IEEE Power & Energy Magazine - November/December 2021 - 106

Bare Field
Plants
Following the revision
of the Heat Supply Act,
the nationwide district
heating networks were
extended with the popularly
labeled " bare
field " plants. Typically,
bare field plants were
natural gas-fueled and
decentralized CHP plants
serving smaller towns
or villages. Heat distribution networks
were established at the same time as the
District heating
systems enable
short-term
(daily) and longterm
(seasonal)
thermal energy
storage.
heat production plants at
these decentralized CHP
plants, and the heat was
generated via a natural
gas-powered motor. In
this way, the natural gas
companies had none of
the risks associated with
a natural gas distribution
network.
When the bare field
plants were constructed,
the price of elect r icity
was high and the price of gas
was low. Despite high rates of heat
loss in the heat distribution network,
the economy of the bare field plants
was sensible from the outset. However,
the price of natural gas increased
unexpectedly, and the economy of the
decentralized CHP plants suffered.
For the end users, this meant increasing
heating bills.
Technologies that allowed for the
use of biomass and biogas in the energy
system matured rapidly during
these years. The biomass agreement
was adopted, and, with this agreement,
also ambitious plans for biomass
integration into the energy system by
the year 2000.
In May 1998, Denmark was energy
self-sufficient. The country no longer
relied upon energy imports.
The Heat Supply Act was revised for
the third time in 2000. With this third
revision, a political majority voted for
supporting the bare field plants economically.
The gas companies also contributed.
Further economic support was
granted in subsequent years.
(a)
2000s: Biomass and
Wind Power Integration
in the Grid
Environmental awareness and concerns
grew in the following decades. Green
speak and sustainability were the order
of the day.
The turn of the century marked
an era of large-scale biomass and
wind power integration into the Danish
energy system. For the national
heat supply infrastructures and CHP
plants, this meant novel challenges
and potentials.
From the outset, biomass was (and
(b)
figure 8. (a) A CHP waste-to-energy plant, CopenHill, which is also an
outdoor recreational facility with (b) an artificial ski slope and other outdoor
activities on the roof. CopenHill opened in 2017. (Source: Press/CopenHill;
used with permission.)
106
ieee power & energy magazine
still is) tax-exempt and considered a
low-carbon fuel. Throughout Denma
rk, transitions to biomass happened
with incredible adaptability
and transitional speed, but the use of
biomass far outgrew locally and nationally
available biomass resources.
Biomass is now imported from several
continents, and the sustainability
of these large-scale biomass imports
is debated.
Moreover, highly fluctuating and
lower electricity prices have challenged
november/december 2021
IEEE Power & Energy Magazine - November/December 2021

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