• Energy Research
• French National Research Agency (AN... close

The objective of the project « CREATIF » is to implement a new « real time » simulation tool of the « Hardware-In-The-Loop » type offering complete interaction models between the various components of a floating wind turbine, in order to: develop new control and estimation architectures based on nonlinear approaches, efficient over a wide operational range for both power generation and wind turbine stabilisation, and relatively easy to adjust; optimize the architecture and sizing of energy conversion chains and their integration into the network based on technical and economic criteria. The project partners cover all components and systems involved in the floating wind turbine process: wind turbine dynamics under the combined action of wave and wind; energy conversion chain and network integration; control strategies; hardware and Power-Hardware-in the-Loop simulation.

Energy conversion is a sector whose development is strategic for our future. The objective of this collaborative project is to develop multifunctional nanocomposites coatings solutions with high performance for concentrated solar thermal conversion into electricity (CSP). CSP technologies are currently in full development (up to 25% of the global electricity production forecast for 2050). Nevertheless, the solar fields of the CSP plants require an increase in their conversion efficiency and a lowering of costs because they represent, whatever the technologies, about 30% of the installation costs and 50% of the yield losses (mirrors, protections, absorbers). NANOPLAST project is focused on the development of high performance coatings for solar absorbers. One of the important points is the sustainability of the systems in function (# 25 years required). Aging studies of coated systems in order to predict their lifetime are therefore imperative, whereas they are almost non-existent at present. In the NANOPLAST project, low environmental impact and commercially transferable plasma processes will be developed. Their versatility will make possible to achieve a wide range of composition and structuring 2D (multi-nanolayer) and 3D (inclusions at the nanoscale) of thin layers. The thermo-optical performance of nanocomposite structures (SiC / metal, TaON) will be evaluated by the consortium (4 laboratories and 1 industrial) recognized in the fields of CSP applications envisaged. The aim of this project is to meet the growing demand for nanocomposites on a European scale through an integrated understanding of the complete chain, from synthesis to performance evaluation. Given the needs for the CSP, the objectives of the NanoPLaST project are: - the development of multilayered multi-functional nanocomposite materials - developed by high-density versatile plasma technologies with high transfer potential to industry - with a high efficiency of solar thermal conversion via spectral selectivity - with high durability: resistance to high temperature into air (500

Few studies showed that the effects of rainfall (rain rate and drop size distribution –DSD-) on wind turbine efficiency are significant, but have surprisingly received little attention. The main goal of WR-Turb is to overcome the current lack of knowledge on this topic through a genuine collaboration between an academic institution (the Hydrology, Meteorology and Complexity laboratory of Ecole des Ponts ParisTech) and a wind power production firm (Boralex). Literature review shows that: (i) wind turbulence is a complex feature requiring appropriate framework such as Universal Multifractals (UM, a parsimonious framework that enables to quantify the variability across scales of fields extremely variable across wide range of scales) for analysis and simulations; and intermittency of the input power is further propagating to the wind turbine and power output; (ii) Rainfall also exhibits scale invariant multifractal features. WR-Turb will combine the existing knowledge on wind turbulence and rainfall fields to create a coupled framework enabling to tackle its objectives. Two distinct aspects will be studied: first the rainfall effect on the wind energy resources notably taking into account its non Gaussian extreme small spatio-temporal scale fluctuations and second the rainfall effect on the conversion process of wind power to electric power by the wind turbine. A scientific programme to be primarily implemented through two PhD projects was designed: - WP 1: Experimental set-up and data collection. An observatory for combined high resolution measurements of wind (speed, direction, shear and turbulence), rainfall (DSD, and fall velocities) and power production will be installed for 2 years on a wind farm operated by Boralex and having a 86 m meteo mast. A user friendly data base will be created and data carefully validated. - WP 2: Analysis and simulation of rainfall effects on the wind power available. It aims at analysing mainly with UM tools the collected data to quantify the influence of rainfall conditions on wind turbulence and air density. A classification of rainfall events will be designed for this purpose. Interpretation will require the development of innovative models. A new 3+1D model of drop fields in a 3D turbulent wind at wind turbine scale will be also developed. Scalar and vector spatio-temporal wind fields for scales ranging from few cm and to wind turbine size over few tens of seconds will be simulated by improving existing tools based on continuous UM cascades - WP 3: Analysis and simulation of rainfall effects on energy conversion by wind turbine. The transfer of wind intermittency to power production will be analysed from the collected data (WP1). Then, two numerical modelling chains with increasing complexity will be developed to simulate and quantify the effect of wind turbulence on power production. The wind fields simulated in WP2 will be used (i) to compute available torque fluctuations, and (2) as input in a multi-disciplinary model for numerical simulation of wind turbine behaviour (existing to be customized). Ensembles of possible inputs will be used to quantify the sensitivity of the modelling chains to various input parameters corresponding to the different rainfall conditions. The share of renewable energy is rapidly growing in France and Europe. Hence it is highly relevant to understand the uncertainty affecting the electricity production by such resources, notably because its intermittent nature raises complex challenges in terms of grid management. WR-Turb will have a strong impact on this field by providing a quantification of rainfall effects of wind power production and opening perspectives for improving nowcasts. Results will be up-scalable to other site because they will mainly be event-based. The novel findings of WR-Turb, which will be disseminated to both the scientific and professional community, will also open the path for future investigations.

Solar energy conversion and storage by Concentrated Solar Power (CSP) technologies receive an increasing attention because the integrated thermal energy storage (TES) system enhances the reliability, the dispatchability (production of electricity on demand) and reduces the operational cost of CSP plants (increase of annual capacity factor). Currently available options of TES system for CSP applications mainly include two-tank storage and single tank thermocline. Two-tank storage is the most common design and widely used in which hot and cold fluids are located into two separate tanks. In single-tank thermocline storage, both hot and cold fluids are stored within the same tank, but separated by a temperature gradient (stratification) during different operating periods. It is a more cost competitive (about 35% cheaper compared to two-tank storage) and efficient option: space compactness, reduced thermal loss, use of cheap solid materials as fillers and no extra heat exchanger needed between hot and cold tanks. However, no industrial-scale prototype was built and tested in the world since about 30 years. The main scientific barriers include: (1) lack of detailed data obtained by independent research organization; (2) reduced controllability of the temperature stratification which may be strongly disturbed by maldistribution of the injected inlet fluid flow; (3) non-optimized packing configurations of solid fillers. How to overcome the flow maldistribution problem is actually one major challenge. In fact, the improper design of fluid distributor/collector may cause the flow non-uniformity, local turbulence and recirculation. The mixing of hot and cold fluids and the disturbance of the temperature stratification (increase of the thermocline thickness) will reduce the energy efficiency of the system and the storage capacity. The general objective of this project is to design and develop a single tank thermocline technology with high energy efficiency and storage capacity by thermal stratification and optimized packing configurations, as a TES system for CSP plants. In fact, this innovative technology is not limited to CSP applications but can be applied in the TES sector in general. The major novelties of the proposal include: (1) systematic studies from the design tools, the modeling, local experiments to the prototypes testing and scaling up guidelines. All these steps were never performed before with the purpose of developing a validated model that can be applied to thermocline tank scaling-up; (2) optimized baffled fluid distributor/collectors to solve the flow maldistribution problem, which was rarely tackled before. The energy efficiency improvement and the storage capacity enhancement by maintaining the undisturbed temperature stratification in the thermocline will be highlighted; (3) use of recycling materials as fillers to reduce the material cost (by a factor of 5 to 10), an idea developed in the framework of a previous ANR project SOLSTOCK, but has never been demonstrated at pilot scale (>100 kWth). The proposal is thus ambitious. It presents a research of multi-scale nature from the fundamentals (3D modeling, fluid management) via a lab-scale experiments for hydrodynamic study and fluid/solid interactions, to the field testing of pilot-scale prototypes with different heat transfer fluids and global performance evaluation/optimization of the TES system. Finally it includes steps towards the system integration optimization, the scaling-up issue and the commercialization of the thermocline technology for CSP plants. The project will be realized in collaboration between two academic partners (LTEN-CNRS and PROMES-CNRS) and two industrial partners (Eco-Tech Ceram and ADF PROCESS INDUSTRIES). The consortium presents excellent and complementary experience and expertise. The strategies and methods for operating the project are well established to ensure its good progression.

Wind energy is one of the promising energy sources to reach the objective set by the French regulation of increasing renewable energies to about one third of the final energy consumption by 2030. In spite of a strong growth of the wind energy sector these last 10 years, and in spite of a solid potential for development, France has fallen behind on this goal. This may be partly explained by the constraint framework in which wind energy is developing, as well as the opposition of wind farm neighbors who very often mention noise as a potential annoyance. First French collaborative research project on wind turbine noise, the goal of the PIBE project is to improve prediction methods for wind turbines noise and to explore new solutions for noise reduction. The project brings together experts in aeroacoustics, sound propagation, experimental characterization of noise, and wind turbine engineering. The research program is structured in 3 work packages (WP). The first WP aims to study the amplitude modulation phenomena, known to be a major source of annoyance when they occur. This axis focuses particularly on characterizing and modeling the dynamic stall of the flow around the blades, as well as the conditions of amplitude modulation generation at the receiver. These phenomena will be studied both in wind tunnels, and near a wind farm managed by one of the project partner. The publication of a detailed database of the wind tunnel characterization of dynamic stall noise will help advance knowledge about a poorly understood phenomenon. The second WP focuses on quantifying the variability of noise predictions. To achieve this goal, the uncertainties and variabilities of the parameters influencing both the noise emission and the noise propagation will firstly be calculated; secondly, a model of uncertainty propagation (associated with advanced and appropriate statistical methods) will estimate the overall uncertainty. The results will be disseminated through the implementation of an open access online database. The last WP of the project will study and propose new noise reducing devices, using blades with modified leading and/or trailing edges. The efficiency of the solutions will be characterized in wind tunnels, from both acoustic and aerodynamic points of view. An estimate of their performance potential at scale 1: 1 will also be conducted. Results of the projects will eventually allow a better control of the risk of wind turbine noise pollution by the wind energy industry from the wind farm design phase, and thus improve the integration of wind power in the territory. It will help to reduce litigation risks by proposing a better response to noise reduction concerns raised by local residents of existing wind farms (efficient noise reduction devices). It will also enable wind farm developers to optimize production of wind turbine energy, thanks to a better prediction of producible energy during the wind farm phase of development. The results for the uncertainties related to the variability of atmospheric phenomena on the emission and propagation of noise will also feed future works of standardization. It will help to improve the practices of noise prediction, even for other environmental noise sources than wind turbines. In a context in which the reduction of noise pollution remains a major challenge for the authorities, the project will contribute to the limitation of noise emissions and of the possible associated extra auditory effects on health, such as effects on sleep or activities cognitive. Wind farms generating less noise pollution, because designed more optimally, will contribute to a better acceptance of wind power by the citizens. It will thereby support the growth of renewable energy development that guarantee the reduction of greenhouse gases, while respecting the well-being of local populations.

The concentrated solar power (CSP) will take a significant part in the diverse scenarios for reduction of greenhouse gas emissions. The CSP sector presents the considerable advantage, in comparison with the other intermittent energies, to be able to integrate a storage function, which allows to shift the electricity production to periods of strong environmental or economic interest. For it, a high-temperature thermal storage has to be integrated between the solar receiver and the power block. Compared to existing systems (sensible or latent heat), the thermochemical storage processes constitute innovative and promising solutions, still in the state of research. The thermochemical processes based on reversible solid /gas reactions are particularly relevant by their high effective energy density (until 400 kWh /m3) and operating temperatures (until 1000°C) depending on the reactants. The aim of this project is to investigate the integration of such a thermochemical process in a CSP installation by an approach which aims at the global optimization of the performances of the power plant integrating this storage. For that purpose, the project focuses on the following key points : 1) The concepts of coupling the thermal storage and the power plant: the objective is to enhanced transfers between the themochemical reactor and the Rankine cycle. The coupling modes will be analyzed in an exhaustive way, then simulated. The most pushed integration of the storage to the Rankine cycle will be looked for. We shall analyze the impact on the sizing, the functioning and the performances of every component, but also globally of the solar plant. 2) The thermochemical reactor: it will achieve a thermal storage adapted to the CSP sector according to several criteria: operating temperature, energy density, stored energy, restored power... A strongly compact reactor (a fixed bed) will be chosen. By means of a local model, we shall model and optimize the gas and heat diffusion network, as well as the kinetics and transfer characteristics of the composite (combining the reactive salt with a binder), according to the above criteria. 3) An experimentation on a pilot: the pilot will couple a reactor of optimized configuration and a complete Rankine cycle, according to the high performance concept selected at point 1. We shall analyze the functioning and the performances of components, and the global performances of the whole system. A particular attention will be paid to the dynamic aspects depending on several causes: variability of the solar source, the intermediate phases of the thermochemical reactor functioning, the variation of the reaction kinetics. 4) The scenarios of storage/production for CSP: they cover from the peak production (a few hours a day) to the base production (over 24 hours) and strongly influence sizing, investments, saling price of the produced electricity, environmental criteria … A global model of solar installation integrating a thermochemical storage will allow to realize an economic optimization by a global approach coupling sizing of the system and choice of the scenarios of storage/production. Several applications are in scope: large-sized power plant, solar installation coupled with a smart-grid, isolated installation. 5) The impact of the thermochemical storage on the CSP sector: in parallel with the scenarios, we shall study the extrapolation to a large-scale reactor, by investigating the size of modules and an adequate manufacturing process optimizing the cost of the reactor. Simulations of these configurations will be done thanks to the tool developed in point 2. Furthermore, a life cycle analysis will allow to direct the choice of the configuration in order to reduce the environmental impacts.

The objective of the CO2-DISSOLVED project is to assess the technical-economic feasibility of a novel CCS concept integrating (1) an innovative post-combustion deep-well CO2 capture and dissolution technology, (2) injection of dissolved CO2 instead of supercritical, and (3) combined geothermal heat recovery in the extracted brine via a doublet/surface heat exchanger system. This approach combines several objectives including renewable energy production, greenhouse gas reduction, and the assessment of a novel, low cost capture and storage method. Further, the proposed use of dissolved CO2 versus injection in a supercritical phase offers substantial benefits in terms of lower brine displacement risks, lower CO2 escape risks, lower to none pressure buildup in the storage aquifer, and the potential for more rapid mineralization. As another contributing novel factor, this proposal targets low to medium range CO2-emitters (10-100 kt/yr), that could be compatible with a single doublet installation. Unlike the standard approach which focuses on very large regional emitters (1-5 Mt/yr), the proposed CO2-DISSOLVED concept opens new potential opportunities for local storage solutions dedicated to low emitters such as food, paper, or glass industry, building materials makers, etc. Since it is intended to be a local solution, the costs related to CO2 transport would then be dramatically reduced, provided that the local underground geology is favourable. On the other hand, the heat recovered could benefit directly to the industrial emitters for their own heating and/or process needs and possibly for heating other collective buildings close to the storage facility. This project is divided in four main technical tasks addressing the following points: - Task 1: Applicability of the Aqueous-based CO2 Capture and Dissolution Facility technology, - Task 2: Efficiency of the Coupled CO2 Injection/Geothermal Heat Extraction System, - Task 3: Monitoring and Risk assessment, - Task 4: Integrated Technical-Financial Feasibility Analysis Applied to two Test-cases (France, Germany). Though being mainly a feasibility study relying on engineering methodologies, the achievement of this project will also have to rely on ambitious research work in order to address the following points: - Standard monitoring and risk analysis approaches need be revisited as a function of the new features and constraints of the CO2-DISSOLVED approach. Innovative geochemical and geophysical monitoring solutions are intended to be evaluated and tested, both on-field and in-lab. A new risk analysis methodology will be specifically designed and applied in accordance with the modelled and observed properties of the whole system. - The potential acidified brine reactivity will now be delivered out of the injection well, unlike the standard supercritical approach where the acid front followed the extension of the CO2 plume. Specific work, focusing on the near-well area and relying on both new experimental and modelling approaches will be carried out in this project. A new experimental facility will be available for future experiments involving injection of dissolved CO2. - The association of CCS to geothermal heat production, applied locally to small CO2-emitters, makes partly obsolete previous conceptual economic models. New models will then have to be developed, validated, and applied to two application test-cases (one in France, one in Germany). The expected results will permit to have at our disposal a complete portfolio of innovative technologies associated with adapted experimental and theoretical tools, so that in case of positive conclusions on the feasibility of this concept, promising industrial applications could be envisaged on the short term by the end of this 30 month project.

Pc2TES aims at developing a new kind of materials with high potential for cost-effective compact thermal energy storage (TES) at high temperature. The proposal is based on a ground-breaking idea which consists in using chemical compounds formed during peritectic transitions. The term peritectic refers to reactions in which a liquid phase (L) reacts with at least one solid phase (a) to form a new solid phase (ß). The reaction is reversible and takes place at constant temperature. The formed phase (a) is either a solid solution of one of the components, an allotropic phase of one of the components, or a new stoichiometric compound. In such materials, the thermal energy will be stored by two consecutive processes: a melting/solidification process and a liquid-solid chemical reaction. On cooling (discharge process), the pro-peritectic phase ß(s) starts to nucleate once the liquid phase reaches the liquidus temperature, and then it grows until the peritectic temperature is reached. At this point, the liquid phase reacts with ß(s) to form a(s). On heating (charging process), the solid a(s) decomposes at the peritectic temperature into a liquid phase and the solid ß (s). Then, the solid ß(s) melts. As far as we know, this idea has never been proposed before and no team in the world is exploring it. It follows the recent preliminary research conducted by partner 1 (I2M) and might lead to a TES technology with higher performances and lower cost than those currently used or investigated. The proposal will focused on the 300-600°C temperature range, which allows covering a wide spectrum of significant and challenging applications. Compared to the state-of-the-art in TES at high temperature, the main expected advantages of using peritectic compounds are as follows: Compact TES. The effective energy density provided by the liquid-solid reaction leading to the peritectic compound lies within the interval 200-400 kWh/m3 in many cases, whereas it can be as high as 400-650 kWh/m3 when the energy associated to the melting/solidification of the pro-peritectic solid is added. These values are comparable (even higher) to those of gas-solid reactions under investigation in the world and make peritectics attractive for large-scale TES applications. Simple TES technology. Contrary to gas-solid reactions in which chemical reactants have to be separated, the liquid phase and the solid phases involved in peritectic formation separate and recombine by themselves. Moreover, the storage material works at atmospheric pressure both in charge and in discharge. As a result, simple storage concepts, like one-single tank with storage material in bulk and embedded heat exchanger, will apply. Cost-effective TES solutions. The investment cost (as well as those of operation and maintenance) will be therefore much lower than that of the technologies based on solid/gas reactions. Moreover, as the expected volumetric energy density is much higher than that of currently used phase-change materials, the investment cost should be lower than that of latent heat storage technologies and probably close to that of the cheapest sensible heat storage systems. To summarize, the perictectic compounds could lead to TES solutions gathering the advantages of the technologies currently used or investigated while avoiding their respective drawbacks.

Geothermal energy, namely the mobilization of the subsurface heat at very low, low or high temperatures, is one of the methods to achieve the energy transition. The energy-climate strategy plans to increase deep geothermal heat produced in Ile-de-France in 2030 by a 3.5 factor compared to 2015. The current average development rate will not allow this objective to be achieved, it would be necessary to reach a 6 to 10 times higher rate, so the new multiannual renewable geothermal energy programming is being revised downwards in France. Feedback on recent operations in Ile-de-France has raised technical and/or scientific locks to be removed for an efficient and sustainable operation of geothermal doublets, such as the high but unquantified risk of low water flow / thin thickness of reservoir (meter-scale), the risk of interference between geothermal systems in high density of well infrastructures or the risk of early thermal breakthrough. There is a real risk that an installation may not reach a geothermal resource with sufficient flow and temperature characteristics to ensure the cost-effectiveness of the project during its life time. This risk constitutes a real obstacle for the future development of geothermal energy in Ile-de-France. It is clearly established in the energy-climate strategy to work on innovation by proposing solutions that optimize and explore the development of new reservoirs. The optimization of the use of deep geothermal energy is a major challenge for the Région Ile-de-France, which has a population of nearly 12 million inhabitants and still growing. This optimization of geothermal production of aquifers requires (1) precise knowledge of the reservoir heterogeneity in terms of sedimentary geometries, porosity/permeability, reservoir connectivity and (2) reliable numerical simulations of flows and temperature evolution in the underground 30 years or even 100 years after production starts. The main objectives are to successfully perform the upscaling pore-scale laboratory measurements and kilometre-scale sedimentary connectivity of reservoir bodies in order to better predict the resource. The homogenization will give the equations valid at every point of the domain, for both fluid and solid constituents, and in the same time the effective coefficients such as porosities, permeabilities, mechanical deformation (Gassman’tensor and Biot’s coefficient) and effective heat dispersivity. Their determination from the geological data will be the main challenge of this project coupling geological and mathematical concepts.