Sustainable power generation expansion with RES and energy storage

Received: February 10th, 2023 ; Accepted: April 30th, 2023 ; Published: July 6th, 2023 ; Correspondence: [email protected] island power systems have a tremendous protentional for RES use. Nevertheless, present infrastructures and system operations emerge with limitations, preventing the technology from further exploitation. Specifically, this paper presents and analyzes a representative interconnected island power system operation and highlights the benefits and challenges of embedding an ultra-high share of RES. This level of power and energy penetration could be technically feasible, taking into account interconnections and electricity storage systems, which could provide under specific implementation strategies advantages in stability, reliability, and energy adequacy

Energy transitions on European islands:Exploring technical scenarios, markets and policy proposals in Denmark, Portugal and the United Kingdom

The energy transition is taking place across the globe and renewable energy facilities are flourishing in many places. Yet, to achieve this transition to a carbon-free economy, fit-for-purpose social and institutional set-ups are just as needed as the technical transition itself. While new energy market regulations and policy designs are proposed, the alignment of these for the transition on remote places like islands is limited. Based on technical scenarios for the transition of three European islands, this article investigates market and policy proposals that will support their technical energy transitions in a socially inclusive way. It is based on a literature study of five policy areas in combination with local stakeholders' engagement and their responses to the suggested proposals. The paper presents a comparative study and design approach for Samsø (Denmark), Orkney (United Kingdom) and Madeira (Portugal), but with transcendent solutions and replicability to other islands, placing them in the global debate on energy policy transitions. Results point to a misalignment between national policies and the policies that would actually support islands' green transition. The recommendations therefore propose to tailor energy relevant policies for islands

GRID STABILITY IMPROVEMENT BY RES-BASED GENERATORS AND BATTERY ENERGY STORAGE SYSTEMS IN SMALL ISLANDS

The integration of Renewable Energy Sources (RES) with power electronics interface to the grid, without the back-up of rotating inertia, endangers frequency stability. This issue becomes particularly critical in isolated power systems, like those of small islands not supplied by the main grid, in the case of high shares of production from unpredictable renewables such as photovoltaic and wind sources. Consequently, to preserve the security and the reliability of these systems, it is necessary to adopt new frequency adjustments mechanisms. In this context, the thesis investigates the transition toward an economically and technically feasible generating system based on RES, to achieve specific decarbonisation targets in two Italian small islands, proposing solutions for preserving grid stability. The optimal energy mix characterised by the lowest Levelized Cost of Energy is evaluated for both Lampedusa and Pantelleria islands (two Italian islands in the Mediterranean Sea), and then a frequency stability analysis is performed showing that, in some operating conditions, the island power systems are no more stable due to the inertia reduction caused by RES. Two solutions are hence proposed: the use of suitable Voltage Source Converters (VSC) for RES interface based on a Virtual Synchronous Machine (VSM) coupled to a traditional Cascaded Current Control (CCC) and the use of Battery Energy Storage System (BESS) able to provide virtual inertia (VI) response. The first aim of the thesis is to show how much important is to consider stability issues in the decarbonisation process of small islands. The second aim is to propose feasible solutions for facing this issue. The thesis's main contribution is the novelty of the proposed study, based on real data provided by the two small island utilities and analysing real scenarios of RES penetration in the two grids. The study results provide precious information for fostering the transition of the two islands towards green smart grid structures

Modelling scenarios for enhancing the effective implementation of secure, affordable and sustainable electricity on the Greek islands

The Greek islands’ power system is fragmented into 29 autonomous electrical systems relying on oil-fired generators to supply 82% of their electricity demand. Local power grids are only allowed to absorb a maximum renewable energy share of approximately 30% to secure the stability of the network and avoid abrupt frequency alterations. Inevitably, fossil-fuel dominated, isolated systems lead to increased generation costs, high carbon intensity and frequent power cuts. A novel integrated methodological approach has been developed to address these challenges consisting of: I) Long and short-term modelling considering interconnections and energy storage in the form of batteries versus the current energy autonomy, using the PLEXOS integrated energy model (Energy Exemplar, 2019) for a projection horizon extending between 2020 and 2040. II) ISLA demand model (Spataru, 2013), adapted to the Greek islands (ISLA_EGI), preceded by an extensive data processing, to anticipate annual demand scenarios. The two models inform each other and support the analysis of 35 scenarios. III) The development of methods to simulate electromobility in PLEXOS considering various charging strategies. This analysis contextualises the impact of innovative technologies in providing feasible solutions on the Greek islands in line with the Energy Trilemma Index (security, affordability, sustainability). It was concluded that when combining submarine interconnections and batteries (Scenario IB.x.1.0.a), generation prices were reduced by 42% at the regional and 10% at the national level compared to a BAU scenario (A.y.1.0.a), while carbon dioxide equivalent (CO2eq) emissions are reduced by 99% and 74% respectively. Also, power outage events are abolished. The benefits of a High-Efficiency demand scenario produced by ISLA_EGI show further reductions of 2.5% in emissions between 2020 and 2040. The results unveil that certain small, remote systems should remain autonomous, supported by battery storage. The operation of EVs highlights that primarily V2G scenarios and occasionally, scheduled unidirectional charging bring the ultimate benefits

Smart Senja electrical network expansion modeling

The addition of variable renewable energy sources into the electrical energy systems of the world has been increasing in recent years. This form of distributed energy production with high production volatility can introduce massive challenges in operating a lower voltage distribution network. One of these affected networks is on the island of Senja in northern Norway, with an eldering radial electrical network with a single connection to the national transmission grid. In this study, prescriptive analysis of the network through mathematical optimization is implemented to investigate if there are more effective solutions to this problem other than building more electrical lines. In selected parts of the island, the electrical network experiences electrical faults of different magnitude and concern affecting 1500 hours a year. In this thesis, the model GenX is presented which prescribes solutions reducing these faults to zero while also cutting costs compared to the baseline scenario of today’s system. Results from the model indicate that simple installments of distributed power generation in conjunction with electrical energy storage drastically improve network capacity and industrial expansion opportunities. Also investigated is the feasibility of operating the electrical network on the island without any connection to the external grid. Meant as a proof of concept for the application of mathematical optimization on electrical grids in other more remote parts of the world. The model proves that investments in local electricity production positively impact the system at a fraction of the cost of building new regional distribution infrastructure. Finally, some drawbacks of the chosen analytical tool used to construct the mathematical optimization model are presented alongside selected methods applicable to apprehend or circumvent these limitations

An evaluation of distributed cogeneration for disaggregated consumer populations on Islands : the case of Guernsey

There is currently no strategic energy conservation management on the island of Guernsey, nor may it be adequate to leave energy management entirely to market forces. Market mechanisms of themselves may not be adequate to balance the intrinsically conflicting objectives of obtaining the cheapest possible energy, ensure security of supply, reduce the risks associated with over-dependence on particular energy sources (such as petroleum products), whilst protecting the environment. Properly formed data sets, together with time-based capital budgeting, are necessary prerequisites for balanced political choice. The thesis deals with the central issues of strategy by use of a soft systems methodology. It develops the proposition that energy needs for communities, or 'clusters' of demand, might be better met and matched by taking local needs for energy and matching them to locally, parish based, generated supplies. This approach runs counter to much current public energy policy in relation to utilities and supply-demand relationships. Quality, Quantity and Timing (QQT) computer based models are developed for each parish on Guernsey which reflect diurnal/seasonal patterns of demand and explain how variability of demand on various time scales may influence supply technology choices. Parish energy sources are compared on a least-cost basis and a simulation model is used to take into account the variability in the supply potential of alternative renewable sources of energy, and it® relationship to variability of demand (as exposed by QQT modelling). The work described uses computer models based upon SuperCalc 5 advanced spreadsheet modelling techniques, dBASE III Plus database/programming language and compiled under Clipper. A TurboPascal simulation programme was also considered but ultimately rejected in the present context. As well as dealing with the central issues of strategy, and the tactics for achieving them, the thesis analyses the prospect that decentralisation of the power and energy base (through distributed cogeneration) could be a much better strategy to follow for an island such as Guernsey. One outcome of the soft system and simulation modelling approaches was a proposed formal 'States of Guernsey Energy Management System' to provide a mobilising strategy and an environment for market forces to operate within. This focuses on the energy service requirements of each parish and attempts to answer such questions as; "do we expand the present centralised Island supply of fuels and electricity, or do we instead use less fossil fuels to meet the energy services we want by other means, at lower cost ?". The fundamental proposition of the thesis is that much improved means exist for the efficient utilisation of important resources (energy, capital, manpower) within Guernsey and importantly, a wide range of other well populated ‘energy clusters’

Power System Modelling A techno-economic analysis of the island of Menorca, Spain

It is hard to overstate the need for humanity to address what is arguably one of the most pressing issues of our generation: climate change. Although electricity generation only accounts for about a quarter of global carbon emissions, it is one of the sectors for which a wide range of technologies are already commercially available and increasingly competitive. The decarbonization of other energy-intensive and high emitting sectors: agriculture, transportation, heating and industrial processes such as cement and steel production, although still lagging behind due to both technical and economic challenges, are beginning to show signs of progress. In some cases, electrification will be the most viable path to decarbonization, as seen in the light-duty transportation sector, where electric vehicles are already a reality. For many others, technological innovation will play a crucial role in bringing viable solutions to market. If approached pragmatically, the power sector is in a position to be the first piece of the puzzle to transition to a fundamentally sustainable way of sourcing energy. The analysis herein presented aims to identify the cost-optimum power system that can reliably supply the Spanish island of Menorca with electricity for the next ten years, from 2021 to 2030. Menorca’s power sector is computationally modelled and simulated using the open-source power system modelling tool Switch 2.0. The study is divided into different scenarios and the results of the techno-economic optimization are presented and discussed in terms of their technical feasibility, carbon footprint and costs. In addition to a standard base case scenario, the impact of factors such as fuel cost fluctuations and policy-related externalities (carbon price and renewable energy mandates) are also assessed as separate scenarios. The results of the techno-economic analysis show a clear and consistent trend across all scenarios: renewable energy technologies, namely solar PV and onshore wind power, represent the cheapest source of new bulk electricity generation in Menorca. As such, they are poised to drastically change the current fossil-based and centralized power system of the island, becoming the main sources of electricity. The base case – the most conservative scenario, in which carbon emissions are not priced, fuel costs are kept constant and no renewable energy mandate is set – solar PV and wind power account for two thirds of the total electricity supply by 2030. The penetration of renewables is even higher for the other scenarios modelled