Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - NEXTOWER (Advanced materials solutions for next generation high efficiency concentrated solar power (CSP) tower systems)

Teaser

NEXTOWER proposes to investigate a set of innovative materials to boost the performance of tower solar power (CSP) systems towards higher-temperature thermal storage. Tower systems are relevant to society for their great environmental compatibility and offer tremendous...

Summary

NEXTOWER proposes to investigate a set of innovative materials to boost the performance of tower solar power (CSP) systems towards higher-temperature thermal storage.
Tower systems are relevant to society for their great environmental compatibility and offer tremendous potential for efficient (electrical and thermal) power generation. Yet, their industrial exploitation has been so far hindered by limitations in the materials used for the central receiver - the core component - and for thermal storage. Such limitations in materials performance determine in fact the maximum working temperature and the in-service overall durability. Improving the efficiency of a tower system entails necessarily improving the central receiver upstream and possibly re-engineering the whole systems downstream to work longer and at much higher temperature, especially in the thermal storage compartment.
The successful development of a new generation of CSP materials in NEXTOWER, allowing both an increased working temperature of the receiver and a new storage concept based on liquid metal shall contribute to the next-generation of CSP towers, capable of competing with other CSP alternatives and sustainable power supply options.
The objectives of NEXTOWER are to deploy a comprehensive conceptual and manufacturing approach to optimize structural materials for durability, while designing a new storage strategy based on liquid metal to go beyond molten salts (limited to 550°C heat storage). Our concept entails, indeed, the pursuit of two important achievements:
(i) the making of better ceramics for high temperature receivers capable of extended service operations (20-25 years) vs. thermal fatigue and thermal shock;
(ii) the usage of liquid lead as high-temperature heat transfer fluid (HTF) and heat storage fluid (HSF) in CSP up and above 800°C, for the very first time.
NEXTOWER demonstration foresees the making of a full-scale joint CSP testing facilities called SOLEAD to be installed and run in Spain at the Plataforma Solare De Almeria (PSA).
The workplan includes also the assessment of market potential and industrial viability of all proposed solutions.

Work performed

From the beginning of the project to the end of the second reporting period, the main results achieved in the project are the following:
• development, manufacturing and delivery of advanced SiC based receivers, benchmarking different state of the art low cost ceramic manufacturing routes;
• conceptual and executive engineering design of the SOLEAD demonstrator, specified in all its parts and submiited to fabrication;
• full development of new steels capable of resisting liquid metal (pure lead) corrosion up to 850°C, fully tested in lab-scale condition on both bulk and welded coupons, for thousands of hours ;
• scaling up of alloy production (batch-size of tons od alloy) and welding qualification by authoritative manufacturer and welding Institutes;
• procurement of such steel materials in almost all the form factor needed for the making of SOLEAD demonstrator (with several formats, e.g. wire or welding strip);
• pre-standardization activities of the new materials and networking with ISO-related entities, particularly about a new testing procedure related to ceramics receivers testing by LFA in the technical committee CEN/TC 184 ;
• development and benchmark of several coating or surface treatment on the base ceramic receiver to reduce emission losses at high temperatures;
• atomistic modelling of liquid lead – steel interaction;
• beginning of dissemination of results through journal papers and conferences (Sustainable Places 2019);
• planning two sponsored events at inetrnational conferences in 2020.

Final results

There are diverse angles to look at the potential progress brought by NEXTOWER but the storage compartment deserves easily the highest ranking. The NEXTOWER thermal storage solution is indeed radically new. In the temperature range of 500-600°C, Molten-Salt heat storage systems have proven efficient and reliable. Existing CSP plants implementing this technology can rely on up to 16 h heat storage and potentially operate continuously. Yet, there is currently no storage solution available for large scale CSP system in the temperature range of 600-800°C and above, which can be achieved by the central receiver CSP tower systems. A technological leap is pursued in NEXTOWER to advance beyond the state of the art by introducing a liquid lead storage concept underpinned by an entirely new class of functional steels. The impact of this result will be broad in the field of materials, with expected cross-cutting benefit in the energy sector beyond CSP, for example from CO2 cycles technology (capture, storage, processing) to GEN-IV nuclear fission.
By delivering new materials that can be produced in large quantities for most energy application and installations, NEXTOWER will contribute solutions to have storage heat at 800°C at competitive LCOE and pave the way to the deployment of solar energy in many industrial processes, traditionally energy demanding and with a heavy carbon footprint. This will reinforce the European leadership in advanced materials and foster the deployment of solar power as a mainstream renewable option. By a societal perspective, apart from the environmental benefits from reduced fossil-fuel dependence, NEXTOWER success would mean associated business opportunities for Europe and the creation of new jobs.

Website & more info

More info: http://www.h2020-nextower.eu/.