Making central receiver plants modular, more efficient and scalable

Solar Thermal Electricity (STE/CSP) Tower Plants with single towers are limited in size as the heliostat field efficiency decreases significatively when the plant becomes larger. As plant size is an important driver in reducing the generation costs of STE plants - due to the relative high impact of the power block - this fact represents a great disadvantage for tower plants as compared with parabolic through ones, which might have unlimited size of the mirror field thanks to the modular loop concept. This effect is much stronger in locations with high atmospheric attenuation factor. This paper points out the optical and conceptual advantages of designing the future solar tower plants with a modular approach. Until now, the only approach was to optimize the field layout and the tower height of single units. Keeping the same central storage system and power block improvements in plant efficiency close to 25% can be achieved by splitting the single surrounding heliostat field into several polar field units. But perhaps the most important impacts in the necessary reduction of cost could be twofold: first, finding out a kind of standard module – perhaps between 30 – 50 MW – which can make designs easier and standardize important components like receivers and heliostats to produce their main parts in large series and second, being able to build STE tower plants in the 500 MW range with single power block units. This would provide a wide range of advantages and can position solar tower technology as a competitive concept for plants of unlimited size, boosting the deployment of STE/CSP tower plants in a standard, modular and cost-efficient way.