ASSUMPTIONS ON GROWTH RATES
Market growth rates used in these scenarios are based on a mixture of historical figures, current policies and trends, new market development, discussions of future energy policy and other factors. While cumulative annual growth rates of more than 25% per year, as envisaged in the 'Advanced' scenario, are unusually high in most industries that manufacture heavy equipment, the wind industry has consistently experienced much higher growth. In fact, the global wind markets have grown by an average 28% per year in terms of total installed capacity during the last decade.
In the GWEO Advanced scenario, the average annual growth for cumulative installed capacity is assumed to start off at 27% in 2010, and then gradually decline to 9% by 2020. by 2030, they will have dropped to 4%. Growth rates as anticipated by the IEA in the Reference scenario start at 17% in 2010, drop to 3% by 2015, stabilising at that level. the growth rates for the Moderate scenario range from 26% in 2010 to 9% in 2020 and to 5% in 2030.
It should also be borne in mind that while growth rates eventually decline to single figures across the range of scenarios, the level of wind power capacity envisaged in 20-40 years' time means that even small percentage growth rates will by then translate into large figures in terms of annually installed megawatts, especially in the advanced and Moderate scenarios.
The IEA's Reference scenario suggests – contrary to the clear upwards trend we have witnessed in the past – that growth rates for wind power would decrease substantially in the coming years, and that 2010 would see an addition of only 26.8 GW, which would represent a decrease of the annual market by 30% in 2010 (compared to an increase of 41% in 2009). the annual market would then continue to shrink until 2015 and only recover to reach its 2009 levels again just before 2030. the cumulative wind power capacity according to this projection would stand at 415 GW in 2020 and 572 GW in 2030. For this to happen, annual additions would need to decline substantially, especially in China, although there is no indication of this happening at present. Overall, the Reference scenario seems disconnected from current developments, and curiously pessimistic.
Dhule wind farm, India
While the Reference scenario suggests that between 20 and 26 GW of new capacity will be added each year between 2010 and 2020, reaching 41 GW/year only in 2030, the Moderate scenario envisages the addition of 40.2 GW two decades earlier (in 2010), followed by 63 GW/year by 2015, close to 90 GW/year by 2020, and almost 150 GW/year by 2030. This translates into 100 GW more installations per year than the Reference scenario by 2030, even though the annual market growth rate would by then have dropped off to a modest 4% per year. In terms of total installed wind power capacity, 830 GW would be reached in 2020 (twice as much as under the reference scenario), and close to 1,800 GW by 2030 (more than three times as much).
In the Advanced scenario, the difference would be even more striking. Annual market growth rates here start at 27% for 2010, and then decrease to 17% by 2015, 9% by 2020 and finally 5% by 2030 – compared to an average cumulative market growth of 28% per year over the past decade. These growth rates would translate into annual markets of 120 GW by 2020, increasing and stabilising at around 185 GW by 2030. These projections would result in a total installed capacity of just over 1,000 GW by 2020 and 2,300 GW by 2030.