The main objective of POLYPHEM is to improve the flexibility and the performance of small-scale Concentrated Solar Power plants. The outcomes of the project will allow in the short term to reinforce the competitiveness of this new low carbon energy technology and therefore to favour its integration in the European energy mix. The technology consists of a solar-driven micro gas-turbine as top cycle and an Organic Rankine Cycle as bottom cycle. There is no water requirement for cooling. A thermal energy storage is integrated between both cycles. The resulting power block is a solar power generation system able to meet the requirements of a local variable demand of energy with a high average conversion efficiency of 18% and a low environmental profile with an investment cost target below 5 €/W. Besides electricity generation, other applications will be considered for future developments, such as heating/cooling of multi-family buildings or water desalination for small communities. The project will build a 60 kW prototype plant with a 2 MWh thermal storage unit and will validate this innovative power cycle in a relevant environment (TRL 5), assess its technical, economic and environmental performances and establish the guidelines for its commercial deployment. POLYPHEM will lead to a supply price of electricity of 21 c€/kWh under DNI of 2050 kWh/m2/year, thus meeting for small scale CSP plants the 40% cost reduction of the SET Plan. POLYPHEM will be carried out by 4 research centers and 5 private companies. The project makes a step forward beyond the state-of-the-art of thermodynamic cycles in CSP plants. The micro gas-turbine will be solarized to integrate solar energy in the cycle. A novel pressurized air solar receiver with 80% efficiency and 0.4 €/W will be developed from a technology of solar absorber currently patented by CEA and CNRS. A thermocline storage at 28 €/kWh will be developed with thermal oil and a filler material in a concrete tank.

HELIOTROPE is a groundbreaking research and development endeavor dedicated to advancing Concentrated Solar Power (CSP) technology to unprecedented heights. This project focuses on developing state-of-the-art molten salts and materials technologies for thermal energy storage systems, pushing the boundaries of operational temperatures beyond the current industry standard of 600ºC. A holistic approach is at the heart of HELIOTROPE's mission. Sustainable novel molten salts as thermal energy storage mediums and the remarkable ability to withstand absorber surface temperatures of up to 850ºC are introduced, promising to enhance CSP plant efficiency and dispatchability. This technological advancement aims to redefine the capabilities of CSP plants. Furthermore, HELIOTROPE aligns closely with key European energy policies and initiatives, contributing significantly to energy security, reducing reliance on fossil fuels, and lowering greenhouse gas emissions. The project supports the vision outlined in the European Green Deal, Clean Energy for All Europeans, and the Fit for 55 legislations, fostering sustainability and competitiveness in the energy sector. HELIOTROPE aspires to reshape the CSP plant landscape, making them not only more efficient but also inherently environmentally friendly. The project represents a significant stride towards a sustainable energy future, where CSP technology leads the way in innovation and progress, redefining the boundaries of what is possible in the pursuit of a cleaner, more sustainable energy world.

RESTORE proposes a radically innovative solution for DHC, based on the combination of two key innovative technologies (TCES+ORC), that allows integrating a wide variety of renewable technologies combined with competitive seasonal storage in DHC networks, allowing them to be 100% renewable to radically improve their environmental sustainability. The first technology the project aims to develop is an innovative thermal energy storage system based on Thermo-chemical reactions, the Thermo-Chemical Energy Storage (TCES), that provides daily and seasonal competitive energy storage due to its high energy density, very low energy losses and its low-cost. The system represents a key development due to the fact that it allows harnessing the enormous amount of energy that is normally wasted due to the mismatch between energy demand (loads) and energy generation (related to the availability of the renewable resource or waste heat), mainly occurring between seasons. In addition, the project aims to develop a second technology that is based on Heat Pump and ORC and is combined with the TCES system. This second technology adapts the energy provided by different renewable technologies to feed the storage system, thus a wide variety of renewable technologies as well as waste heat can be integrated into the whole system to finally supply the energy demand under the specific conditions laid down by each DHC. This radically innovative solution would tackle the main barriers for a wide deployment of renewable energy technologies and waste heat in the existing and future DHC networks. The projects consider the experimental validation of the RESTORE concept and also the demonstration of the concept replicability potential, adapting and optimizing the proposed solution to different real sites (different network conditions and local particularities as the available renewable technologies/waste heat) spread over the EU, and quantifying its potential benefits via virtual use-cases.

MOSAIC project aims to exceed the goal of the Strategic Energy Technology (SET) Plan - European Commission of producing CSP electricity at a cost below 0.10 €/kWh. To exceed this goal a commercial CSP plant of > 1GW of nominal capacity is foreseen, in which high nominal capacity of CSP plant is reached in a modular way where each MOSAIC module delivers thermal energy to linked thermal energy storage systems that supply their energy to a high capacity power block (>1GW). This modular configuration guarantees reliability, flexibility and dispatchability according to the needs of the electrical grid while reduces significantly the specific cost of the Power block (€/MW installed). Each MOSAIC module consists of an innovative fixed spherical mirror concentrator arranged in a semi-Fresnel manner and an actuated receiver based on a low cost closed loop cable tracking system. This configuration reduces the moving parts of the whole system decreasing solar field cost while keeping high concentration ratios. This will assure high working temperatures thus high cycle efficiencies and a cost effective use of thermal storage systems. Energy from the sun is collected, concentrated and transferred to the heat transfer fluid at module level where, due to the modular concept, distances from the solar concentrator to the receiver are much shorter that those typical from solar tower technologies. As a result, the efficiency of energy collection is maximized, atmospherical attenuation is minimized and accuracy requirements can be relaxed. All these technical benefits contribute to a much lower capital cost of the whole system while keeping efficiency and reliability. This has consequently a strong impact in the final cost of electricity production. First figures show LCOE estimated values below 0.10€/kWh for CSP power plants of 100 MW nominal power based in MOSAIC concept, additional cost reductions are expected for greater capacities (>1GW) exceeding the goal of the SET plan

Highly efficient energy conversion of solar power and storage will play a vital role in a future sustainable energy system. Thus, this project focuses on the development of a novel high-efficiency solar thermal power plant concept with an integrated electricity storage solution. The project combines air-based central receiver Concentrated Solar Power (CSP) and Compressed Air Energy Storage (CAES) to maximize conversion efficiency and power grid energy management, enabling a new operation strategy and business models. The hybrid concept initiates a futuristic era with adaptive renewable power plants, producing both electrical and thermal energy, including process heat supply and reverse osmosis desalination. Because cheap off-peak electricity is used to provide the air compression work of the topping Brayton cycle, the overall peak solar-to-electric energy conversion efficiency of the proposed power plant may reach up to 40% efficiency, which roughly doubles the peak efficiency with respect to state-of-the-art CSP technology. The project’s activity will cover the techno-economic-environmental optimisation of the innovative CSP-CAES plant using representative boundary conditions, provided by grid operators and specialised partners, as well as the development and extensive testing of key components needed for its implementation. The main development will cover: (i) an advanced high-efficiency solar receiver, (ii) optical sensors and AI-based control, (iii) optimized CAES with heat exchangers and compressor/expander detailed designs and (iv) innovative integration of desalination. The proposed technology is set forth by an interdisciplinary partnership spanning the entire CSP value chain. Targeting a TRL of 6-7, the ASTERIx-CAESar concept will be validated with a demonstration scale of 480 kWth prototype in a relevant environment.