by the European Commission under FP5 with 5,000,000€ and the Andalusian
Regional Government with 1,200,000€. Total cost: 35,000,000€.
of the PS10 power tower plant
during plant construction
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
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 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.
PS10thermal storage tanks
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.