The United States promoter NEXTERA ENERGY RESOURCES, one of the leading operators in solar energy generation in the American continent owns the thermo-solar power plants TERMOSOL 1 and 2, built in the municipality of Navalvillar de Pela (Badajoz, Spain) together with one of the worldwide benchmark, Spanish engineering firms SENER at the head, where the company TRACELEC has carried out the engineering project, supply and installation of its TRACELEC® global electrical heat-tracing solution in both the molten salts and in the oil (HTF) and steam (BOP) parts.
Technical requirements, although largely already resolved by TRACELEC in many projects executed in thermo-solar plants with parabolic trough technology and salt (TES), oil (HTF) and steam (BOP) accumulation, included such important aspects for the correct operation of the plant:
These thermo-solar power plants are sustainable electric production facilities that use the sun as a clean energy source, by means of the solar field of parabolic trough collectors, that represent the hot spot of the cycle, using concentrated solar power (CSP) techniques . These plants contribute to energy safety as they use a local resource and do not emit greenhouse gases.
The main characteristic of this type of plants is their parabolic trough mirror technology together with the use of specific fluids for transferring solar/thermal energy and its respective accumulation. Tracing is critical auxiliary service for the plant, as it guarantees maintaining the temperature of the fluids, essential for its operation.
Specifically, the operation of the parabolic trough reflectors consists of turning around an axis, tracking the sun, while at the same time concentrating solar radiation in receiving tubes. A heat capturing fluid (synthetic oil) circulates inside the receiving tubes that is heated by the solar rays concentrated in the tube up to a temperature of around 400 ºC.
The heat transferring oil (HTF) is used to generate steam overheated at high pressure which by means of its turbining in a Rankine cycle, it becomes electric energy. The heat transferring oil is also used to be exchanged with molten salts, that result in an excellent heat accumulator, hence capable of generating overheated steam when there is not enough solar radiation. With an amount of salts of around 30,000 tonnes 1,000 thermal MWh of energy can be stored.
As can be inferred from the plant’s operating description, the pumpability of the related fluids is essential for the generation of electric energy and for maintaining all the facilities. This gives the tracing system a particularly critical character, as it is in charge of the maintenance of conditions of the entire system.
Electrical heat-tracing systems are one of the main devices in the industrial heating or temperature maintenance market. This is a proposal suitable for large and small plants with a very low maintenance cost, guaranteeing the safety and reliability of their operation, given their great robustness and resistance to adverse weather conditions and unforeseen mechanical stresses they guarantee the maintenance of an even and controlled temperature as well as being subjected to thorough controls and periodic tests, according to current international standards.
The TRACELEC® electrical heat tracing solution TRACELEC has installed in the TERMOSOL 1 and 2 thermo-solar power plants allows the maintaining of the temperature of both the heat transferring fluid (HTF) and the molten salts of the accumulation system (TES) above their freezing point, in periods of low or zero solar radiation and/or in periods in which no electric generation occurs. The TRACELEC® solutions guarantees a zero operating risk in the plant, as it prevents the freezing of the fluids required for its operation with several safety factors. Specifically, it guarantees the pumpability of both the molten salts in the accumulation system (raising them to temperatures of 265 ºC) and the thermal oil. The TRACELEC® solution also allows minimising the electric energy required for protecting against freezing, which allows the production of both plants to be energetically efficient.
The difference provided by the TRACELEC solution for this two plant project is that technical innovations have been introduced in the TRACELEC® solution, for both electrical heat tracing and control systems and power and control cabinets, guaranteeing the process in the salt concentration part and in oils (HTF) and steam (BOP) and reducing the investment costs.
Work in the two facilities has been overlapped in time, highlighting TRACELEC’s main qualities, customer proximity, which has provided it with all the necessary engineering documentation, flexibility, taking part in managing the supplies and, in short, the capacity for carrying out the different works simultaneously.
TRACELEC started the Termosol 1 and 2 Thermosolar Power Plants project in November 2011 and finished the last one in March 2013, with a power of 50 MW, preventing the emission of 149,000 tonnes of CO2 a year. The power plant has been built on 470 hectares of land with over 624 collectors. The plant supplies the grid with enough energy for the consumption of 60,000 households.
c/ Josep V. Foix 10-43007 Tarragona – Spain
Founded in 1985, the TRACELEC Group specialises in hydrocarbon detection and electric heat tracing for freeze protection, temperature maintenance and industrial heating equipment.
Electric heat tracing
Hydrocarbon detection
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