Offshore Electricity Infrastructure in Europe - European Wind Energy ...

Annex d – details of results
D.I Wind output statistics
D.I.I Spatial smoothing of
wind power
There are several techno-economic benefits directly
linked to an offshore grid as outlined in the introduction.
One of these benefits is the additional
interconnection of wind energy generation centres
across Europe which smoothes the wind energy variability
towards a more steady generation profile. This
issue was already studied by the TradeWind study and
was further elaborated within OffshoreGrid as more
accurate wind power time series were available.
This smoothing effect is illustrated in Figure 13.1,
displaying the gradients for three different sizes of
regions in Denmark (a gradient is the percentage by
which power goes up or down in one hour, or % fluctuation
in an hour). It can clearly be seen that the
gradient, or fluctuation in wind power, is much less
when looking at a large region such as the whole of
Denmark, when compared to the gradient of just one
wind farm.
The effect is even more pronounced when aggregating
on a European level, as shown in Figure 13.2.
Whereas offshore EU wind power still exhibits hourly
gradients of 8% during a noticeable time per year, total
EU wind power (onshore plus offshore) hardly shows
hourly gradients in excess of 5%.
The smoothing effect on wind variability is clearly visible
in Figure 13.3 where it is clearly shown that the
wind power generation of the OffshoreGrid 2030 scenario
across a large area as EU27 (incl. Norway and
Switzerland) exhibits a significantly lower variability
compared to the wind power generated in e.g. Belgium
alone.
A way of representing the beneficial effect of aggregation
at power system scale is by plotting the load
duration curve of wind power plants. This is a graph
which shows how many hours the power plant is operating
above a certain power output. Examples for a
single wind turbine, a small country (Belgium) and the
whole of the EU are given in Figure 13.4. Aggregating
wind power flattens the load duration curve. A single
offshore turbine in this example produces rated
(100%) power for 1,500 hours and zero power during
FiGuRe 13.1: FRequency OF Relative pOweR chanGes in inteRvals OF One hOuR FOR a sinGle danish OFFshORe wind
FaRm, 25 danish OFFshORe wind FaRms expected in 2030 and all wind FaRms (On&OFFshORe) that aRe expected in
denmaRk in 2030. a pOsitive value ReFlects an incRease in pOweR and a neGative value a decRease
Occurence
(hours per year)
6,000
5,000
4,000
3,000
2,000
1,000
0
-20 -15 -10 -5 0 5 10 15 20
Total Danish wind power 25 Danish offshore wind parks 1 Danish offshore park
128 OffshoreGrid – Final Report