Liquid hydrocarbon fuels are ideal energy carriers for the transportation sector due to their exceptionally high energy density and most convenient handling, without requiring changes in the existing global infrastructure. Currently, virtually all renewable hydrocarbon fuels originate from biomass. Their feasibility to meet the global fuel demand and their environmental impact are controversial. In contrast, SUN-to-LIQUID has the potential to cover future fuel consumption as it establishes a radically different non-biomass non-fossil path to synthesize renewable liquid hydrocarbon fuels from abundant feedstocks of H2O, CO2 and solar energy. Concentrated solar radiation drives a thermochemical redox cycle, which inherently operates at high temperatures and utilizes the full solar spectrum. Thereby, it provides a thermodynamically favourable path to solar fuel production with high energy conversion efficiency and, consequently, economic competitiveness. Recently, the first-ever production of solar jet fuel has been experimentally demonstrated at laboratory scale using a solar reactor containing a ceria-based reticulated porous structure undergoing the redox cyclic process. SUN-to-LIQUID aims at advancing this solar fuel technology from the laboratory to the next field phase: expected key innovations include an advanced high-flux ultra-modular solar heliostat field, a 50 kW solar reactor, and optimized redox materials to produce synthesis gas that is subsequently processed to liquid hydrocarbon fuels. The complete integrated fuel production chain will be experimentally validated at a pre-commercial scale and with record high energy conversion efficiency. The ambition of SUN-to-LIQUID is to advance solar fuels well beyond the state of the art and to guide the further scale-up towards a reliable basis for competitive industrial exploitation. Large-scale solar fuel production is expected to have a major impact on a sustainable future transportation sector.

The main objective of the SCARABEUS project is the reduction of the CAPEX and OPEX in concentrated solar power technologies by about 32% and 40% respectively, leading to a final cost of Electricity below 96 €/MWh (lower than 30% of the actual value) through an innovative power cycle based on CO2 blends. This cost reduction will be able to close the gap between CSP and other renewable technologies. This project fits in the call "New cycles and innovative power blocks for CSP plants." as a brand new power cycle concept will be developed. With respect to state-of-the-art sCO2 cycles, the addition of small quantities of selected elements to pure CO2 (i.e. inorganic compounds and fluorocarbons), known as CO2 blending, can increase the CO2 critical point allowing the adoption of condensing cycle even in typical CSP plant locations. Condensing sCO2 cycles have higher thermal-to-electricity conversion efficiency with respect to conventional steam and sCO2 cycles.In addition, higher maximum operating temperature with respect to steam cycles can be adopted with further efficiency increase. The combination of these two aspects enables drastic reductions of the levelised cost of electricity In the project, CO2 blends stable at temperatures up to 700°C (which corresponds to 100°C above current CSP maximum temperatures) and with a pseudocritical temperature of about 50°C will be investigated. A preliminary screen was performed identifying some potential candidates (i.e. TiCl4). Assuming the simple cycle configuration, the TiCl4-blended CO2 outperforms the cycle using pure CO2 by 5% points at 700°C . When using the advanced sCO2 cycle, the efficiency gain is reduced to 2% points, but with significant cost savings. The proposed CO2 blend will be tested in a loop at 300 kWth scale with typical CSP fluids for 300 hours. Long term stability will be measured for 2000 hours and material compatibility assessed through dedicated experiments.

The main objective of the SOLPART project is to develop, at pilot scale, a high temperature (950°C) 24h/day solar process suitable for particle treatment in energy intensive industries (e.g. cement or lime industries). The project aims at supplying totally or partially the thermal energy requirement for CaCO3 calcination by high temperature solar heat thus reducing the life cycle environmental impacts of the process and increasing the attractiveness of renewable heating technologies in process industries. This will be achieved by the demonstration of a pilot scale solar reactor suitable for calcium carbonate decomposition (Calcination reaction: CaCO3 = CaO + CO2) and to simulate at prototype scale a 24h/day industrial process (TRL 4-5) thereby requiring a high-temperature transport and storage system. The system will operate at 950°C and will include a 30 kWth solar reactor producing 30 kg/h CaO and a 16h hot CaO storage. Life cycle environmental impacts of the solar-based solution in comparison with standard processes will be developed as well as economic evaluation. The project develops and merges three advanced technologies: high temperature solar reactor, transport of high-temperature solid materials and high temperature thermal storage. The synergy between these technologies lies in using the solar-treated particles as storage medium. The development of a such innovative technology for continuous particle processed by concentrated solar energy at about 950°C is unique in the world. Thanks to the solar unit integration in the industrial process (potentially combined with CO2 capture), this should result in the considerable reduction of the carbon footprint of the CO2 emitter industries and open a new market for renewable energies.

According to JRC CSP platform, with an increased efficiency of component and price reduction, 11 % of EU electricity could be produced by CSP by 2050. In the EC energy strategy, CSP finds mention as a potential dispatchable RES thus increasing potential market/need for CSP if coupled with flexible, high performant and low CAPEX power conversion units. In this sense sCO2 has been worldwide studied for several years as enabling technology to promote CSP widespread. SOLARSCO2OL presents sCO2 cycles as key enabling technology to facilitate a larger deployment of CSP in EU panorama which is composed (also considering available surfaces and DNI) by medium temperature application (most of them Parabolic trough – Tmax = 550°c) and small/medium size plants enhancing their performances (efficiency, flexibility, yearly production) and reducing their LCOE. Considering that compared to organic and steam based Rankine, sCO2 cycles achieve high efficiencies over a wide temperature of range of heat sources with lower CAPEX, lower OPEX, no use of water as operating fluid (a plus for arid CSP plants area), smaller system footprint, higher operational flexibility, SOLARSCO2OL would like to demonstrate in Evora Molten Salt platform facility the first MW Scale EU sCO2 power block operating coupled with a MS CSP. SOLARSCO2OL will capitalize previous EU expertise (SCARABEUS, sCO2-flex, MUSTEC), bridging the gap with extra-EU countries R&D on these topics and studying different plant layouts also to enhance CSP plants flexibility to enable them to provide soon grid flexibility services. SOLARSCO2OL is driven by an industry oriented consortium which promotes the replication of this concept towards its complete marketability in 2030: this will be properly studied via scale up feasibility studies, environmental and social analysis encouraging business cases in EU (particularly in Italy and Spain as two of the most promising EU CSP countries) and Morocco thanks to MASEN.