5MW with location picture [updated with videos] | 43 comments (43 topical, 0 editorial, 0 hidden)

Re: 5MW (4.00 / 2)

Q36. How many units make up a commercial deepwater wind farm? What area would this cover and what would be the size of the machines?
A36. The simple fact is we don't know at this stage and that this is the very essence of the Demonstrator learning process. A two turbine Demonstrator Project is clearly not a commercial wind farm but will help us determine what one might constitute.
The commerciality of a larger wind farm will be determined by many factors such as turbine size and fabrication and tie-in costs. Depending on what we learn from operating the Demonstrator, we may be able to define what will constitute a commercial wind farm.

Hmm, they don't know?

As a convenient rule of thumb one can assume that a wind farm will produce on the order of 1 MW/Km^2 on average. Bigger turbines have to be spaced farther apart (up to 15 blade lengths away) so there's no gain (except possibly being able to build taller turbines to take advantage of higher wind speeds farther from the surface).

So, at 1MW/Km^2, Beatrice's 30MW would require 30Km^2 (e.g., 5Km x 6Km) of wind farm. Each of these 5MW turbines would stand in the centre of a 5Km^2 circle (1.3 Km radius)

A 1GW field would have a radius of about 18 Km. Beatrice is 25 Km away from the coast, so a 36 Km-diametre field would cover 80 degrees of the horizon.

Can the last politician to go out the revolving door please turn the lights off?

by Migeru (migeru at eurotrib dot com) on Sun Jul 15th, 2007 at 03:06:19 PM EST
[ Parent ]

Re: 5MW (none / 1)

I think, they really only answer the first question, is this going to be commercially viable way to create energy - they are not really concerend with the other questions, but you are quite right.

by PeWi on Sun Jul 15th, 2007 at 03:13:28 PM EST
[ Parent ]

Re: 5MW (none / 1)

As a matter of interest, starting at (say) 250kW and doubling to 500kW then 1Mw, 2Mw and 4Mw, what are the costs per Mw, approximately?

And what about the density per km^2 ?

Is it REALLY the case that big is always better?

I'm also thinking about the availability of baby ones etc etc

I read somewhere that oil refineries don't necessarily scale the way you might think.

"The future is already here -- it's just not very evenly distributed" William Gibson

by ChrisCook (cojockathotmaildotcom) on Sun Jul 15th, 2007 at 03:21:40 PM EST
[ Parent ]

Re: 5MW (4.00 / 2)

Is it REALLY the case that big is always better?

Yes, taller is always better, because the farther away from the ground the larger can the wind speeds be while staying within the laminar (as opposed to turbulent) boundary layer. The surface of the sea is smoother than the surface of land, which also helps.

The density per square kilometer is at least 1 MW/Km^2 (effective). Depending on the average capacity factor (25%, 30%, 40% - I think it is larger on the sea than on land) this is between 2.5 and 4 MW/Km^2 (nominal). But this is a function of wind speeds (goes as the cubic power), which are better at higher altitudes and on water (back to boundary layers).

Can the last politician to go out the revolving door please turn the lights off?

by Migeru (migeru at eurotrib dot com) on Sun Jul 15th, 2007 at 03:34:43 PM EST
[ Parent ]

Density (none / 1)

Distance between turbines is usually 7 rotor diameters, i.e. less than a kilometer. So in that case that would give you 8MW nominal per sq.km, or close to 4MW real per sq. km.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Sun Jul 15th, 2007 at 03:40:17 PM EST
[ Parent ]

Re: Density (none / 1)

The power depends only on the wind speed, given that the 7 diam rule is respected as the size of the turbine increases.

Can the last politician to go out the revolving door please turn the lights off?

by Migeru (migeru at eurotrib dot com) on Sun Jul 15th, 2007 at 03:44:06 PM EST
[ Parent ]

Re: 5MW (none / 1)

the key issue here is the cost of deep (> 30 metres) offshore wind energy. if 2 turbines with average output 4 MW cost 162 million (is this GBP?), installation cost per GW is about 40 billion GBP. For comparison, nuclear power stations cost about 1.25 billion GBP per GW to build.

Shallow offshore wind energy is much cheaper, but even for the UK realistic estimates are that the area available can't provide more than about 100 TWh/yr out of a total energy consumption of 2700 TWh/yr.

by paulm on Wed Jul 18th, 2007 at 06:37:32 AM EST
[ Parent ]

Re: 5MW (none / 1)

well the faq states:

Q43. How much do you anticipate it will cost to develop a fully operational offshore wind farm?
A43. The full development would cost in the region of £1 billion.

The two turbine cost is £35mil - the 162 (actually 163 is the asci code for the pound symbol , which might have crept in when the diary was transfered to the front page...

When I asked my colegues about the future they were very cautious. as described in q44:

Q44. How confident are you that the commercial project will go ahead?
A44. The commercial project depends on many things including the future price of electricity and the performance and learning associated with the Demonstrator Project. It is impossible at this stage to give any definitive answer, but it certainly should not be regarded as an inevitability.

by PeWi on Wed Jul 18th, 2007 at 07:27:30 AM EST
[ Parent ]

Re: 5MW (none / 1)

two further notes

I edited the diary to correct the error with the asci code

the other thing I have not mentioned is of course, that one of the other reasons, why this is being build where it is, means it is not visible from the coast (further than 15km away) and unlike the situation with Jeromes project cannot be built on a sandbank, but needs the seafloor, a (I would suggest - but really haven't got a clue as to what I saying) far more likely scenario at that distance to a shore.

Maybe Jerome could give some indication as to what the overall cost of his project is coming to?

by PeWi on Wed Jul 18th, 2007 at 07:39:06 AM EST
[ Parent ]

Current offshore projects (4.00 / 2)

i.e. those that are actually being built, cost around 3,000 EUR/MW (notional), so that would be 6,000 EUR/MWe.

But then you have to take into account the cost of operating these, the cost of fuel (nil), and the cost of decommissioning (usually required to be provisioned upfront for wind projects, I wodner why there isn't such a requirement for nuclear plant, or for all factories, for that matter) for the cost that realyl has relevance, that per MWh.

In the long run, we're all dead. John Maynard Keynes

by Jerome a Paris (etg@eurotrib.com) on Wed Jul 18th, 2007 at 02:02:40 PM EST
[ Parent ]

5MW with location picture [updated with videos] | 43 comments (43 topical, 0 editorial, 0 hidden)

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