AckermannTh. (ed) Wind Power in Power Systems
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Nevertheless, owing to special government support schemes in certain countries (e.g.
in Denmark) further development in the field of wind energy utilisation took place. The
single most important scheme was the Public Utility Regulatory Policies Act (PURPA),
passed by the US Congress in November 1978. With this Act, President Carter and the
US Congress aimed at an increase of domestic energy conservation and efficiency, and
thereby at decreasing the nation’s dependence on forei gn oil. PURPA, combined with
special tax credits for renewable energy systems, led to the first wind energy boom in
history. Along the mountain passes east of San Francisco and northeast of Los Angeles,
huge wind farms were installed. The first of these wind farms consisted mainly of 50 kW
wind turbines. Over the years, the typical wind turbine size increased to about 200 kW at
the end of the 1980s. Most wind turbines were imported from Denmark, where com-
panies had developed further Poul LaCour’s and Johannes Juul’s design philosophy of
upwind wind turbines with stall regulation. At the end of the 1980s, about 15 000 wind
turbines with a capacity of almost 1500 MW where installed in California (see also
Chapter 12).
At this time, the financial support for wind energy slowed down in the USA but
picked up in Europe and later in India. In the 1990s, the European support scheme was
based mainly on fixed feed-in tariffs for renewable power generation. The Indian
approach was mainly based on tax deduction for wind energy investments. These
support schemes led to a fast increase in wind turbine installations in some European
countries, particularly in Germany, as well as in India.
Parallel to the growing market size, technology developed further. By the end of the
twentieth century, 20 years after the unsuccessful worldwide testing of megawatt wind
turbines, the 1.5 to 2 MW wind turbines had become the technical state of the art.
2.3 Current Status of Wind Power Worldwide
The following section will provide a brief overview of the wind energy status around the
world at the end of the twentieth century. Furthermore, it will present major wind
energy support schemes. The overview is divided into grid-connected wind power
generation and stand-alone systems.
2.3.1 Overview of grid-connected wind power generation
Wind energy was the fastest growing energy technology in the 1990s, in terms of percent-
age of yearly growth of installed capacity per technology source. The growth of wind
energy, however, has not been evenly distributed around the world (see Table 2.4). By the
end of 2003, around 74 % of the worldwide wind energy capacity was installed in Europe,
a further 18 % in North America and 8 % in Asia and the Pacific.
2.3.2 Europe
Between the end of 1995 and the end of 2003, around 76 % of all new grid-connected
wind turbines worldwide were installed in Europe (see Tables 2.4 and 2.5). The countries
with the largest installed wind power capacity in Europe are Germany, Denmark and
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Table 2.4 Operational wind power capacity worldwide
Region Installed capacity (MW) by end of year
1995 1997 1999 2000 2001 2002 2003
Europe 2518 4766 9307 12972 17500 21319 28706
North America 1676 1611 2619 2695 4245 4708 6677
South and Central America 11 38 87 103 135 137 139
Asia and Pacific 626 1149 1403 1795 2330 2606 3034
Middle East and Africa 13 24 39 141 147 149 150
Sources: Wind Power Monthly; European Wind Energy Association.
Table 2.5 Operational wind power capacity in Europe
Country Installed capacity (MW) at end of year
1995 2003
Germany 1136 14609
Denmark 619 3110
Spain 145 6202
Netherlands 236 912
UK 200 649
Sweden 67 399
Italy 25 904
Greece 28 375
Ireland 7 186
Portugal 13 299
Austria 3 415
Finland 7 51
France 7 239
Norway 4 101
Luxembourg 0 22
Belgium 0 68
Turkey 0 19
Czech Republic 7 10
Poland 1 57
Russia 5 7
Ukraine 1 57
Switzerland 0 5
Latvia 0 24
Hungary 0 3
Estonia 0 3
Cyprus 0 2
Slovakia 0 3
Romania 0 1
Total 2518 28706
Sources: Wind Power Monthly; European Wind Energy Association.
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Spain. For a map of the wind power installations in Germany see also Plate 1; for a
similar map for Denmark see Plate 2.
In these countries, the main driver of wind power development has been the so-called
fixed feed-in tariffs for wind power. Such feed- in tariffs are defined by the governments
as the power purchase price that local distribution or transmission companies have to
pay for local renewable power generation that is fed into the network. Fixed feed-in
tariffs reduce the financial risk for wind power investors as the power purchase price is
basically fixed over at least 10 to 15 years.
In Germany, for instance, the Renewable Energy Sources Act (EEG) defines the
purchase price (feed-in tariffs) for wi nd en ergy installation in 2004 as follows: 8.8
eurocents per kWh for the first five years and 5.9 eurocents per kWh for the following
years. The German government currently works at changing the EEG and the power
purchase price. The aim is to introduce incentives for offshore wind power development
through higher power purchase prices. At the same time, onshore wind power is
expected to be forced to become more competitive by decreasing power purchase prices
over the next years. It is also important to mention that the EEG and similar laws in
other countries require ne twork companie s to connect wind turbi nes or wind farms
whenever technically feasible.
More and more European countries (e.g. England, the Netherlands and Sweden) are
switching to an approach that is known as ‘fixed quotas combined with green certificate
trading’. This approach means that the government introduces fixed quotas for utilities
regarding the amount of renewable energy per year the utilities have to sell via their
networks. At the same time, producers of renewable energy receive a certificate for a
certain amount of energy fed into the grid. The utilities have to buy these certificates to
show that they have fulfilled their obligation.
Table 2.6 presents the average size of wind turbines installed in Germany for each
year between 1988 and 2003. It shows that the average size per newly installed wind
turbine increased from 67 kW in 1988 to approximately 1650 kW in 2003. That means
that in 2003 the typical wi nd turbine capacity was app roximately 25 times higher than
16 years earlier. Such a development is almost comparable to that of information
technology. Heavy machinery industry, however, has never experienced such a rapid
development. In other European countries, the introduction of multimegawatt turbines
progressed at a slower pace because of the infrastructure required for the road transport
and the building equipment (e.g. cranes). By 2003, however, multimegawatt wind
turbines dominated the market almost all over Europe.
Finally, it must be mentioned that the first offshore projects have materialised in
Europe (see Chapter 22 for more details).
2.3.3 North America
After the wind power boom in California during the mid-1980s, development slowed
down significantly in North America. In the middle of the 1990s the dismantling of old
wind farms sometimes exceeded the installations of new wind turbines, which led to a
reduction in installed capacity.
In 1998 a second boom started in the USA. This time, wind project developers rushed
to install projects before the federal Production Tax Credit (PTC) expired on 30 June
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1999. The PTC added $0.016–$0.017 per kWh to wind power projects for the first 10 years
of a wind plant’s life. Between the middle of 1998 and 30 June 1999, more than 800 MW of
new wind power generation were installed in the USA. That includes between 120 and
250 MW of ‘repowering’ development at several Californian wind farms. A similar devel-
opment took place before the end of 2001, which added 1600 MW between mid-2001 and
December 2001 as well as at the end of 2003, with an additional 1600 MW (see also Table
2.7). Early in 2004 the PTC was again on hold and wind power development in the USA
slowed down. However, in September 2004 the PTC was renewed until the end of 2006.
In addition to California and Texas, there are major projects in the states of Iowa,
Minnesota, Oregon, Washington, Wyoming and Kansas (see also Table 2.8). The first
large-scale wind farms have also been install ed in Canada.
Table 2.6 Average size of yearly new
installed wind capacity in Germany
Year Average size (kW)
1988 66.9
1989 143.4
1990 164.3
1991 168.8
1992 178.6
1993 255.8
1994 370.6
1995 472.2
1996 530.5
1997 628.9
1998 785.6
1999 935.5
2000 1114
2001 1278
2002 1394
2003 1650
Source: German Wind Energy Institute.
Table 2.7 Operational wind power capacity in
North America
Country Installed capacity (MW)
by end of year
1995 2003
USA 1655 6350
Canada 21 327
Total 1676 6677
Sources: American Wind Power Association;
Wind Power Monthly.
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The typical wind turbine size installed in North America at the end of the 1990s was
between 500 and 1000 kW. In 1999, the fir st megawatt turbines were erected and, since
2001, many projects have used megawatt turbines. In comparison with Europe, how-
ever, the overall size of the wind farms is usually larger. In North America, typically,
wind farms are larger than 50 MW, with some projects of up to 200 MW. In Europe,
projects are usually in the range of 20 to 50 MW. The reason is the high population
density in Central Eur ope and consequently the limited space. These limitations led to
offshore developments in Europe. In North America, offshore projects are not a major
topic.
In several states of the USA, the major driving force for further wind energy devel-
opments is the extension of the PTC as well as fixed quotas combined with green
certificate trading, known in the USA as the Renewable Portfolio Standard (RPS).
The certificates are called Renewable Energy Credits (RECs). Other drivers include
Table 2.8 Operational wind power capacity in
the USA at end of 2003
State Installed capacity (MW)
California 2042
Texas 1293
Minnesota 562
Iowa 471
Wyoming 284
Oregon 259
Washington 243
Colorado 223
New Mexico 206
Pennsylvania 129
Oklahoma 176
Kansas 113
North Dakota 66
West Virginia 66
Wisconsin 53
Illinois 50
New York 49
South Dakota 44
Hawaii 18
Nebraska 14
Vermont 6
Ohio 2
Tennessee 2
Alaska 1
Massachusetts 1
Michigan 1
Total 6350
Source: American Wind Energy Association.
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financial incentives [e.g. offered by the California Energy Commission (CEC)] as well as
green pricing programmes. Green pricing is a marketing programme offered by utilities
to provide choices for electricity customers to purchase power from environmentally
preferred sources. Customers thereby agree to pay higher tariffs for ‘green electricity’
and the utilities guarantee to produce the corresponding amount of electricity by using
‘green energy sources’ (e.g. wind energy).
2.3.4 South and Central America
Despite large wind energy resources in many regions of South and Central America, the
development of wind energy has been very slow (Table 2.9) because of the lack of a
sufficient wind energy policy as well as low electricity prices. Many wind projects in
South America have been financially supported by international aid programmes.
Argentina, however, introduced a new policy at the end of 1998 that offers financ ial
support to wind energy generation, but with little success. In Brazil, some regional
governments and utilities have started to offer higher feed-in tari ffs for wind power. The
typical size of existing wind turbines is around 300 kW. Larger wind turbines are
difficult to install because of infrastructural limitations for larger equipment
(e.g. cranes). Offshore wind projects are not planned, but further small to medium-size
(100 MW) projects are under development onshore, particularly in Brazil.
2.3.5 Asia and Pacific
India achieved an impressive growth in wind turbine installation in the middle of the
1990s, the ‘Indian Boom’. In 1992/93, the Indian government started to offer special
incentives for renewable energy investments (e.g. a minimum purchase rate was guar-
anteed, and a 100 % tax depreciation was allowed in the first year of the project).
Furthermore, a ‘power banking’ system was introduced that allows electricity producers
to ‘bank’ their power with the utility and avoid being cut off during times of load
shedding. Power can be banked for up to one year. In addition, some Indian States have
Table 2.9 Operational wind power capacity
in South and Central America at end of 2003
Country Installed capacity (MW)
Costa Rica 71
Argentina 26
Brazil 22
Caribbean 13
Mexico 5
Chile 2
Total 139
Source: Wind Power Monthly.
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introduced further incentives (e.g. investmen t subsidies). This policy led to a fast devel-
opment of new installations between 1993 and 1997. Then the development slowed
down as a result of uncertainties regarding the future of the incentives but picked up
again in the new millennium after a more stable policy towards wind power was
provided (for some aspects of wind power in India, see Chapter 15).
The wind energy development in China is predominately driven by international aid
programmes, despit e some government programmes to promote wind energy (e.g. the
‘Ride-the-Wind’ programme of the State Planning Commission). In Japan, the devel-
opment has been dominated by demonstration projects testing different wind turbine
technologies. At the end of the 1990s the first commercial wind energy projects started
operation on the islands of Hokkaido as well as Okinawa. Interest in wind power is
constantly growing in Japan. Also, at the end of the 1990s, the first wind energy projects
materialised in New Zealand and Australia. The main driver for wind energy develop-
ment in Australia is a green certification scheme.
In China and India, the typical wind turbine size is around 300–600 kW; however,
some megawatt turbines have also been installed. In Australia, Japan and New Zealand,
the 1–1.5 MW range is predominantly used (for installed capacity in countries in Asia
and the Pacific, see Table 2.10).
2.3.6 Middle East and Africa
Wind energy development in Africa is very slow (see also Table 2.11). Most projects
require financial support from international aid organisations, as there is only limited
regional support. Projects are planned in Egypt, where the government agency for the
New and Renewable Energy Authority (NREA) would like to build a 600 MW project
near the city of Zafarana. Further projects are planned in Morocco as well as in Jordan
(25 MW). The typical wind turbine size used in this region is around 300 kW, but there
are plans to use 500–600 kW turbines in future projects.
Table 2.10 Operational wind power capacity
in Asia and Pacific at end of 2003
Country Installed capacity (MW)
India 1900
China 468
Japan 401
Australia 196
New Zealand 50
South Korea 8
Taiwan 8
Sri Lanka 3
Total 3034
Source: Wind Power Monthly.
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2.3.7 Overview of stand-alone generation
Stand-alone systems are generally used to power remote houses or remote technical
applications (e.g. for telecommunication systems). The wind turbines used for these
purposes can vary from between a few watts and 50 kW. For village or rural electrifica-
tion systems of up to 300 kW, wind turbines are used in combination with a diesel
generator and sometimes a battery system. For more details about the current status of
stand-alone systems, see Chapter 14.
2.3.8 Wind power economics
Over the past 10 years, the cost of manufacturing wind turbines has declined by about
20 % each time the number of manufactured wind turbines has doubled. Currently, the
production of large-scale, grid-connected wind turbines doubles almost every three
years. Similar cost reductions have been reported for photovolt aic solar and biomass
systems, even though these technologies have slightly different doubling cycles.
A similar cost reduction was achieved during the first years of oil exploitation about
100 years ago, but the cost reduction for electricity production between 1926 and
1970 in the USA, mainly from economies of scale, was higher. For this period, an
average cost reduction of 25 % for every doubling of production has been reported
(Shell, 1994).
The Danish Energy Agency (1996) predicts that a further cost reduction of 50 % can
be achieved until 2020, and the EU Commission estimates in its White Book that energy
costs from wind power will be reduced by at least 30 % between 1998 and 2010.
(1)
Other
authors emphasise, though, that the potential for further cost reduction is not unlimited
and is very difficult to estimate (Gipe, 1995).
A general comparison of electricity production costs is very difficult as production
costs vary significantly between countries, because of the differing availability of
Table 2.11 Operational wind power capacity
in Middle East and Africa at end of 2003
Country or Region Installed capacity (MW)
Egypt 69
Morocco 54
Iran 11
Israel 8
Jordan 2
Rest of Africa 3
Total 150
Source: Wind Power Monthly.
(1)
The White Book is available at http://europa.eu.int/comm/off/white/index_en.htm.
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resources, diff erent tax structures and other reasons. In particular, the impact of wind
speed on the economics of wind power must be stressed: a 10 % increase in wind speed,
achieved at a better location for example, will in principal result in 30 % higher energy
production at a wind farm (see also Chapter 3).
The competitive bidding processes for renewable power generation in England
and Wales [The Non-Fossil Fuel Obligation (NFFO)] in the 1990s, however, provide a
good comparison of power production prices for wind power and other generation
technologies. The NFFO was based on a bidding process that invited potential project
developers of renewable energy projects to bid for buildi ng new projects. The developers
bid under different technology brands (e.g. wind or solar) for a feed-in tariff or for an
amount of financial incentives to be paid for each kilowatt-hour fed into the grid by
renewable energy systems. The best bidder(s) were awarded their bid feed-in tariff for
a predefined period.
Owing to changes in regulations, only the price development of the last three bidding
processes can be compared. They are summarised in Table 2.12. It shows that wind
energy bidding prices decreased significantly; for example, between 1997 (NFFO4) and
1998 (NFFO5), the average de crease was 22 %. Surprisingly, the average price of all
renewables for NFF05 is 2.71 British pence per kWh, with some projects as low as 2.34
pence per kWh, with the average power purchase price (PPP) on the England and Wales
spot market, based on coal, gas and nuclear power generation, was 2.455 pence per kWh
between April 1998 and April 1999.
The question arises, why would a project developer accept a lower-priced contract
from NFFO if he or she could also sell the energy for a higher price via the spot
market? The reason probably is that NFFO offered a 15-year fixed contract, which
means a reduced financial risk, and additional costs for trading via the spot market
make the trade of a small amount of energy unfeasible. Furthermore, as project
developers have a period of five years to commission their plants, some developers
have used cost predictions for their future projects based on large cost reductions
during the following five years. In summary, wind power can be competitive in some
countries, depending on the available wind speed, the prices of competing energy
resources and the tax system.
Table 2.12 Successful bidding prices in British pence per kilowatt-hour
NFFO3 (1994) NFFO4 (1997) NFFO5 (1998)
Large wind 3.98–5.99 3.11–4.95 2.43–3.14
Small wind — — 3.40–4.60
Hydro 4.25–4.85 3.80–4.40 3.85–4.35
Landfill gas 3.29–4.00 2.80–3.20 2.59–2.85
Waste system 3.48–4.00 2.66–2.80 2.34–2.42
Biomass 4.90–5.62 5.49–5.79 —
Source: Office of Electricity Regulation, 1998 — There was no bidding within
NFFO3 and NFFO4 for small wind projects.
Note: 1 ecu ¼1 euro ¼1.15 US dollar ¼0.7 pounds sterling, as at January
1999; NFFO ¼ Non-Fossil Fuel Obligation.
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2.3.9 Environmental issues
Wind energy can be regarded as environmentally friendly; however, it is not emission-
free. The production of the blades, the nacelle, the tower and so on, the exploration of
the material and the transport of equipment leads to the consumption of energy
resources. This means that emissions are produced as long as these energy resources
are based on fossil fuel. Such emissions are known as indir ect emissions. Table 2.13
provides an overview of the most important emissions related to electricity production
based on different power generation technologies. The data comprise direct emissions
and indirect emissions. The calculation is based on the average German energy mix and
on typical German technology efficiency.
In addition, the noise and the visual impact of wind turbines are important consider-
ations for public acceptance of wind energy technology, particularly if the wind turbines
are located close to populated areas. The noise impact can be reduced through technical
means (e.g. through use of variable speed or reduced rotational speed). The noise impact
as well as the visual impact can also be reduced with an appropriate siting of wind
turbines in the landscape (helpful guidelines as well as important examples for the
appropriate siting of wind turbines can be found in Nielsen, 1996; in Pasqualetti, Gipe
and Righter, 2002; Stanton, 1996).
Table 2.13 Comparison of energy amortisation time and emissions of various energy technologies
Technology Energy payback
time in month
Emissions per GWh
SO
2
(kg) NO
x
(kg) CO
2
(t) CO
2
and CO
2
equivalent for
methane (t)
Coal-fired (pit) 1.0–1.1 630–1370 630–1560 830–920 1240
Nuclear — — — — 28–54
Gas (CCGT) 0.4 45–140 650–810 370–420 450
Hydro:
large 5–6 18–21 34–40 7–8 5
mico 9–11 38–46 71–86 16–20 —
small 8–9 24–29 46–56 10–12 2
Windturbine:
4.5 m/s 6–20 18–32 26–43 19–34 —
5.5 m/s 4–13 13–20 18–27 13–22 —
6.5 m/s 2–8 10–16 14–22 10–17 11
Note: All figures include direct and indirect emissions based on the average German energy mix,
technology efficiency and lifetime. The last column also includes methane emissions, based on
CO
2
equivalent. — Data not available in the source studies.
Sources:PaybacktimeandSO
2
,NO
x
and CO
2
emissions: Kaltschmitt, Stelzer and Wieser,
1996. CO
2
and CO
2
equivalent for methane, Fritsch, Rausch and Simon, 1989; Lewin, 1993.
For a summary of all studies in this field, see AWEA, 1992; for a similar Danish study, see
Schleisner, 2000.
20 Historical Development and Current Status