1.2 The renewables - what is the challenge? 11
demand, but there are still periods where the wind power is far from enough.
Denmark,1st-14thMay2015
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Figure 1.11: Energy demand, red line, and wind power production, in green, for a
two week period in January 2014, Denmark. In shaded blue, the doubled wind power
production is shown. Data from 30.
Integration of a signicant amount of renewables in the energy infrastructure
will put the electricity grid under a high degree of stress. The existing fossil
fuel power plants will have to accommodate for the uctuating sources, which
could lead to lower eciencies due to non-optimal operation. A way to mitigate
this is to dramatically increase the export and import options so that larger
regions can share the load. However, there is no guarantee that southern Europe
will import electricity every time northern Europe experience periods of
wind and vice versa. Smart grids are also expected to alleviate some of the
problems with uctuating power supply by turning electricity demanding utilities
into intelligent components of the grid. Essentially these utilities will follow
the electricity supply and spend energy when there is excess (cheap) electricity
and be on stand by when there is low (expensive) supply 31. However, for
the smart grids to make a signicant impact energy storage technologies must
be implemented. For example, the IEA expects energy storage technology capacity
to reach 8 % of the total power generation capacity in 2050, under their
ETP 2DS proposal 32. Among these technologies are: pumped hydropower,
ywheels, batteries, thermal storage, supercapacitors and hydrogen production
with electrolysis. Hydrogen production with electrolysis presents a promising
technology, where electricity is used to produce a chemical which can be stored