3.8.4.3.3 Wind Power
Wind power supplies around 0.1% of total global electricity but, because of
its intermittent nature and relatively recent emergence, accounts for around
0.3% of the global installed generation capacity. This has increased by an average
of 25% annually over the past decade reaching 13,000MW by 2000, with estimates
of this increasing to over 30,000MW capacity operating by 2005 (EWEA, 1999).
The cost of wind turbines continues to fall as more new capacity is installed.
The trend follows the classic learning curve and further reductions are projected
(Goldemberg, 2000). In high wind areas, wind power is competitive with other
forms of electricity generation.
The global theoretical wind potential is on the order of 480,000TWh/yr, assuming
that about 3¥107 km2 (27%) of the earth’s land
surface is exposed to a mean annual wind speed higher than 5.1 m/s at 10 metres
above ground (WEC, 1994). Assuming that for practical reasons just 4% of that
land area could be used (derived from detailed studies of the potential of wind
power in the Netherlands and the USA), wind power production is estimated at
some 20,000 TWh/yr, which is 2.5 times lower than the assessment of Grubb and
Meyer (1993) (see Table 3.32). The Global Wind Energy
Initiative, presented by the wind energy industry at the 4th Conference
of Parties meeting in Buenos Aires (BTM Consult, 1998), demonstrated that a
total installed capacity of 844GW by 2010, including offshore installations,
would be feasible. A report by Greenpeace and the European Wind Energy Association
estimated 1,200GW could be installed by 2020 providing almost 3,000TWh/yr or
10% of the global power demand assumed at that time (Greenpeace, 1999).
Table 3.32: Assessment of world wind
energy potential on land sites with mean annual wind speeds greater than
5.1m/s
(Grubb and Meyer, 1993) |
 |
| Region |
Percent of land area
|
Population density
|
Gross electric potential
|
Wind energy potential
|
Estimated second order potential
|
Assessed wind energy potential
|
| |
%
|
capita/km2
|
TWh x103/yr
|
EJ/yra
|
TWh x103/yr
|
EJ/yra
|
| |
| Africa |
24
|
20
|
106
|
1,272
|
10.6
|
127
|
| Australia |
17
|
2
|
30
|
360
|
3.0
|
36
|
| North America |
35
|
15
|
139
|
1,670
|
14.0
|
168
|
| Latin America |
18
|
15
|
54
|
648
|
5.4
|
65
|
| Western Europe |
42
|
102
|
31
|
377
|
4.8
|
58
|
| EITs |
29
|
13
|
106
|
1,272
|
10.6
|
127
|
| Asia |
9
|
100
|
32
|
384
|
4.9
|
59
|
| World |
23
|
-
|
498
|
5,976
|
53.0
|
636
|
| |
| |
Many of the turbines needed to meet future demand will be sited offshore, exceed
2MW maximum output, and have lower operating and maintenance costs, increased
reliability, and a greater content of local manufacture. Shallow seas and planning
consents may be a constraint.
Various government-enabling initiatives have resulted in the main uptake of
wind power to date occurring in Germany, Denmark, the USA, Spain, India, the
UK and the Netherlands. Typically turbines in the 250 – 750kW range are
being installed (Gipe, 1998). Significant markets are now emerging in China,
Canada, South America, and Australia.
Denmark aims to provide 40%-50% of its national electricity generation from
wind power by 2030 and remains the main exporter of turbine technology (Krohn,
1997; Flavin and Dunn, 1997). China and India, based on recent wind survey programmes,
have a high technical wind potential of 250–260GW and 20–35GW respectively,
and are major turbine importers (Wang, 1998; MNES, 1998). However, following
various government incentives, both China and India now manufacture their own
turbines with export orders in place (Wang, 1998; AWEA, 1998).
Wind power continues to become more competitive, and commercial development
is feasible without subsidies or any form of government incentives at good sites.
In 1999, for example, a privately owned 32MW wind farm constructed in New Zealand
on a site with mean annual wind speed of greater than 10m/s was competing at
below US$0.03/kWh in the wholesale electricity market (Walker et al., 1998).
The rapidly falling price of wind power is evidenced by the drop in average
prices (adjusted for short contract lengths). Over successive rounds of the
British NFFO (non-fossil-fuel obligation), average tendered kWh prices declined
from 7.95p in 1990 to 2.85p (US$0.043/kWh) in 1999 (Mitchell, 1998; UK DTI,
1999). These confirm the estimate of Krohn (1997) that wind generated electricity
costs from projects >10MW would decline to US$0.04/kWh on good sites. The
global average price is expected to drop further to US$0.027–0.031/kWh
by around 2020 as a result of economies of scale from mass production and improved
turbine designs (BTM consult, 1999). EPRI/DOE (1997) predicted the installed
costs will fall from US$1,000 to US$635/kW (with uncertainty of +10% -20%),
and operating costs will fall from 0.01c/kWh to 0.005c/kWh. However, on poorer
sites of around 5m/s mean annual wind speed, the generating costs would remain
high at around US$0.10-0.12/kWh (8% discount rate).
Since wind power is intermittent the total costs will be higher if back-up
capacity has to be provided. In large integrated systems it has been estimated
that wind could provide up to 20% of generating capacity without incurring significant
penalty. In systems that have large amounts of stored hydropower available,
such as in Scandinavia, the contribution could be higher. The Denham wind (690kW)/diesel(1.7MW)
system in Western Australia uses a flywheel storage system and new power station
controller software to displace around 70% of the diesel used in the mini-grid
by wind (Eiszele, 2000).
