Concentrating solar power

Concentrating solar power (CSP) technology is based on the concept of concentrating solar radiation to produce steam or hot air, which can subsequently be used in conventional electricity plants. Capturing solar energy, which has a relatively low density, is one of the major challenges of developing solar-thermal plants. Abengoa has accumulated more than 80 patent applications in this field.

The solar energy sector is relatively young and highly dependent on technology. This means that innovation is a key element, enabling better technologies to be developed with costs that are competitive with fossil fuels, including the cost of CO2 emissions. A reduction in costs will be driven by two main factors – an improvement in the supply chain and the introduction of new but more efficient technologies. Innovation is an essential component in the latter.

CSP energy encompasses various types of technology, of which tower technology, parabolic-trough technology and Stirling dish technology are the most widely known.

Abengoa is a world leader in tower technology and was the first company in the world to construct a commercial-scale plant with 10 MW of power, which it has operated since 2003. In 2008, it added an additional tower, with 20 MW of power. Both are operating satisfactorily, above and beyond their design parameters.

In tower systems, a field of heliostats or mobile mirrors track the position of the sun and reflect the solar radiation to concentrate it at up to 600 times its strength on a receptor located in the upper part of a tower. This heat is transmitted to a fluid in order to generate steam, which expands in a turbine coupled to a generator to produce electricity.

The technological challenge lies in increasing the temperature in the upper part of the tower in order to generate steam with sufficient calorific power. Since 2009 Abengoa has operated a pilot plant called Eureka that has managed to generate super-heated steam in a stable and controlled way. We are also experimenting with new heat-bearing fluids.

One of the differentiating advantages of concentrating solar power (CSP) technology compared to other renewable technologies is its capacity to store energy efficiently, which makes it possible to generate electricity at peak times, for example early evening. Abengoa is successfully operating a thermal storage pilot plant using molten salts, which the company is transferring to a commercial scale at its Solana plant (USA).

Parabolic trough collectors positioned on the flat roof of the buildings to Campus Palmas Altas, in Seville, (Spain)

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