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 4^th 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
a The energy equivalent in TWh is calculated on the basis of the electricity generation potential of the referenced sources by dividing the electricity generation potential by a factor of 0.3 (a representative value for the efficiency of wind turbines including transmission losses) resulting in a primary energy estimate.

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).

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