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.

The share of renewable energy is growing rapidly driven by the objective to reduce greenhouse gas emissions. The amount of electric power which can be supplied to the grid depends on the time of the day and weather conditions. A conventional fleet of thermal power plants is required to compensate for these fluctuations before large scale energy storage technologies will be mature and economically viable. All power market projections expect this to be the case for the next 50 years at least. For a strong expansion of renewables, this fleet has to operate flexibly at competitive cost. Current power plants cannot fill this role immediately without impeding their efficiency and engine lifetime through increased wear and damage induced by the higher number of (shorter) operating/loading cycles. New technologies need to be introduced to balance demand peaks with renewable output fluctuations at minimal fuel consumption and emissions without negative effects on cycling operation. The FLEXTURBINE partners have developed a medium to long term technology roadmap addressing future and existing power plants. The FLEXTURBINE project presented hereafter is the first step in such technology roadmap and consists of: (1) new solutions for extended operating ranges to predict and control flutter, (2) improved sealing and bearing designs to increase turbine lifetime and efficiency by reducing degradation/damages, and (3) an improved lifecycle management through better control and prediction of critical parts to improve competitive costs by more flexible service intervals and planned downtime, and by reducing unplanned outages. In all areas, individual technologies will be developed from TRL 3 to TRL 4-6. FLEXTURBINE brings together the main European turbine manufacturers, renowned research institutes and universities. It involves plant and transmission system operators to include user feedback and to prepare the take-up of the FLEXTURBINE technologies in power plants world-wide.

The energy sector accounts for two thirds of the global CO2 emissions and is therefore crucial to ensure future green growth and to achieve the global emission reduction targets. Substantial reduction of CO2 emissions can only be achieved by large scale deployment of renewable energy sources, including in particular the most abundant energy sources, wind and sun. Their intermittent nature however poses significant challenges for the energy system as peak demand from the system and peak production form those intermittent sources do not overlap. As there are no large scale storage solutions available yet, other backup capacities are needed. The installed fossil capacity is large enough to provide this back-up power. However, the plants were designed for baseload operation, which results in increased wear and costs through cyclic operation and unnecessarily high emissions in the start-up phase. Providing technology upgrades to retrofit the installed power plants to enable flexible operation without penalties on life, cost and emissions is an opportunity to quickly provide the necessary backup capacity to keep the energy system stable and resilient and at the same time enabling higher renewable shares. TURBO-REFLEX will follow this approach and has selected technologies for retrofitting critical parts of thermal power plants which have already seen experimental proof-of-concept and are expected to significantly contribute to flexible operation. The technologies will reduce the minimum load, increase the ramp rates and reduce the costs per cycle. This will be achieved by new compressor designs for off-design operability, technologies in the hot gas path, in combustor and turbine, and by new materials, models and sensors to monitor and ensure the mechanical integrity in flexible operation. An integrated assessment will provide not only the technological but also the economic benefits for plant operators, thus ensuring a swift implementation of TURBO-REFLEX technologies.