Heat your city with Solar Thermal
Solar District Heating (SDH) systems use solar thermal technology to produce hot water for district heating networks, reducing reliance on fossil fuels and contributing to decarbonisation efforts in communities and cities. Well-established in Europe, particularly in Northern countries like Denmark, SDH holds significant potential to further decarbonise heat across diverse regions.
Currently, several large SDH systems are under construction in different countries, including
- Germany
- Netherland
- Serbia
- Kosovo
Description of use
Heating and cooling account for half of Europe’s energy consumption, a significant portion of which is used in the form of hot water or space heating in buildings. This demand can be met through different systems, like individual boilers or centralised networks like district heating.
District heating is a network providing heat, usually in the form of hot water. This heat serves space heating and domestic hot water needs, and in some cases, covers certain industrial heat demand too. The main advantage of these systems is that they are more efficient, more economic and create less pollution than decentralised fossil fuel-based boilers. The heat generated in a centralised manner is then distributed to urban areas through a system of pipelines specially designed for transporting heat, which is then supplied to each house.
Integrating large solar thermal plants into local district heating networks ensures a clean and renewable heat supply to these networks. During warmer periods, they can entirely replace other sources, usually fossil fuels, used for heating. Thanks to the developments in large scale thermal storage, it is also possible to store heat in summer for winter use. Solar heat can also meet a share of the heating demand during winter.
Benefits of Solar Thermal
Systems!
The benefits of solar thermal systems, in particular for such large systems, cover environmental, political and economic aspects.
Environmental benefits relate to the capacity to reduce harmful emissions, impacting both our environment and our health. The reduction of CO2 emissions depends on the quantity of fossil fuels replaced directly or indirectly when the solar thermal system replaces the use of carbon-based electricity used for water heating. Depending on the location, a 1.4MWth (2000 m2) system could generate the equivalent of 1.1GWh/year, a saving of around 2000 tonnes of CO2
Political benefits are associated with the possibility of improving energy security by reducing energy imports while creating local jobs related to the manufacturing, commercialization, installation, and maintenance of solar thermal systems. The solar thermal sector has a strong European manufacturing base, supplying over 90% of the local demand and exporting worldwide. Most solar thermal systems in Europe use solar collectors produced by European companies, boosting the European economy and creating green jobs.
Economic benefits are associated with the potential savings in energy costs. Even though solar thermal systems require higher upfront costs, they offer an economic advantage in the longer term. Solar thermal systems ensure price stability for at least 20 years. Analysis of existing systems demonstrates that solar heat is economically competitive, even in comparison to gas, as seen during Europe’s recent energy crisis. For instance, in a 110 MW plant, the levelised cost of solar heat varies between 18 and 33 EUR/MWh over 25 years.
There are three main aspects to consider that have a bigger impact on the comparable costs of the energy produced by a solar thermal system. These are the initial costs of the system, the lifetime of the system, and the system’s performance. These factors depend on the location (affecting climate, insulations, taxes, cost of living, etc.) and quality of the system (affecting performance, lifetime, and cost). This can vary significantly from country to country.
Therefore, average investment costs for solar thermal systems can vary greatly between different countries and systems
Explore Solar District Heating Case Studies
Worldwide applicability
SDH systems are applicable wherever district heating networks exist, often found in cold climates with high heat demand during autumn and winter. Despite initial assumptions, the feasibility and competitiveness of using solar thermal energy in such climates have been proven. Europe leads the way, with 80% of the total Solar District Heating networks worldwide located on the continent.
Currently, 282 European towns and cities have embraced Solar District Heating, showcasing its effectiveness. Key adopters include Sweden, Denmark, Germany, and Austria, with Denmark leading the way by setting impressive world records.
The economic and environmental benefits of SDH systems, supported by decades of technical expertise, facilitate the increased adoption and drive their commercial success.
Solar Heat Europe partners with Euroheat & Power, the international network for district heating promoting sustainable heating and cooling solutions, to raise awareness about the potential of solar thermal for decarbonising district heating networks.
Watch our joint webinar from March 2023 on the rise of Solar District Heating.
Technical information
SDH systems consist of solar thermal plants, made up of hundreds of solar thermal collectors. Considering the requirements of such large systems, larger collectors working with bigger loads have been designed specifically for such applications. For smaller systems (block heating), normal solar thermal collectors, either flat plate, evacuated tube or even concentrating, can be used.
These solar thermal plants supply heat to a district heating network. It can consist of a centralized supply, where a very large collector field delivers heat to a main heating central. It can also provide, directly or indirectly, a large seasonal heat store that will contribute to increasing the input of solar thermal plants to the whole system.
The other possible configuration is a decentralised supply or distributed solar district heating. In this case, solar collectors are placed at suitable locations (buildings, parking lots, small fields) and connected directly to the district heating primary circuit on site. This solution can also be interesting for smaller district heating networks or block heating networks. A system is considered large when it is over 350 kWth (500 m²) but solar district heating systems can reach sizes 300 times bigger, i.e. over 100 MWth.
Temperature: between 40 and 100 degrees
40°C to 100°C temperature is the typical usage of solar thermal systems. The temperature requirements highly depend on the currently used temperature in the grid and just follow the demand.
Control: Advanced controls and metering, remote monitoring.
Solar district heating systems require advanced control and metering because an adequate control strategy in place is paramount for improving the performance of the system. This control is usually done remotely.
Operation & Maintenance: Low
The operating and maintenance requirements are in line with operating such large systems, either solar thermal or using other technologies. Correct operation is also required to maximize performance.
