Green Economy in a Blue World-Full Report

Looking further offshore and in deeper waters

Average distance from shore in kilometres

20

40

60

80

100

120

140

0

20

40

60

in a Blue World

80

Offshore wind farms: Installed between 1991 and 2007

100

Installed and planned between 2008 and 2014 Planned for Germany between 2015 and 2026

120

Planned for the United Kingdom between 2015 and 2026 Planned for other European countries between 2015 and 2026

Source: Frauenhofer Institute for Wind Energy and Energy Systems, 2011.

140

Average water depth in metres

generated by wind power are almost constant over the lifetime of the turbine, following its installation. Hence, even if wind power might currently be more expensive per KWh, it is economically advantageous in the long run, since it hedges against an unexpected rise or fall in prices of fossil fuels, thereby providing more certainty to investors (Awerbuch, 2003). A few of the main parameters governing the economics of offshore wind farm are: weather and wave conditions; water depth; type of foundation used; distance from the coast; investment costs, such as auxiliary costs for foundation and grid connection; operation and maintenance costs; electricity production against average wind speed; turbine lifetime; and the discount rate of the initial investment. The initial setup costs for offshore wind are more than 50 per cent higher than onshore wind (EWEA, 2009). The higher offshore costs are due to associated high initial investments for larger

structures and the complex logistics of installing the towers. For instance, in Europe, the expected average investment costs for a new offshore wind farm are in the range of 2.5-US$2.7 million (2005 ec) per MW. However, these higher costs are compensated by a higher total electricity production due to higher offshore wind speeds. For example, an onshore installation normally has around 2 000-2 300 full-load hours per year, while for a typical offshore installation this figure reaches more than 3 000 full-load hours per year (EWEA, 2009). The high capital cost of offshore foundations bounds offshore wind energy to near shore locations. Most of the capacity has been installed in relatively shallow waters (under 20 m deep) no more than 20 km from the coast in order to minimize the extra costs of foundations and sea cables (EWEA, 2009). Most of the recently added capacity is installed in water depths of up 40 metres, as far as 60 kilometres off the coast, as shown in the figure to the left.

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