The sun was shining high and bright when Denmark’s first CSP plant was opened in Thisted on Thursday 11 October.
The system is based on concentrated solar power (CSP) technology where parabolic shaped mirrors concentrate the sun’s rays on an insulated pipe where water is pumped through and heated. The parabolic troughs use a custom designed sun tracking technology, where a computer calculates and calibrates the troughs into the required position for receiving the optimal radiation of sunrays throughout the day.
Facts about the CSP plant in Thisted:
- The system consists of 144m parabolic shaped mirrors
- Has an aperture area of 830m2
- Heats water to 140°C
- Supplies around 500MWh a year for the district heating production
Aalborg CSP’s system for district heating is an add-on unit which can be connected to any plant producing district heating. The concentrated solar power system can be attached as a means to reduce emissions or ensure stability of production costs for bio and fossil fueled plants.
The sun is a powerful renewable energy source that supplies the earth with incredible amounts of energy every day. At Aalborg CSP, we are working innovatively on optimizing solutions for harnessing these great amounts of energy and are here introducing the concentrated solar power technology for the production of district heating.
When the sun’s rays hit a surface there is a direct impact, but if the rays are reflected onto a burning point, a concentration of the energy occur and a significant better utilization of the sun’s energy is obtained. This is the point of origin for concentrated solar power (CSP) technology.
The CSP technology is, when dealing with production of district heating, a system of parabolic shaped mirrors. The mirrors concentrate the sun’s rays onto a pipe running through the burning point of the parabolic shaped mirrors. The solar energy heats the water in the pipes to the desired temperature (80-95 degrees C) whereupon it is pumped directly or indirectly into the district heating pipelines.
The systems can differ in size from 1MW to 30MW depending on the specific requirements.
Aalborg CSP’s system for district heating is an add-on unit which can be connected to any plant producing district heating. The concentrated solar power system can be attached as a means to reduce emissions or ensure stability of production costs for bio and fossil fueled plants.
The concentrated solar power systems can be used for several purposes for district heating plants:
- Production of district heating (Deliver 80-95 degrees hot water)
- Production of district cooling
- Heating up geothermic water
- Production of high pressure hot water
- Production of steam
At present Aalborg CSP has a CSP plant for district heating under construction at Thisted, Denmark. The solar energy is to heat the water in the pipes to 160°C. The water is then directly or indirectly pumped to the district heating pipelines.
Tracking the sun’s daily circuit
The parabolic troughs use a custom designed sun tracking technology, where a computer calculates and calibrates the troughs into the required position for receiving the optimal radiation of sunrays throughout the day – see figure 1.
Figure 1. The parabolic troughs’ tracking of the sun.
The sun tracking technology achieves a very high efficiency per m2 mirrors. Suppliers of district heating can therefore experience an optimal utilization of the land they have available for such purposes.
When the sun shines, the CSP system produces heat. Therefore, the CSP technology can produce heat for an entire year. Moreover, there is an anemometer installed registering if the average wind speed surpasses 15 metres per second, when this is registered the parabolic troughs automatically go to a lock-down position.
Strong performance and long longevity
The CSP systems have an almost constant performance, even at high middle temperatures. The reason for this is among other things that the pipes in which the water is heated are isolated with special glass vacuum tubes, which ensure minimal heat loss.
The CSP systems require a very limited amount of maintenance and have a life expectancy of over 30 years. Similar facilities were established in USA back in the 1980s and are continuously running commercially*.
*SEGS I – VIII, Mojave Desert, California, USA with a total production of 353,8MWe.
The sun tracking technology is calibrating the troughs to obtain optimal sun radiation, but the system can defocus the mirrors or shut them down if required. By doing so the CSP technology is avoiding problems like overproduction of heat.
The CSP technology is a perfect match with an accumulation cistern. By setting the heat production temperature to 95-98 degrees a good exploration of the accumulation cistern is obtained, and for days where the production is high enough to provide enough heated water to exploit the full capacity of the accumulation cistern, the parabolic troughs can defocus till the capacity issue has passed.
Aalborg CSP A/S is the result of the merger between the EPC company BK Aalborg A/S and the engineering company BK Engineering A/S. The merger happened 1 January 2011.
Aalborg CSP A/S is a world leader in steam generators for large scale concentrated solar power (CSP) plants. Our services consist of design and delivery of steam generators for CSP systems for utility size, CSP module system for industrial size, gas- and oil-fired steam boilers and engineering services.
Our work within CSP is based on 25 years of experience with traditional steam boilers. We have adapted our knowledge and combined it with the innovative technology of solar power plants. We have delivered steam generator systems for parabolic trough plants with capacities of 50MWe as well as solar tower boiler solutions for both superheated and saturated steam with capacities of 20MWe. At present, we have plants up to 250MWe on the drawing board.
In addition to this, we are developing systems for molten salt as heat transfer media, for heat storage as well as steam generators – the next generation of concentrated solar power.
Our projects vary from main component deliveries to complete turnkey installations including piping, instrumentation, mounting of valves and pumps as well as electrical and control systems, erection of steel structures and galleries and finally commissioning.
