References of "Fonteneau, Raphaël"
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See detailEmpirical Analysis of Policy Gradient Algorithms where Starting States are Sampled accordingly to Most Frequently Visited States
Aittahar, Samy ULiege; Fonteneau, Raphaël ULiege; Ernst, Damien ULiege

in IFAC-PapersOnLine (in press)

In this paper, we propose an extension to the policy gradient algorithms by allowing starting states to be sampled from a probability distribution that may differ from the one used to specify the ... [more ▼]

In this paper, we propose an extension to the policy gradient algorithms by allowing starting states to be sampled from a probability distribution that may differ from the one used to specify the reinforcement learning task. In particular, we suggest that, between policy updates, starting states should be sampled from a probability density function which approximates the state visitation frequency of the current policy. Results generated from various environments clearly demonstrate a performance improvement in terms of mean cumulative rewards and substantial update stability compared to vanilla policy gradient algorithms where the starting state distributions are either as specified by the environment or uniform distributions over the state space. A sensitivity analysis over a subset of the hyper-parameters of our algorithm also suggests that they should be adapted after each policy update to maximise the improvements of the policies. [less ▲]

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See detailModelling and Assessing the Impact of the DSO Remuneration Strategy on its Interaction with Electricity Users
Manuel de Villena Millan, Miguel ULiege; Gautier, Axel ULiege; Ernst, Damien ULiege et al

E-print/Working paper (2020)

This paper presents a simulation-based methodology for assessing the impact of employing different distribution system operator’s remuneration strategies on the economic sustainability of electrical ... [more ▼]

This paper presents a simulation-based methodology for assessing the impact of employing different distribution system operator’s remuneration strategies on the economic sustainability of electrical distribution systems. The proposed methodology accounts for the uncertainties posed by the integration of distributed electricity generation resources, and the roll out of smart-meters. The different remuneration strategies analysed in this paper include notably new distribution tariffs based on individual peak power consumption and time-dependent rates that are contingent on the time of energy consumption, both requiring smart-meters to work. The distributed electricity generation resources are modelled through an optimisation framework and an investment decision process that gradually deploys household photovoltaic installations depending on their profitability and the electricity charges, including the distribution rates. The impact of the distribution system operator’s remuneration strategy is measured by an accurate modelling of the remuneration mechanism of this entity, which can adapt to various distribution tariff designs. We analyse this impact over a discrete time horizon. Our methodology is illustrated with several examples of distribution tariffs including old –based on energy consumption or on per-connection fees– as well as new –based on power consumption or time-of use fees– designs. Finally, we provide a comprehensive sensitivity analysis of the proposed simulation environment to the main parameters of the methodology. [less ▲]

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See detailThe Role of Hydrogen in the Dutch Electricity System
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Ryszka, Karolina et al

Report (2020)

This technical report investigates the role power-to-gas, hydrogen and battery storage technologies may play in the Dutch electricity system using a recently published optimization-based energy system ... [more ▼]

This technical report investigates the role power-to-gas, hydrogen and battery storage technologies may play in the Dutch electricity system using a recently published optimization-based energy system model. [less ▲]

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See detailThe Role of Power-to-Gas and Carbon Capture Technologies in Cross-Sector Decarbonisation Strategies
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Fonteneau, Raphaël ULiege et al

in Electric Power Systems Research (2020), 180

This paper proposes an optimisation-based framework to tackle long-term centralised planning problems of multi-sector, integrated energy systems including electricity, hydrogen, natural gas, synthetic ... [more ▼]

This paper proposes an optimisation-based framework to tackle long-term centralised planning problems of multi-sector, integrated energy systems including electricity, hydrogen, natural gas, synthetic methane and carbon dioxide. The model selects and sizes the set of power generation, energy conversion and storage as well as carbon capture technologies minimising the cost of supplying energy demand in the form of electricity, hydrogen, natural gas or synthetic methane across the power, heating, transportation and industry sectors whilst accounting for policy drivers, such as energy independence, carbon dioxide emissions reduction targets, or support schemes. The usefulness of the model is illustrated by a case study evaluating the potential of sector coupling via power-to-gas and carbon capture technologies to achieve deep decarbonisation targets in the Belgian context. Results, on the one hand, indicate that power-to-gas can only play a minor supporting role in cross-sector decarbonisation strategies in Belgium, as electrolysis plants are deployed in moderate quantities whilst methanation plants do not appear in any studied scenario. On the other hand, given the limited renewable potential, post-combustion and direct air carbon capture technologies clearly play an enabling role in any decarbonisation strategy, but may also exacerbate the dependence on fossil fuels. [less ▲]

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See detailCritical Time Windows for Renewable Resource Complementarity Assessment
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Fonteneau, Raphaël ULiege et al

in Energy (2020)

This paper proposes a framework to assess the complementarity between geographically dispersed variable renewable energy resources over arbitrary time scales. More precisely, the framework relies on the ... [more ▼]

This paper proposes a framework to assess the complementarity between geographically dispersed variable renewable energy resources over arbitrary time scales. More precisely, the framework relies on the concept of critical time windows, which offers an accurate, time-domain description of low-probability power production events impacting power system operation and planning. A scalar criticality indicator is also derived to quantify the spatiotemporal complementarity that renewable generation sites may exhibit, and it is leveraged to propose optimisation models seeking to identify deployment patterns with maximum complementarity. The usefulness of the framework is shown in a case study investigating the complementarity between wind regimes in continental western Europe and southern Greenland, using roughly 300 candidate locations and 10 years of reanalysis and simulated data with hourly resolution. Besides showing that the occurrence of low wind power production events can be reduced on a regional scale by exploiting diversity in local wind patterns, results highlight the fact that aggregating wind power production sites located on different continents may result in a lower occurrence of system-wide low wind power production events and point to potential bene ts of intercontinental electrical interconnections. [less ▲]

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See detailThe Smart Grids lab at the University of Liège
Ernst, Damien ULiege; Fonteneau, Raphaël ULiege

Speech/Talk (2020)

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See detailAssessing the Economic Value of Renewable Resource Complementarity for Power Systems: an ENTSO-E Study
Radu, David-Constantin ULiege; Berger, Mathias ULiege; Dubois, Antoine ULiege et al

E-print/Working paper (2020)

Complementarity of variable renewable energy sources (RES) in both space and time has received a great deal of attention recently however, its value for power systems is still not properly understood ... [more ▼]

Complementarity of variable renewable energy sources (RES) in both space and time has received a great deal of attention recently however, its value for power systems is still not properly understood. This research gap is tackled in the current work by evaluating the benefits of siting RES assets according to resource complementarity criteria. For this purpose, a two-stage method is employed. First, the complementarity between RES is assessed and the locations sets that maximize it are selected using an integer programming model. Subsequently, the outcome of the first stage is used within an expansion planning framework which identifies the optimal system design and serves as basis for assessing the economic value of RES complementarity for power systems. The analysis is conducted on a realistic case study targeting the deployment of 450GW of offshore wind in Europe by 2050. Results show that siting based on RES complementarity is particularly attractive when the power density of wind developments is relatively high and when the inter-annual variability of the underlying resource is considered. More specifically, such a siting strategy leads to yearly savings between 0.3 and 1.2 billion EUR compared with conventional schemes seeking to deploy generation capacity at the most productive locations. [less ▲]

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See detailNetwork tariffs and the integration of prosumers: the Case of Wallonia
Manuel de Villena Millan, Miguel ULiege; Jacqmin, Julien; Fonteneau, Raphaël ULiege et al

E-print/Working paper (2020)

In Wallonia, Belgium's southern region, the distribution component of the overall electricity retail tariff is essentially volumetric, i.e. based on the user' energy consumption (in euro/kWh). Residential ... [more ▼]

In Wallonia, Belgium's southern region, the distribution component of the overall electricity retail tariff is essentially volumetric, i.e. based on the user' energy consumption (in euro/kWh). Residential prosumers, moreover, are connected to the grid via a net-metering system. In this paper, we rely on a multi-agent tariff simulator -- developed in Manuel de Villena et al. (2019) — calibrated to this specific regional context to model the integration of prosumers into the distribution grid. This simulator enables us to highlight how the emergence of prosumers impacts the distribution network tariff, and to evaluate several tariff reforms currently under discussion. Without smart meters, short-run reforms can only change the structure of the tariff paid, either to all consumers or to prosumers only. In the long run, with smart meters, we consider both the introduction of a net-purchasing system and of a tariff with a capacity component. Our analysis highlights one key added value of smart meters: they can ensure a fair and sustainable financing of the distribution network. [less ▲]

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See detailGlobal electricity network - Feasibility study
Yu, J.; Bakic, K.; Kumar, A. et al

Report (2019)

With the strong development of renewable energy sources worldwide, the concept of a global electricity network has been imagined in order to take advantage of the diversity from different time zones ... [more ▼]

With the strong development of renewable energy sources worldwide, the concept of a global electricity network has been imagined in order to take advantage of the diversity from different time zones, seasons, load patterns and the intermittency of the generation, thus supporting a balanced coordination of power supply of all interconnected countries. The TB presents the results of the feasibility study performed by WG C1.35. It addresses the challenges, benefits and issues of uneven distribution of energy resources across the world. The time horizon selected is 2050. The study finds significant potential benefits of a global interconnection, identifies the most promising links, and includes sensitivity analyses to different factors, such as wind energy capacity factors or technology costs. [less ▲]

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See detailComplementarity Assessment of South Greenland Katabatic Flows and West Europe Wind Regimes
Radu, David-Constantin ULiege; Berger, Mathias ULiege; Fonteneau, Raphaël ULiege et al

in Energy (2019), 175

Current global environmental challenges require vigorous and diverse actions in the energy sector. One solution that has recently attracted interest consists in harnessing high-quality variable renewable ... [more ▼]

Current global environmental challenges require vigorous and diverse actions in the energy sector. One solution that has recently attracted interest consists in harnessing high-quality variable renewable energy resources in remote locations, while using transmission links to transport the power to end users. In this context, a comparison of western European and Greenland wind regimes is proposed. By leveraging a regional atmospheric model specifically designed to accurately capture polar phenomena, local climatic features of southern Greenland are identified to be particularly conducive to extensive renewable electricity generation from wind. A methodology to assess how connecting remote locations to major demand centres would benefit the latter from a resource availability standpoint is introduced and applied to the aforementioned Europe-Greenland case study, showing superior and complementary wind generation potential in the considered region of Greenland with respect to selected European sites. [less ▲]

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See detailOn overfitting and asymptotic bias in batch reinforcement learning with partial observability
François-Lavet, Vincent; Rabusseau, Guillaume; Pineau, Joëlle et al

in Journal of Artificial Intelligence Research (2019), 65

This paper provides an analysis of the tradeoff between asymptotic bias (suboptimality with unlimited data) and overfitting (additional suboptimality due to limited data) in the context of reinforcement ... [more ▼]

This paper provides an analysis of the tradeoff between asymptotic bias (suboptimality with unlimited data) and overfitting (additional suboptimality due to limited data) in the context of reinforcement learning with partial observability. Our theoretical analysis formally characterizes that while potentially increasing the asymptotic bias, a smaller state representation decreases the risk of overfitting. This analysis relies on expressing the quality of a state representation by bounding L1 error terms of the associated belief states. Theoretical results are empirically illustrated when the state representation is a truncated history of observations, both on synthetic POMDPs and on a large-scale POMDP in the context of smartgrids, with real-world data. Finally, similarly to known results in the fully observable setting, we also briefly discuss and empirically illustrate how using function approximators and adapting the discount factor may enhance the tradeoff between asymptotic bias and overfitting in the partially observable context. [less ▲]

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See detailEvaluating the Evolution of Distribution Networks under Different Regulatory Frameworks with Multi-Agent Modelling
Manuel de Villena Millan, Miguel ULiege; Fonteneau, Raphaël ULiege; Gautier, Axel ULiege et al

in Energies (2019), 12(7), 1-15

In the context of increasing decentralised electricity generation, this paper evaluates the effect of different regulatory frameworks on the evolution of distribution networks. This problem is addressed ... [more ▼]

In the context of increasing decentralised electricity generation, this paper evaluates the effect of different regulatory frameworks on the evolution of distribution networks. This problem is addressed by means of agent based modelling in which the interactions between the agents of a distribution network, and an environment are described. The consumers and the distribution system operator are the agents, which act in an environment that is composed by a set of rules. For a given environment, we can simulate the evolution of the distribution network by computing the actions of the agents at every time step of a discrete time dynamical system. We assume the electricity consumers are rational agents that may deploy distributed energy installations. The deployment of such installations may alter the remuneration mechanism of the distribution system operator. By modelling this mechanism, we may compute the evolution of the electricity distribution tariff in response to the deployment of distributed generation. [less ▲]

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See detailTariff simulator
Manuel de Villena Millan, Miguel ULiege; Fonteneau, Raphaël ULiege; Ernst, Damien ULiege

Speech/Talk (2019)

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See detailCentralised Planning of National Integrated Energy System with Power-to-Gas and Gas Storages
Berger, Mathias ULiege; Radu, David-Constantin ULiege; Fonteneau, Raphaël ULiege et al

in Proceedings of the 11th Mediterranean Conference on Power Generation, Transmission, Distribution and Energy Conversion (Medpower2018) (2018, November)

This paper proposes an optimisation-based framework to tackle long-term centralised planning problems of integrated energy systems with bi-directional electricity-gas carriers coupling under various ... [more ▼]

This paper proposes an optimisation-based framework to tackle long-term centralised planning problems of integrated energy systems with bi-directional electricity-gas carriers coupling under various policy constraints. The framework is leveraged to gain insight into possible configurations of the future Belgian energy system, and identify the cost-optimal energy mix as well as short and long-term storage requirements to satisfy CO2 emissions reductions and energy security targets. Results shed light on the economics of a transition to a low-carbon energy system and reveal the potential of power-to-gas and storage in gas form to help achieve ambitious emissions reduction goals. [less ▲]

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See detailDistributed Control of Photovoltaic Units in unbalanced LV Distribution Networks to Prevent Overvoltages
Olivier, Frédéric ULiege; Fonteneau, Raphaël ULiege; Mathieu, Sébastien ULiege et al

in Proc. of the 6th IEEE International Conference on Smart Energy Grid Engineering (SEGE 2018) (2018, August 12)

As more and more photovoltaic units are being installed, some LV networks have already attained their maximum hosting capacity, i.e. the maximum amount of distributed energy resources that they can ... [more ▼]

As more and more photovoltaic units are being installed, some LV networks have already attained their maximum hosting capacity, i.e. the maximum amount of distributed energy resources that they can accommodate during regular operations without suffering problems, such as overvoltages. As an alternative to network reinforcement, active network management (ANM) can, to a certain extent, increase their hosting capacity by controlling the power flows. In the framework of ANM, a distributed control scheme was previously presented. It makes use of a distress signal sent by each participating unit, when its terminal voltage is higher than 1.1 p.u. All units then proceed to absorb the maximum reactive power available. If the problem is not resolved, the units proceed to active power curtailment. This paper extends this control scheme to the case of unbalanced three-phase four-wire distribution networks with single- and/or three-phase inverters. The control scheme works by first partitioning the inverters into four groups, three for the single-phase inverters (one for each phase), and one for the three-phase converters. Each group then independently applies a distributed algorithm similar to the one previously presented. Their performance are then compared to those of two reference schemes, an on-off algorithm that models the default behaviour of PV inverters when there is an overvoltage, and the other one based on an unbalanced OPF. Its resulting total curtailed energy always lies between the two, with the on-off algorithm presenting the poorest performance, and the proposed algorithm losing its edge when the network is strongly unbalanced. [less ▲]

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See detailPhase Identification of Smart Meters by Clustering Voltage Measurements
Olivier, Frédéric ULiege; Sutera, Antonio ULiege; Geurts, Pierre ULiege et al

in Proceedings of the XX Power Systems Computation Conference (PSCC 2018) (2018, June)

When a smart meter, be it single-phase or threephase, is connected to a three-phase network, the phase(s) to which it is connected is (are) initially not known. This means that each of its measurements is ... [more ▼]

When a smart meter, be it single-phase or threephase, is connected to a three-phase network, the phase(s) to which it is connected is (are) initially not known. This means that each of its measurements is not uniquely associated with a phase of the distribution network. This phase information is important because it can be used by Distribution System Operators to take actions in order to have a network that is more balanced. In this work, the correlation between the voltage measurements of the smart meters is used to identify the phases. To do so, the constrained k-means clustering method is first introduced as a reference, as it has been previously used for phase identification. A novel, automatic and effective method is then proposed to overcome the main drawback of the constrained k-means clustering, and improve the quality of the clustering. Indeed, it takes into account the underlying structure of the low-voltage distribution networks beneath the voltage measurements without a priori knowledge on the topology of the network. Both methods are analysed with real measurements from a distribution network in Belgium. The proposed algorithm shows superior performance in different settings, e.g. when the ratio of single-phase over three- phase meters in the network is high, when the period over which the voltages are averaged is longer than one minute, etc. [less ▲]

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See detailModelling of three-phase four-wire low-voltage cables taking into account the neutral connection to the earth
Olivier, Frédéric ULiege; Fonteneau, Raphaël ULiege; Ernst, Damien ULiege

in Proc. of CIRED Workshop 2018 (2018, June)

Local energy communities (LECs) usually occur at the level of low-voltage distribution networks, which are inherently unbalanced due to single-phase household appliances and distributed generation. To ... [more ▼]

Local energy communities (LECs) usually occur at the level of low-voltage distribution networks, which are inherently unbalanced due to single-phase household appliances and distributed generation. To simulate and optimise the behaviour of an LEC, the three phases and neutral must be modelled explicitly. This paper aims at numerically assessing the influence of the modelling of the earth and the connection between the neutral and the earth, in terms of voltages and currents. The simulations are performed on an existing Belgian low-voltage feeder supplying 19 houses, which are all equipped with a smart meter measuring the mean voltage, current, and active and reactive power every minute for each phase. The simulations show that the explicit modelling of the earth using Carson's equations has a moderate effect on the simulation results. In particular, it creates differences in the simulations that are around ten-times smaller than the errors between simulations and measurements. [less ▲]

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See detailA multi-agent system approach to model the interaction between distributed generation deployment and the grid
Manuel de Villena Millan, Miguel ULiege; Gautier, Axel ULiege; Fonteneau, Raphaël ULiege et al

in Proc. of CIRED Workshop 2018 (2018, June)

This paper introduces a multi-agent dynamical system of the interaction between electricity consumers, the electricity distribution system operator, and the technological (generation, storage) and ... [more ▼]

This paper introduces a multi-agent dynamical system of the interaction between electricity consumers, the electricity distribution system operator, and the technological (generation, storage) and regulatory (tariff design, incentive schemes) environments. For any type of environment, our dynamical system simulates the evolution of the deployment of distributed electricity generation, as well as the evolution of the cost of distribution. The system relies on the assumption that individual electricity consumers behave statistically as rational agents, who may invest in optimised distributed renewable energy installations, if they are cost-efficient compared to the retail electricity tariff. The deployment of these installations induces a change in the aggregated net consumption and generation of the users of a distribution network. By modelling the cost recovery mechanism of the distribution system operator, the system simulates the evolution of the retail electricity tariff in response to such a change in the aggregated consumption and production. [less ▲]

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