Despite the big deployment of concentrating solar power (CSP) plants, their environmental evaluation is still a pending issue. In this paper, a detailed life cycle assessment (LCA) of a CSP tower plant with molten salts storage in a baseload configuration is carried out and compared with a reference CSP plant without storage. Results show that the plant with storage has a lower environmental impact due to the lower operational impact. The dependence on grid electricity in a CSP tower plant without storage increases its operation stage impact. The impact of the manufacturing and disposal stage is similar in both plants. When analyzed in detail, the solar field system and the thermal energy storage (TES) and heat transfer fluid (HTF) systems are the ones with higher impact. Within the storage system, the molten salts are those with higher impact. Therefore, in this study the impact of the origin of the salts is evaluated, showing that when the salts come from mines their impact is lower than when they are synthetized. Results show that storage is a key element for CSP plants not only to ensure dispatchability but also to reduce their environmental impact.

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The high intermittency of solar energy is still a challenge yet to be overcome. The use of thermal storage has proven to be a good option, with phase change materials (PCM) as very promising candidates. Nevertheless, PCM compounds have typically poor thermal conductivity, reducing their attractiveness for commercial uses. This paper demonstrates the viability of increasing the PCM effective thermal conductivity to industrial required values (around 4 W/m·K) by using metal wool infiltrated into the resin under vacuum conditions. To achieve this result, the authors used an inert resin, decoupling the specific PCM material selection from the enhancement effect of the metal wools. To ensure proper behavior of the metal wool under standard industrial environments at a broad range of temperatures, a set of analyses were performed at high temperatures and an inert atmosphere, presenting a thorough analysis of the obtained results.

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Supercritical CO2 (sCO2) power cycles have been identified as technology enablers for increasing the cost-competitiveness of Concentrating Solar Power (CSP) plants. Compared to steam cycles, sCO2 cycles have the advantage of allowing higher inlet turbine temperatures, while also deploying turbomachinery that can be a ten-fold more compact. Ongoing research in CSP focuses mainly in developing new receiver and storage concepts able to withstand such required higher temperatures, alongside new heat exchangers that enable coupling to a sCO2 cycle. Meanwhile, advancements in sCO2 turbomachinery have taken place in research projects aimed at investigating the technical feasibility of the cycle, including the optimized design of its individual components and new cycle configurations. Among these, only few focus in demonstrating a full-integrated system, including cycle control and dynamics, and only two worldwide have started plans for MW-scale pilots, none of them in Europe. The EU-funded SOLARSCO2OL project aims at demonstrating a first-of-a-kind 2 MW gross simple-recuperated sCO2 Brayton cycle driven by heat provided by molten salts similar to those deployed in commercial CSP plants, which are able to operate at temperatures of up to 580°C. This paper introduces the project objectives and implementation plan, to then focus primarily on the results derived from the first year in specific relation to the conceptual design of each of 2 MW scale power cycle and its key components, including also the proposed integration and operational regimes, expected thermodynamic performance at nominal point, and up-scaling considerations.