In the last decade of the 20th century 80 MW of offshore wind power was installed in Europe. These wind farms have operated successfully and have proved that offshore wind energy is technically, economically and environmentally viable. Continued monitoring and detailed investigation of these wind farms will provide invaluable data for use in better evaluating and harnessing the offshore wind resource and for meeting the challenges of installing large wind farms.
The next generation of wind farms in the 100 MW range consisting of multi-megawatt turbines provide new challenges. Hub-heights are beyond typical measuring heights, wakes within such large farms are not well-understood and the influence of upwind farms requires further research. The technology is less -proven than was the case for the first offshore demonstration projects. Larger distances to the coast and deeper water give harsher conditions for the turbines and supporting structures. Access for maintenance is more difficult, combined with the demand for better availability. However, the physical and environmental challenges are within the grasp of the offshore and wind energy industries. A greater challenge is posed by market uncertainty which has not been detailed in this report.
1
1
0
ES
3
2
1
3
2
1
0
SE
3
3
3
2
3
1
0
UK
3
2
3
3
3
1
0
Mean
2.4
2.1
2.3
2.4
2.3
1.4
1.8
1=low,2=medium,3=high, 0=no data
No data for Portugal.
|
Table 2: Offshore resources by country |
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|
|
Resource estimate |
Target installation |
Comments |
Reference |
||
|
|
MW |
TWh/y |
MW |
YEAR |
|
|
|
BE |
1200 |
4 |
200 |
2004 |
Two projects of 100 MW have been announced . |
http://www.electrabel.com |
|
DK |
8000 |
26 |
4000 |
2030 |
Additional 4000 MW water depth> 20 m Exploitable resource ~ 83-287 TWh/y |
(Krohn, 1998), (DEA/CADDET, 2000), (BWEA, ) |
|
FI |
6000 |
20 |
0 |
|
|
|
|
FR |
13000 |
44 |
0 |
|
EED studies indicate potential in four areas of 9125 MW or 30.1 TWh. |
(DEA/CADDET, 2000) |
|
D |
13000 |
45 |
0 |
|
|
(DEA/CADDET, 2000) |
|
GR |
1500 |
5 |
0 |
|
|
(DEA/CADDET, 2000) |
|
EI |
3300 |
11 |
|
|
Water depth< 20 m, Min distance 5km, 32% of nat. electricity |
|
|
I |
3000 |
10 |
1000 |
2030 |
|
(Gaudiosi, 1999), (DEA/CADDET, 2000) |
|
NL |
10000 |
33 |
1250 |
2020 |
~11% of national electricity consumption |
(Greenpeace, 2000) , (International Energy Agency, 2001) |
|
PL |
600 |
2-3 |
0 |
|
Technical potential is 11 PJ offshore wind energy. Two projects have consents and two more are pending. |
Baltic Energy Conservation Agency, EC Brec, Elektownie Wiatrowe S.A. |
|
PT |
0 |
0 |
0 |
|
|
|
|
ES |
2000 |
7 |
0 |
|
Two projects in planning, monitoring at one |
(International Energy Agency, 2001) , |
|
SE |
7000 |
22.5 |
650 |
2005 |
Many projects at planning stage |
(DEA/CADDET, 2000) , (Border Wind, 1998a) |
|
UK |
70000 |
230-334 |
2600 |
2010 |
Planned 2% of UK supply by 2010 |
(Border Wind, 1998a) |
|
Total |
138600* |
460*1 |
5500 |
|
|
|
*Resource supplied converted if necessary assuming 1000 MW ~ 3.3 TWh/y. (International Energy Agency, 2001) give 3530 'net full load hours' for North Sea sites and 3000 -3300 at interior water sites at Danish sites.
1 Note that this figures varies substantially depending on the constraints (physical, social, environmental) used for the estimate and does not include all countries. It therefore differs from the (DEA/CADDET, 2000) estimate taken from BTM Consult which is 327 TWh/ year or from estimates without constraints.
|
Table 3. Offshore wind energy exploitation plans by country |
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|
|
Plans |
References |
|
BE |
3% electricity from renewables. Offshore wind energy is not yet eligible for green certificates (under discussion). |
(Greenpeace, 2000) |
|
DK |
Government target set and plans for large scale developments in five areas mandated. |
(Energistyrelsen, 1997) , (Krohn, 1998) |
|
FI |
Plans to develop one wind farm |
|
|
FR |
Several plans discussed. |
|
|
D |
Target 5-6% electricity from renewables by 2010 and 50% by 2050, research project on on- and off-shore development. In spring 2001 a number of sites were announced. |
(Greenpeace, 2000) , (Schmidt, 2001) |
|
GR |
None publicly available |
|
|
EI |
Measurements underway |
|
|
I |
Discussion of 1000 MW target installation. Local feasibility studies. |
(Ragusa, 1998) |
|
NL |
Targets set of about 1250 MW for offshore wind. Several feasibility/environmental studies underway. Two wind farms developed in Ijsselmeer. Demonstration wind farm 100MW planned at Egmond an Zee. |
(Greenpeace, 2000) , (International Energy Agency, 2001) |
|
PL |
Two wind farms of ~100 MW have consent near Bialogra and near Karwia |
Baltic Energy Conservation Agency, EC Brec, Elektownie Wiatrowe S.A. |
|
PT |
None publicly available |
|
|
ES |
Some monitoring studies. |
|
|
SE |
No target set but construction of wind farms undertaken by private developers. |
|
|
UK |
Targets set. Measurements underway at 5 sites. One site developed. In April 2001 preliminary licences for 18 offshore sites were awarded. |
http://www.offshorewindfarms.co.uk/ |
|
Table 4: Status of offshore resource assessment: |
|
|
On site data |
Necessary because of project financing Resource has to be quantified with high degree of confidence |
|
Available data |
Typically useful for broad assessment (Ships, satellites etc) |
|
Models |
Useful tools, under development, still uncertainties |
|
Physical limits |
Maritime data (sea depth etc) - available for most countries Typically > 5 km from shore Water depth limit 20-30 m? North Sea: Large tidal range, water depth Baltic Sea: Ice and ice floes Mediterranean: Sea bed slope, water depth |
|
Planned activity |
Highly variable by country Targets set, plans in place: DK Targets set, feasibility studies: UK, NL, I No target set, monitoring underway ES, FI ,EI No target set, wind farms underway SE, FR Preliminary consents given: PL No plans publicly available: GR, PT |
|
Comparison with national consumption |
Not a major issue Varies from 2-40% Grid compatibility and penetration is more of a problem
|
|
National potential |
(Table 2) |