In May 2000 the European Commission unveiled proposals to increase the proportion of energy supply from renewable sources to 12 percent� (22 percent of electricity supply) by the year 2010 (Environment News Service, 2000). Offshore wind energy is expected to play a significant role in this expansion.
By the end of the year 2000, approximately 80 MW of offshore wind energy were installed and operating in Denmark, Holland and Sweden and the UK. Some Northern European countries have relatively detailed plans for offshore wind farm development and these are described. If all plans are realised, more than 11,000 MW of offshore wind capacity will be installed by the year 2030.
To provide a review of offshore resources and economics two data sources are used. The first is the country by country survey (given in the Appendix) which has been summarised in the Tables and Figures below. The second source are the myriad of reports on offshore wind energy which have appeared from local, national and international governmental and independent agencies.
Table 1 summarises the importance ascribed by each country to use of measurements or modelling to assess offshore wind resources. Clearly this is intended as an overview - the views expressed by the participants cannot be assumed to reflect governmental actions and policies. On the whole most important factors appear to be the physical constraints followed by onsite measurements and modelling with less importance given to comparison with national electricity consumption. This may reflect changes in the electricity market with individual countries wishing to exploit their available offshore wind resource whether it can provide a small or a large fraction of national consumption.
Table 2 gives an overview of resource assessment by country and the major criteria used in its development. Most studies are built on the first predictions of offshore wind energy resources from (Matthies and Garrad, 1993) which uses voluntary observer ship data compared with WAsP. Their estimate of available wind resource was 500 TWh in water depths of less than 10 m and less than 10 km from the coast increasing to over 3000 TWh if water depths up to 30 m were considered with distance to the coast of less than 40 km. (DEA/CADDET, 2000) estimate the total European resource in water depths of less than 40 m and with the distance to the coast of less than 30 km (excluding Norway, Finland and Sweden) accounting for major but not local constraints to more than 3000 TWh/year. This is greater than European electricity consumption of about 2700 TWh/year. Different constraints substantially alter the resource estimate as shown in (DEA/CADDET, 2000). (BWEA, 2000) suggest a European resource of about 1623 TWh/y at water depths of less than 20 m and distance to the coast of less than 20 km. (Greenpeace, 2000) estimate potential from the North Sea areas of Belgium, The Netherlands, Denmark, the UK and Germany as a maximum of 1900 TWh per year, almost twice the annual consumption of these five countries.
Individual countries also have useful reports and papers e.g. studies of offshore data sets or modelling of wind resources; for the Netherlands (Cleijne et al., 1991), (Van Wijk et al., 1990), (Coelingh et al., 1996) for Denmark (Barthelmie et al., 1999a), (Frandsen S. (editor) et al., 1996) and the UK (Moore, 1982), (White, 1983).
National exploitation plans are highly variable by country and are summarised in Table 3 below. Activities and plans range from none which are publicly known to full and detailed plans which are being implemented. Other countries are letting the market decide by allowing private developers to select sites and build offshore wind farms after negotiating individual planning and permit requirements.
The European Commission is supportive of both research and demonstration projects. Demonstration projects include a number of projects under the Thermie A program. These include the first and second phases of the Blyth Harbour and Blyth Offshore (UK) wind turbines and Bockstigen wind farm in Sweden. In addition, Thermie supported a semi-offshore (beach) development in Crete and the Scroby Sands wind farm in the UK. The status of the latter projects is not known. The European Commission has also supported research projects assessing resource and economics such as (Matthies and Garrad, 1993), Opti-OWECS (Kuhn et al., 1999), POWER (Halliday et al., 2001), Cost-optimisation (Svenson and Olsen, 1999), Vindeby (Frandsen S. (editor) et al., 1996) and ENDOW (Barthelmie et al., 2001).
Wind energy developers and manufacturers are optimistic about the offshore market. A company report on Vestas (Carnegie, 2000) predicts up to 7400 MW of offshore installations in the period 2000-06, 6% of the global market. These are based on Denmark 8.5%, Sweden 18%, Germany 31%, the Netherlands 15%, UK 11%, Ireland 7%, Belgium 4% and Norway 5%. Offshore wind energy is also supported by non-governmental organisations such as Greenpeace (Greenpeace, 2000), wind energy groups� (BWEA, 2000) and the Danish energy Agency and IEA CADDET Renewable energy Technologies Programme (DEA/CADDET, 2000).
Development of offshore wind energy has to date been focussed on Europe due to pressure for land and resources, relatively low water depth and good wind resources. However, studies have also been conducted in the USA (Manwell et al., 2001) and Japan (Nagai and Ushiyama, 2000). (Fioravanti, 1999) compared offshore wind energy with plutonium based power costs in Japan and concluded that offshore wind energy would be less expensive and faster to develop.
|
Table 1. Offshore wind resource: importance of various factors by country |
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|
Topic |
1.a Onsite Measure-ments |
1.b Available data |
1.c Model estimates |
1.d Physical limits |
1.e Planned activity |
1.f Electricity cons. |
1.g. National potential |
|
BE |
2 |
1 |
2 |
1 |
1 |
3 |
1 |
|
DK |
3 |
3 |
3 |
2 |
3 |
1 |
2 |
|
FI |
2 |
3 |
3 |
3 |
3 |
1 |
3 |
|
FR |
3 |
2 |
3 |
3 |
2 |
1 |
0 |
|
D |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
|
GR |
2 |
2 |
3 |
2 |
1 |
0 |
0 |
|
EI |
3 |
1 |
2 |
2 |
3 |
1 |
0 |
|
I |
1 |
1 |
1 |
3 |
3 |
2 |
1 |
|
NL |
3 |
3 |
2 |
3 |
3 |
2 |
0 |
|
P |
1 |
2 |
2 |
2 |
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 |
||
|
|
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 Bialog�ra 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) |