Scroby Sands

Scroby Sands background

Scroby sand’s was developed by Powergen Offshore Renewables(E On UK) and Vestas wind turbine manufacturers over 2003.
It is a 75 million pound project for an expected 60MW of power provided by 30 2MW turbines from the Vestas the Danish company. The site is located on a sandbank about two miles off the Norfolk coastline called Scroby Sands. E ON UK and Vestas were also involved in building the first offshore 2 turbine project in Northumberland, they then used their experience to implement the now operational wind farm at Scroby Sands.
The development of this site shows how businesses governments and people as a whole are recognising the energy problems that we and future generations are dealing with.
It also Coheres with the Kyoto agreement, which is a legally binding document signed by countries to reduce levels of CO2 emissions by 2012 relative to the 1990 level of emissions.

About Scroby sands comparison with another site North Hoyle.

Scroby Sands was one of the UK’s first offshore sites, along with North Hoyle. They are identical wind farms both comprising 30 2MW Vestas turbines, the only real difference is that they are on opposite sides of the country. North Hoyle just off the coast of Wales and Scroby sands on the east just off the Norfolk coastline.
These similarities make it feasible to conduct comparison on the two sites.
I looked at the availability data for both sites, the availability when talking about wind farms is the percentage of time the turbines blades are in motion and therefore producing power.
I first looked at the availability data for Scroby Sands it had an expected availability of around 95%

http://www.berr.gov.uk/files/file34791.pdf

It was close to its target availability of only four months out of the year, and the average over the year was well below expectations.

By comparison North Hoyle although older than Scroby sands was doing much better. Its yearly average was almost 7% higher than Scroby sands and it seemed to keep a good level of availability when compared to the very erratic data received from Scroby sands.

http://www.berr.gov.uk/files/file41542.pdf

What did cause this erratic availability data from Scroby Sands?

It seems that the availability drop at Scroby Sands was caused by a number of things. One factor was turbine failure. During the last few months of the year Scroby Sands had a large amount of failures. In total there have been 27 generator side intermediate speed shaft bearings and 12 high speed shaft bearings that have needed to be changed. Four of the generators themselves have also been replaced.
In my opinion another very large and also overlooked problem is that of weather days. A weather day only applies to offshore wind farms. The problem occurs when an offshore site is to be maintained. Turbines are accessed either using a transfer vessel or an inflatable dingy which is not ideal at the best of times. Transferring from the vessel to the turbine is not deemed to be safe when the wave heights are above 2m, and it is illegal for work to be carried out on these days hence the term a contractual “weather day”.
During the 2005 period there was a total of 143 weather days, this combined with the bearing and generator failures was undoubtedly the cause of the availability drop off towards the end of the year.
Although, North Hoyle was not without its failures. They were much the same as Scroby sands but less frequent with 6 gearbox faults and 2 bearing faults over the year. This does single out some quite major design flaws in the Vestas V80 design, as without these failures both of the sites in question would have undoubtably produced more energy over the year. Although, Vestas is working on the technical alternatives to the V80 design, it does bring into question their testing methods.

http://www.berr.gov.uk/files/file34791.pdf

What effect has this availability had on the Scroby Sands site? Unfortunately and obviously, not a very good one. The operational costs over 2005 were well below what the budget needed. The energy budget was £1,714,460 and the actual energy that was produced and sold was only £1,484,135. This was quite substantially below budget and increased the price of the energy coming from the wind farm
.

Political and Economic impact
The political connotations with a site like Scroby Sands are large when considering the nature of today’s society. It has become very clear that the energy consumption of the world has caused some damage to the climate. And that the burning of fossil fuels cannot and should not be what we rely on to power our homes and businesses.
The government want to be seen to be moving forward with these new opinions and facts, a greener government in today’s society. Taking into account these views sites like Scroby Sands will receive backing from the government and yes that means the UK taxpayer. So financially at the present these projects may be costing us a little bit more out of our paycheques. But, I think the recognition of the problems we could encounter if we didn’t try to find greener fuel sources outweighs the obvious taxpayer funding.
Although in the first year of implementation Scroby Sands has not done well in stabilising concerns about renewable energy sources. financially it hasn't lived upto expectations, it was headlined to be the second largest energy producing farm in europe at its time of construction but fell well short of budget in the first year.

Offshore sites like Scroby sands seem to be better at reducing public uproar, onshore sites are more likely to receive resistance for environmental issues, also noise pollution, ruining the countryside. Offshore sites are out of the way and also are not affected by space as much and therefore turbine size should be able to grow and produce more power.
The economic impact of wind energy has potential to be very large; it is in the early stages of its life cycle at the moment so time will tell. If the turbine manufacturers iron out some difficulties in their designs and larger turbines are produced. There are already some 6MW turbines being tested in Denmark. Then the amount of energy coming from wind especially in Great Britain (with its shallow surrounding water) could be a substantial chunk. Economically this would reduce the need to utilise fossil fuel reserves. Also, if renewable energy scources are working well we could see a new energy market appearing selling excess energy to other countries.

Conclusion

Offshore wind has great potential to power a large percentage of energy for Britain and for many other countries around the world. It has the benefits of a larger amount of space which can increase the turbine size producing more power. Less public uproar when planning permission for new sites is requested, as has been experienced with the onshore sites. Also the larger open space in offshore sites provides a more reliable wind source than that of on land.
Particularly around the UK, with its shallow waters. there is a huge amount of potential for producing a very large amount of energy from offshore wind.
If we are to fully utilize this resource, which we need too in order to sustain future generations we must be able to maintain offshore sites. This will involve some breakthroughs in technology, not only with the designs of the turbines themselves. There needs to be a feasible way of accessing the turbines for maintenance, this may involve changing the turbine design (how they are accessed) or with the vessels that are too access the turbines offshore.This in my opinion is something that must be done because being unable to maintain offshore sites like Scroby Sands devalues wind energy as a renewable energy source. If in the future we heavily rely on wind power, being unable to maintain sites could cause massive power shortages as inevitable faults will occur. As for this present moment, i can see wind being a fair proportion of the sustainable fuel industry but as a complete solution it appears to be too problematic.

References

http://www.berr.gov.uk/files/file41542.pdf

http://www.berr.gov.uk/files/file34791.pdf

http://www.eon-uk.com/481.aspx

http://www.ref.org.uk/images/pdfs/UK_Wind_Phase_1_web.pdf

http://www.renewableenergyaccess.com/rea/news/story?id=24229

http://www.yes2wind.com/nonflash_details.php?Region=North+Wales&SiteId=136