In the global pursuit of decarbonization electrofuels have emerged as the key protagonist, offering a multifaceted solution across various sectors. At the forefront of this energy revolution is hydrogen, showing immense promise as a clean, sustainable and versatile energy carrier, capable of accelerating the transition to a carbon-neutral future. Since most demand for hydrogen production is in areas with scarce grid and good wind resource, the simplest most cost-effective approach to guarantee its "green-ness" is an islanded setup. This paper presents such a concept for large-scale green-hydrogen production from water electrolysis via electricity produced directly from a co-located onshore wind power plant. Special off-grid wind turbines and electrolyzer are used with a battery energy storage system and optimized plant controller. EMT simulations have been performed in PSCAD® using source code models to accurately assess plant stability and robustness. A load-flow study has also been conducted to verify the operational limits without additional network compensation. The results show that optimized control tuning can ensure operation of the off-grid green-hydrogen plant with a reduced battery unit size without additional stabilizing elements, thus achieving a minimum cost solution and attractive return of investment. The plant design solution is modular and scalable.

As the penetration of PV increases worldwide, improved accuracy and finer spatial and temporal resolution of solar data sets are needed to optimize the performance of these technologies in the energy system of a particular region or country. This work is part of a research project aiming to quantify the effects of aerosols and clouds on solar resource and forecasting through a combination of: solar resource measurements, estimation of aerosol/cloud information, solar radiation forecasting at short time scales using sky-imagers, DNI, GHI and dust forecasting by a three-dimensional chemical transport/weather model. We make use of long-term solar radiation data from a dense network of solar stations in Qatar. Qatar is located in the Arabian Gulf, in the Middle East, and has an arid desert climate. Its capital, Doha, sits on the east coast of the country. The main objective of the project is to optimally design an application for a hybrid PV-CSP system (with Thermal Energy Storage) for the community of Education City in Doha, Qatar, using 100% renewable energy sources throughout the year.

Most of microgrids are still powered by fossil fuels thermal plant today, but an increasing share of renewable generation is planned in these territories to meet our objectives our greenhouses gases emissions reduction. For the grid operator, the question of keeping or downsizing the thermal plant may arise but it needs to ensure that it will keep the same security of power supply. In this paper, a methodology that estimates the probability of power failures in a microgrid is used. This method is based on a Monte-Carlo simulation of the dispatch of the microgrid with uncertain inputs such as the failure rate of generation and storage assets. It is applied to an example of microgrid and shows that even with a high share of renewable, an important thermal power is still needed to cover events when the energy storage is empty and keep the number of power failures tolerable. A probabilistic approach to quantify the risk of power failure is proposed.

Energy security and global climate goals are driving the world evermore towards an energy transition. As many other small islands, the Canary Islands depend heavily on fossil fuel imports. Currently the archipelago’s electric system is characterised by an electric mix where about the 80% of the power supply comes from thermoelectric and co-generation power plants. Although the penetration of different renewable energy sources (REs) has been increasing within the island’s electricity market, they currently constitute only 20% of the electricity supply (wind, solar PV, hydroelectric, hydric and biogas). Moreover, land availability is often scarce in these islands due to significant and extensive natural and biosphere reserves, as well as a high degree of competition for the available land among various users . However, the archipelago has great marine energy potential, and thus constitutes an attractive opportunity for the development of marine renewable energy (MRE) technologies.

Motivated by the archipelago’s energy transition towards a more sustainable and self-sufficient electricity system, this research assesses the optimal configuration of a hybrid stand-alone grid system for the Canary Islands that attains 100% renewable energy penetration, removing fossil fuel reliance and boosting self-sufficiency. The use of offshore renewable energies has been prioritized. Each island microgrid has been designed to combine currently existing inland renewable energy technologies, complemented by a utility-scale battery and different novel forms of offshore renewable energy: namely offshore wind, floating PV, and wave energy. A genetic algorithm is used to solve the optimization problem, which aims to minimize the total cost of electricity generation by the system, while being subject to reliability and spatial constraints such as the Loss of Power Supply Probability and the maximum available marine space for the exploitation of offshore marine energy.

Input data about climate, technology performance, energy costs and electric demand are retrieved from climate simulation reanalyses, technology developers’ inputs, literature reports and regional statistics, respectively. The ArcGIS tool has been used for the delineation of available marine space, while the MATLAB software has been utilized to program and resolve the optimization problem. Furthermore, the annual operation of the optimum system for each scenario is simulated and the power generation and cost benefits of each component have been analysed.

The results aim to demonstrate the relevance and feasibility of MRE penetration into the Canary Island’s electricity market. They are expected to support energy planners and other decision-makers in prioritising RE integration as part of the electricity sector development, and in defining marine areas for the implementation of new MRE technologies.

The ongoing replacement of fossil fuel-based power plants by inverter-based generation is posing severe challenges to system planning and operation in power grids. Novel sources are supposed to take the responsibility of maintaining grid stability and providing adequate services. In particular, black start is one functionality that, as of today, still relies on the presence of conventional power plants, to the extent that some of these need to be kept online for the sole purpose of providing black start capabilities if needed. In comparison with conventional power plants, inverter-based resources are very flexible and controllable, but are characterized by their limited ratings.

In this work we focus on the restoration of MV grids, under the assumption that a top-down restoration is not possible, given that the high voltage grid is not available. The MV grid aims at restoring the power using the generation units present in its grid. We consider the case of a MV grid in the Austrian province of Styria, equipped with a storage unit and distributed photovoltaic (PV) units, forming a hybrid power plant. These types of configurations are as of lately gaining popularity, as the different dynamic characteristics of each asset can be leveraged to provide a wide range of services, considering all time scales. As a by-product, in this work the minimum required rating of said battery will be explored. While PV plus storage for black start has already been explored, the focus has been on the unit behaviour and long-term feasibility. Instead, here we focus on the system-wide transient aspects that occur during the early (and critical) phase of the grid restoration process. Long term, the MV grid is supposed to be resupplied by the transmission grid once this is re-energized. We assume the presence of a central controller that is able to receive the status of the grid and send commands to the storage unit and the PV systems.

In our proposed strategy, the storage unit first soft energizes the medium voltage lines and some of the MV/LV transformers (as many as possible), and afterwards connects the PV unit to leverage its reactive power capabilities. Given the smaller ratings of inverters (compared to conventional generation), it is expected that the collaboration of inverter-based resources would be needed to properly black start a grid of a decent size. This would drastically augment the amount of reactive power available for the black start. Then, the rest of the transformers can be connected in a sequentially manner. Finally, critical loads can be connected.

The proposed ideas have been evaluated against a medium voltage grid in Austria, equipped with a battery and a large PV facility with adequate performance of the grid and the inverter-based generation. The starting model is provided by the distribution system operator (DSO), namely Energienetze Steiermark. The model corresponds to a MV grid with 174 transformers, 323 lines, 1465 switches and 469 loads. Next to the planned storage unit, a solar plant rated at 1MW is to be installed. The connection to the transmission grid is assumed to be open, as the initial status corresponds to a system wide blackout. Simulation results show the adequate response of the inverter-based resources and the successful grid restoration, despite the large number of transformers to be energized.

General Scope

The Hydrogen Lab Bremerhaven (HLB) is a test field set up in Bremerhaven that offers a widely networked infrastructure. Consisting of two electrolysers (1 MW PEM, 1,3 MW alkaline), a fuell cell, a CHP-plant, high- and low-pressure storage units, trailer filling station and the associated peripherals, the HLB at Fraunhofer IWES offers a hydrogen system that provides a wide range of operating options and testing possibilities. The HLB can also be flexibly expanded with up to ten free test stations. A wind turbine, a converter test stand and a 44 MVA grid emulator are integrated into the HLB to enable any number of test scenarios and various stand-alone grid operating modes. The waste heat from the PEM electrolyser will be used to operate a desalination system with the aim to integrate electrolysis into offshore applications. The associated test stand, including a seawater basin, is also part of the HLB.

Main results obtained

In general, there is a lack of real data to validate the simulations in larger power classes. Various influences resulting from the size of the electrolysers are neglected or not considered in the simulations. Scientific projects and investigations on real objects are often conducted only on a (very) small scale - a few 100 kW or smaller. Experience in setting up and operating a test field on a real and industrial dimension is therefore essential and extremely important for further development.
There are no standardized test protocols that are sufficiently tested or standards for electrolysers. This is an important step in the rapid expansion of the technology, which is being driven forward by the long-term tests at HLB.

Methods used

Fraunhofer IWES began planning, implementing, commissioning and the current trial operation of the HLB in 2020. The operation of the individual devices provides a fundamental understanding of the individual systems. All devices will be equipped with extensive measurement technology, which, in addition to performance data and product flow data, also provides information on the mechanical, acoustic, seismic or thermoscopic behavior of the system. The electrolysers will be validated in long-term test campaigns and various test protocols will be run and developed. The direct coupling with an 8 MW wind turbine enables a fluctuating generation line to be run under real conditions. The coupling with the 44 MVA grid emulator can, among other things, realize tests of various grid and fault scenarios. Overall, a great deal of experience can be gained along the entire hydrogen chain and the electrotechnical integration of the systems.

Relevance of the subject matter

There is a pressing need for comprehensive standardization and testing of hydrogen systems to achieve the self-imposed hydrogen goals (10 GW in Germany, 40 GW in the EU in 2030). The absence of established standards and technical guidelines for the integration of hydrogen systems into the existing power grid presents a significant obstacle to large-scale deployment. To close knowledge gaps in the operation, testing methods, and instrumentation of hydrogen systems and to advance the standardization of test methodology, a detailed investigation of these systems under real conditions, connected to the public grid, in combination with renewable energies, and in island mode operation is required. The HLB will make a decisive contribution.

Major conclusions drawn

For 2030 H2-targets, standardized testing is crucial. The absence of integration standards hinders progress. Understanding electrolyser characteristics is vital for reliable operation, especially in isolated and offshore grids.
Results from the operation of the Hydrogen Hybrid Power Systems in real time scale are an inevitable step towards the fulfillment of the targets and the expansion of the technology.

The most pressing concerns prioritize sustainability by addressing local pollution issues (including noise and air quality) and encouraging affordability through strategies that promote independence from fluctuations in fossil fuel costs, increasing production from renewables-based energy systems. For remote and off-grid areas, characterized by a mix of renewable energy sources, energy storage, and conventional generators that meet local energy demands, the absence of a backbone network poses additional technical challenges to this change in paradigm. Optimized Energy Management Systems (EMS) play a pivotal role in enhancing such isolated systems' efficiency, reliability, and sustainability. This paper presents a mathematical model for an optimized energy management system and the compelling techno-economic advantages of using it on a real photovoltaic, battery, and diesel generator hybrid power system located on Bora Bora, an island in the Pacific Ocean. Based on real historical data from the island power system operation, the analysis elaborates on fuel consumption reduction and generation spinning reserve margin based on the N-1 criteria. The paper further describes the impact of battery energy storage systems on spinning reserve management.

This paper investigates the stability of a converter-dominated islanded power system when the island's battery energy storage converters are operated in different control modes (Grid Forming and Grid Following) and combined with different volumes of synchronous compensation. The study is conducted in a realistic simulation model of the future Madeira Island, where no thermal generation is present, and the share of converter-based Renewable Energy Sources is large (75 to 80 % of instantaneous penetration).
The impact of the different combinations of synchronous condensers and BESS converter control modes on the system stability is evaluated using a stability index-based approach that accounts for multiple operation scenarios. In this procedure, the system's dynamic response to the reference disturbances (short-circuits in the Transmission and Distribution Network) is obtained via RMS dynamic simulation and is then analyzed to extract two stability indices (Nadir and Rocof). Such indices are computed for the synchronous generator speed and the grid electrical frequency (measured in different points using a PLL) and are later used as the basis for discussion and conclusion drawing.

The arctic off-grid facility ‘Isfjord Radio’ situated at 78° North in Svalbard, Norway has been working as an important telecommunication hub for Svalbard and its surroundings since 1933, and still is. In addition to its critical telecommunication services, it today also functions as a hotel for tourists.

Isfjord Radio has traditionally been running solely on diesel as energy source, both for its heat and electricity needs. The direct costs and CO2 emissions related to the high diesel consumption, and the operational costs related to the diesel generators was reaching unacceptable levels for the owner, Store Norske. Since 2020 Isfjord Radio has therefor been subjected to an energy transition project, whereas Store Norske is gradually changing Isfjord Radio’s energy system from a diesel based system to become a hybrid energy system including renewable energy production, energy storage and a smart control system for better utilisation of the diesel generators. By 2024 the off-grid hybrid energy system consists of both ground and roof mounted PV facilities, a battery pack, a thermal storage and diesel generators. The results so far show a 60 % reduction in diesel consumption and CO2 emissions, and a reduction in operation hours on the diesel engines of 82 %.

The introduction of Distributed Energy Resources (DER) onto distribution networks presents a number of constraints on the management of the protection scheme, among which the well-known “blinding phenomenon” of protection relays. Indeed, DER can reduce the short-circuit current measured by feeder protection relays which blind the relays. For conventional synchronous and asynchronous generators, their short-circuit contribution can easily be calculated and the blinding evaluated. On the other hand, with the Inverter-based resources, the short-circuit contribution depends on the regulation laws of the generators that is usually not known precisely. In this paper, the maximum blinding of overcurrent protection relays caused by Inverter-based Distributed Energy Resources is addressed by formulating a nonconvex optimization problem. This optimization problem is reformulated as a Semi Definite Program to allow a resolution with convex optimization tools. The program is implemented and compared to another similar method based on random draws, on a real MV/LV microgrid.

Island grids, characterized by peak loads in the hundreds of megawatts and transmission lines spanning tens of kilometers are in the front line of power grids decarbonization. To achieve this goal, the integration of new technologies featuring advanced and smart control solutions is essential. One such technology leap is the Grid-Forming (GFM) inverter, notably when paired with Battery Energy Storage Systems (BESS). The adoption of GFM control transforms the behavior paradigm of these devices introducing new challenges and opportunities, especially in island grids. These grids tend to be weak in terms of short-circuit level with low inertia, making them susceptible to significant voltage phase jumps when major production units are abruptly disconnected. These instantaneous deviations could trigger current and power limitations in GFM inverters and undesired trips may occur. Moreover, these transient events are accompanied by frequency deviations, demanding that GFM inverters demonstrate their capability to maintain synchronism while the power system rides through these disturbances. As an important step towards the deployment of GFM inverters, validation tests are needed to verify their full potential. This paper presents a simplified scenario aimed at emphasizing the significant challenges posed by abrupt transients to GFM inverters. The objective is to provide insight into the establishment of robust requirements.

EDF SEI (Systèmes Electriques Insulaires) which operates French isolated power systems in Overseas Departments and Territories, is facing significant challenges in achieving the decarbonization of the energy mix. These power systems vary in size, from low-voltage (LV) and medium-voltage (MV) microgrids supplying isolated areas, such as in French Guiana or in the Cirque de Mafate in La Réunion, to high-voltage (HV) insular grids with peak loads ranging from 150 MW to 500 MW (French Guiana, Martinique, Guadeloupe, Réunion, and Corsica).

This target implies to develop different renewable energy resources and storage capacities, and significant capacity of both solar and wind farms are expected to be connected to distribution networks and interfaced with power electronics.

This shift has several implications for network adaptation, with one key challenge being the robustness of the protection scheme responsible for ensuring the safety of people and assets.

This paper specifically addresses the unintentional islanding of MV feeders, which is one of the main issues often mentioned in the literature. Unintentional islanding occurs when a portion of the network such as a feeder is disconnected from the upstream but remains energized due to a fortuitous consumption-generation balance between loads and DGs. To prevent these situations, DGs are equipped with interface protection relays monitoring voltage and frequency. Direct transfer trip systems can also be used to disconnect DGs.

First, network interface protection setting values must meet conflicting objectives. Voltage and frequency ranges need to be broad to minimize unwanted disconnections of DGs during HV and MV faults or large consumption-generation unbalances at the system level, and yet be narrow to mitigate the risks of unintentional islanding. In the same vein, while Grid Forming control of the inverters at MV voltage level is strongly recommended to ensure system frequency stability, it may raise the risk of unintentional islanding.

Also, in the absence of a fault on the MV feeder, this situation is to be cleared but does not pose an immediate risk to people and assets. However, in the presence of a fault, if the fault remains energized after the substation breaker opens, it must be cleared. If the fault affects an accessible and grounded facility, the fault duration must comply with the requirements regarding touch voltage limits. For example, it is necessary to ensure the safety of pedestrians near facilities such as MV/LV substations.

In this context, unintentional islanding is a major concern for EDF-SEI and EDF R&D. The focus is on finding solutions that harmonize with safety of people and assets, ensure supply quality and power system stability, and maintain economic sustainability.

The paper's first section will detail the topology of French networks, earthing systems and protection schemes. It will also outline the measures implemented to keep touch voltages within specified limits.

The second section will delve into the issues raised by DGs, ranging from the importance of limiting untimely disconnections to ensure stability, to unintentional islanding and its impacts on the safety of people and assets.

The third section will propose solutions, accompanied by an analysis of their advantages and disadvantages, among which increasing outage times for clients, and unwanted disconnection of DGs. This panel of solutions will help SEI to build the most adapted strategy to tackle this issue.

In this paper simulations using detailed models of battery cells which take the electrochemical properties of the cells into account are used to examine the impact of transient load shifts on battery cells. This is done in order to look at possible limitations in the ability of grid forming inverters to provide instantaneous reserve set by the electrochemical properties of different battery cell types. The model takes the impact of the state of charge of the battery cells on the voltage and the internal resistance as well as capacitive effects from the cell chemistry and inductive effects from the geometry and interconnection of the cells into account. In addition to that the dc link controller and the choice of capacitor size is looked at to evaluate the limitations on providing instantaneous reserve with a battery as a primary energy source. The simulations carried out for this paper show the behaviour of the battery voltage as well as the behaviour of a grid forming inverter in the case of a frequency change.

Hybrid offshore renewable energy systems are becoming a promising resource in the energy production field. The integration of Wave Energy Converters (WEC) into floating wind turbine represents a cost-effective solution that could improve the overall power absorption of the system, reducing the platform dynamic responses and reducing the power production inoperativeness. The present study regards a floating wind turbine integrated with Oscillating Water Columns (OWC). The novel hybrid platform is composed of a spar buoy rigidly connected with three OWCs, structured as cylindrical air chambers arranged symmetrically around the spar buoy. This layout is consistent with the current design approach of floating harnessing systems.
A time-domain model is developed to analyse the behaviour of the floating hybrid platform. In particular, the coupling of aero-hydrodynamic numerical models with the thermodynamics of the OWC air chambers is implemented. The boundary value problem is solved considering a multibody problem approach. The substructure is represented by a single rigid body, while the water inside the air chambers is modelled as piston-like rigid body with the same water density. The thermodynamic model is coupled considering the air homogeneous and the process adiabatic. Sloshing and spray effects are neglected.
Different model approaches could be carried out to represent the thermodynamics of the air chambers to be coupled with the hydrodynamic problem. Since the complexity of the device, a linear model that approximate the pressure and the volume flow rate inside the chamber, suits the requirements of simplicity and lower computational costs towards a control-oriented model and towards design optimization of the floating platform. On the other side, a nonlinear model better represents the phenomena and the physics of the systems, giving a higher quality of numerical analysis on the investigation of the system dynamics. Based on these considerations, the identification of the non-linearities associated to the effect of the air compressibility inside the OWC air chambers is carried out. The aim is to evaluate the air chambers behaviour that affects the dynamics of the whole platform. A quantification of the differences between the two approaches is presented.

The integration of Battery Energy Storage Systems (BESS) in microgrids or islanded systems provides an enabler for generation decarbonization, through the possibility of maximizing the share of renewable sources and thus the reduction of fossil fuels consumption. Furthermore, the integration of BESS helps providing the stability required to face the challenges of energy transition, the intermittency of distributed renewable resources and electrification, through its capability of improving grid resilience and safety, responding to system outages and preventing blackouts.

The Azores archipelago has nine small independent electrical systems, without any capability of exporting or importing energy, since the electrical interconnections between islands are expensive and not economically viable. EDA - Electricidade dos Açores, the system operator, was willing to assess the technical and economic viability of integrating BESS in their islanded systems. The challenges were to increase the share of renewable generation by reducing their conventional generation dependency, while ensuring the reliability of the electrical system.
Siemens Power Technologies International (PTI) developed a three-application methodology with the objective of assessing the feasibility of this integration, as well as providing the optimal BESS sizing for each use case:

• Spinning reserve replacement: the BESS replaces the spinning reserve of thermal units, whilst ensuring grid stability.
• Primary frequency regulation: unbalance events due to the intermittency of renewable generation must be covered quickly by the BESS.
• Integration of renewables: the BESS allows to store or release the surplus of energy resulting from mismatches between generation and demand.

For complying with the applications mentioned above, some analyzes were made through the usage of planning and simulation software to guarantee the BESS correct sizing and technical requirements:

• Techno-economic analysis: Simulation of different energy balance scenarios using PSS®DE to obtain key technical and economic KPIs.
• Short-circuit analysis: PSS®SINCAL short-circuit analysis considering different scenarios of operation for the electrical system.
• Protection System analysis: Assessment of the protection system in PSS®SINCAL for future scenarios with BESS. Recommendation of new settings, if needed.
• Dynamic analysis: RMS and EMT transient analysis based in PSS®E and PSCAD simulations considering different events and perturbations.

This paper intends to go in detail through each of these applications, outlining the methodology and considerations made through each analysis, as well as the challenges and limitations imposed by software state-of-the-art.

Among renewables shared around the globe, offshore wind is projected to increase in the coming decades, reaching almost 1000GW capacity by 2050. In today’s transitioning power systems, ensuring a high level of reliability is crucial to prevent outages that can jeopardize grid stability and result in substantial economic losses. Despite the efforts to enhance reliability, the occurrence of a blackout necessitates the implementation of an effective restoration plan, commonly known as the black-start procedure, to return the grid to normal operation. With the dynamics of the grid rapidly changing due to the large-scale phasing out of synchronous generators, there is a greater need and interest in the market for providing black start as a service to the grid. Offshore wind farms (OWFs), equipped with their substantial capacity and efficient controllers, can serve as innovative black start units based on renewable energy, offering the advantage of both large-scale power generation and rapid response capabilities. The feasibility of providing black start services from an OWF remains to be demonstrated and is particularly relevant when considering that the OWF is operated off-grid and involves an electrolyser unit with the capability to respond proportionally to frequency variations, enhancing its adaptability to the evolving grid dynamics.

The hybrid of using traditional grid-following (GFL) wind turbines (WT)s along with an external power source (e.g. diesel generator or energy storage) for black start have been investigated. An equipment able to self-start (i.e., energisation without relying on the transmission grid) is the highest priority requirement being demanded and grid-forming (GFM) converters with their inherent quality can achieve this, supporting the transition towards 100 % renewable-based black start strategy.

In an off-grid islanded system with a bottom-up restoration approach, incorporating primary frequency control (PFC) enhances the efficiency of large-scale offshore wind energy utilization and, also be beneficial for a Battery Energy Storage System (BESS) in OWFs. The electrolyzer units can act as PFC service providers reducing the burden on the BESS. These dynamic electrolyzer’s offer dual benefits: Firstly, during wind turbine startup, they convert excess electricity into green hydrogen, reducing BESS dependence. Secondly, the BESS is strategically preserved for controlled power modulation during soft-start and transient events. This integrated strategy improves system efficiency, contributes to green hydrogen production's economic viability, providing an approach to offshore wind power storage and utilization.

This paper discusses the utilization of an electrolyzer unit for providing the necessary support as a PFC tackling the challenges for integration of a BESS equipped with GFM control into an islanded off-grid OWF to perform black start service work in parallel with GFL WTs using a soft-start approach. There is a notable absence of challenges addressed with energization procedure of an islanded off-grid OWF placing the BESS at the offshore platform and utilizing the electrolyzer unit for a black start process. The simulations developed using Matlab/Simulink, allow the adoption of a black start procedure and the verification of the islanding operation of the off-grid OWF with wind-speed variations. Additionally, a parallel feeder energization is shown using an already energized feeder. Conclusions on sizing of BESS is drawn.

Island systems need to be self-sufficient with respect to load-generation balancing, frequency control, system strength, resource adequacy, and other key aspects. The effects of faults and loss-of-generation events on island grids tend to be larger in proportion to the size of the system – for example, a transmission fault is likely to bring voltage very low throughout the entire system, increasing the likelihood of severe stability challenges. Similarly, a trip of the largest generator on an island system may result in the loss of 50% or more of generation, whereas on continental systems the largest contingency tends to be less than 5% of generation. System strength concerns also tend to be more challenging because by adding one or two large inverter-based plants, island systems can find their generation mix dominated by non-synchronous generation during certain hours. The challenges of operating with high levels of wind and solar include lower inertia, inverter/converter control instability, reduced fault current (and varying fault-current characteristics), etc. The ongoing maturation of grid-forming battery inverter controls for grid-connected applications represents a significant step forward relative to the past state-of-the-art, where grid-forming inverter controls were typically only deployed in isolated microgrid applications, and not in larger power systems (10s of megawatts and larger). At the same time, replacement of synchronous generators by grid-fomring inverter-based resources introduces major changes grid operations.

This panel sessions will provide real-world examples of these challenges and some potential solutions from the power systems of Galapagos, Jamaica, and Hawaii.

Speaker Topics:

ElecGalapagos operates the four independent power systems power systems of the Galapagos Islands, all of which have ambitious plans to transition from primarily diesel-based power to primarily renewable power by 2030. Cristian Fernandez, Head of Renewable Energy for ElecGalapagos, will summarize the various technical and economic challenges and opportunities presented by this plan. Technical challenges include integration of large-scale solar and battery plants, integration of microgrid controllers with existing control systems, and management of resource variability.

Rick Case will summarize Jamaica Public Service’s experience integrating over 100 MW of wind generation and over 50 MW of solar PV in its ~700 MW peak load power system. In addition, he will describe JPS’s plans to add 298 MW of additional PV, energy storage, and wind generation in 2025 via an solicitation that closed in late 2023.

KIUC’s 75 MW peak power system operates with 90% inverter-based generation at times, a record for a system of its size. This highly renewable operation is supported by two grid-forming PV-battery plants and one synchronous condenser. Cameron Kruse will summarize KIUC’s operations and the challenges it faces, in particular challenges with protective relay coordination for high-IBR operations.

The final presentation will summarize field and laboratory experience with grid-forming inverter controls in island power systems with very high levels of inverter-based resources. Lessons learned related to grid-forming IBR operations will be described based on simulation studies, MW-scale power hardware-in-the-loop experiments, and field experience with utility partners who plan and operate island power systems.

The general scope the present model-based research is to analyse climate-neutral scenarios for Europe and to assess the respective resilience of the energy system. Two scenarios are therefore examined, one with an unrestricted global hydrogen market and the other with improved European energy resilience that limits pipeline imports of hydrogen from non-European countries. Key findings include increasing electrification of the heat and transport sectors, widespread use of Power-to-X appliances and, as a result, a doubling of total electricity consumption in Europe. On the power generation side, there is a need for massive expansion of renewables such as wind and photovoltaics. The analysis shows that a more resilient energy system will require additional electrolysis capacity, hydrogen storage and hydrogen grid capacity. The marginal cost of hydrogen will also increase as a result, and a higher price level will subsequently reduce the demand for hydrogen. The overall conclusion is that a transition from fossil fuels to renewables will, in any case, make the energy system much less dependent on imports and thus more resilient.

The decarbonisation of islands’ energy systems requires unique solutions due to their isolated geographies. IANOS, a Horizon2020 European Commission funded project running 2020 to 2025, aims to harness innovative renewable energy technologies on two lighthouse islands: Terceira and Ameland to progress their island’s energy autonomy. The main objectives of IANOS’s demonstration, targeted by different use cases, is linked to island-level RES self-consumption maximisation and curtailment minimisation, while improving grid resilience and reliability towards a progressive decarbonisation of the island’s energy mix. This paper presents the methodology and early results of the installed technologies for the Terceira demonstration in the Terra Chã neighbourhood managed by an intelligent virtual power plant (iVPP). These already installed technologies include PV panels, heat batteries, electric water heaters, smart solar inverters, hybrid transformer, and a flywheel.

In a future renewable energy system, electrolyzer, as coupling elements between power and gas systems, convert renewable electricity into storable hydrogen, which can be used in further consumption sectors.
The general scope of this investigation is a controlled proton exchange membrane electrolyzer at a low voltage grid. For this, the proton exchange membrane electrolyzer as well as the power electronics for grid connection are developed as components for the “Extended Node Method” based on electrical equivalent circuit diagrams. It is shown how these components are especially defined for this method, how their topology affects the node definitions and how the AC/DC and DC/DC transitions are realized. As a study case, a sample model of a 40 kW stack is considered. The setpoints for electrolyzer current as well as reactive power are adjusted and transient calculations are carried out. The results are compared with models in Simulink/Simscape and show general agreement.

This paper explores the use of Li-Ion battery systems in off-grid applications. The study includes the development of a table that classifies and categorizes various off-grid battery systems based on their applications. A case study on photovoltaic battery off-grid systems is executed, providing practical insights into their application. User profiles of different systems are analyzed to draw an overview of their applications. The paper is finalized with a comparison of the case study with the simulation tool of Fraunhofer ISE called NRGISE. Overall, this research aims to contribute to the understanding and optimization of Li-Ion battery systems in off-grid applications. The paper is developed in the context of IEA PVPS task 18.

In regional Western Australia, where the utility Horizon Power is an operator of multiple remote microgrids in a wide rating range between 10 kW and 30 MW, a transition towards a renewables-dominated generation fleet is occurring at a rapid pace. Distributed Energy Resources (DER) and inverter-based generation in form of solar photovoltaics and energy storage are the prevalent type of new sources deployed in these off-grid systems. Past projects and field trials have revealed integration challenges in systems with high instantaneous penetration of renewables which include heavy reliance on a single genset for frequency control, instabilities between gensets and energy storage and unequal participation in frequency control.

A new approach is considered in which a broad range of devices will share the isochronous and frequency control function. This foresees operating battery energy storage systems in grid-forming droop mode, in parallel and in analogy to the reciprocating engines. This paper outlines the integration challenges and change in frequency control strategy and provides an overview of the investigations performed via modelling studies of the new approach, outcomes of in-factory and in-field tests, including lessons learned and benefits already being seen across a range of projects both in size and generation mix.

Over the past decade, equipment and control technologies for operating island microgrids have made significant progress. Incorporating increasing amounts of renewables and energy storage into island systems, displacing fossil fuels, maintaining operational reliability, significantly reducing levelized cost of electricity, and increasing energy access to remote communities are the dominant drivers for transitioning diesel-based conventional systems to renewable energy based microgrid systems.

While equipment costs have declined, the specialized expertise required and the engineering costs of developing, deploying, and supporting hybrid island energy systems remain high limiting the broad adoption of these solutions. This presentation will focus on an integrated approach to the design, simulation, performance validation, field deployment, operations, and technical support of hybrid power systems using a standardized digital platform.

The case study will cover how three islands in the Philippines were transformed from diesel-based systems delivering power for about 8 hours per day to high penetration renewable energy systems with battery energy storage and upgraded diesel gensets that deliver reliable power continuously to the local community. The energy service provider that competitively won the franchise rights to serve the communities, partnered with Spirae to take the systems from concept to operations. They also incorporated prepaid metering facilities to support commercial operation of the system. The end result is a reliable island energy system that operates commercially with high penetration of renewables including period when the diesel gensets are completely turned off. While the long-term socio-economic benefits to the positively-impacted communities have yet to be quantified, the expectation is that the availability of clean, reliable, power will transform these communities from marginalized to mainstream communities.

The case study will show how a standardized, model-driven approach to hybrid energy systems development in a zero-coding environment substantially reduces project lifetime costs and opens up opportunities for large scale deployment of hybrid energy systems for island and grid-connected applications.

In line with national commitments on net zero emissions, many island jurisdictions demonstrate significant progress in decarbonising power production. We use empirical evidence to show what already has worked on a selection of islands, proving that the advantages of the energy transition outweigh the perceived risks. Wind power and, to a lesser extent, solar PV are allowing islands to become self-sufficient in generating affordable electricity from renewable sources. On volcanic islands, geothermal energy is also successfully utilised. There are currently no plans for nuclear power plants or electrolysers for green hydrogen whilst tidal and wave energy barely feature. One obvious shortfall in future systems appears to be an inadequate amount of grid-scale energy storage. Significant storage capacity will be needed to match variable supply to fluctuating demand and to provide ancillary services, both on islands that are interconnected (for resilience against subsea cable faults) and those that are not (assuming fossil fuels are to be completely phased out). There are as yet only limited plans to strengthen distribution networks for wholesale electrification, whilst more effort is needed to get the public fully behind societal changes. Nonetheless, it is clear that the first movers have benefitted economically and their continuing success will help demonstrate to others the value in moving rapidly away from fossil fuels to renewable energy.

Energynautics CEO Dr. Thomas Ackermann will provide an introduction to the world of hybrid power systems, focusing especially on small power systems on islands or in remote areas. This session intends to give an insight into the current state of small power systems, which are typically still mainly powered by diesel generators, and the challenges and opportunities of supplementing or replacing conventional generation with renewables in such systems.
Furthermore, he will present insights on the Hawaiian power system.

The Faroe Islands have been aiming for a 100% renewable electricity sector in 2030 since 2014. In order to reach this goal, there have been several studies conducted and state of art approaches tested. Recently there have been large battery systems and synchronous condensers installed. These allow for 100% wind power, when the resource is available, and the load is less than the rated wind power. This lecture will share the experiences running on a high penetration of renewable resources.

Indonesia comprises more than 10,000 islands, and the Indonesian state utility PLN runs several hundred diesel-based small power systems to supply electricity to the majority of inhabited islands. The exorbitant cost of diesel generation has been a long time concern to PLN as well as the Indonesian government, and a shift towards renewable generation promises significant economic advantages on top of the obvious positive environmental impact. Hence, the Indonesian government recently started an ambitious „de-dieselization“ program, with the goal of replacing the majority of diesel-fired generation with PV and battery systems. This is contrasted by the fact that while PV integration in Indonesian islands has been economically feasible for a number of years, only very few hybrid systems operate in the country as of today. The lecture will cover technical, economic and regulatory aspects encountered during Energynautics‘ five year engagement in Indonesia, which involved integration studies in seven different island systems of different sizes.

The vast size and sparce population of the US State of Alaska have long presented a spectrum of reliability and economic challenges for electricity supply. The long, thin backbone “Railbelt” power system connects and serves the state’s major population centers over vast distances. Hundreds of electrical islands, including some physical islands, serve more remote communities. Reliability considerations can have extreme human factors, with sustained outages being life-threatening in some communities that experience extreme cold and complete transportation isolation for extended periods. As with many island systems, liquid fossil fuels have high costs. In some places, the handling and transport costs are extreme. Today, these factors provide strong economic motivation to use renewable resources. But even before the modern era of rapid VER growth, Alaska adopted a variety of cutting edge inverter-based technologies for economy and reliability. Of particular interest now, multiple battery energy storage projects were built in the state in the 1990s. This lecture will examine the history and motivations for some of the projects, and then delve into the particulars of the 1st generation grid-forming inverters and controls used in the Metlakatla Power & Light BESS. This project included many of the features that now, nearly 30 years later, are identified as crucial for success.