The Competitive Solar Power Towers project

The main goal of the Competitive Solar Power Towers (CAPTure) project is to significantly reduce costs of concentrated solar power (CSP), in order to pave the way for its deserved competitiveness on the power market.

In order to increase plant efficiencies and reduce levelized cost of electricity (LCOE), the project will develop all relevant components that allow implementing an innovative plant configuration.

Figure 1

Figure 1: The CAPTure plant configuration is based on a multi-tower decoupled advanced solar combined cycle approach

This plant configuration is based on a multi-tower decoupled advanced solar combined cycle approach that not only increases cycle efficiencies but also avoids frequent transients and inefficient partial loads, thus maximizing overall efficiency, reliability as well as dispatchability, all of which are important factors directly related to cost competitiveness on the power market.

The innovative solar receiver will be an open volumetric receiver allowing operating temperatures beyond 1200ºC, providing the absorbed solar heat to the pressurized air circuit of the Brayton cycle via a network of fixed bed regenerative heat exchangers working in alternating modes (non-pressurized heating period, pressurized cooling period).

The global objective of this project is to increase concentrated solar power plant efficiencies and reduce levelised cost of electricity (LCOE) by developing the key components of an innovative plant configuration. This plant configuration is based on a multi-tower decoupled advanced solar combined cycle approach (see Figure 1) that not only increases cycle efficiencies but also avoids frequent transients and inefficient partial loads, maximizing overall efficiency, reliability as well as dispatchability.

More specifically, CAPTure will focus on the following activities

  1. The development of an innovative, highly efficient open volumetric solar receiver:
    • As of November 2016, first receiver prototypes are being tested at the PSA in the south of Spain
  2. A network of highly efficient fixed-bed regenerative heat exchangers working in alternating modes – atmospheric heating and pressurized cooling
    • During the first half of 2017, the design of the system will be optimized and during the second half it will be manufactured and assembled
  3. A high efficiency two-stage, intercooled Brayton gasturbine cycle.
    • Progress as of February 2017 includes a full thermodynamic model of a two-stage intercooled Brayton cycle. This model uses a hybrid of known performance for the low pressure and power turbine stages together with models developed for the high pressure and intercooler parts.
  4. Validation-scale prototypes for the key elements as well as a complete solar-receiver, regenerator and turbine unit will be developed and tested.
  5. Development of small-area downsized heliostats that will enable improved solar flux control at the solar receiver through automatic heliostat field calibration.
    • An accurate cost effective small size heliostat has been developed based on low cost “off the shelf” available motors and low cost cable transmission.
  6. The complete theoretical assessment and optimisation of the modular multi-tower decoupled solar combined cycle concept (DSCC) for easing capital investments.

Updated scheme 2017

 

The solar receiver prototypes tests started in November 2016. The chosen test facility is the ‘’Plataforma Solar de Almería’’, a well-known solar test area in southern Spain, where all required infrastructure for the validation of the concept, such as an experimental tower and heliostat field are already available.:

PSA_Vista_Aerea_Panoramica.