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

In 2016 the Danish capacity of SDH increased by 347 MW.

In 2017 the amount of new SDH dropped with about 328 MW compared with 2016, and the total new installed SDH net capacity was 19 MW. This drop was mainly due to the end of an approximately 10% subsidy scheme at the end of 2016.

In 2018 the net change in SDH capacity was 47 MW.

In 2019 134 MW new SDH capacity was installed.

In 2020 the amount of new SDH capacity dropped to 16 MW, and only one plant has been built in 2021 with a capacity of 6 MW.

The market for individual systems has been at a low level, in the range of 2 - 10 MW/year for the last 10 years, with a downward trending market.

The above numbers are based on data from The Danish Energy Agency, and PlanEnergi.

Figur 1 List of installations larger than 1,000 m2 prepared by PlanEnergi

The typical applications are:

• District Heating (5,000 - 15,000 m²)

Figur 2 List of solar installations sizes in Denmark created by PlanEnergiAnalysis from PlanEnergi

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.

Typical performance of large solar collector fields in Denmark is approximately 450 kWh/m2/year. This corresponds to an efficiency of around 40%. [Technology Data - Energy Plants for Electricity and District heating generation].

The energy production of the majority of solar plants in Denmark can be seen on the following website: SOLVARMEDATA.DK

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 the heat price of gas and some kinds of biomass. And, heat pumps are now very competitive.

The small systems are not as competitive as the large systems, and over the past several years people seem more interested in PV systems.

Main manufacturers:

• After the sale of ArconSunmark to GreenOneTec in 2020, there are no producers of large solar collectors in Denmark

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

Now it is must lower, but with the sale of ArconSunmark to GreenOneTec in 2020, there is now established a company, with about 10 employees, that service solar plants.

Costs of large systems for district heating: In the table below 2015 prices (excluding VAT) of different collector fields installed are seen. The prices include 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 2,400-4,140 € 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:  40,500 € (405 €/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].

The above section " Status of the market for solar thermal systems" was reviewed by: Christian Sjøstrann Jørgensen, 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 found on the following webpages: http://ens.dk/en/our-responsibilities/research-development/eudp and http://innovationsfonden.dk/en.

In 2022, EUDP granted two IEA SHC projects. Detailed information on funded projects and public energy research can be found on https://energiforskning.dk/en/projects. 

EUDP is a general support programme for new and effective energy technologies with a general annual budget for 2022 of about 50 million EUR.

National Research Initiatives and Results

New silicone-based lenses for low cost Concentrated Solar Heat granted by EUDP (2019-2021, grant 5.81 million DKK and a total budget of 9.26 million DKK) will develop and demonstrate more effective, safe and durable lenses for concentrated solar power. Efficiency and durability will be improved by using better materials than 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 million DKK and total budget of 86.24 million 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 residents in a small Danish city with district heat at a lower cost than the present natural gas fired boilers and to reduce the CO₂ impact by reducing gas ad biomass use. The responsible company is Aalborg CSP.

Collaborative Research

The Danish Energy Agency/EUDP directly supports or through international cooperation schemes Danish companies, universities, and research institutions 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: establishment grant is a scheme that allows a number of district heating companies to get a grant to establish a heat pump or a solar heating system. The aim of the start-up aid is to displace fossil fuels from district heating companies' heat production. In 2022, applications for the start-up grant were open until 31 October. In the application round, a total of DKK 52.1 million can be granted to projects.
• (Building) regulation: Solar thermal counts in the calculation of the energy performance of new buildings and major renovations; these have to fulfill 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.