IEEE Power & Energy Magazine - November/December 2021 - 113

in my view (continued from p. 116)
more than 750 km long will connect Denmark
to England in 2023. A 1,000-MW
ac connection to Germany is also under
construction. The Danish development is
summarized in Figure 1.
The share of electricity production
from solar and wind has increased
from approximately 10% of demand
in 2000 to about 50% in 2020. After
2030, the cross-border wind capacity
may expand even further with the
Danish political decision to establish
two energy islands, potentially connecting
more than 12 GW of offshore
wind with Denmark and neighboring
countries. The Danish case shows that
the transmission grid is an important
enabler of this efficient integration
of variable renewables. The electricity
market has played an important part in
assessing socioeconomic benefits and
passing the benefit on to consumers
and producers through the development
of electricity prices and tariffs.
Unbundling and
Liberalization
Expansion of the transmission grid can
be done without an electricity market,
which the Danish case also proves as
half of the existing cross-border capacity
was established before the Nordic
and European electricity market. Without
a market and the transparency of
mutual benefits, there is a risk that it
will take a longer time to identify the
most beneficial transmission grid expansions
and negotiate agreements to
reflect the mutual benefits.
The business case for the first transmission
grid connections between
Denmark and neighboring countries
was based on the possibility of exports
from Danish thermal power plants to
hydro-dominated Norway and Sweden.
Large seasonal differences in demand
and the benefit of low electricity prices
for Danish consumers from import during
seasons with excess hydroelectricity
made this beneficial. Operation was
handled via long-term contracts between
the integrated transmission and production
companies. Although the production
companies were bundled at the time, they
november/december 2021
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12
10
8
4
6
2
Thermal
Generation
Wind and
Solar Power
Cross Border
Transmission
Peak Demand
figure 1. Danish development of power generation, cross-border transmission
capacity, and peak demand.
exchanged electricity based on the differences
in marginal costs.
The unbundling of production and
transmission as laid down in European
regulation in 1998 and 2009 has been
decisive for third-party access to the grid
and equal requirements for connection to
the grid supporting efficient electricity
markets. It also underpins the acceleration
of investments in a socioeconomically
efficient transmission grid.
In combination with the development
of the European coordination of
long-term grid planning and through
a potential reduction of differences in
electricity prices, the electricity market
demonstrates the benefits of new crossborder
capacity compared to an expansion
of generation capacity. The unbundling
promoted higher transparency in
the decision whether or not to invest
in generation capacity or transmission
grid expansion. Similarly, the unbundling
also increased export opportunities
with overcapacity in electricity
generation including abundant renewable
energy resources. This is the case
for the new connection between Western
Denmark and Holland and the new
interconnector to the United Kingdom
and increased capacity to Germany.
Transmission of
Renewable Electricity
to Load Centers
Moving toward a climate-neutral energy
system, electrification will significantly
increase electricity demand,
which is expected to be compensated
by the large increase in variable renewable
generation. To connect and
deliver flexibility between production
and demand,
the electricity market
will be a crucial enabler for an efficient
expansion of transmission capacity
and reducing curtailment, location
of new demand, storage, and sectorcoupling
possibilities.
The Danish political objective is
100% green electricity by 2030 and a
climate-neutral energy system by 2050.
The solar and wind buildout changes the
role of the transmission grid from facilitating
seasonal exchanges of excess generation
capacity to enabling today's daily
and hourly flexibility to even more shortterm
capacity adequacy. With the development
and utilization of extensive
offshore wind resources, the transmission
grid must transport renewable electricity
over long distances to load centers
as well as support the interconnection
and energy exchange between countries.
The first example is the Danish development
of the 400-MW Kriegers
Flak combined grid solution that connects
three offshore wind parks to Denmark
and Germany. The next project is
the planning of the two energy islands
in the Danish Sea, starting with 2-3 GW
of offshore wind generation connected
to Denmark and other countries.
The green transition will increase the
focus on flexibility in the electricity
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113
Danish Capacity Development, GW
2000 2010
2020 2030 (est)
IEEE Power & Energy Magazine - November/December 2021

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