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International audience; This paper identifies the underlying physical mechanisms that frame the flexibility and operation of nuclear technologies, with analysis focused on the effects of two structural characteristics of nuclear fleets, i.e. nuclearschedule optimization and minimal power variations, on simplified French power system simulations. We develop a method to simulate nuclear schedule optimization to reflect how plant managers maximize plant availability during peak-demand periods. Using this schedule optimization, we compute each plant’s minimum power level and its variation over time to evaluate the flexibility potential. Three nuclear flexibility hypotheses are considered: one where fleet schedule is considered constant, which is standard practice in the energy systems modeling literature, one with an optimized fleet schedule with constant minimum power, and one with an optimized fleet schedule with physics-induced minimum power variations. Sensitivity analysis highlights thelinks between the fleet’s schedule optimization, minimal power variations, relative share of nuclear and renewables in the capacity mix, and results of simulation models. We find that the nuclear fleet’s optimization andassociated realistic minimum power variations gain in importance with increasing relative share of nuclear in the capacity mix. The schedule’s importance holds as renewables’ installed capacities heighten as the residual demand level decreases. This paper highlights the potential benefits of modeling nuclear schedule optimizations and the resulting minimum power evolutions. Both aspects are crucial for evaluating nuclear flexibility characteristics in simplified low-carbon electric systems that use a significant share of renewable energy.

While the transportation sector is responsible for a growing share of greenhouse gas emissions, electric vehicles (EVs) offer solutions for greener mobility. The proportion of electric vehicles in transportation fleets is increasing, but wider adoption will not be possible without an appropriate charging infrastructure. The deployment of such infrastructure should follow a strategy that considers both the environment in which it is deployed and the behavior patterns of electric vehicle users. If these aspects are not taken into consideration, there is a risk of failing to meet users’ needs and generating additional costs. Here we review the literature on location problems for electric vehicle charging stations. We aim to draw up a comparative overview of approaches that have been used up to 2020 for optimizing the locations of charging infrastructure. We first briefly review the issues raised by the deployment of charging infrastructure, namely technical, economic and user acceptance concerns. We then look at the goals of the infrastructure location models in the literature. Schematically, those goals fall into two categories: minimizing the cost of charging infrastructure for a given level of service, or maximizing the service provided for a given cost. Finally, we focus on the approaches used to achieve these goals. Three categories of approaches are identified: node, path, and tour- or activity-based approaches. We then discuss these approaches in relation to technical, economic and user acceptance factors in order to provide a comprehensive analysis for stakeholders involved in EV charging infrastructure planning. Directions are given for future research to develop models that better reflect the real-world picture.

International audience; Electric vehicle (EV) grid integration presents significant challenges and opportunities for electricity system operation and planning. Proper assessment of the costs and benefits involved in EV integration hinges on correctly modeling and evaluating EV-user driving and charging patterns. Recent studies have evidenced that EV users do not plug in their vehicle every day (here called non-systematic plug-in behavior), which can alter the impacts of EV charging and the flexibility that EV fleets can provide to the system. This work set out to evaluate the effect of considering non-systematic plug-in behavior in EV grid integration studies. To do so, an open-access agent-based EV simulation model that includes a probabilistic plug-in decision module was developed and calibrated to match the charging behavior observed in the Electric Nation project, a large-scale smart charging trial. Analysis shows that users tend to plug-in their EV between 2 and 3 times per week, with a lower plug-in frequency for large-battery EVs and large heterogeneity in user charging preferences. Results computed using our model show that non-systematic plug-in behavior effects reduce the impact of EV charging, especially for price-responsive charging, as fewer EVs charge simultaneously. On the other hand, non-systematic plug-in can reduce available flexibility, particularly when considering current trends towards larger battery sizes. Counter-intuitively, large-battery fleets can have reduced flexibility compared to small-battery fleets, both in power and stored energy, due to lower plug-in frequency and higher energy requirements per charging session. Improving plug-in ratios of EV users appears as key enabler for flexibility. In comparison, augmenting charging power can increase the flexibility provided by EV fleets but at the expense of larger impacts on distribution grids.

The high penetration of distributed energy resources and electric vehicles is changing the way the electricity system is managed. In turn, the way utilities have been recovering their expenditures through tariffs needs reformulation. We investigate the impact of different retail tariff designs from a Californian scenario on private investment incentives and cost-shifting using solar PVs, stationary batteries, and electric vehicles. The commercial private facilities studied do not own the vehicles and the vehicle owners receive compensation for energy services provided, which strongly depends on the type of tariff applied. We found that energy-based tariffs with on-peak periods synchronized with solar PV production brought the highest private gains, but with high cost-shifting. On the other hand, the capacity-based tariffs reduced the economic benefits and cost-shifting concomitantly, mainly when on-peak periods defined by the rate matched the most constrained grid time window. Batteries are incentivized mostly to offset maximum demand charges rather than to arbitrage energy, but this will strongly depend on the spread between on-peak and off-peak periods. Coincident peak rates, coupled with EVs, can bring high remuneration for EV owners, second-highest net present value, and second-lowest cost-shifting among all rates. Finally, we derive policy implications from the results and earmark more sophisticated tariff designs for investigation.

International audience; Chromatin organization is essential for appropriate interpretation of the genetic information. Here, we demonstrated that the chromatin associated proteins HP1 are dispensable for hepatocytes survival but are essential within hepatocytes to prevent liver tumor development in mice with HP1β being pivotal in these functions. Yet, we found that the loss of HP1 per se is not sufficient to induce cell transformation but renders cells more resistant to specific stress such as the expression of oncogenes and thus in fine, more prone to cell transformation. Molecular characterization of HP1-Triple KO pre-malignant livers and BMEL cells revealed that HP1 are essential for the maintenance of heterochromatin organization and for the regulation of specific genes with most of them having well characterized functions in liver functions and homeostasis. We further showed that some specific retrotransposons get reactivated upon loss of HP1, correlating with over-expression of genes in their neighborhood. Interestingly, we found that, although HP1-dependent genes are characterized by enrichment H3K9me3, this mark does not require HP1 for its maintenance and is not sufficient to maintain gene repression in absence of HP1. Finally, we demonstrated that the loss of TRIM28 association with HP1 recapitulated several phenotypes induced by the loss of HP1 including the reactivation of some retrotransposons and the increased incidence of liver cancer development. Altogether, our findings indicate that HP1 proteins act as guardians of liver homeostasis to prevent tumor development by modulating multiple chromatin-associated events within both the heterochromatic and euchromatic compartments, partly through regulation of the corepressor TRIM28 activity.

International audience; Distribution system operators face a challenging environment marked by increased decentralization, digitalization, and the decarbonization of transport and heating sectors. In particular, the integration of large numbers of electric vehicles (EVs) will pose challenges for distribution grid operation and planning. However, EVs also open the opportunity to offer flexibility services to different actors in the electricity system using smart charging and vehicle-to-grid (V2G) technology. This work reviewed the scientific literature and key European demonstrator projects on the proactive integration of EVs into distribution grids. The main technical, economic, regulatory, and user-related aspects were analyzed and the associated barriers identified. There is a broad scientific literature on the technical feasibility of EV flexibility provision and coordination schemes, which has as well been proved in demonstrator projects, even though the required technologies for V2G (bidirectional chargers, communication protocols) are not yet widespread. On the other hand, main barriers are economic and institutional, largely due to a lack of regulatory frameworks to value flexibility at distribution level and thus uncertainty on the value of these flexibility services. In particular, this work analyzed four possible value frameworks (grid codes, connection agreements, tariffs and market platforms) to use flexibility at the distribution level, and their implementations with EV fleets in demonstrator projects.

International audience

Distribution system operators (DSO) are starting to implement market-based mechanisms to use the flexibility offered by distributed energy resources (DER) such as electric vehicles (EV). Several European countries are trialing a range of real-life tests and market designs, and local flexibility tenders that allow DSOs to procure medium- to long-term flexibility have found early success. Here we set out to: i) identify the remaining barriers to entry for DER aggregators in these new flexibility schemes, and ii) quantify the participation of EV fleets in long-term flexibility tenders. We built a model to evaluate the potential EV aggregator gains on local flexibility tenders considering market rules, definitions of flexibility product, and different EV fleet compositions. Our model shows that the main parameters affecting EV fleet aggregator participation and remuneration are bidirectional capability (V2G), fleet reliability, and the right match-up between availability profiles and tender requirements. In best-case scenarios, EV fleet aggregators can expect revenues of over €1400/EV/year providing services for only a few hours or months per year. The paper concludes with policy recommendations based on best practices to boost DER participation in local flexibility markets.

International audience; Environmental policies are pushing cross-sector electrification, including the transport and heating sectors. However, the large integration of distributed energy resources, such as electric vehicles (EV), heat pumps (HP), and photovoltaic (PV) systems, has a strong influence on the stability of low voltage (LV) distribution grids and can lead to high reinforcement costs. This work develops a methodology to quantify the impacts of a joint integration of EVs, PV, and HPs into LV distribution grids and the ability of a decentralized EV smart charging strategy to reduce the constraints. A central occupancy model generates demand and generation profiles for the studied technologies, which are then used to carry out Monte Carlo simulations for unbalanced power flow analysis of LV grids. A case study of a typical Belgian rural grid shows that the main impacts arise from HP integration, creating voltage deviations and transformer overloading. EV integration impacts are less significant, creating grid issues only at high-penetration levels and to a lesser extent than HPs. The proposed smart charging strategy allows reducing the impacts of EV integration; however, it does not allow increased penetration of the other technologies. Other smart charging and Vehicle-to-Grid (V2G) strategies should be analyzed to further increase DER penetration.

Transmission topology control is a tool used by system operators in the role of a control action taken into account as a preventive or corrective action relative to a specific outage or set of outages. However, their inclusion in most electricity market frameworks is limited. With the increasing penetration of intermittent energy sources, optimal topology can be used as a lever of flexibility to decrease the total system cost. This paper demonstrates the evolution of optimal topology control on systems with increasing quantities of intermittent renewable energy along two axes. First, the effects of the increased variable sources on the variations of optimal topology are explored. Second, we elaborate on the growing advantages of exploiting transmission level grid flexibility in terms of total system cost. Case studies are performed on a modified RTS-96 network., Accepted at IEEE Powertech 2021 Madrid (virtual)

International audience

International audience

International audience; Distribution system operators are starting to implement market-based mechanisms to use flexibility from distributed energy resources. Flexibility tenders allow distribution system operators to procure flexibility for the medium to long-term, with the first implementations in Europe in the UK since 2018, and a recent pilot in France. This work seeks to quantify the potential participation of electric vehicle aggregators in a flexibility tender, considering the role of market rules and product definitions. The main parameters that affect fleet participation and remuneration are the bidirectional capability (V2G), the reliability of the fleet and the match of availability profiles to the tender requirements.

International audience; Electric vehicles (EVs) could be a solution to reduce final energy consumption and carbon emissions in the road transport sector. Moreover, the mobility characteristics of drivers (i.e., their average driving distance) fit better with current EV technical features on a small island than in the mainland. This paper analyzes willingness-to-change (WTC) and willingness-to-pay (WTP) for an EV in Tenerife (Canary Islands), both of which are key factors for understanding potential for EV penetration. WTC and WTP in Tenerife island are estimated based on data collected through a face-to-face survey-based contingent valuation approach. We go on to assess the impact of a set of explanatory variables on both WTC and WTP, in order to characterize the representative profile of a potential EV buyer. Informing on the basic properties of an EV and environmental concerns are found to be key factors for WTC, while income level, mobility patterns, environmental concerns and attitude-to-tech of potential buyers are found to be important factors for WTP.

International audience; One major issue that is source of uncertainty holding back the hydrogen deployment, is the infrastructure development needs and costs. Different studies in the literature tackled this issue in France but partially, assessing either one part of the hydrogen supply chain or the whole supply chain but for one possible delivery pathway. This paper compares five hydrogen pathways, going from the production step up to the fuelling station and tackling pipeline and truck options. In order to capture the time evolution aspect of the infrastructure deployment needs, three demand scenarios are investigated, going from 1% of market penetration up to 15%. Additionally, two scenarios are taken into account when it comes to the location of the hydrogen production sites vis-à-vis the demand centres. According to the results, economies of scale that can be driven by higher market penetration rates have significant impact on lowering the hydrogen cost.

International audience

International audience

International audience; Massive integration of electric vehicles (EV) into power systems will pose significant challenges, in particular to distribution systems. Additional peak demand by EV charging can induce congestion or voltage issues, which would require costly infrastructure investments. However, these impacts can be reduced by using smart charging mechanisms. The impacts of EV charging and the efficacy of smart charging algorithms will depend on user behavior (namely travel and charging patterns). This study analyses the impact of non-systematic EV charging on base load, at the HV/MV substation level, and on smart charging potential. Case studies on realistic substations, based on real travel and grid data from France, exemplify the results.

International audience; Distributed Energy Resources (DERs), mostly in the form of solar photovoltaic (PV) or lithium-ion batteries, and electric vehicles (EVs) are emerging as three disruptive innovations in power grids. Recent studies have pointed out the potential synergies between these technologies, while others have studied the difficulty to design adequate network tariff when some consumers can adopt DERs (prosumers). In this paper, we investigate the combined effect of DERs and EVs on grid cost recovery. To study these effects, we formulate a non-cooperative game between a regulator that sets tariffs to recover grid costs and the four classes of network users depending on whether they are prosumer (resp. EV owners) or not. We study how tariff structures and the levels of EV penetration and prosuming affect tariffs. First, we find that grid cost recovery concerns caused by load-defecting prosumers installing DER can be balanced by the diffusion of EVs in the network. Second, we highlight that EVs and DERs adoptions are conflicting through the network tariff design. In particular, we find that the more a tariff structure gives incentives for DERs, the less beneficial it is for EVs.

Chromatin organization is essential for appropriate interpretation of the genetic information. Here, we demonstrated that the chromatin-associated proteins HP1 are dispensable for hepatocytes survival but are essential within hepatocytes to prevent liver tumor development in mice with HP1β being pivotal in these functions. Yet, we found that the loss of HP1 per se is not sufficient to induce cell transformation but renders cells more resistant to specific stress such as the expression of oncogenes and thus in fine, more prone to cell transformation. Molecular characterization of HP1-Triple KO premalignant livers and BMEL cells revealed that HP1 are essential for the maintenance of heterochromatin organization and for the regulation of specific genes with most of them having well characterized functions in liver functions and homeostasis. We further showed that some specific retrotransposons get reactivated upon loss of HP1, correlating with overexpression of genes in their neighborhood. Interestingly, we found that, although HP1-dependent genes are characterized by enrichment H3K9me3, this mark does not require HP1 for its maintenance and is not sufficient to maintain gene repression in absence of HP1. Finally, we demonstrated that the loss of TRIM28 association with HP1 recapitulated several phenotypes induced by the loss of HP1 including the reactivation of some retrotransposons and the increased incidence of liver cancer development. Altogether, our findings indicate that HP1 proteins act as guardians of liver homeostasis to prevent tumor development by modulating multiple chromatin-associated events within both the heterochromatic and euchromatic compartments, partly through regulation of the corepressor TRIM28 activity.

International audience; Renewable development can be leveraged through a variety of energy carriers. The aim of this paper is to assess the potential of producing low-carbon hydrogen from electricity surplus considering the French case for the timeframe of 2035. The analysis is conducted on a regional basis, in order to investigate the potential locations for electrolyser placements. To do so, it builds on an assessment of the land and ocean eligibility to identify a precise geographic distribution of the renewable energies (photovoltaics, and onshore and offshore wind) across France. The surplus energy is assessed regionally using a dispatch model showing that little energy is actually available to produce hydrogen when only considering the renewable curtailments. Using the nuclear available energy allows to enhance the hydrogen production potential while respecting the low carbon footprint criteria.

The Nigeria Power sector reform was performed between the year 2010 and 2013 but it has undoubtedly been adjudged unsuccessful by most stakeholders. The failure of the reform is evidenced by a myriad of seemingly insurmountable economic, institutional, technical, financial and socio-political challenges exacerbated by the recent macroeconomic crisis. This paper performs a comparative analysis of the Nigeria reform with the “Standard model” of electricity reform to understand the root cause of the reform failures while taking cognizance of the starting conditions of Nigeria. Our result reveals that incomplete privatization coupled with the horizontal integration of the transmission and network operations, the underdeveloped gas supply infrastructure network and the ineffective/weak regulatory framework as the root problems. Thereafter, we recommended strengthening the regulatory framework as a good starting point to resolve sectoral problems. We argued that, considering the depth of the regulatory concerns, strengthening the framework will resolve the problems of investment, access and pricing and improve the overall sectoral performance (ex-post). Furthermore, we recommended the need for a workable market design and regulatory framework for decentralized solar PV generation and integration that is adaptable and nicely fits with a strengthened centralized generation framework.

The decarbonization of both power and mobility sectors are two main goals established during international environmental summits. Distributed battery storage, such as electric vehicles batteries and stationary ones, ranging from around a dozen to a few hundred kWh and photovoltaic (PV) systems are disruptive technologies not only because they can individually contribute to CO2 emissions reduction but also due to the positive synergies between them. Batteries can store electricity surplus produced by PVs during the day, avoiding curtailment, and restore it to the grid to shave peak load or when external grid constraints are identified. We provide an analytical framework identifying the main research areas dealing with PV—EV–battery relationships to academics, stakeholders and policymakers willing to acquire further knowledge on this topic. The coupling between PV—EV–battery depends not only on the technological progress or economic regulations, but also on the under-explored user acceptance towards the technologies. First, emerging technologies (e.g. microgrids, vehicle-to-grid and blockchain) will deeply impact PV–EV–battery synergy, forcing electricity grid operators to readjust the way how the grid is managed. Second, inappropriate economic regulations (e.g obsolete tariff and ancillary services market designs) and outdated strategies formulated by the automotive sector could jeopardize all the potential benefits brought by the coupling. Then, user acceptance is found to be a decisive variable in whether people are willing to invest in distributed energy systems. Finally, we identify the literature gaps that warrant further investigation.

Solving the hydra-headed economic, technical and institutional electrification challenges in the Nigeria Power sector requires innovative insights that decentralized offgrid reverse auction with solar power plus storage offers. However, running a successful auction requires a meticulous design with in-depth understanding of the environment and data access to provide insight on what capacity to procure, locations, costs and regulatory governance.Combining GIS, energy system optimization and market/regulation design expertise, we contribute to bridging this knowledge gap for the Nigeria Power sector. We identified the most populated consumer clusters without electricity access, made load demand projections and determined the techno-economically optimized PV plus battery storage sizes to achieve high quality power supply with some demand side management. Furthermore, we analysed the land requirements/availability to achieve a shortlist of 233 clusters with 7.2 million people that require 3280 MW solar PV for the proposed auction. Finally, we discussed the pathway to adapt our design to the existing market/regulatory framework. Keywords: Nigeria Power Sector, Reverse auction, Geographical information System (GIS), Market design, Energy Policy

Nowadays electromobility is more and more becoming a cross-sectorial innovation. Electromobility is the convergence of technical innovations in battery technologies and charging systems, on Internet of things and finally on new business model developed by classical original equipment manufacturers and innovative newcomers. This developing phenomenon is really challenging for the ecosystem made of car manufacturers, electricity industry, local and national public actors dealing with clean energy transition. We review these challenges and highlight the most promising way of future researches in each of these dimensions for the EU actors.

International audience

This paper aims to quantify, from an economic and environmental lens, the impacts of the interconnection Tenerife–La Gomera in terms of energy independence, emissions and costs. Alternatively, the development of La Gomera as an isolated system through a high deployment of renewable energies and energy storage systems is also assessed. The results reveal that the interconnection is the most promising alternative in terms of cost, emissions and energy independence, provided that generation is powered by NG. If not, the isolated development mainly based on electric batteries and photovoltaic systems would be the best option. The results of this work may be very useful for policy-makers and energy planners in other territories with similar characteristics.

International audience; As the share of Renewable Energy Sources is increasing as well as Electric Vehicles sales, storage of Vehicles is now studied as a potential provider of flexibility products, such as reserve. As offering this service is remunerated, it would allow to decrease Total Cost of Ownership of Electric Vehicles and to facilitate their adoption. However, provision should satisfy technical requirements as well as mobility needs. In this paper, we analyze how degrees of freedom in the technical requirements, such as dead-band or possibility of over-solicitation could increase provision of reserve and reduce constraints on mobility needs.

International audience; For several years the European Commission has been advocating the creation of integrated electricity markets. After the wholesale market, the establishment of a common reserve market has begun with cooperation related to a Frequency Containment Reserve (FCR), a common platform for the cross-border procurement of primary reserves. The aim of this paper is to study the implications of the decision of the French regulator to join the FCR Cooperation. Two aspects will be analyzed: 1) the cost of procurement and the increase in social welfare thanks to cross-border procurement and 2) implications for the arrival of new entrants such as aggregators of distributed resources (Electric Vehicles fleet are considered in our survey). We conclude that joining the FCR Cooperation will have a negative impact on the participation of aggregators and might not play a useful role in lowering costs for the procurement of reserves. We propose new rules to solve these issues.

International audience

International audience; In a context of increasing share of renewable energy sources (RES) in the electricity mix, flexibility will become an increasingly valuable resource for System Operators to manage balance between generation and consumption. Electric Vehicles (EVs) are a potential provider of this flexibility, by managing their charging patterns in function of specific needs of the network, in particular, provision of Frequency Containment Reserve (FCR). The aim of this paper is to study the profitability of an investment in a fleet of bidirectional EV chargers able to provide FCR by an aggregator, through Net-Present Value (NPV) analysis.

International audience

The aim of this paper is to analyze Rogers-system categories of electric vehicle adopters in Tenerife (Canary Islands) to highlight the psychological factors defining each category. The paper runs a model to calculate willingness to change and willingness to pay for an electric vehicle following the contingent valuation methodology. A survey performed in Tenerife Island collected data from 444 private cars drivers. The survey contained a set of questions on psychological and car-features issues, as well as other items querying the socioeconomic factors and mobility characteristics of the drivers. This paper brings key contributions to the literature. First, it uses two theoretical frameworks to define the categories of innovators from a psychosocial standpoint. Second, the results will usefully inform both policymakers and automaker marketing departments on specific actions to accelerate the uptake of electric vehicles. Our results confirm that electric vehicle adopter categories are similar in proportion and characteristics to those of Rogers&rsquo, diffusion of innovation theory, and can be collapsed into two macro-groups of adopters distributed in a 50%&ndash, 50% split in our sample, i.e., the earlier adopters and the later adopters.

International audience; Isolated regions are highly dependent on fossil fuels. The use of endogenous sources and the improvement in energy efficiency in all of the consumption activities are the two main ways to reduce the dependence of petroleum-derived fuels. Tenerife offers an excellent renewable resource (hours of sun and wind). However, the massive development of these technologies could cause important operational problems within the electric power grids, because of the small size of the system. In this paper, we explore the option of coupling an electric vehicle fleet as a distributed energy storage system to increase the participation of renewables in an isolated power system, i.e., Tenerife Island. A model simulator has been used to evaluate five key outputs, that is the renewable share, the energy spilled, the CO 2 emissions, the levelized cost of generating electricity and fuel OPEN ACCESS Sustainability 2015, 7 2 dependence, under alternative scenarios. Comparing to the current situation, combining a gradual renewable installed capacity and the introduction of an electric vehicle fleet using alternative charging strategies, a total of 30 different scenarios have been evaluated. Results shows that the impact of 50,000 electric vehicles would increase the renewable share in the electricity mix of the island up to 30%, reduce CO 2 emissions by 27%, the total cost of electric generation by 6% and the oil internal market by 16%.