and is then replaced by denser, cooler air. In sum, wind can be thought of as the circulatory system of the planet, distributing energy from warmer areas to cooler areas. (needs more researching regarding this area still so as to confirm whether wind is a form of solar energy)

Economics and Future Prospects (more on the pros and cons of using wind energy)

Of all the renewable energy technologies, wind power is currently the most cost competitive when compared to traditional, fossil-fuel-based energy production technologies. In fact, wind power is the fastest growing energy source around the world. The United States now has a total of 2,600 megawatts of installed wind capacity. This is equivalent to about three or four large coal-fired power plants.

Utility-scale wind farms produce electricity at about 4.5 ¢/kWh which makes wind power competitive with fossil-fuel-generated electricity. It should be noted that these economics are made possible by a federal production tax credit of 1 ¢/kWh. Even though wind is an intermittent resource, meaning wind speeds vary from day to day and month to month, wind power can be easily integrated into the existing supply mix, making a significant contribution to our nationÕs energy supply. Most analysts agree that technological improvements and economies of scale in wind turbine production will contribute to even further cost reductions in the price of wind-generated electricity.

Environmental Issues (more on the pros and cons of using wind energy)

Wind-generated electricity provides a pollution-free source of electricity. None of the harmful emissions associated with fossil fuels occur when the wind is utilized to produce electricity. Increased use of wind power in the Northeast would be a valuable step toward improving the health of the regional environment.

The main concern regarding wind energy development in the Northeast revolves around siting. Given that the best wind sites are located along mountain ridges, wind farms could alter the aesthetic character of pristine wilderness areas in northern New England and New York. On the other hand, we need to remember the serious health and environmental impacts of most other energy sources when compared to pollution-free wind power. There will always be, and should always be, places where wind development will not make sense for aesthetic reasons, but environmentally-minded citizens should seek to identify as many suitable wind sites as possible.

In the past, some people raised serious concerns about the swishing noise made by wind turbines and their impacts on migratory bird species. These concerns have largely been dealt with through technological improvements and proper siting.

article taken from: http://www.nesea.org/energy/info/wind.html

posted by sze yuan on 4/4/08

Youtube short clip

 http://www.youtube.com/watch?v=QL-cRuYAxg0

This is a short clip of a Danish Wind Turbine accident. Can serve as evidence against the building of windmills, for no matter how rare these cases are, the chances exist, and thus serve as a potential harm to people who happen to be nearby. It looks pretty bad, and quote on of the commentors who watched the film:

They have been trying to stop the mill for a few days. This was not an accident that happened within seconds. Actually it was in the news in Denmark the evening before, and everybody was just waiting for the thing to collapse in the strong wind. First collapse in 30 years. Also why it got videoed…

It is up to us to debate if this is credible or not. I haven’t found information regarding the damage of windmills. Anyone?

posted by chia2 on 3/4/08

Wind Energy Basics

Basic concepts about wind energy…although I have one question. Is wind a form of solar energy? I tried referencing on the net but I couldn’t find much. Will check again soon.  

Wind Energy and Wind Power

Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface, and rotation of the earth. Wind flow patterns are modified by the earth’s terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, when “harvested” by modern wind turbines, can be used to generate electricity.

How Wind Power Is Generated

The terms “wind energy” or “wind power” describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity to power homes, businesses, schools, and the like.

Wind Turbines

Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current. Simply stated, a wind turbine is the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity.

Wind Turbine Types
Modern wind turbines fall into two basic groups; the horizontal-axis variety, like the traditional farm windmills used for pumping water, and the vertical-axis design, like the eggbeater-style Darrieus model, named after its French inventor. Most large modern wind turbines are horizontal-axis turbines.

Turbine Components
Horizontal turbine components include:

• blade or rotor, which converts the energy in the wind to rotational shaft energy;  
• a drive train, usually including a gearbox and a generator;
• a tower that supports the rotor and drive train; and
  other equipment, including controls, electrical cables, ground support equipment, and interconnection equipment.
  Wind turbine diagram – click for enlarged image.

 
Turbine Configurations
Wind turbines are often grouped together into a single wind power plant, also known as a wind farm, and generate bulk electrical power. Electricity from these turbines is fed into a utility grid and distributed to customers, just as with conventional power plants.

Wind Turbine Size and Power Ratings
Wind turbines are available in a variety of sizes, and therefore power ratings. The largest machine has blades that span more than the length of a football field, stands 20 building stories high, and produces enough electricity to power 1,400 homes. A small home-sized wind machine has rotors between 8 and 25 feet in diameter and stands upwards of 30 feet and can supply the power needs of an all-electric home or small business. Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping.

See Wind Energy Photos page for wind farm photographs.

See Wind Energy Photos page for wind turbine photographs.

—

Text and diagram from: http://windeis.anl.gov/index.cfm

I have included the links that they provided to view pictures. Enjoy!

 

Posted by: Jenny on 3 April 2008

Renewable Energy

Here is an introduction to renewable energy of several forms that I found online.

—

The need for Renewable Energy

From our day to day living energy has been part of it. We used energy almost in every aspect of our lives. From food preparations and storage, entertainment, maintenance, doing our jobs and earning a living, keeping us warm or cold and so on. Simply to say almost every appliances, equipments and machines in our homes and work requires energy. And as the number of households, buildings industrial and commercial, population; the need for abundunat energy is always a question. If a city or town is growing so fast will the current energy level will meet its demand? in this case an increase in energy should sustain that demand.

Where will those additional energy should come from?. The current sources of energy we have now are the coal fired powerplants, nuclear power plants and hydro electric power plants. And with the present source of energy coal and fossil power plants, the increase in air pollution rises rapidly. As for nuclear power plants the danger of a melt down. However there are safe sources of energy. These are renewable energy, which are gifts from nature. Generally renewable energy are sources of energy which naturally occurs and are abundant in nature.

There are several types of renewable Energy

Solar Energy – This comes from the light from the sun. Depending on the type of process used the sunlight can be converted into electricity.
Wind Energy – To take advantage of this energy man created wind mills and turbines that converts wind into electricity.
Geothermal Energy – This form of energy utilizes the heat fromm earth itself
Other renewable energy sources are tidal power from seas and oceans, and biomass from garbage

With the increased demand in energy, thus the need for supply should increase but it does not mean that we should neglect consequences to nature. Because of the increased pollutants in the air the harm of global warming is taking effect. If we are looking for additional sources of energy we should look for a safe a pollutant free as possible source of energy should be utilized. Not only that we must now start eradicating those energy sources which greatly harms our ecosystem.

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Taken from: http://www.atlantic-renewable.com/

 

Posted by: Jenny on 3 April 2008