Azteq - Warm Cooperation on Solar Thermal Energy

Azteq aims to revolutionise European green heat technologies on an industrial scale and is developing solar heating systems to do so. The Belgian start-up cooperates in projects with technical service providers, who in turn call upon Breemes, sister company of itsme, for advice and the supply of components. For a major project in Seville, there were challenges regarding the delivery times of the decentralised PLCs and on how they could communicate with each other in the large facility.

Azteq's solar thermal energy concept is based on parabolic mirrors that focus solar rays on collector tubes filled with oil. The oil can be heated up to 400°C, after which, in a heat exchanger, the energy is transferred to the medium for industrial application. After successfully implementing a few projects at home, the company was awarded a project in Seville, Spain. This concerned the construction of the largest solar thermal power plant for industrial application in Europe; with a mirror surface area of more than 40,000 m², it can supply 30 MW.

Subcontractors and supplier

Azteq’s Pascal Vranken coordinates the electrical drawing work, enclosure construction and software. "We carry out the concept study and the necessary physical studies.  Azteq outsources the elaboration of the design and the actual construction to subcontractors." One of the subcontractors is Mike Ramaekers from MR-Engineering. He does some of the drawing work and the installation of low-voltage panels and sub-distribution boards. "Mike also helps with the start-up of construction. Putting in the big power supply lines is no problem for a local installer, but for specific instrumentation, it is still nice to have the person who made the drawing on site. That way it goes ten times faster."

"Azteq outsources the elaboration of the design and the actual construction"

Vranken in turn, calls upon Breemes for advice and supplies. "Pascal was already in contact with us for other customers and projects," explains Gert Vanwezemael, electrical consultant at Breemes. "We were in the picture ever since the Azteq project in Turnhout." With a surface area of 5,500 m2, it was the previous record holder and still is the solar thermal power plant with the highest output temperature (285°C). "Pascal approached us for the project in Seville, for support in the preparation and elaboration of the design. So, we did the complete low-voltage study. This included short-circuit and cable section calculations and configuration of the low-voltage board and cooling units. We also worked out the PLC configuration."

Delivery times, communication and power supply

"The biggest challenge for the project in Spain was the delivery times of certain components," says Vranken. "We had worked out a concept. The question was whether we could get it done within the timeframe and if not, which alternatives were available, taking into account the specifications we had to meet." For control, Vranken included the Siemens ET 200SP decentralised PLC islands in the design. "Pascal actually presented this to me last summer," says Arno Degroot, product specialist Industrial Automation at Breemes. "They wanted to start construction after the summer. However, I had to tell him to expect a delivery time of 1 to 1.5 years. So I started investigating what decentralised PLCs Siemens had as alternatives. That's how I ended up with the ET 200AL, the more robust little brother of the ET 200SP. That one did have a reasonable delivery time. I had done this conversion in previous projects, so I started to figure it out with Pascal. It turned out to be feasible, without compromising performance." The incorporation of the larger ET 200AL did require some attention though. "This alternative was slightly more expensive, but cancelled out the loss due to later delivery if we had stuck to the first option." Vranken: "It is not a given that we will switch to this alternative by default in subsequent projects. We do have a stock of spare parts now, but in the future we may go back to the ET 200SP provided it is still available at that time."

"We built the entire structure together with Breemes"

"Another challenge was the enormity of the installation," Vranken continues. "With a large number of control units spread over a large area, a standard network cable would not be sufficient for communication. A fibre array was needed to communicate with all 18 remote PLC islands via PROFINET and Modbus TCP/IP. We built the entire structure together with Breemes, which brought in the expertise of Siemens."

The power supply was also crucial. The mirrors rotate with the sun, but must be able to go out of focus if the radiated energy becomes too high, to avoid overheating the collectors. "The system must therefore have power supply at all times in all parts. Besides the normal power supply, a UPS is provided and if that fails, a generator has to take over. For the power distribution, we therefore needed a system that could switch between those options; that's called an APS ("Adjustable Power Supply", ed.). Gert submitted a proposal for that and we went with it. From that APS, the power distribution goes into the field. Conceptually, I worked that out in Simaris (Siemens' planning tool for calculating electrical installations, ed.) in consultation with Gert, who always specified which components could be available at which time."

Partnership

Construction in Seville has now been completed and the plant is running properly. "This is partly due to the good cooperation between all parties," says Vranken. Vanwezemael agrees with him on this.  "As far as I am concerned, the cooperation is actually very good. For the part in which I supervised Pascal, the low-voltage part, he was always very well prepared whenever he had a question. He had already looked for a certain solution himself at that point, which is something that almost never happens. Then he would suggest a solution for us to discuss and, if necessary, adjust. That made it so much easier for us. I had the same good feeling about Mike from MR-Engineering."

Degroot concurs with his colleague. "Pascal knew very well where he wanted to go and from his first drawing we already had a good idea of the design. On top of that, he was always honest about the expenses." Vranken: "Breemes is a regular supplier, but my clients do occasionally require me to benchmark prices with others. If I am presented with a good solution that costs a few percent more, that's OK. Because you will always find a party that is cheaper but that has not been involved in the development like Breemes. You have to find some middle ground, but I always try to go for a partnership."

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