The market for solar district heating (SDH) has been growing very fast in the decade up to 2016.

In 2016 more than 500,000 m² (350 MW) was installed for SDH.

In 2017 the SDH market dropped to below 20 MW - mainly due to the end of an approximately 10% subsidy scheme at the end of 2016.

In 2018 the SDH market went a little up again: 45 MW.

In 2019 the SDH market was more than 130 MW - 2020 does not look very good, most probably again a dramatic drop.

The market for individual systems has been on a low level in the range 2 - 10 MW/year the last 10 years - with a tendency to a decreasing market.

The typical applications are:

• district heating (5 000 - 160 000 m²)

Flat plate large module collectors are by far the most common collector type used for district heat in Denmark. The collectors are typically installed on the ground in long rows connected in series. The solar heating system normally takes in the return water and heats it up to the desired forward flow temperature. All plants have the solar collectors mounted on the ground. Ground mount foundations can be concrete blocks, concrete foundations or steel foundations.[Technology Data - Energy Plants for Electricity and District heating generation].

For the large systems for district heating, the main market drivers are the relatively low and stable solar heat price. Heat from large solar fields is competitive with heat price of gas and some kinds of biomass. Heat pumps have good conditions these years, and are now very competitive.

The small systems are not as competitive as the large systems - and during the last years people seem much more interested in PV systems.

Main manufacturers:

• ARCON/SUNMARK Solar: Large flat plate collector modules and systems for district heating and industrial applications.
• SavoSolar: Large flat plate collector modules and systems for district heating and industrial applications.
• Aalborg CSP: Large CSP modules and systems for disrict heating, industrial applications and electricity production.
• Heliac: Large  focusing modules and systems for disrict heating, industrial applications and electricity production.
• SolarVenti: Airheating collectors / systems.

The estimated employment related to the production and installation of solar heating systems in the record year 2016 is approximately 1,300 full time jobs. [according to calculation method given in Fakta om Solvarme, faktablad G07].

Now it is more likely only 500 - 600 full time jobs.

Costs of large systems for district heating:In the table below 2015 prices (excluding VAT) of different collector fields installed are seen. The prices are  including piping in the field, heat exchangers, pumps, control, etc.

Costs of individual systems:

The price for a small domestic hot water system for individual houses, 6 m² collector is between 2400-3600 € excluding VAT, depending  on whether it is an existing, renovated or new building. [Technology Data for heating installations]

Medium size hot water system for (e.g., institutions) 100 m² collector:  42,000 € (420 €/m²) excluding VAT. The price is the additional price to install a solar water heater instead of a conventional water heater. [Fakta om Solvarme, faktablad G09a].

Reviewed by: Filip Gamborg, Christian Sjøstrann Jørgensen and Jeppe Rydahl Mols, Danish Energy Agency, Denmark.

The two largest public funding programs related to technical and societal energy solutions are The Energy Technology Development and Demonstration Programme (EUDP) and Innovation Fund Denmark (IFD). The Danish Energy Agency administrates the EUDP, which supports private companies and universities to develop and demonstrate new energy technologies, including solar heating and cooling. Innovation Fund Denmark supports strategic and applied energy research. Detailed information on the funding programs can be fund on the following webpages: http://ens.dk/en/our-responsibilities/research-development/eudp and http://innovationsfonden.dk/en.

In 2019 EUDP grated 2 IEA SHC project, and had a total of 6 active solar heating and cooling projects. Detailed information on funded projects and public energy research can be found on https://energiforskning.dk/en/projects. The total budget in 2019 for energy research in the two programs were 86 million EUR (96 million USD).

EUDP is a general support programme for new and effective energy technologies - annual budget 2020 is about 66.6 million EUR.

National Research Initiatives and Results

New silicone-based Lenses for Low Cost Concentrated Solar Heat grated by EUDP (2019-2021, grant 5.81 mill. DKK and a total budget of 9.26 mill. DKK) will develop and demonstrate a more effective, safe and durable lenses for concentrated solar power. Efficiency and durability will be improved by using better materials that the current thermoplastics, and safety and to some degree efficiency will be improved by new lens geometry designs. The responsible company is Heliac.

In 2015 EUDP granted the project Concentrated Solar Power (thermal) combined with biomass fired boiler and ORC plant, (2016-2020, grant 19.91 mill. DKK and total budget of 86.24 mill. DKK). The concentrated solar power plant is installed in order to supply heat for an ORC (Organic Ranking Cycle) plant, either alone or together with a Biomass fired boiler. The purpose of the Solar Power plant is to supply the citizens in a small Danish city with district heat at a lower cost than the present natural gas fired boilers and to reduce CO2 impact by less firing with gas and biomass. The responsible company is Aalborg CSP.

Collaborative Researce

The Danish Energy Agency/EUDP supports directly or via international cooperation schemes Danish companies, universities, and research institutions when participating in international projects. This includes the direct financial support for participating in the TCPs under the International Energy Agency (IEA) and indirectly by means of common calls in the European Union (ERA-net schemes) and Nordic Energy Research.

The innovative trend right now in Denmark is solar district heating systems (up to 160,000 m²) with seasonal storage (up to 200,000 m3) - and in some cases combined with large heat pumps.

Danish Energy Agency: www.ens.dk

• Financial support schemes: Minor support to energy savings (incl. solar) in district heating
• (Building) regulation: Solar thermal counts in the calculation of the energy performance of new buildings and major renovations; these have to fulfil strict requirements for energy use
• RD&D Funding: EUDP
• Quality control:
  1. Installers can join voluntary certification schemes for solar thermal installers: KSO (www.kso-ordning.dk) and VE Godkendelsesordningen (www.ens.dk/forbrug-besparelser/byggeriets-energiforbrug/ve-godkendelses-ordningen)
  2. Most large systems are sold with a guaranteed power performance

At the moment there is no national solar thermal association in Denmark.