PS10

Participants

Solúcar (E)

Inabensa (E)

Ciemat (E)

DLR (D)

Fichtner (D)

Contact:

Rafael Osuna González-Aguilar,

Solúcar Energ-ía, S.A.

Duration:

July 1, 2001 – December 31, 2005

Funding:

Co-funded by the European Commission under FP5 with 5,000,000€ and the Andalusian Regional Government with 1,200,000€. Total cost: 35,000,000€.

Aerial view of the PS10 power tower plant

Aerial view during plant construction

Construction of the PS10 project, an 11 MW Solar Thermal Power Plant in Southern Spain has been completed. The main project goals for design, construction and commercial operation have been achieved. The plant is a first-of-its-kind Solar Central Receiver System (CRS) producing electricity in grid-connected mode.
The PS10 solar power plant, which is located in Sanlúcar la Mayor, 15 km west of the city of Seville, is promoted by Solúcar Energía, S.A., an Abengoa Group company, through the regis-tered IPP Sanlúcar Solar S.A.
The project makes use of well proven technologies, like glass-metal heliostats, a pressurized water thermal storage system, and a saturated steam receiver and turbine. These technologies have been developed by European companies, and already tested and qualified at the solar test facility located at the Plataforma Solar de Almería.
In this sense the project avoids technological uncertainties, giving priority to scale-up, subsystem integration, demonstration of dispatchability, and reduction of O&M costs. The project also focuses on writing the first standards from the information com-piled.
PS10 might itself be considered a solar tower technology mi-lestone in market penetration, since it is the first plant based on this technology operating for the sale of electricity with a purely commercial approach.

The PS10 power tower/heliostat field technology has a solar field composed of 624 120 m2 heliostats with a mobile curved reflective surface that concentrate solar radiation on a receiver at the top of a 100 m tower. The receiver, which produces 40 bar 250ºC saturated steam from thermal energy supplied by the concentrated solar radiation flux, has a cavity design to reduce radiation and convection losses.

Aerial view of the tower




The steam is sent to the turbine, where it expands, producing mechanical work and electricity. The turbogenerator output goes to a water-cooled 0.06-bar pressurized condenser. The condenser output is preheated by 0.8 bar and 16 bar turbine extractions. The output of first preheater is sent to a deaerator fed with steam from another turbine extraction. A third and last preheater is fed with steam coming from the receiver. This preheater increases the water temperature to 245ºC. This flow is mixed with the flow of water returning from the drum, raising the temperature of water fed to the receiver to 247ºC.
For cloud transients, the plant has a 20-MWh thermal capacity saturated water thermal storage system (equivalent to 50 minutes of 50% load operation). The system is made up of 4 tanks that are sequentially operated in order of their charge status. During full-load plant operation, part of the 250ºC/40 bar steam produced by the receiver is employed to load the thermal storage system. When energy is needed to cover a transient period, the energy is recovered from the saturated water at 20 bar to run the turbine at 50% load.

The four PS10thermal storage tanks

PS10 in operation

The tower was designed to reduce the visual impact of such a tall structure (115 m total height), so the body of the tower is rather thin (8 m) when seen from the side. The front needs to be about 18 m wide to allocate the 14 m wide receiver. A large space has been left open in the body of the tower to give the sensation of a lightweight structure. An accessible platform at a height of 30 m provides visitors with a good view of the heliostat field lying north of the tower, and the Sevilla PV plant (1.2 MWe, 2-axis-tracking, 2X-concentrating solar PV installation) south of the PS10 tower.
Inside the receiver at the top of the tower, concentrated solar radiation is transferred to the working fluid, where its enthalpy is increased. The PS10 receiver’s cavity concept reduces radiation and convection losses as much as possible. The receiver is basically a forced-circulation radiant boiler with a low steam ra-tio at the panel outlet to ensure wet inner walls in the tubes. Special steel alloys were used in its construction in order to operate under high heat flux and temperatures. It was designed to generate over 100,000 kg/h of 40 bar/250ºC saturated steam from thermal energy from concentrated solar radiation flux.
Solúcar is also promoting five more plants, PS20, AZ20 and Solnova50-1, Solnova50-2, Solnova50-3, in the same area where PS10 is being built, for a total of over 300 MW electric power,. PS20 and AZ20 are twin 20 MWe tower plants based on the same concept as PS10. PS20 construction will be launched in the first part of 2006.