Spotlight on SDH potential in Germany, the Netherlands and Austria

2021-03-11T20:28:45+01:00Feb 2nd, 2021|

Solar thermal will have a key role to play in growing western Europe’s solar district heating markets over the next decades.

Dutch, German and Austrian SDH experts updated attendees during a workshop organized by IEA SHC research platform Task 55 on the current situation and the potential in their respective markets. For example, the collector area installed in Germany, they said, could triple from about 100,000 m2 used in 41 systems today to more than 300,000 m2 by 2025 (see the chart above). As announced in December 2020, the country’s soon-to-be biggest SDH plant will have 13 MWth, a good deal more than the 10 MWth installation in Ludwigsburg (10 MWth). This new plant will be put up in Greifswald, in northeast Germany, and is scheduled for completion by 2022.

Luuk Beurskens, of TNO, Netherlands’ organization for applied scientific research, presented the initiative for a Solar Thermal Roadmap (“Aanzet tot Routekaart Zonnewarmte”). The authors of the 32-page report looked at what experts had to say about the solar thermal market in the Netherlands, and what actions need to be taken for a strong growth in the years ahead. The Dutch building sector alone could potentially see its solar capacity grow from 1.2 PJ in 2019 to 35 PJ in 2050. And adding seasonal heat storage could raise the country’s solar potential to as much as 54 PJ, which would be enough to meet 26 % of the total demand for thermal energy by 2050. The assessment shows important potential contributions to be provided by individual residential systems (34.3 PJ) and new solar district heating networks (18.8 PJ).

Hamid Aghaie, of the Austrian Institute of Technology (AIT), spoke about a possible evolution of Austria’s DH sector and the role of solar thermal over the next decade. Currently, 60 % of the country’s district heat is generated by CHP plants, though heat pumps and solar thermal are expected to increase their share in the market.

Using open-source dispatch and the investment model Balmorel, AIT estimated what proportion of Austria’s DH capacity solar thermal systems could provide by 2030. The results show that the share of solar heat in DH networks could increase by a factor of 60, from essentially zero in 2018 to 3.8 %, in 10 years. At the same time, demand for district heat would grow from 23 to 28 TWh.

Source and full article:

Graph: Solites

Quick Check BIOSOL: New tool helps utilities make the right choices

2021-03-11T20:21:49+01:00Jan 27th, 2021|

As early as November 2020, the national association Austria Solar put a new decision-making tool called Quick Check BIOSOL on its website. In essence, the program helps plant owners to find out whether their district heating networks could benefit from solar heat integration.

At a German-language webinar following the upload, Austria Solar’s Managing Director Roger Hackstock explained how the tool works. It requires only a couple of basic system parameters to determine whether solar collectors can supply as much energy in summer as the biomass or fossil fuel boilers grid operators have in place today.

According to March 2018 data, 1,546 of Austria’s 2,108 biomass plants used for heating are also run in summer despite some drawbacks. For one, the devices produce soot, which hampers efficiency and increases wood chip consumption. Switching to solar thermal can solve these issues, reduce operation cost, and lower air pollution. But instead of immediately turning to detailed – and costly – feasibility studies on solar district heating sites and systems, stakeholders can now use Quick Check BIOSOL for a first, free analysis of whether a retrofit is worth the effort. The tool was developed in partnership with several Austrian experts and was sponsored by solar thermal system supplier Gasokol.

The tool utilises only a dozen parameters, including buffer tank volume, annual district heating demand, usable roof surface, grid temperature in summer, boiler type (biomass or fossil) and type of auxiliary heating (heat pump, waste heat or CHP system). Aside from that, the tool will automatically fill in some values, for example, the average collector yield. Almost immediately after entering the parameters, a note pops up, indicating a system’s potential for solar heat integration. This means the tool shows how much collector area is needed to replace a boiler partly or entirely in summer and how much land the collectors require if roof space is limited. In addition, Quick Check BIOSOL provides recommendations e.g. on how to reduce grid temperatures and more.

You can find a recording of the webinar and Hackstock’s presentation at:
Austria Solar’s Quick Check Biosol:
Source and full article:
Photo: Solid

World´s largest solar district heating plant with concentrating collectors

2021-03-11T15:38:03+01:00Sep 28th, 2020|

The Chinese parabolic trough collector manufacturer Inner Mongolia XuChen Energy has successfully operated a huge solar district heating plant since 2016 in a village near Baotou in Inner Mongolia, an autonomous region of China.

The installation in Baotou consists of two fields of parabolic trough collectors, a 22,000 m2 rooftop field on XuChen’s factory hall next to the company’s headquarters and a 71,000 m2 system put up at ground level. The 93,000 m2 (65 MWth) SDH plant is the world’s second-largest after Denmark’s Silkeborg (110 MWth) installation but the biggest using concentrating collectors. It provides 500,000 m2 of residential buildings, buildings in a neighbouring industrial zone and a shopping mall with solar heat.

The 93,000 m2 solar plant is part of the government’s green heat policy to improve air quality in China’s northern provinces and phase out coal boilers. This policy is part of the overall trend to improve social living conditions and provide affordable housing which is summarized under the slogan “livelihood”- a term created by the Chinese government. Wang confirmed that the installation of the solar plant in Baotou is the first livelihood project introducing solar space heating to the region. ‘The government has completely taken over the RMB 0.55 billion in capital costs for the solar field, including the storage tank and the newly built heat network,’ Wang explained in an interview with This 100 % public subsidy was what prompted XuCheng’s investment in a collector factory in the same city. XuChen, founded in spring 2016, also invested Renminbi (RMB) 1.05 billion, i.e., USD 154.7 million, in putting up headquarters as well as a 50,000 m2 factory for parabolic trough collectors in Baotou’s green industrial park.

Solar heat transported to nearby heat consumers by truck

Wang said that he has observed an increase in solar heat demand from China’s northern provinces. He added that surplus heat generated in summer, when none of the buildings connected to the SDH system require space heating, is transported by truck to nearby consumers, including hotels, swimming pools and spas. As China’s green heat policy requires the phase-out of coal boilers and because heat pumps rack up high electricity bills, purchasing solar heat from Baobou’s SDH plant is an economically viable option for those requiring large amounts of heat all year round.

Another huge solar district heating system is currently being built by XuChen in Han Dan, in the north of China. According to Wang, this plant will provide heat to a new all-weather, four season ecotourism vacation and leisure park. Due to the green heat policy of the government the construction of the leisure park would not have been possible without a source of clean energy for heating, in this case provided by SDH.

Sources and full article:
Photo: XuChen

Acquisition of strategic importance for the SDH sector

2020-04-29T10:46:04+02:00Apr 3rd, 2020|

Beginning of April, a historic acquisition took place in the solar heating and cooling industry. Greenonetec, the largest collector manufacturer in Europe, purchased key parts of the business of Danish-based Arcon-Sunmark, the European leader in developing solar district heating projects.

The acquisition followed months-long negotiations between Greenonetec CEO Robert Kanduth and Torben Sørensen, Group Executive Officer at VKR Holding, the corporate group that owns Arcon-Sunmark. VKR Holding decided to terminate most of the solar thermal business within the group because of huge price drops faced by suppliers of large solar fields and fluctuations in the contracting market, which resulted in considerable losses for Arcon-Sunmark in recent years.

The week started with the publication of a press release stating that parts of Arcon-Sunmark will be sold off because of a large financial deficit in recent years. “The financial development with heavy losses is intolerable,” Thomas Karst, current CEO of Arcon-Sunmark, is quoted as saying in the press release from 30 March. “We are sorry about the situation. However, we respect the decision of the owners.”

Three days later, on 2 April, Arcon-Sunmark sent out a second press release stating that Greenonetec acquired key assets of Arcon-Sunmark and that the Chinese Solareast Group (which owns the Sunrain and Micoe brands) bought the shares in Chinese-Danish joint venture Solareast Arcon-Sunmark Large-Scale Solar Systems Integration, which has put up two solar district heating plants in Tibet over the last years.

“We have taken an important step towards consolidating the solar thermal industry by bringing Arcon-Sunmark’s extensive expertise in project development and large-scale collector production to our highly streamlined solar manufacturing business,” Kanduth explained. He plans to integrate the fully automated production line for large-scale collectors into the company’s factory in Austria and retain the majority of the project development and sales team of Arcon-Sunmark. He also confirmed that he wants to focus on sales and project development in Europe and North America and has no plans for the Asian market. The latter is why Arcon-Sunmark’s assets in Asia, including the factory in Vietnam, were split off and sold to the Solareast Group.

Source and full article:

Picture: Arcon-Sunmark

Significant growth in the German solar district heating market in 2019

2020-04-28T16:59:40+02:00Feb 27th, 2020|

Mainly public utilities have installed large solar thermal collector arrays in Germany in the year 2019. The new solar thermal collector arrays for the application in district heating networks cover a total area of around 35,000 square metres. This means that the installed peak power has increased by around 50 percent.

According to the Steinbeis Research Institute Solites in Stuttgart, around 70 megawatts of solar thermal capacity is available for district heating systems in Germany. Some of the new systems are scheduled to start operation in the beginning of 2020. However, as the collector fields have already been erected in 2019, the growth in solar district heating is already prepared. The map below gives an overview of the plants in operation, in planning and in preparation in Germany.

Stadtwerke Ludwigsburg-Kornwestheim, for example, supplied solar heat into the grid for the first time in the course of the first quarter of 2020. With 14,800 square metres, the collector field is currently the largest of its kind in Germany. In Bernburg the situation is similar. Here, the thermal storage is all that is missing for the full operation of the solar thermal collector field that has already been installed in December. The municipal utility of Bernburg plans to finalize it in spring 2020.

“In 2019, mainly municipal utilities in urban areas discovered solar district heating for themselves,” summarized Thomas Pauschinger, member of the Solites management board. Pauschinger considers it a remarkable development that solar heat is now an economically interesting alternative to conventional energy sources for district heating network operators. Key in this development were certainly many successful reference plants and many good arguments as the fact that solar heat supports decarbonising the district heating networks.

Large-scale solar district heating is technically mature. The information of good operating results of the first commercial plants has spread among German utilities. The disadvantage of renewable energies of high investment costs has been addressed and is met with strong governmental support programmes. Thus, the advantage of permanently low operating costs are even more convincing. Furthermore, the decided CO₂ price contributes to further growth and market prospects for large solar thermal systems.

However, the status quo of large solar district heating systems should not be overestimated, Pauschinger emphasizes: “The share of solar heat in district heating sales is still low today. However, we assume a market potential of around 20 gigawatts and expect the market to continue to grow in the coming years”.

Text and map: Solites
Picture: Guido Bröer

SDH prefeasibility studies for Serbian cities

2020-04-28T15:30:11+02:00Feb 19th, 2020|

Renewable district heating has become a hot topic in Serbia. The conference Renewable Energy Sources in District Heating and Cooling, held at the same time as the 50th International HVAC&R Congress and Exhibition in early December in Belgrade, attracted more than 400 attendees.

“The great interest shown by experts and the media during the December conference helped us a lot in forging new relationships with high-level representatives for municipalities, local governments and public utility companies to raise the profile of SDH,” said Bojan Bogdanovic, who launched the event. He is also Principal Fund Manager of Renewable District Energy in the Western Balkans (ReDEWeB), a programme supported by Austria and implemented by the European Bank for Reconstruction and Development (EBRD).

ReDEWeB has already supported several prefeasibility and feasibility studies on solar district heating in Serbia and Kosovo. The most advanced project in terms of planning is the one in the Serbian town of Pancevo, where the two-year test of a 906 m² solar field put up in January 2017 has convinced the local council of the benefits of solar heat. Together with the Kotež power plant, the field supplies hot water to about 2,200 citizens. The council then commissioned the installation of 198 large collectors, mounted onto the roof of the Kotež plant, to meet an even higher share of the hot water needs in the district heating network with solar energy. The council members are now looking into adding an SDH system with seasonal storage. A prefeasibility study prepared by the Austrian engineering firm Solid mentions a 35,000 m² field of collectors, 150,000 m³ of storage volume and a 15 MW absorption heat pump.

All presentations from the 50th International HVAC&R Congress have been posted online and are available for download here.

Source and full article:
Picture: Milica Knežević for SMEITS©2019

Solar Heat for Cities – IEA brochure and infographics

2020-04-29T13:40:26+02:00Jan 15th, 2020|

Solar heat improves energy security, keeps heat costs stable for at least 20 years and cuts air pollution in towns and cities. To encourage more mayors, local council members and municipal utilities to look into this cost-effective solution, researchers working on IEA Task 55, Towards the Integration of Large SHC Systems into District Heating and Cooling Networks, published the brochure Solar Heat for Cities in November.

The SHC Task 55 of the International Energy Agency aims to develop technical and economic requirements for the commercial market introduction of solar district heating and cooling (DHC) for a broad range of countries. The activities aim to improve technological know-how, market know-how and understanding of the boundary conditions as well as to provide expert know-how for project initiation and implementation and for training. This consumer promotion material includes 11 infographics that illustrate solar district heating (SDH) technologies, their advantages and market growth. The files, available in English, German and French, can be downloaded in JPG or PDF format and can be used free of charge in third-party publications.

“SDH markets are growing in Denmark, Germany and China, and new markets are starting to emerge, for example, in France, Italy, Poland and Spain,” explained Sabine Putz, Chair of Task 55. “With this brochure, we aim to address new investors and local decision-makers.” The case studies into successful SDH projects shown in Solar Heat for Cities brochure are real-world testimony to the benefits of solar district heating for municipalities. Satisfied SDH investors explain why they chose a specific mix of technologies, including solar energy, to reduce their dependence on fossil fuels or lower heat prices for their customers. The logic behind this approach is: “If it works for them, it could work for us too.”

The brochure showcases nine SDH systems built in Austria, China, Denmark, France, Germany, Latvia and Serbia. The infographic above shows a usual set-up and main elements of SDH systems.

The brochure and the information charts were sponsored by the following Task 55 participants, in cooperation with the Belgian-based European Copper Institute: Solites (Germany), Solareast Arcon-Sunmark Large-Scale Solar Systems Integration (China), Aalborg CSP (Denmark), newHeat (France), Savosolar (Finland) and Greenonetec (Austria).

Download the SDH infographics here.
Download the ‘solar heat for cities’ brochure here.

Images: IEA SHC Task 55
Source and full article:




15 MW SDH plant inaugurated in Latvia

2020-04-28T14:15:01+02:00Oct 27th, 2019|

On 12th September, district heating operator Salaspils Siltums inaugurated a 21,672 m² solar field and a wood chip boiler, put up in the middle of the woods near the town of Salaspils, Latvia, to meet 90 % of the demand from the local district heating network.

The inauguration came after a three-week test run of the solar district heating plant and its new 8,000 m³ storage tank. The system was installed by the Latvian-based company Filter, which signed an EPC contract with Salaspils Siltums in August 2018. The collectors were delivered by the Danish manufacturer Arcon-Sunmark.

Salaspils Siltums started planning the solar system after a neighbouring cogeneration plant was shut down. “We have been working on this project since coming back from a visit to Denmark, where we attended the solar district heating conference 2016 in Billund (which was held under the H2020 Project SDHp2m). The aim is to lower our carbon footprint and become less dependent on fossil fuels,” said Ina Berzina-Veita, Managing Director of Salaspils Siltums. After conducting a feasibility study in January 2017, the utility was able to secure EU funding in February of the same year. The EU’s Cohesion Fund has contributed EUR 2.73 million to the EUR 7.08 million invested in the solar field, the storage tank and the 3 MW biomass boiler. The project could reduce the company’s district heat tariff by at least 5 %, utility staff confirmed. Salaspils Siltums is also about to sign additional heat contracts with new customers.

Salaspils Siltums is a relatively new utility, founded as recently as 1996. Since 2010, the company has grown rapidly but has kept its focus on eco-friendly solutions. Each year, it supplies about 65 GWh to 17,000 customers. 85 % of all households in Salaspils use district heating already.

Picture: Salaspils Siltums

Video: Vision 2050 for District Heating and Cooling by Euroheat & Power

2020-04-28T14:01:38+02:00Oct 22nd, 2019|

Within their vision 2050, Euroheat & Power has published this video “Decarbonising DHC For Our Cities” for the promotion of district heating and cooling (DHC) . Besides the animated video, different city representatives shared their experiences and plans.


Find out more about the Vision 2050 on

Source: Euroheat & Power



Solar thermal is on the rise in German district heating networks

2019-08-01T12:03:08+02:00Jul 31st, 2019|

34 large solar thermal plants with a total capacity of 44 megawatts and a gross collector area of 62,700 square meters are currently integrated into district heating grids in Germany. The industry, which discussed its perspectives at the conference “Forum Solare Wärmenetze” in Stuttgart in June 2019, expects accelerated growth in the coming years and anticipates a fiftyfold market increase in the long term.

In 2019, additional 23 megawatts with a collector surface of 33,000 m2 are expected to be built. Germany’s district heating suppliers have discovered the sun, most of all the public utility company Stadtwerke Ludwigsburg-Kornwestheim (Baden-Württemberg), which is currently building the largest German solar thermal plant with 14,800 m2 collector area. So far, the Stadtwerke Senftenberg (Brandenburg) has kept the German record. Last year, Stadtwerke Senftenberg harvested 4,720 megawatt-hours for their district heating network from the 8,300 m2 of solar collectors.

For the next five years, Dirk Mangold, head of the Steinbeis Research Institute Solites, expects the number of plants to be roughly doubled to 70 large solar systems with a tripling of capacity to 140 MW. “This figure is calculated from ongoing projects and concrete feasibility studies, whereby we have calculated the respective probability of realization as a factor”, explained Mangold at the conference. Compared to the official national targets, as set out in the Federal Government’s energy efficiency strategy for the building sector, the current very positive market development can only be regarded as a start. The scientist emphasized: “By 2050, the Federal Government would like to massively increase the contribution of solar thermal energy to district heating. With a share of 15 percent, this corresponds to 12 terawatt-hours per year. This requires an installed capacity of around 21 gigawatts, i.e. a collector area of around 30 million square meters. We therefore need an additional 1 million square meters per year. That means that the roll-out has to increase by a factor of 50 compared to this year!”

Solar district heating systems are developing positively in all market segments. At present, mainly large systems for urban district heating are in preparation for the coming years.

A factsheet with more information on the current market status of solar heating in Germany can be found here.  (German language).

Text: Thomas Pauschinger, Solites; Picture: Eins Energie in Sachsen GmbH &Co. KG; Graph: Solites



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