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

table 13.7: cORRelatiOn cOeFFicients
Base case direct design Split design
Base case Final design Δ Base case Final design Δ Base case
All wind / all hydro -0.29 -0.32 -0.03 -0.32 -0.03
All wind / all gas -0.05 -0.04 0.01 -0.05 0.01
All wind / all lignite coal -0.36 -0.30 0.06 -0.31 0.05
All wind / all hard coal -0.41 -0.39 0.02 -0.40 0.01
All wind / all “other
renewable”
-0.65 -0.64 0.01 -0.63 0.02
All wind / all nuclear 0.40 0.40 0.00 0.40 0.01
All wind / demand 0.29 0.28 -0.01 0.28 -0.01
Due to the price level changes and the immediate impact
on the benefits of already existing infrastructure
a large number of iterations had to be carried out in
order to indentify the most beneficial interconnectors.
Please note that the absolute price levels in the countries
might increase with further connections. Norway
e.g. exhibits very low price levels in the Hub Base
Case scenario 2030. If thus this low price electricity is
sold to other countries the internal price level rises as
higher priced generation capacity will have to be used.
Please note that Table 13.5 and Table 13.6 only show
price level differences and not absolute price levels.
These price levels decrease in general, but also here
increasing price level differences are possible.
D.III.V Power system impact
Balancing of wind power variability
The offshore grid leads to the spatial smoothing of
short term renewable energy variations and as such
reduces the needs for balancing power in the system
to a certain extent. This paragraph illustrates how the
balancing of variable wind power is affected by the offshore
grid, with a special focus on the hydro power in
Scandinavia.
A priori, there are two competing hypotheses:
• the offshore grid enables cheaper generation units
farther away from demand centres to momentarily
replace more expensive generation units independently
of Scandinavian hydro capability,
OffshoreGrid – Final Report
• the offshore grid improves the utilisation of
Scandinavian hydro capability. At low price periods,
Scandinavia will import cheaper power from the
surrounding areas, and at high price periods, will
export power. This makes more expensive generation
units in the surrounding areas unnecessary.
Although it was shown in section 4.5.6 that there is
an overall shift from hard coal and gas towards the
cheaper category “other renewables” it is not immediately
clear when in time this shift occurs. For example,
it could be a shift that is evident hour by hour (first
hypothesis), or a shift that occurs indirectly via hydro
balancing (second hypothesis).
Measuring the balancing of wind power can be done by
evaluating the correlation coefficients between wind
power production and other power production. A generation
type that balances wind power has a negative
correlation with wind power. This means that it produces
when there is low wind generation and it stops
production when wind power is generated. Table 13.7
shows correlation coefficients between total wind production
and total production of other generation types.
For the assessment of grid influence on wind power
balancing, the interesting information in Table 13.7 is
the change in correlation coefficients relative to the
base case.
Both the direct and split grid designs have an increased
anti-correlation between wind and hydro
compared to the base case. This is interpreted as an
increased balancing of wind by the hydro systems. For
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