Prva stran - WBC-INCO Net

c€/kWh at windy coastal locations. The electricity purchase
price is crucial for WPP cost effectives.
Fig. 6. Calculated costs per kWh produced using wind power
IV. ENVIRONMENTAL CHARACTERISTICS OF WIND ENERGY
USE
As all power production facilities, wind turbines have
environmental impacts, which include noise, visual impacts,
atmospheric emissions during the materials processing and
components production, birds’ mortality and
electromagnetic interference [8].
Noise from wind turbines can be of mechanical and
aerodynamic origin. Aerodynamic noise is caused by
interaction of the turbine blades with the surrounding air.
Mechanical noise is due to the moving parts in the nacelle
and it is transmitted to the environment both directly
through the air and via the rest of the structure, including the
tower [9]. The noise problem is the most emphasized wind
turbine environmental impact. However, modern turbines
are seldom heard at distances further than 300 m as
background noise from wind in trees, for example, will be
higher.
The impact of wind turbines on visual amenity is the
most controversial and difficult to quantify. In general,
concern over visual impact is highest in areas of special
importance and beauty and it is clear that care should be
taken in the sitting and design of the turbines in other areas.
Techniques for assessing visual impacts exist and are used
within the planning process for wind power plants.
Although there are no direct emissions to the atmosphere
caused by wind turbine operation, emissions from nonoperational
phases of the life cycle do exist. It has been
shown that atmospheric emissions from the wind fuel cycle
are insignificant in comparison to those from fossil fuels [9].
The major potential impact of wind turbines on birds are
collision in flight with turbines and behavioral disturbance
from blade avoidance. Although numerous studies show that
birds rarely collide with rotor blades this is an issue
sometimes raised.
The electromagnetic signals may be reflected from the
turbine blades, so that a nearby receiver picks up both a
direct and reflected signal. Interference occurs because the
reflected signal is both delayed (due to difference in path
length) and Doppler shifted (due to the blade motion).
However these problems can be minimized by careful sitting
of a wind facility.
V. WIND ENERGY STATUS IN CROATIA
Renewable energy sources have already quite large share
in total energy production and total energy supply in
Croatia, which is a consequence of the large share of hydro
power. When it comes to electricity production, 51% of
installed capacities are in hydro power plants. Apart from
hydro power, there is very small share of other renewables
in electricity production, as shown in Table II. In 2004 the
share of RES excluding large hydro power plants was equal
to approximately 0,8% of total electricity consumed.
TABLE II
INSTALLED RES CAPACITIES AND ELECTRICITY PRODUCTION IN CROATIA IN
2004 [11]
Type of RES Installed power Electricity
capacity
production
Sun 12,74 kW 12,63 MWh
Wind 5,95 MW 1,96 GWh
Biomass 0 4 GWh
Small hydro 26,7 MW 126,3 GWh
Geothermal 0 0
TOTAL 32,663 MW 132,27 GWh
However, according to the Strategy of energy sector
development [12], renewables will gain more significant
role in Croatian energy supply and their increased use is one
of the most important strategic goals of Croatian energy
policy. The Strategy considers three different scenarios all
characterized by the increase of RES use from
approximately 75 PJ in year 2000 to 100 PJ (business-asusual
scenario), 130 PJ (moderate scenario) and 160 PJ
(distinctively ecological scenario) in year 2030.
Wind potential assessed within the national wind energy
program ENWIND in 29 locations equals to about 400 MW
and electricity production capacity equals to 800 GWh per
year [4]. These potentials can be exploited in Croatia in one
of the following ways:
On-grid installations (wind farms);
Off-grid installations (hybrid systems);
Water pumping, desalinization and irrigation
installations.
The most usually considered applications are central-grid
electricity generation facilities – wind farms. Currently there
is only one wind power plant in operation in Croatia – a
5,95 MW wind park at the island of Pag for which a power
purchase agreement has been signed by the investor and the
Croatian power utility. A similar agreement has been signed
for a wind power plant Krtolin near Šibenik which is yet to
be constructed with a planned capacity of 5 MW as well as a
wind power plant near Obrovac with a capacity of about 10
MW. The interest for wind potentials exploitation comes
mainly form foreign investors. However, one good example
can be found within Croatian industry. Namely, Končar
Group, the leading electric industry in Croatia, has a
strategic goal to wider their activities to wind power. Since
Končar already produces all necessary electric equipment
like generators and switchgear, they have decided also to
develop own wind turbine concept. It is expected that the
first wind turbine prototype will be erected by the end of
September 2006. In this way the completely domestic
product will be developed. These aspects of RES use –
creating new employment opportunities and strengthening
domestic industry – are extremely important and socially
beneficial, but still not emphasized strongly enough. The
significant work, especially measurements ad mapping of
wind potentials, has been done within ENWIND program.
The program has also suggested a pilot project of 6,3 MW
5