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

Past trends for the UK Energy Scenarios: How close are their predictions to reality?

This study provides an exploration of the future energy trends in the UK by assessing existing energy scenarios studies and their predictions compared with actual data. The criteria for inclusion were to be national in scope, backcasting and comprehensive (covering the electricity sector). The importance of assessing the historic energy system projections could conduct us to improvements in future energy scenarios. The three studies considered relate to the same four factors: growth indicators, fuel prices, new installations and power stations retirement. The scenarios review revealed several common and different themes although all were developed under the same national targets

Sustainable island power system – Scenario analysis for Crete under the energy trilemma index

Sustainable energy supply is an essential part for economic and social development in every society. Islands as geographical isolated regions have to confront a number of challenges to secure a reliable and clean energy system. Currently, electricity demand on the Greek island of Crete is supplied by oil-fired engines imposed to new emissions restrictions applied from 2020. Thus, a capacity upgrade is necessary and new solutions driven by renewable energy, energy storage and interconnections. This study investigates three scenarios: Business as Usual (BAU); Natural Gas (NG); and the Interconnection of Crete with the National Grid System (Int.) to assess the potential techno-economic and environmental impact of the required transition under the Energy Trilemma Index. A capacity expansion and operation optimisation process has been applied through a high resolution spatio-temporal analysis performed with PLEXOS Integrated Energy Model. It was concluded that no BAU Scenario could facilitate a future plan for the electricity system of Crete or any European island imposed to such constrains. The optimum scenario incorporates interconnectors and energy storage systems that manage to deliver 52% reduction in the total system costs (2020-2040), 79% in electricity prices and 48% reduction in GHG emissions by 2040, compared to the BAU

Long Term analysis of submarine transmission grid extensions between the Greek islands and the mainland

Interconnections' infrastructure is considered fundamental to implement the common rules for the internal electricity market according to 2009/72/EU. Greece currently consists of 29 non-interconnected island systems, experiencing frequent forced outages and high generation costs. A number of interconnection plans are in the pipeline between the Greek islands in the Aegean Sea archipelago and the Greek bulk continental grid. This paper investigates interconnection scenarios and their impact in terms of security of supply, costs and renewable energy integration into the system. PLEXOS® Simulation Software by Energy Exemplar is used to simulate the Greek electricity system. The results show a twofold growth of renewables share between 2020 and 2040 while electricity generation costs recorded on the non-interconnected islands mirror continental costs following the grid extensions. Loss of load probability and unserved energy are eliminated, whilst greenhouse gas emissions are reduced by 73% (vs 1990) in 2040

Renewable and Sustainable Energy Transition

For decades, the Greek islands have been facing challenges in terms of quality of power supply, increased carbon dioxide equivalent (CO2eq) emissions, and costs due to their reliance on oil-fired generation subsidised by the Greek state. In light of the recent reforms to decarbonise the islands' region while enhancing their local grids, this study investigates the impact of electromobility considering an autonomous electricity system supported by storage versus an interconnected one. Two Electric Vehicles (EVs) deployment scenarios coupled with several charging strategies have been modelled using the PLEXOS energy systems model. The results highlight that the Vehicle-to-Grid (V2G) scenarios demonstrate the most evident benefits for the islands' electricity systems, performing adequately under both the Autonomous and Interconnection scenarios concerning the economic and environmental impact. Such scenarios have the potential to reduce emissions by 8.5% while dropping costs up to 20% by 2040, when combined with the required renewables expansion plan. From the security of supply perspective, the results demonstrate improvements under the interconnected context accompanied by thermal generation restrictions without however eliminating power shortages recorded already in a non-EV case. The analysis also showcases an escalated impact on power shortages and curtailments during the maximum week, particularly when combined with an ambitious EV deployment. Yet, V2G may increase renewables share up to 7% in 2040. In this context, EVs could mobilise the additional deployment of 600 MW renewables by 2040 if interconnections with the mainland are realised. Assuming islands continue operating as autonomous electricity systems, the additional capacity to accommodate may reach 720 MW

Modelling electrical interconnections for Rhodes island power system

Remote island power systems often fail to enjoy the right to secure, clean energy supply. This paper presents a short-term analysis for the electrical system of Rhodes-Halki in South Aegean, with the use of a mixed-integer dispatch module in PLEXOS® Simulation Software. While examining the impact of submarine grid extensions, the results show that following the interconnection of Rhodes' power system, rapid renewable energy deployment is recorded, allowing for electricity exports equal to 220 MWh by 2040. Power generation costs decline by 58.9% for the week recording MAX demand and 54.8% for the week recording MIN demand, compared to the BAU autonomous scenario. The scenario imposing generation restrictions according to directives 2010/75/EU and 2015/2193/EU shows high levels of unserved hourly energy equal to 70%-85%

Investigation of high renewable energy penetration in the island of Syros following the interconnection with the national grid system

This paper aims to assess the potential of high renewable energy (wind and solar) integration in the Greek island of Syros, following the scheduled interconnection with the national grid system. Currently, Syros operates an oil fired autonomous power system (APS), emitting large amounts of carbon emissions. Interconnection among a number of islands in the Cyclades and the mainland will eliminate the use of APS, will reinforce islands’ power network and will allow exploitation of high wind and solar potential. It has been concluded that following the interconnection, the installation of 33.5 MW of wind and solar energy is feasible. The assumed capacity will cover the total energy demand by 2030 allowing also electricity exports to the Greek mainland. Transforming Syros into a regional renewable energy hub will contribute to the energy security, providing access to its own energy resources

An analysis of the impact of bioenergy and geosequestration in the UK future energy system

Three different energy scenarios have been considered to analyse the impact of bioenergy and geosequestration to GHG emissions in the UK for 2050. The analysis was accomplished with the use of the DECC 2050 Pathways Calculator. The outcomes focused on energy demand and supply and GHG emissions. The results showed that bioenergy and geosequestration are key factors for a low carbon energy system as they are capable of reducing significanlty carbon emissions, in parallel with the deployment of other clean energy techlogies

Wind offshore energy in the Northern Aegean Sea islanding region

The Greek state estimated a potential of 1,500 MW wind offshore capacity, which can be exploited by 2020, while 943.15 MW are located in the Northern Aegean Sea islanding region. This study presents a techno-economic assessment of wind offshore energy in the Northern Aegean Sea. Different topologies are proposed, taking into account wind offshore and islands interconnections using HVDC and HVAC technology. Investment indicators are based on the expected power generated by the Weibull wind speed probability density function and the total investment cost required for wind offshore engineering. The results show that the two wind offshore farms can secure the complete electrification of the neighboring islands and supply approximately 3,379 GWh to the main consumption centers in northern and central Greece on an annual basis. A sensitivity analysis towards investment optimization has been performed, proposing different wind turbine technologies and interconnection scenarios

Διερεύνηση της γεωγραφικής διαφοροποίησης των επιδράσεων της υψηλής θερμοκρασίας στη θνησιμότητα στην ευρύτερη περιοχή της Αθήνας

Επιδημιολογικές μελέτες έχουν δείξει τις επιβαρυντικές συνέπειες των υψηλών θερμοκρασιών και των καυσώνων στην υγεία των ανθρώπων, ιδιαίτερα στα μεγάλα αστικά κέντρα. Οι μελέτες επικεντρώθηκαν στη διερεύνηση της ολικής και κατά αιτία θνησιμότητας, ενώ τα αποτελέσματα υποστηρίζουν την ύπαρξη ετερογένειας των επιπτώσεων μεταξύ περιοχών με διαφορετικές κλιματικές συνθήκες. Περιορισμένη ωστόσο είναι η έρευνα που έχει διεξαχθεί για την μεταβλητότητα των επιδράσεων αυτών μέσα στις περιοχές ενός μεγάλου αστικού κέντρου, όπως η Αθήνα. Σκοπός της παρούσας εργασίας είναι αρχικά η εκτίμηση του σημείου καμπής της σχέσης θερμοκρασίας-θνησιμότητας, πάνω από το οποίο παρατηρείται αύξηση της θνησιμότητας (θερμοκρασία ελάχιστης θνησιμότητας) και εν συνεχεία η εκτίμηση των επιβαρυντικών επιδράσεων των υψηλών θερμοκρασιών στην ολική, καρδιαγγειακή και αναπνευστική θνησιμότητα, συνολικά για όλες τις ηλικίες και ανά ηλικιακή ομάδα, αλλά και η διερεύνηση της διαφοροποίησης των επιδράσεων μεταξύ των περιοχών της πόλης. Οι αναλύσεις για τη διερεύνηση της σχέσης θερμοκρασίας και θνησιμότητας έγιναν για την ευρύτερη περιοχή της Αθήνας, συνολικά, ανά τομέα (6 τομείς) και ανά δήμο (42 δήμοι). Η περίοδος της μελέτης αφορά τα έτη 2000-2012 και μόνο τους μήνες της θερινής περιόδου, Απρίλιο-Σεπτέμβριο. Για τις ζητούμενες αναλύσεις χρησιμοποιήθηκαν μοντέλα εξάρτησης Poisson. Ως βασική έκθεση θεωρήθηκε ο μέσος όρος της μέγιστης θερμοκρασίας της ίδιας και των 3 προηγούμενων ημερών. Τα μετεωρολογικά δεδομένα που χρησιμοποιήθηκαν προέρχονται από τις μετρήσεις του σταθμού που βρίσκεται στο Θησείο και από την βάση δεδομένων E-OBS για τους 6 τομείς ξεχωριστά. Οι διαφορετικές μεταβολές στην ολική και κατά αιτία θνησιμότητα των τομέων και των δήμων που εκτιμήθηκαν από τα διάφορα μοντέλα μετα-αναλύθηκαν προκειμένου να διερευνηθεί η ύπαρξη χωρικής μεταβλητότητας. Σε περίπτωση που τα αποτελέσματα παρουσίαζαν ετερογένεια έγιναν μετα-παλινδρομήσεις ώστε να βρεθούν παράγοντες, που σχετίζονται με τα χαρακτηριστικά κάθε περιοχής, και ενδεχομένως να αποτελούν τροποποιητές των επιδράσεων των υψηλών θερμοκρασιών στη θνησιμότητα. Η θερμοκρασία που βρέθηκε να αντιστοιχεί στην ελάχιστη θνησιμότητα για την Αθήνα ήταν οι 31.5°C μέγιστης θερμοκρασίας, ενώ για τους 6 τομείς οι θερμοκρασίες αυτές διαφοροποιούνταν από 24.8°C (δυτικός τομέας) έως 27.5°C (κεντρικός τομέας). Για αύξηση της θερμοκρασίας κατά 1°C πάνω από τους 31.5°C , εκτιμήθηκε αύξηση της ολικής θνησιμότητας κατά 4.16% (95% ΔΕ: 3.73, 4.6) , της καρδιαγγειακής κατά 5.34% (95% ΔΕ: 4.74, 5.93) και της αναπνευστικής κατά 5.9% (95% ΔΕ: 4.57, 7.24). Όσο αφορά τους 6 τομείς, η ανάλυση με τα δεδομένα θερμοκρασίας της βάσης E-OBS έδειξε πως η ολική και αναπνευστική θνησιμότητα ατόμων του τομέα Πειραιά(3.08%, 95% ΔΕ:2.38, 3.78 και 6.53%, 95% ΔΕ: 4.34, 8.77 αντίστοιχα) επηρεάζεται περισσότερο από την αύξηση της θερμοκρασίας, ενώ η επίδραση στην καρδιαγγειακή θνησιμότητα βρέθηκε μεγαλύτερη στον κεντρικό τομέα (3.96%, 95% ΔΕ: 3.12, 4.81). Εφαρμόζοντας διαφορετικά μοντέλα για τη διερεύνηση των επιδράσεων της θερμοκρασίας στη θνησιμότητα σε επίπεδο τομέων, με τις μετρήσεις θερμοκρασίας του σταθμού του Θησείου, καταλήγουμε σε παρόμοια μοτίβα. Η ηλικιακή ομάδα των άνω των 75 ήταν αυτή που φαίνεται να επηρεάζεται περισσότερο από τις υψηλές θερμοκρασίες όσο αφορά την ολική και καρδιαγγειακή θνησιμότητα (7.68%, 95% ΔΕ: 4.39,11.08 και 6.17 ,95% ΔΕ: 5.49, 6.86 αντίστοιχα), ενώ η αναπνευστική θνησιμότητα με τις μεγαλύτερες μεταβολές υπό αυξημένες θερμοκρασίες είναι αυτή των ατόμων 65-74 ετών (7.68%, 95% ΔΕ: 4.39,11.08). Οι μετα-αναλύσεις που έγιναν επισήμαναν την παρουσία ετερογένειας των επιδράσεων στην ολική και στην καρδιαγγειακή θνησιμότητα. Η πυκνότητα πληθυσμού, τα ποσοστά κάλυψης γης από κτίρια και από δρόμους και οι ακραίες θερμοκρασίες που επικρατούν κατά μέσο όρο σε μία περιοχή έδειξαν να σχετίζονται με την παρατηρούμενη χωρική μεταβλητότητα των εκτιμήσεων. Τα αποτελέσματα αυτά θα μπορούσαν να αποτελέσουν έναυσμα για περεταίρω έρευνα στην διερεύνηση πιθανών τροποποιήσεων στη σχέση θνησιμότητας και θερμοκρασίας στις περιοχές μεγάλων αστικών κέντρων και να φανούν χρήσιμα στη λήψη στοχευμένων προληπτικών μέτρων για την προστασία του πληθυσμού από επερχόμενους καύσωνες, οι οποίοι προβλέπεται να γίνονται συχνότεροι και εντονότεροι λόγω της κλιματικής αλλαγής.Many studies have provided strong evidence that high temperatures and heat waves are strongly associated with adverse effects on people’s health and especially on mortality in most large cities. They investigated the temperature effects on all cause and cause specific mortality. Heterogeneity in these effects between different cities or areas with different climate conditions is well studied but there is limited evidence about spatial variability of the effects of temperature on mortality within a metropolitan area, like Athens, known as within-city variability. We estimated the temperature threshold, which is the temperature of minimum mortality, and the heat-related risk of total, cardiovascular and respiratory mortality (all ages and by age-group) in Athens metropolitan area. The study area was divided into 6 sectors and 42 municipalities, in order to explore heterogeneity in heat-related effects within the city. The temperature-mortality association was estimated for Athens area, for six sectors separately and for 42 municipalities. We studied the warm period (April-September) of years 2000-2012. Poisson regression used to estimate Athens’ and sectors’ temperature thresholds and the change in mortality risk. The average of lags 0-3 of maximum temperature was considered as the daily exposure. Meteorological data were derived from the E-OBS dataset for Athens’ sectors and from the meteorological station in Thiseio for total area. We evaluated the variability of temperature effects that were estimated in sectors and municipalities. We tried to explain the observed heterogeneity using spatial factors that could behave as effect modifiers. The temperature threshold was 31.5°C for Athens metropolitan area and varied between the 6 sectors from 24.8°C (west) to 27.5°C(center). The percent increase in total mortality per 1°C increase in maximum temperature above the threshold of 31.5°C was estimated to be 4.16% (95% CI: 3.73, 4.6) when the estimated increase in cardiovascular mortality was 5.34% (95% CI: 4.74, 5.93) and in respiratory mortality was 5.9% (95% CI: 4.57, 7.24). Using the E-OBS dataset for the sectors, the highest increase in total and respiratory mortality was in Piraeus (3.08%, 95% CI:2.38, 3.78 and 6.53%, 95% CI: 4.34, 8.77 respectively) and in center for cardiovascular mortality (3.96%, 95% CI: 3.12, 4.81). The same pattern was found considering different models for the investigation of temperature-mortality relationship in the sectors, using temperature measurements from Thiseio station. Higher effect was estimated among the elderly (> 75 years old) for total and cardiovascular mortality (7.68%, 95% CI: 4.39,11.08 and 6.17, 95% CI:5.49, 6.86 respectively) and for respiratory mortality in age group 65-74 (7.68%, 95% CI: 4.39,11.08). There was evidence for spatial variability of the effects of temperature on total and cardiovascular mortality within the city. Population density, percent of buildings’ area, road length and average maximum temperatures of an area were associated with the observed heterogeneity in temperature effects. The results could be used for further investigation of the within city variation of heat-related effects and help public health authorities to implement mitigation strategies to protect the population from temperature extremes and heat waves that tend to be more often and intense