The massive Solucar Complex in the Spanish Andalusian countryside is Europe’s largest solar complex. While currently operating at a capacity of 180MW, it is forecasted that the group of plants will reach a combined capacity of 300MW before 2014 – enough to power the nearby city of Seville. The Complex consists of two Concentrated Solar Power (CSP) plants, PS10 and PS20, together with the Solnova Solar Power Station, which uses parabolic troughs to concentrate solar rays.
PS10 was the world’s first commercial CSP plant. Using an array of moveable mirrors called heliostats, the plant focuses a large area of sunlight onto a small area atop a solar power tower. This concentrated solar energy is used to store heat in tanks of pressurised water, which is used to generate electricity. PS10 went online in mid-2007, making it the first power plant of its kind in the world
The 624 heliostats were produced by Spanish firm Abengoa, an offshoot of Solucar. Utilising a curved, reflective surface area of 120 sq m, each heliostat concentrates solar radiation on the receiver of PS10’s iconic 40-storey tower, generating temperatures of up to 1,000°c. Contained within a cavity designed to minimise radiation and convection loss, this thermal energy produces 40 bar 250°c saturated steam which in turn drives turbines.
The tower was designed by Alternativas Actuales de Construcción (ALTAC), a Spanish engineering firm specialising in the construction of industrial chimneys and tall concrete structures. Standing at 115 metres, the concrete tower has an opening which begins at an elevation of 100m and extends 15.3m in height and 14.1m in width – enabling the rays of sunlight clear passage to the receiver. This opening between the two shafts also serves to reduce wind load on the tower. Engineered by another Spanish firm,Tecnical-Tecnicas Reunidas, the solar receiver weighs a total of 240.5 metric tons. To bear this heavy load, a steel structure is located 0.2m below the tower’s composite platform.
The entire plant took four years to build.
A larger version of PS10, PS20 operates at double the capacity (20MW). Producing the lion’s share of the output, the Solnova Power Station consists of three separate CSP units, operating at 50MW each. Three more plants – the AZ20 (20MW), Solnova 2 (50MW) and Solnova 5 (50MW) – are scheduled for completion before the end of the year.