Leading the world in solar heating

By Jan Aagaard

Denmark is located in northern latitudes where the winter is long
and dark. It is not a place one immediately associates with solar
energy. Nevertheless, Denmark is a world leader in large-scale
solar thermal plants that ensure efficient exploitation of the
world’s largest energy resource – the Sun.

The world’s largest and second-largest solar thermal plants,
covering 18,300 and 15,000 square metres respectively, are
located in Denmark, while new giant plants are springing up
throughout the country these days. In southern Jutland, ground
was recently broken for a 17,000 square metre plant, while in
northern Jutland it has just been agreed to build a 35,000 square
metre plant.

One of the reasons why Denmark excels in solar heating is the
way in which the heat supply is structured in the country. More
than 60 percent of Danish households are supplied with district
heating, which is unique for a western European country. The
district heating is supplied by more than 400 plants which produce
heat in a variety of ways including coal, gas, waste, wood
chips and straw. 40 percent of Denmark’s district heating is today
based on renewable energy sources.

Solar heating pays
For district heating plants, it will become increasingly good business to invest in large-scale solar heating plants. Prices and taxes on fossil fuels such as oil and gas have gone only one way in recent years – up – while solar thermal technologies are steadily getting cheaper and more efficient. The district heating sector in Denmark is thus seeing rapid growth in the number of solar
thermal plants.

“The large-scale solar thermal plant will probably be the first
renewable energy technology that is fully competitive with fossil
fuels – even when taxes on fossil fuel are excluded. Solar heating
is a good business and enables the heating plants to invest in
solar thermal plants without public subsidies,” says chief consultant
Flemming Ulbjerg of consulting engineering firm Rambøll.
The plants are typically dimensioned to handle each district
heating plant’s needs during summer, and so solar heating
can cover up to 20 percent of the total annual need for heating
and hot water. The remaining need is covered by other energy
sources such as natural gas.



Exporting and expanding
District heating companies around the world are starting to see
the opportunities of solar heating, The Danish company Arcon
recently delivered the first solar thermal plant for district heating
in the US – an 1,800 square metre facility in St. Paul, Minnesota.
The plant supplies heat to a major sports and conference centre
and surplus heat to the city’s local district heating network.

Another Danish company – Sunmark – has for example supplied
a 7,000 square metre plant for the Netherlands. At the same time
expansion in Denmark continues at a rapid pace. In the near
future, 17 new plants are expected to be established across the
country, and several existing plants are being expanded.

On the island of Ærø, the world’s largest solar thermal plant
is being expanded to almost twice its current capacity – in total
35,000 square metres of solar thermal panels. More than half of
the heat supplied to district heating users will thus be generated
from solar energy, while the remaining heat will come from locally
produced biomass.

The project also comprises a storage system that makes
it possible to store some of the solar energy for use in colder
periods that have fewer hours of sunshine, and a unit that can
produce electricity.

The aim of the project on Ærø is to demonstrate an efficient,
stable and 100 per cent renewable energy system on a large
scale. The project is supported by the EU , and the experience
gained will be communicated to 10 EU countries with a view to
establishing 20 similar plants in Europe.

Future solar thermal plants

• 16 large-scale solar thermal plants (more than 100,000 square metres) were in operation in Denmark by the
• end of 2010
• Over the next few years at least 17 new plants are expected to be
• established, while a number of existing plants will be expanded.
• By the end of 2012, around 245,000 square metres of solar thermal panels are expected to be in operation in Denmark, according to consulting engineering firm Rambøll .
• Several Danish district heating plants are working on plans to establish solarthermal plants of more than 100,000
• square metres.
• The Danish District Heating Association, together with Rambøll and
• Aalborg University, are recommending an 8 million square metre expansionof large-scale solar thermal plants inDenmark by 2030

This article is from Focus Denmark Magazine, June 2011