Andasol Solar Power Station, Andalusia

Andasol solar power station, the first parabolic trough solar power plant in Europe, is constructed at Andalusia in southern Spain. The plant is constructed on the Guadix plateau in Granada province.

It comprises three power plants: Andasol 1, 2 and 3, which form one of the largest solar power projects in the world. The total investment of the Andasol project is €900m ($1.2bn).

Andasol 1 and 2 were set up in September 2008 and June 2009. They generate a net electricity output of 150GWh per annum for each plant. The third plant, Andasol 3 was inaugurated in September 2011. Andasol 3 has generating electricity of 175GWh and cuts 150,000t of carbon emissions annually.

The Andasol plant supplies solar energy to approximately 450,000 residents in Spain.

Andasol solar power station ownership

Central Termosolar Uno owns the plant and Andasol 2. Cobra Sistemas y Redes and Solar Millennium Verwaltungs are the partners in Central Termosolar Uno. Cobra Sistemas y Redes is a subsidiary of the ACS / Cobra Group. The Andasol 1 and Andasol 2 plants were developed by ACS / Cobra Group and Solar Millennium.

Andasol 3 is owned and developed by Marquesado Solar SL (MSS). The shareholders of MSS are Solanda, Stadtwerke München and RWE Innogy & RheinEnergie. Solanda is a joint venture between Solar Millennium and MAN Ferrostaal.

Andasaol solar power plant details

The Andasol power station is constructed in an area of 575ha. Each plant has 312 collector rows generating 50MW in each plant. Each collector is formed by 28 mirrors and three absorption pipes. The collectors include 90km of absorption pipes and curved mirrors.

Plants are equipped with solar fields, thermal storage systems, heat exchangers, steam turbines, generators and condensers. Dry-cooling system in the Andasol plants reduces significant water consumption.

Siemens built the turbines for Andasol 1 and 2. Each turbine, weighs 160t and generates 50MW of power. MAN Turbo of Oberhausen, UK, built the turbines for the third plant. Schott Solar and Solel Solar Systems manufactured the required 22,500 absorption pipes for each facility.

Flabeg Group manufactured and supplied the mirrors for Andasol 1 and 2, while Rioglass Solar did same for the third plant. The mirrors of Andasol power plant are made of silver-coated and curved white glass.

Andasol plant consists of a heat accumulator along with two thermal storage tanks, which have a storage capacity of 30,000t. Molten salt mixture is heated in the accumulator and transferred to the tanks for storage. The stored heat is used for running the power plant after sunset for a maximum time period of 7.5 hours.

Andasol power station construction

Construction of Andasol 1 began in July 2006 and the plant officially became operational in March 2009. Construction of the second power plant started in February 2007 and started operating in June 2009. Construction on Andasol 3 began in August 2008 and started operations in September 2011.

The three Andasol power plants have a similar design. Construction works included fixing of the steel support rods, and attaching mirrors and absorption pipes to the steel rods. Metal support structures were combined with the steel pylons.

Hydraulic drives were connected to the collector chains of 150m length. The 312 collector rows follow the sun from east to west along a single axis and are fixed in north-south axis.

Andasol solar power plant makeup

The precision mirrors in the Andasol power station are arranged in a parabolic cross section. Each mirror is equipped with a collector. The light falling on the mirrors is reflected onto a focal line by the collectors.

The light energy is then concentrated on the focal line. Absorber tubes in the focal line contain special surface coating, which converts solar energy into heat. These tubs also contain thermo-oil, which is heated and the heat is transferred to a thermal transfer unit where steam is generated.

Produced steam is used to drive a turbine in the same way as a conventional power plant. Turbines combined with generator produce electrical power.

Distribution

The electricity generated in the Andasol solar power plant is sold to Endesa, a Spanish energy supplier.

Contractors involved with the Andasol solar power project

Engineering services, plant planning, design, construction supervision and control works for the Andasol solar power project were assigned to Flagsol, a subsidiary of Solar Millennium.

Cobra Instalaciones y Servicios and Sener Ingenieria y Sistemas were responsible for construction of Andasol 1 and 2. Installation of turbines and generators, and plant periphery works were performed by Sener Ingenieria y Sistemas.

Duro Felguera Group was responsible for the engineering, procurement, construction and commissioning of Andasol 3.