Hossein Farahmand

• PhD
• Professor at Norwegian University of Science and Technology

This paper introduces a shape‐based inflow scenarios reduction framework applied in long‐term hydro‐thermal scheduling. This scheduling problem involves strategically managing the limited stored hydro energy in coordination with the electricity system. The scenario fan problem, selected as a long‐term hydro‐thermal scheduling approach, can effectiv...

As the power system is becoming more weather-dependent and integrated to meet decarbonization targets, the level and severity of uncertainty increase and inevitably introduce higher risk of demand rationing or economic loss. This paper reviews the representation of uncertainty in power market models for operational planning and forecasting. A synth...

p>Local energy communities are forming as a way for prosumers and consumers to invest in distributed renewable energy sources, community storage and share electricity. Meanwhile, several distribution grids have voltage problems at certain hours of the year. Local energy communities consisting of generation and storage units might be valuable flexib...

Climate change affects patterns and uncertainties associated with river water regimes, which significantly impact hydropower generation and reservoir storage operation. Hence, reliable and accurate short-term inflow forecasting is vital to face climate effects better and improve hydropower scheduling performance. This paper proposes a Causal Variat...

p>This paper proposes an inflow scenario reduction framework applied in long-term hydro-thermal scheduling. The strategic management of limited stored hydro energy in interaction with the electricity system is defined in long-term hydro-thermal. The Scenario Fan Problem (SFP) is selected as a long-term hydro-thermal scheduling approach. This approa...

p>This paper proposes a framework consisting of a forepart precursor and the Scenario Fan Problem (SFP) for long-term hydropower scheduling, using shape-based feature extraction. The domain feature of the forepart precursor is scenario decomposition and scenario selection. Then, the selected scenarios will be the input of SFP, based on the feature...

p>This paper proposes a framework consisting of a forepart precursor and the Scenario Fan Problem (SFP) for long-term hydropower scheduling, using shape-based feature extraction. The domain feature of the forepart precursor is scenario decomposition and scenario selection. Then, the selected scenarios will be the input of SFP, based on the feature...

p>Local energy communities are forming as a way for prosumers and consumers to invest in distributed renewable energy sources, community storage and share electricity. Meanwhile, several distribution grids have voltage problems at certain hours of the year. Local energy communities consisting of generation and storage units might be valuable flexib...

p>Local energy communities are forming as a way for prosumers and consumers to invest in distributed renewable energy sources, community storage and share electricity. Meanwhile, several distribution grids have voltage problems at certain hours of the year. Local energy communities consisting of generation and storage units might be valuable flexib...

Unlocking flexibility assets from the consumer side and developing a well-functioning flexibility market (FM) is crucial to address the oncoming challenges in the EU power grid. In these conditions, the coordination between distribution system operators (DSOs) and transmission system operators (TSOs) remains a critical task for optimally harvesting...

The integration of energy efficiency programs and renewable resources in energy communities (EC) incorporating smart microgrids might be the future development of sustainable cities. Cooperation among EC with high penetration of renewable energy resources will support energy procurement. Mutual energy efficiency programs in EC associated with deplo...

Abstract Photovoltaic (PV) generation has high impact on the decarbonization pathways of power systems. Accuracy of day‐ahead PV power forecasting has become crucial in the operation and control of power system with high PV penetration. This paper develops a hybrid approach based on generative adversarial network (GAN) combined with convolutional a...

This paper proposes a stochastic continuous-time optimization model for coordinating the operation of flexibility reserve in a hybrid hydro-thermal-wind power system. The proposed continuous-time model captures the sub-hourly uncertainty and variations of wind power and load, and accurately models and schedules the ramping flexibility of the hydrot...

With the considerable increase of Distributed Energy Resources (DER), reliable and cost-effective operation of distribution grids becomes challenging. The efficient operation relies on computationally dependable and tractable optimisation solvers, which may handle: 1) non-linear AC power flow constraints, and 2) time-linking variables and constrain...

It is essential to have accurate and reliable daily-inflow forecasting to improve short-term hydropower scheduling. This paper proposes a Causal multivariate Empirical mode Decomposition (CED) framework as a complementary pre-processing step for a day-ahead inflow forecasting problem. The idea behind CED is combining physics-based causal inference...

In this work, we investigate how flexible assets within a residential building influence the long-term impact of operation. We use a measured-peak grid tariff (MPGT) that puts a cost on the highest single-hour peak import over the month. We apply a mathematical model of a Home Energy Management System (HEMS) together with Stochastic Dynamic Program...

While volume-based grid tariffs have been the norm for residential consumers, capacity-based tariffs will become more relevant with the increasing electrification of society. A further development is capacity subscription, where consumers are financially penalised for exceeding their subscribed capacity, or alternatively their demand is limited to...

The increasing share of variable renewable energy sources creates a need for flexibility resources in the power system operations. This paper presents suggestions for characterizing flexibility, including dimensions of time, spatiality, resource type, and risk in power systems. We present interrelations between these flexibility dimensions, product...

In order to unlock the flexibility potential of energy consumers and prosumers, the development of market mechanisms for flexibility planning and procurement is necessary. The authors propose a stochastic local flexibility market to solve grid issues such as voltage deviations and grid congestion in a distribution grid. Their proposed solution incl...

While volume-based grid tariffs have been the norm for residential consumers, capacity-based tariffs will become more relevant with the increasing electrification of society. A further development is capacity subscription, where consumers are financially penalised for exceeding their subscribed capacity, or alternatively their demand is limited to...

The primary objective of Zero Emission Buildings (ZEBs) is to achieve net zero emission over the buildings’ lifetime. To achieve this goal, accurate cost-effective emission compensation is needed during the operational phase. This paper presents a stochastic planning model comprising an emission inventory for the operation of ZEBs. The operational...

This paper presents a hydrothermal scheduling toolchain suitable for detailed studies of procurement of spinning reserves in the hydro-dominated Nordic power system. The toolchain combines a long-term model to find the expected marginal value of water in the hydropower reservoirs and initial states for thermal generators, and a short-term model to...

The authors provide a comprehensive overview of flexibility characterization along the dimensions of time, spatiality, resource, and risk in power systems. These dimensions are discussed in relation to flexibility assets, products, and services, as well as new and existing flexibility market designs. The authors argue that flexibility should be eva...

Over-voltage in low voltage feeders due to the increasing penetration level of photovoltaic (PV) is a crucial issue to be addressed. There is a need to use more advanced voltage control methods to satisfy the response time of the control system. In this paper, a two-level voltage control strategy is presented. In the first level, based on day-ahead...

The resilient smart distribution system is intended to cope with low probability, high-risk extreme events, including extreme natural disasters. In this regard, the flexible partitioning distribution system into supply-sufficient microgrids can be considered an interesting subject. This paper introduces a novel technique for partitioning a smart di...

The authors focus on a model for system operators that uses centralized scheduling of multiple flexibility assets and services to minimize the cost of managing problems with grid congestion, voltages, and losses. The model schedules flexibility assets using stochastic optimization for AC optimal power flow in an active distribution network. The nov...

In this work, we investigate how flexible assets within a residential building influence the long-term impact of operation. We use a measured-peak grid tariff (MPGT) that puts a cost on the highest single-hour peak import over the month. We apply a mathematical model of a Home Energy Management System (HEMS) together with Stochastic Dynamic Program...

In recent years, power systems have undergone changes in technology and definition of the associated stakeholders. With the increase in distributed renewable generation and small- to medium-sized consumers starting to actively participate on the supply side, a suitable incorporation of decentralized agents into the power system is required. A promi...

With the considerable increase of Distributed Energy Resources (DER), the reliable and cost-effective operation of the electricity distribution grid becomes challenging. This relies on computationally dependable and tractable optimisation solvers, which may handle: 1) non-linear AC power flow constraints, and 2) the multiple numbers of input variab...

In this paper, we introduce an Interior Point-based (IP) Multi-Period AC Optimal Power Flow (MPOPF) solver for the integration of Stationary Energy Storage Systems (SESS) and Electric Vehicles (EV). The primary methodology is based on: 1) analytic and exact calculation of partial differential equations of the Lagrangian sub-problem, and 2) exploiti...

With the introduction of massive renewable energy sources and storage devices, the traditional process of grid operation must be improved in order to be safe, reliable, fast responsive and cost efficient, and in this regard power flow solvers are indispensable. In this paper, we introduce an Interior Point-based (IP) Multi-Period AC Optimal Power F...

Continuous-time optimization models have successfully been used to capture the impact of ramping limitations in power systems. In this paper, the continuous-time framework is adapted to model flexible hydropower resources interacting with slow-ramping thermal generators to minimize the hydrothermal system cost of operation. To accurately represent...

In this work, a continuous-time unit commitment formulation of a hydrothermal system with integration of offshore wind power is used to model the North European system operation. The cost of covering the structural imbalances in the system is quantified by a cost comparison to an analogous discrete-time model. If the discrete-time unit commitment i...

Scheduling a residential building short-term to optimize the electricity bill can be difficult with the inclusion of capacity-based grid tariffs. Scheduling the building based on a proposed measured-peak (MP) grid tariff, which is a cost based on the highest peak power over a period, requires the user to consider the impact the current decision-mak...

The H2020 project INVADE has addressed optimal activation of the different flexibility services using the cloud-based solution in the electricity domain. The results have been tested full-scale at different sites around Europe. Both business aspects and technical issues have been addressed. To provide effective instruments for practice sharing, co...

This paper presents a robust planning of distributed battery energy storage systems (DBESSs) from the viewpoint of distribution system operator (DSO) to increase the network flexibility. Initially, the deterministic model of the proposed problem is expressed by minimizing the difference between the DBESS planning, degradation and operation (chargin...

As the penetration of variable renewable power generation increases in power systems around the world, system security is challenged. It is crucial to coordinate the available flexible generating resources, such as hydropower, to meet the need for system balancing. However, reserved capacity on hydropower plants should only be activated if there is...

Continuous-time optimization models have successfully been used to capture the impact of ramping limitations in power systems. In this paper, the continuous-time framework is adapted to model flexible hydropower resources interacting with slow-ramping thermal generators to minimize the cost of system operation. To accurately represent the non-linea...

This paper presents a two-stage formwork for the coordinated distributed battery energy storage systems (DBESSs) planning and the flexible energy management (FEM) in a smart distribution network (SDN) in the presence of electric vehicles’ (EVs’) parking lot and variable renewable energy sources (VRESs). In the first stage, from distribution system...

With an increasing share of volatile renewables, more flexibility is needed to balance the electricity system. In order to enable local flexibility, we suggest a three-stage stochastic market clearing model using community-based peer-to-peer (P2P) trading with participation in the short term reserve markets. With this approach, internal intraday (I...

This paper investigates the optimal grid reconfiguration (OGR) strategy in the smart grids with the random behavior of the many electric vehicle mobility (EVM) fleets and wind energy uncertainty. The increased utilization of EVMs in the power system with stochastic volatile behavior along with the high penetration of wind energy sources (WESs) can...

This paper concerns the development of a costeffective approach to deploy the flexibility that electrical battery storage can offer to support the secure operation of medium voltage electrical networks under varying operating conditions. To this aim, and unlike related studies of the current state-ofthe- art, the approach presented in this paper is...

What modelling time resolution will capture more accurately the actual performance of generators in the bulk power system operation? This paper analyses the generation portfolio in a unit commitment (UC) model that represents the generators’ behavior for a given demand and renewable generation on very short time intervals (down to 1 minute). The UC...

The deployment of batteries in the distribution networks can provide an array of flexibility services to integrate renewable energy sources (RES) and improve grid operation in general. Hence, this paper presents the problem of optimal placement and sizing of distributed battery energy storage systems (DBESSs) from the viewpoint of distribution syst...

Norway has implemented economic incentives over several years to encourage a transition from conventional vehicles to electric vehicles (EVs), and now has the largest share of EVs per capita in the world. In this study, the authors explore the impacts of increasing EV penetration levels in a Norwegian distribution grid, by using real power measurem...

As the penetration of variable renewable powergeneration increases in power systems around the world, systemsecurity is challenged. Ensuring that enough reserve capacity isavailable to balance the increased forecast errors introduced bywind and solar power are and will be an important challengeto solve for system operators. This is also true in sys...

This paper presents the design of a single-phase electric vehicle (EV) on-board bidirectional charger with the capability of power conditioning. This charger can control its charging/discharging active power based on the demand of EV battery/network or load. Also, it controls reactive power and harmonic current based on the characteristics of the n...

In order to effectively utilize hydro production flexibility, a sufficient amount of transmission capacity has to be available between the hydro‐dominated part of the system and the part that requires operational flexibility. This chapter starts with a rough categorization of “base” hydropower flexibility, investigating the types of hydropower plan...

As renewable energy sources (RESs) penetration increases in the power system, the transmission system operators face new challenges to ensure system reliability and flexibility while ensuring high utilisation of uncertain RES generation. Controllable transformers with on-load tap changers and phase shifting capability are the promising flexibility...

In this paper, firstly, a formulation for Multi-Period AC Optimal Power Flow is developed to incorporate intertemporal constraints and, specifically, equations representing energy storage systems. Secondly, a solution method for the resulting optimisation model is proposed based on the primal-dual interior point method and the mathematical details...

A potentially beneficial new opportunity is emerging around the exchange of energy between electric vehicles and the electrical energy grid, particularly as more low-carbon energy sources are connecting to the grid. Accordingly, this paper presents an optimization framework to activate the potential capabilities of electric vehicles equipped with b...

The North Sea Offshore Grid (NSOG) is considered an important contributor towards large-scale integration of renewables and electricity market coupling. Different typologies have been studied for such a multinational power grid, ranging from radial point-to-point connections to more integrated meshed typologies. An artificial island enables a high...

This paper introduces various models for optimal and maximal utility-based distributed generation penetration in the radial distribution systems. Several problems with different probabilistic indices as objective functions constrained by power flow equations, distributed generation penetration, voltage, and thermal limits are proposed to obtain the...

This paper presents a systematic procedure for partitioning smart distribution systems into supply-sufficient microgrids. Firstly, renewable distributed generations (DGs) are optimally allocated in the distribution system. A multiobjective performance index including voltage profile and energy losses indices is utilized in this problem as the objec...

This study jointly addresses two major challenges in power system operations: (i) sustained growth of intermittent offshore wind farms (OWFs) connected to AC grid via multi-terminal voltage source converter (VSC)-based high-voltage DC (HVDC) grid that brings new challenges to the power system operation, and (ii) dealing with non-linearity of the AC...

An increasing share of variable power feed‐in is expected in the next decades in the European power system, with a particularly high offshore wind potential in the North Sea region. This demands more temporal‐ and spatial flexibility in the system, an adequate grid infrastructure can provide both. This study presents an engineering‐economic approac...

This study proposes combined framework for proactive operation, i.e. bidirectional active and reactive power management, of the smart distribution network as well as harmonic compensation of non-linear loads using electric vehicles (EVs) equipped with bidirectional chargers. The problem is in the form of non-linear programming (NLP) where the objec...

Different possibilities were assessed to supply energy to a large offshore oil and gas area in the North Sea. The concepts studied involved: (i) onsite power generation by means of simple gas turbine cycles, (ii) full electrification of the plants with power taken from the onshore grid, and (iii) a hybrid solution where power can be either generate...

This study presents a validation study of an approximated model of the European power system in 2014. A lightweight and open-source power-flow tool is used for this study. The tool and the model are publicly available and can be adapted to study future impact of large investments in the power system, specifically large-scale integration of renewabl...

Hydro power is one of the most flexible sources of electricity production. Power systems with considerable amounts of flexible hydro power potentially offer easier integration of variable generation, e.g., wind and solar. However, there exist operational constraints to ensure mid-/long-term security of supply while keeping river flows and reservoir...

Grid investments are considered as sunk costs with a very long lifetime, particularly in an offshore grid context. The market mechanisms for cost recovery of these investments are exposed to an increasing share of variable power generation at the supply side, demanding more flexibility in the system. Hence, it is of great interest to account for th...