Page 91 - Fundamentals of Ocean Renewable Energy Generating Electricity From The Sea

84 Fundamentals of Ocean Renewable Energy

FIG. 4.1 Persian windmills (vertical axis turbines) at Nashtifan Village, constructed around the
9th century. (Reproduced from [2], with permission from Elsevier.)

Province. Recently, wind energy is a rapidly growing industry, and can compete
with fossil fuels at similar levelized costs of electricity. Fig. 4.2 shows the global
trend of wind power capacity since 2002. Wind energy, along with solar energy,
can be regarded as the fastest growing renewable energy sectors [3]. So far,
the majority of wind farms have been installed on land (over 90%), whilst the
offshore wind industry is also very popular in many countries such as the United
Kingdom and Germany.
In general, offshore wind farms are more expensive and challenging to build
compared with their onshore counterparts due to several factors: the foundation
and supporting structure of offshore wind turbines, grid connection, installation
of turbines, and the operation and maintenance of offshore wind projects are
all more expensive and complicated. However, due to lower surface roughness
(absence of building, mountains, trees), the wind energy resource is better
offshore. Further, the visual impact and noise of offshore wind projects are