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Valle 1&2

Project Sheet

  • TEMPORARY JOINT VENTURE: SENER and COBRA PLANTAS INDUSTRIALES
  • PROMOTER: TORRESOL ENERGY
  • CSP TECHNOLOGY: Parabolic trough collector CSP with molten salts, oils (HTF) and steam.
  • LOCATION: San José del Valle (Cádiz-Spain)
  • HEAT TRACING SYSTEM TECHNICAL DATA:
  • AKOTRACE® electrical heat-tracing system turnkey solution
  • 6 engineers and 30 fitters.
  • 20 km of mineral insulation heating cable
  • 370 active circuits in molten salts
  • 164 active circuits in oils (HTF)
  • 30 active circuits in steam (BOP)
  • Over 2,000 control i/o
  • 9 months of execution

Background

Torresol Energy is a renewable energy company that owns the two VALLE 1 & VALLE 2 thermo-solar power plants respectively, built in the municipality of Cádiz (Spain), in which AKO has supplied and installed its complete AKOTRACE® electrical heat-tracing solution, in the molten salts and oil (HTF) and steam (BOP) areas.

The most important feature in this type of power plants is their parabolic trough mirror technology where tracing is a critical auxiliary service, necessary for its correct operation.

  • Rated electrical power: 50 MW
  • Total electricity production: 170 million GWh/year
  • The solar field has two 510,120 m2 solar fields with mirrors and 624 solar collectors each, that allow reducing the energy capturing costs.
  • Salt system that includes molten salt storage tanks with a capacity of 7 hours, to sustain the stability of the electricity grid for 4000 hours of yearly production per plan, as well as heat exchangers and salt pumps.
  • Thermal oil system that includes main and auxiliary pumping installations, tanks, oil boilers and steam generation equipment.
  • Water-stream cycle auxiliary installations (BOP).

SENER has carried out the project engineering and it has been built by a Temporary Joint Venture made up of SENER and COBRA PLANTAS INDUSTRIALES.

These Concentrated Solar Power Plants (CSP) are a type of sustainable installation that uses solar radiation to produce clean and safe energy capable of covering the electricity supply of 40,000 households, demonstrating the differentiating factors of the CSP technologies, contributing to energy safety, on using a local resource, without emitting greenhouse gases.

The use of concentrated solar radiation as primary energy allows Valle 1 and Valle 2 to reduce yearly CO2 emissions by over 90,000 tonnes. Maintaining the transport fluid's temperature above its freezing point, in periods of low solar irradiation, either at night or with cloudy weather, makes VALLE 1 & VALLE 2's production energetically efficient.

The relevant factor this project has provided is that it is the first thermo-solar project in which a scale prototype has been included, the storage of cold and hot salts in the same tank, called "single-tank". A Research and Development Project headed by the Engineering Firm SENER in which AKO has participated adapting its AKOTRACE® solution to the new requirements of this innovation, demonstrating its high degree of involvement in new technologies, its application in thermoelectric energy and investment in the R&D&i area to be able to prepare studies, field tests and to be able to make technological progress in this type of facilities.

To answer this technical challenge, the engineering firm SENER has contracted AKO as a partner to provide its electrical heat-tracing solution, AKOTRACE® in the salt concentration (TES), oils (HTF) and steam (BOP) parts.

Project Challenge

Technical requirements, although largely already resolved by AKO in many projects executed in thermo-solar plants with parabolic trough and salt accumulation technology, HTF oil and BOP steam, added important differences such as:

· The process working and maximum temperatures of materials in this type of plants with a risk of fire and explosion, in the circulation of the oil flow.
· Tracing of critical points such as valves, pump heads and vertical pipelines, providing in the first case, a specific and improved solution to the one used up to the moment.
· Special solution for the storage of cold salts in a single-tank prototype in Valle 2. · The scope and capacity of AKO's management in the simultaneous execution of two complete plants, that represent a total of 50 MW, applying its knowledge and experience and guaranteeing the efficiency and profitability of the two installations.

AKOTRACE® Solution

The scope of AKO's solution has been the execution of the turnkey AKOTRACE® electrical heat-tracing system for the two installations, as well as adapting AKOTRACE® to the new innovation needs that SENER has included for the first time in a Concentrated Solar Power Plant (CSP), a scale "single-tank" as the only molten salt storage tank. AKO's Innovation Director, Miguel Angel González, referring to this project: "For us it is essential to take part in all of these types of innovations to be able to offer a commercial solution and help them to be technically and financially viable. The activities we perform in our Research plan and these types of challenges allow us to continuously improve our AKOTRACE® solution, project after project".

In the AKOTRACE® solution, it is worth mentioning that we have chosen different key technical characteristics for this project:

  • Mineral insulating cable for the Salt and HTF area and constant, self-adjusting and mineral insulated power for the BOP area.
  • PT100 and RTD type probes (double redundancy in salt circuits)
  • Additional safety temperature control protections
  • Specific design of heaters for singular points: valves and pumps, in the salt storage part.
  • Installation of AKODUO Control Trace PLC's in HTF for circuit control
  • Connectivity with the DCS
  • Operator interface displays in the plant for quick identification of the system's status.

All of the above in an execution deadline of 9 months, in which both installations have been overlapped in time and in which AKO's main qualities, customer proximity, which has provided it with all of the necessary engineering documentation, flexibility, taking part in managing the supplies and, in short, the capacity for carrying out the different works simultaneously, have been highlighted.

Results

AKO started the Valle 1 & 2 Concentrated Solar Power Plants (CSP) in April 2011 and finished in January 2012. The results obtained in the introduction of the AKOTRACE® solution in such an emblematic project are:

The results obtained in the introduction of the AKOTRACE® solution in such an emblematic project are:

  • Introduction of improvements in the basic engineering area: definition of design criteria and process optimisation, as well as in R&D&i in the form of technical and technological solutions.
  • Assurance of the criticality of the system with an efficient investment, guaranteeing the circulation of the fluid at high temperatures, to prevent undesired Plant shutdowns or a loss of performance in its operation.
  • The company guarantees the quality of the equipment it supplies with specific preliminary "Stress Test" studies to guarantee correct operation and it carries out spare part management, with the necessary material and staff to address any incident in the installation, as well as strictly meeting safety, health and hygiene standards.
  • Project planning and coordination, equipment supply and start-up including coordination with the other companies participating in the installation, providing an on-time response to cover two simultaneous installations, in view of the rapid pace of the building, that required the planning set to conclude the two plants.
  • Specialised training of the plant's staff on the correct operation of the tracing system and its installation.
  • Transparent integration with the plant's management system to make plant maintainability easier.

The execution of this project complements the experience and knowledge acquired by AKO throughout its over 30 years of experience, which has positioned it as the world leader, committed to renewable energy future technologies in parabolic trough and concentration tower Concentrated Solar Power Plant (CSP) Projects.

About AKO

Over 30 years of innovation and with 130 people team of in-house professionals AKO Electromecànica, S.A.L. is a Spanish company leader in the Regulation and Control of Temperature with Electrical Heat Tracing Solutions for Concentrated Solar Power Plants (CSP), that offers comprehensive support from project design and manufacturing, to technical assistance, to the System commissioning (turnkey projects) and after-sales service. Electrical Heat Tracing System AKOTRACE® based the heating cable technology, providing advantages and savings on energy and the overall cost of the installation, with a reliable and secure management, ensuring the health, safety and respect for the environment.

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