The International Renewable Energy Agency (IRENA) has published an industry roadmap for Renewable Energy in District Heating and Cooling (DHC) as part of its REmap 2030 project. This study analysed the current state of the DHC market in eleven countries – with a focus on district heating in seven and one on district cooling in the other four – and examined the long-term potential of the two technologies in these countries (see the attached PDF). The countries chosen for the study have distinctly different market environments. Two of them are Denmark and Switzerland, which have had the highest share of renewables in their energy supply (around 40 %); a third one is China, the largest market for DHC today, but one on which renewable energy has yet to play a role at all. The chart shows the key factors impacting the potential of renewable DHC. The aim of the renewable energy roadmap (REmap) programme is to show a path towards doubling the share of renewables in the global energy mix by 2030.
Last year was a record-breaking one for new solar district heating (SDH) installations in Denmark. With 31 new SDH systems and 5 plant expansions, the newly installed collector area grew at double the rate of 2015 and totalled 495,226 m² (347 MWth). The year prior saw 15 plants built and three expanded, while collector area increased by 250,161 m² (175 MWth). Almost all plants newly installed or expanded in 2016 were equipped with flat plate collectors, except for the 18.9 MWth parabolic trough installation in Brønderslev. The annual statistic on SDH installations is maintained by Daniel Trier from Danish consultancy PlanEnergi and starts with the very first large SDH plant in 1988. Trier said that at the end of 2016, there had been 104 SDH plants in operation with a combined collector area of 1.3 million m² (911 MWth).
Denmark’s success story in solar district heating, with 2016 having been another record year which almost doubled newly installed collector area to around 500,000 m², showcases the large potential of this type of application across Europe. Cost cuts in the supply chain are key: Two vital factors are fast installation and less hydraulic work on site. The answer by manufacturers to these challenges has been to design large-scale prefabricated collectors. Suppliers of vacuum tube collectors offer modular designs for easy mounting of collectors above 10 m²; large flat plate versions come as one piece and certified by Solar Keymark. The yearly market surveys by German magazine Sonne Wind & Wärme show that the number of certified flat plate collector panels above 10 m² of gross collector area has increased in Europe in recent years. As of 29 March 2017, the magazine’s online collector database listed 62 models from eight brands compared to 20 types of collectors in October 2015.
During the last seven years, a group of scientists has monitored selected large solar thermal installations in Austria on behalf of the Austrian Climate and Energy Fund. The gathered data confirms that these plants have been reliable and produce satisfactory yields. Particularly the new generation of large-scale medium-temperature collectors either with a foil or with a second glass cover shows remarkable results in district heating use. The 2,490 m² solar field (see photo) which has fed heat into the district heating network of Graz, Austria, reached a yield of 489 kWh/m².
The Danish town of Silkeborg now holds the record for having the world’s largest solar heating system. The SDH plant of 156,694 m² (110 MWth) came online as scheduled in December 2016 after only seven months of construction. Municipal utility Silkeborg Forsyning intends to use the harnessed solar energy to meet 20 % of the annual heating demand of the 21,000 plant-connected users. The solar field was divided into four subfields to make it possible to set up the installation and hydraulics systems on this irregularly shaped piece of land (see photo). The former record holder is another installation in Denmark, in Vojens, boasting 70,000 m² (48.90 MWth) of installed solar thermal capacity. Both plants were turnkey deliveries from Danish collector manufacturer Arcon-Sunmark.
The ranking of the largest flat plate collector manufacturers is headed by the same four companies as last year: Greenonetec from Austria, Fivestar from China, Soletrol from Brazil and Bosch Thermotechnik from Germany. But aside from the continuity at the top, last year shows what different paths some markets have taken. Whereas Australian-based Solahart, one of the pioneers of global solar collector trade, as well as Soletrol, the largest Brazilian manufacturer, have lost ground, several others – such as Sunrain from China, Hewalex from Poland and Eraslan from Turkey – were able to report above-average growth for 2015 and rise through the ranks. The produced collector area of the overall 21 companies added up to 4,212,462 m². The number was 21 and not 20 because the last and second-last spot were occupied by companies with equal production output.
The Solar Keymark Network (SKN) discussed and approved new complaint procedures during its most recent meeting on the Greek island of Crete in mid-October 2016. Action had to be taken, as the first series of complaints filed in late 2015 against Swedish test lab SP about the certificates of Danish collector manufacturer Arcon-Sunmark was not resolved to the satisfaction of all parties involved. The results of the October meeting are described in a publicly available draft of the minutes on the SKN webpage.
The recording of the webinar Think big - Design rules and monitoring results of solar district heating systems is now available. Experts from Austria, Denmark and Germany reported on the hot topics in SDH development: Use and performance of seasonal heat storage units for increasing solar coverage, distributed SDH plants connected to specific points of district heating grids as well as large centralised SDH plants employed in particular in Denmark and combined with other renewable energy sources. They emphasised the fact that solar district heating has an enormous potential and monitoring data shows the high reliability of the systems as well as the high performing new generation of collectors. You find the presentations as attachments below.
Last year, the amount of newly installed glazed collector area added up to 2.7 million m² (1.9 GWth) in the European Union’s E28 and Switzerland combined. It is another decline compared to the previous year, this time by 7 %. The annual market statistics of the European Solar Thermal Industry Federation (ESTIF) show 23,700 people to have been employed by the solar thermal sector Europe-wide, whereas turnover was EUR 1.9 billion overall. The four-page market survey published in November includes the country-specific figures of all 28 EU countries and Switzerland. Most of the data was provided by national associations, energy agencies or industry companies, although the markets of six smaller countries were estimated by the ESTIF team. The survey can be downloaded by filling in a form on the organisation’s website. A full report will be available to ESTIF members in early December.