The overall objective of WEDISTRICT is to demonstrate DHC as an integrated solution that exploits the combination of RES, thermal storage and waste heat recycling technologies to satisfy 100% of the heating and cooling energy demand in new DHC and up to 60-100% in retrofitted DHC. For this purpose, the focus of WEDISTRICT is large-scale replication of best practice: better valorisation of local resources, like renewable and waste heat by making District Heating and Cooling networks more efficient in relation to the use of new resources. In parallel, systems will evolve to provide even more flexible solutions by the integration of innovative molten-salts based thermal storage, the interaction with other energy networks (electricity and gas) and the involvement of end-users (operators and consumers) through ICT-based control and decision making. Finally, to enable significant expansion, cost-effectiveness will be enhanced by transitioning from handicraft to more industrialised solutions that integrate LEAN methodologies to optimise processes and lower costs.

A fully decarbonised European energy system must be equipped with very large flexibility capacities, enabling the uptake of intermittent renewable sources, coupling energy sectors, and increasing the energy system efficiency. The TREASURE project paves the way for the accelerated realization of large pit thermal energy storages that serve as the enabler for fully renewable district heating networks and industrial heating systems. With the project, 7 demonstrators are being realized in 5 different countries. The projects` aim is to use synergies in order to improve cost effectiveness through the targeted development of improved components and the collective improvement of design and building processes. Monitoring data from an already operating storage and from the demonstrators are used for better numerical simulation of actual and future system performance. Through the participation of market-oriented partners possible solutions to the financing, permitting, and social challenges in the realisation of large pit thermal energy storage projects are mapped and discussed with the broad group of stakeholders, with a core group of 15 satellite initiatives. The experience with the operation, maintenance and refurbishment of especially Danish pit thermal storages is used to improve the design and operation of the demos, the satellite initiatives and future storages in broad. The project consortium is composed of partners from the complete value chain; component suppliers, building companies, engineering companies, research and developments institutes, contractors, energy service providers, district heating companies and professional organizations. The developed roadmap and generated knowledge in the fields of planning, design, components, building, system integration, financing, permitting and business plans is actively disseminated to experts and to decision makers in order to accelerate the realisation of more than 2000 large PTES needed for the full decarbonisation.

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.

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