Solar solutions for District heating
The global solar district heating market is expected to drive over the forecast period, as the technology is a cost-effective method in line with global climate goals.
District heating is rapidly expanding in southern Europe and China as solar energy reduces the cost of fuel and CO2 emissions.
Solar District Heating
Solar district heating (SDH) plants are a large-scale application of solar thermal technology.
These plants are integrated into local district heating networks for both residential and industrial use.
Investments in solar in district heating networks are rapidly expanding worldwide:
- In Denmark, they plan to completely switch from natural gas to renewable energy in district heating and expand their solar park by thousands of square meters every year;
- In China, the government set an ambitious five-years program to reduce Co2 emissions through renewable sources;
- In Sweden, Absolicon is building Sweden’s largest district heating-connected solar collector field with small concentrating solar collectors for large-scale solar heating.
How it works and advantages
District heating is a ground-based network providing heat, usually in form of hot water. Large district heating plants are more efficient, more economic, and create less pollution than decentralized fossil fuel-based boilers.
Designed to improve air quality in cities by moving combustion to one place and replace individual boilers, Solar district heating now improves the process further by replacing combustion also in heating plants with clean solar energy.
To cope with the high temperatures sometimes required in district heating networks, Absolicon Solar Collectors are equipped with a silver mirror that concentrates the light in a narrow line on a receiver tube filled with pressurized water.
The solar thermal trough follows the sun during the day to maximize irradiation and keeps the heat under a protective glass.
The patented Absolicon T160 solar collectors are designed to generate steam up to 160°C and 8 bar pressure and heat from the collectors are fed directly into the city district heating network.
Introducing solar in district heating reduces the dependence on biomass in the heating sector and saves biomass that would have been burnt in summer, until wintertime.
As such, biomass is a “way to store” solar energy from summer to winter with low losses.
One can also store thermal energy in hot water from summer to winter.
Such seasonal storages give a possibility of even higher solar fractions and biomass savings.
Sweden’s largest solar park for district heating
In Västernorrland, Absolicon is building a unique demonstration facility for large-scale solar district heating, Högslätten 2023 Solar Thermal Park. The plant will be Sweden’s largest solar field with small concentrating collectors connected to district heating.
The solar collectors are designed to produce up to 160°C working temperature and will provide the district heating network with temperatures up to 120 degrees.
The Solar Thermal Park will showcase the solar thermal technology of the future. The concentrated sunlight from the solar thermal field will provide the high temperature needed for district heating feeding heat directly into the grid.
In May 2020, the Swedish Energy Agency granted € 800 000, co-financing the Absolicon plant for large-scale solar heating.