Renewable energy has developed very fast in Spain in the last few years thanks to favorable legislation based on economic benefits. Solar thermal technology is found among these clean technologies.
The main requirements to build these plants are a hot climate and a nearby water resource. At this time different companies are building verious plants but in this article we will give information about the solar thermal plant in Orellana la Vieja (Extremadura) that is being built by Acciona.
The process of operation is as follows:
1. Solar concentration with parabolic solar collectors. These elements were built with mirrors and concentrate solar light in the metal tube of a cylinder.
2. That way, the concentrated heat in the tube is transferred to synthetic oil.
3. This oil gives heat to the water inside steam heat exchangers to produce water vapor.
4. Generation of electricity with vapor in a turbine. This electricity is conducted to the electrical substation where the voltage is raised.
5. Cooling system. After the turbine, the vapor goes back to liquid in a condenser.
Another main characteristic of this technology is that it is possible to produce electricity for some hours after the sun goes down because the synthetic oil can keep the heat.
These kinds of plants need many different kinds of companies to build them (companies of structures, electrical, boiler making, form works etc). My company (INDUSTRIAS METÁLICAS INTEGRALIA) built and assembled the entire metal structure of the plant, 1700 Tons in three months. We worked day and night in order to achieve the planning. Moreover, our technical department designed all the details and unions of the different structures and buildings in time.
Finally, these are the work site details of this project:
• A maximum of 400 construction workers on the construction site.
• Electrical production equivalent to 30.000 homes.
• Cost of €5 million to install a MW, €250 million in total.
• The area of solar capture covers about 500.000 m2; the total surface area of the plant is 200 hectares.
• The plant consumes 3000 liters of water per MWh.
• The water can be used in 2 cycles and after must be recycled.
• The temperature of the oil can reach 450°C.
Francisco Gallego Sanchez, Graduate Member in Spain