The Unbearable Lightness of Wind
The omens for wind power are very good, and there is cause to believe that the EU’s 2020
targets in this area will be exceeded. However, as capacity grows, it may be wind’s impact
on electricity prices that presents the most immediate problem. Wind’s intermittency
cannot be wished away, even if it can be ameliorated, and the development of the
infrastructure needed to deal with it is lagging behind the installation of wind power itself.
By Ross McCracken
T
here are few renewable energy policies that do not Wind would appear to tick all the right boxes in terms of
depend heavily on wind power and wind is certainly at energy, environmental and industrial policy, suggesting, as
the heart of the most ambitious, the EU’s binding target some non-governmental pressure groups do, that the EU’s
of sourcing 20% of final energy consumption from renewable targets for wind are in fact not that ambitious and could well
resources by 2020. As the EU’s target for transport is half that be exceeded.
for energy consumption as a whole, it follows that the power
sector will be required to source a proportion of energy from The Desirability of Wind
renewables that is much higher than 20%. According to the Justbecauseyoucan,doesn’tmeanyoushould.Windpower
European Wind Energy Association (EWEA) the figure is 35%. has its critics and they feel that their reservations have been
Within that, wind will be the largest contributor, accounting overridden by policy makers whose imaginations have been
for just over one-third of ‘green’ electricity, suggesting that capturedbyagreenagendathatdownplayswind'slimitations.
between11.6-14.3%oftheEU’spowerwillbesuppliedbywind Wind’s intermittency cannot be ignored just because it is the
by 2020, according to the EWEA. most readily available and domestically attractive technology
This would mean the installation of 180 GW of wind power to hand, they argue. Any electricity system needs a mix of
by 2020, up from 56.535 GW installed in the EU-27 at end- baseload generation power –– which tends to be relatively
2007, producing about 477 TWh of power. (Figure 1). The inflexible in terms of switching on and off – and peaking
transport element of the EU plan is also dependent on future plants, which are more flexible and, as their name suggests,
scientific advances, for example, that second generation designedtotakeadvantageofhighelectricitypricesattimesof
biofuels become commercially available. This uncertainty will peak demand. Wind falls into neither of these categories
put more pressure to achieve in areas that are already within because it is essentially unreliable.
technological reach. Proponents of wind power dislike the negative connotations
of the word ‘unreliable’, pointing out that on average the
... wind additions in Europe accounted
amountofpowersuppliedbyagivencapacityofwindturbines
is reasonably predictable. But, according to the EWEA, wind
for more new generation capacity
turbines produce no electricity at all between 15% and 30% of
than any other power source the time. On average, the load factor for onshore turbines is
about 30%. This means that over 24 hours, 1 MW of wind
But if these targets seem ambitious, it is also evident that capacity would provide about 7.2 MWh of power – but there’s
wind capacity is being installed at much higher rates than no knowing exactly how much or when until the last minute.
previously forecast by bodies such as the International Energy As wind provides neither baseload nor peaking plant it has no
Agency. According to Stefan Gsänger, Secretary General of the impactonreservecapacity.Therewillalwaysbethepossibility
World Wind Energy Association, worldwide capacity had risen that, at some point, no power will be produced at all.
toabout120,000GWbyend-2008,anincreaseof30%on2007. This threat falls as more wind capacity is added; some
Accordingto Platts Power in Europe,windadditionsinEuropefor analyses suggest 26 GW of back-up is needed for 100 GW of
the first time in 2008 accounted for more new generation wind, others that back-up needs range from 60-95%,
capacity than any other power source, including gas. A study depending on the make-up and size of the system. But wind’s
carried out by the Deutsches Windenergie-Institut in 2008 intermittency ultimately means that a system reserve must
estimated that the annual worldwide installation capacity of remain in place. The system must be set up to accommodate
the industry would have risen above 100 GW by 2017. wind, but also to work as if it did not exist.
Experience in Europe shows that with the right policy
framework, wind capacity can rise fast. While the ‘binding’ Wind Surges
natureoftheEU’stargetsmeanslittleinpractice,itisaserious If wind turbines add little or no reserve capacity, they do
statement of intent. Renewable energy also promises new jobs, produce power. The impact they have depends on a range of
making it an attractive sector for policy makers on a counter- factors, including when the power is produced, the ability of
recessionary spending spree. the system to add and withdraw non-wind capacity and how
146 worldPower2009
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