Maintenance, upgrading and extension of the Decision Support System for the management of the Athens water resource system
Duration: October 2008–November 2011
Budget: €72 000
Project director: N. Mamassis
Principal investigator: D. Koutsoyiannis
This research project includes the maintenance, upgrading and extension of the Decision Support System that developed by NTUA for EYDAP in the framework of the research project “Updating of the supervision and management of the water resources’ system for the water supply of the Athens’ metropolitan area”. The project is consisted of the following parts: (a) Upgrading of the Data Base, (b)Upgrading and extension of hydrometeorological network, (c) upgrading of the hydrometeorological data process software, (d) upgrading and extension of the Hydronomeas software, (e) hydrological data analysis and (f) support to the preparation of the annual master plans
G.-F. Sargentis, R. Ioannidis, T. Iliopoulou, P. Dimitriadis, and D. Koutsoyiannis, Landscape planning of infrastructure through focus points’ clustering analysis. Case study: Plastiras artificial lake (Greece), Infrastructures, 6 (1), 12, doi:10.3390/infrastructures6010012, 2021.
Even though landscape quality is largely a subjective issue, the integration of infrastructure into landscapes has been identified as a key element of sustainability. In a spatial planning context, the landscape impacts that are generated by infrastructures are commonly quantified through visibility analysis. In this study, we develop a new method of visibility analysis and apply it in a case study of a reservoir (Plastiras dam in Greece). The methodology combines common visibility analysis with a stochastic tool for visual-impacts evaluation; points that generate high visual contrasts in landscapes are considered Focus Points (FPs) and their clustering in landscapes is analyzed trying to answer two questions: (1) How does the clustering of Focus Points (FPs) impact the aesthetic value of the landscape? (2) How can the visual impacts of these FPs be evaluated? Visual clustering is calculated utilizing a stochastic analysis of generated Zones of Theoretical Visibility. Based on the results, we argue that if the visual effect of groups of FPs is positive, then the optimal sitting of FPs should be in the direction of faint clustering, whereas if the effect is negative, the optimal sitting of FPs should be directed to intense clustering. In order to optimize the landscape integration of infrastructure, this method could be a useful analytical tool for environmental impact assessment or a monitoring tool for a project’s managing authorities. This is demonstrated through the case study of Plastiras’ reservoir, where the clustering of positively perceived FPs is found to be an overlooked attribute of its perception as a highly sustainable infrastructure project.
Full text: http://www.itia.ntua.gr/en/getfile/2083/1/documents/infrastructures-06-00012-v2.pdf (5634 KB)
R. Ioannidis, and D. Koutsoyiannis, A review of land use, visibility and public perception of renewable energy in the context of landscape impact, Applied Energy, 276, 115367, doi:10.1016/j.apenergy.2020.115367, 2020.
Landscape impacts associated with aesthetics have been a persistent cause of opposition against renewable energy projects. However, the current uncertainty over the spatial extents and the rationality of reported impacts impedes the development of optimal strategies for their mitigation. In this paper, a typology of landscape impacts is formed for hydroelectric, wind and solar energy through the review of three metrics that have been used extensively for impact-assessment: land use, visibility and public perception. Additionally, a generic landscape-impact ranking is formed, based on data from realized projects, demonstrating that hydroelectric energy has been the least impactful to landscapes per unit energy generation, followed by solar and wind energy, respectively. More importantly, the analysis highlights the strengths and weaknesses of each technology, in a landscape impact context, and demonstrates that, depending on landscape attributes, any technology can potentially be the least impactful. Finally, a holistic approach is proposed for future research and policy for the integration of renewable energy to landscapes, introducing the maximum utilization of the advantages of each technology as an additional strategy in an effort to expand beyond the mitigation of negative impacts.
Download site: https://authors.elsevier.com/c/1bbKL15eiezzux
G.-F. Sargentis, P. Dimitriadis, R. Ioannidis, T. Iliopoulou, E. Frangedaki, and D. Koutsoyiannis, Optimal utilization of water resources for local communities in mainland Greece (case study of Karyes, Peloponnese), Procedia Manufacturing, 44, 253–260, doi:10.1016/j.promfg.2020.02.229, 2020.
Water is the basis of our civilization and the development of society is intertwined with the exploitation of water resources in various scales, from a well dug to irrigate a garden, to a large dam providing water and energy for a large area. However, for remote mountainous areas, intermittent natural water resources and high seasonal demand the above tasks become challenging. Here we discuss various alternative management options and appropriate solutions on how to exploit water resources meeting the above restrictions under limited infrastructure budgets. As a case study we examine the area of Karyes in Peloponnese that meets the above criteria, exploring various solutions to satisfy the water demand.
R. Ioannidis, T. Iliopoulou, C. Iliopoulou, L. Katikas, A. Petsou, M.-E. Merakou, M.-E. Asimomiti, N. Pelekanos, G. Koudouris, P. Dimitriadis, C. Plati, E. Vlahogianni, K. Kepaptsoglou, N. Mamassis, and D. Koutsoyiannis, Solar-powered bus route: introducing renewable energy into a university campus transport system, Advances in Geosciences, 49, doi:10.5194/adgeo-49-215-2019, 2019.
We investigate the application of a solar-powered bus route to a small-scale transportation system, as such of a university campus. In particular, we explore the prospect of replacing conventional fossil fuel buses by electric buses powered by solar energy and electricity provided by the central grid. To this end, we employ GIS mapping technology to estimate the solar radiation at the university campus and, accordingly, we investigate three different scenarios for harnessing the available solar power: (1) solar panels installed on the roof of bus stop shelters, (2) solar panels installed at an unused open space in the university, and (3) solar roads, i.e. roads constructed by photovoltaic (PV) materials. For each of the three scenarios, we investigate the optimal technical configuration, the resulting energy generation, as well as the capital cost for application in the case of NTUA campus in Athens (Greece). The preliminary feasibility analysis showcases that all three scenarios contribute to satisfying transportation demand, proportionately to their size, with scenario (2) presenting the lowest capital cost in relation to energy generation. Therefore, we further explore this scenario by simulating its daily operation including the actions of buying and selling energy to the central grid, when there is energy deficit or surplus, respectively. A sensitivity analysis is carried out in order to ascertain the optimal size of the solar panel installation in relation to profit and reliability. Overall, results indicate that, albeit the high capital costs, solar-powered transportation schemes present a viable alternative for replacing conventional buses at the studied location, especially considering conventional PV panels. We note that present results heavily depend on the choice of capacity factors of PV materials, which differ among technologies. Yet, as capacity factors of PV panels are currently increasing, the studied schemes might be more promising in the future.
Full text: http://www.itia.ntua.gr/en/getfile/2016/1/documents/adgeo-49-215-2019.pdf (8167 KB)
G.-F. Sargentis, P. Dimitriadis, R. Ioannidis, T. Iliopoulou, and D. Koutsoyiannis, Stochastic evaluation of landscapes transformed by renewable energy installations and civil works, Energies, 12 (4), 2817, doi:10.3390/en12142817, 2019.
Renewable energy (RE) installations and civil works are beneficial in terms of sustainability, but a considerable amount of space in the landscape is required in order to harness this energy. In contemporary environmental theory the landscape is considered an environmental parameter and the transformation of the landscape by RE works has received increasing attention by the scientific community and affected societies. This research develops a novel computational stochastic tool the 2D Climacogram (2D-C) that allows the analysis and comparison of images of landscapes, both original and transformed by RE works. This is achieved by a variability characterization of the grayscale intensity of 2D images. A benchmark analysis is performed for art paintings in order to evaluate the properties of the 2D-C for image analysis, and the change in variability among images. Extensive applications are performed for landscapes transformed by RE works. Results show that the 2D-C is able to quantify the changes in variability of the image features, which may prove useful in the landscape impact assessment of large-scale engineering works.
Full text: http://www.itia.ntua.gr/en/getfile/1984/1/documents/energies-12-02817.pdf (2772 KB)
Other works that reference this work (this list might be obsolete):
|1.||Ding, L., Q. Li, J. Tang, J. Wang, and X. Chen, Linking land use metrics measured in aquatic-terrestrial interfaces to water quality of reservoir-based water sources in Eastern China, Sustainability, 11(18), 4860, doi:10.3390/su11184860, 2019.|
G.-F. Sargentis, R. Ioannidis, G. Karakatsanis, S. Sigourou, N. D. Lagaros, and D. Koutsoyiannis, The development of the Athens water supply system and inferences for optimizing the scale of water infrastructures, Sustainability, 11 (9), 2657, doi:10.3390/su11092657, 2019.
Modern organized societies require robust infrastructures, among which hydraulic projects, such as water supply and drainage systems, are most important, particularly in water-scarce areas. Athens is a unique example because it is a big city (population 3.7 million) located in a very dry area. In order to support the development of the city, large hydraulic projects had to be constructed during its history and, as a result, Athens currently has one of the largest water supply systems in the world. Could Athenians choose smaller scale infrastructures instead? Analyzing social, technical and economical historical data, we can see that large capital investments were required. In order to evaluate these investments this paper presents a technical summary of the development. An economic analysis displays historical values of these investments in present monetary values. The cost of existing infrastructure is compared to the cost of constructing smaller reservoirs and a model is created to correlate the price of water and the cost of water storage with the size of reservoirs. In particular, if more and smaller reservoirs were built instead of the large existing ones, the cost of the water would significantly increase, as illustrated by modelling the cost using local data.
Full text: http://www.itia.ntua.gr/en/getfile/1970/1/documents/sustainability-11-02657-v3.pdf (6450 KB)
See also: https://www.mdpi.com/2071-1050/11/9/2657
E. Klousakou, M. Chalakatevaki, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, G. Karakatsanis, A. Efstratiadis, N. Mamassis, R. Tomani, E. Chardavellas, and D. Koutsoyiannis, A preliminary stochastic analysis of the uncertainty of natural processes related to renewable energy resources, Advances in Geosciences, 45, 193–199, doi:10.5194/adgeo-45-193-2018, 2018.
The ever-increasing energy demand has led to overexploitation of fossil fuels deposits, while renewables offer a viable alternative. Since renewable energy resources derive from phenomena related to either atmospheric or geophysical processes, unpredictability is inherent to renewable energy systems. An innovative and simple stochastic tool, the climacogram, was chosen to explore the degree of unpredictability. By applying the climacogram across the related timeseries and spatial-series it was feasible to identify the degree of unpredictability in each process through the Hurst parameter, an index that quantifies the level of uncertainty. All examined processes display a Hurst parameter larger than 0.5, indicating increased uncertainty on the long term. This implies that only through stochastic analysis may renewable energy resources be reliably manageable and cost efficient. In this context, a pilot application of a hybrid renewable energy system in the Greek island of Astypalaia is discussed, for which we show how the uncertainty (in terms of variability) of the input hydrometeorological processes alters the uncertainty of the output energy values.
Full text: http://www.itia.ntua.gr/en/getfile/1864/1/documents/adgeo-45-193-2018.pdf (559 KB)
See also: https://www.adv-geosci.net/45/193/2018/
G.-F. Sargentis, R. Ioannidis, M. Chiotinis, P. Dimitriadis, and D. Koutsoyiannis, Aesthetical issues with stochastic evaluation, Data Analytics for Cultural Heritage, edited by A. Belhi, A. Bouras, A.K. Al-Ali, and A.H. Sadka, doi:10.1007/978-3-030-66777-1_8, Springer, 2021.
Throughout human history, the quantification of aesthetics has intrigued philosophers, artists, and mathematicians alike. In this chapter, a methodology based on stochastic mathematics is applied for the quantification of aesthetic attributes of paintings and landscapes. The paintings analyzed include Da Vinci, Pablo Picasso, and various other celebrated paintings from 1250 AD to modern times. In regard to landscapes, the analysis focuses on the aesthetic transformations imposed to landscapes from wind energy projects. The methodology used is called stochastic 2D-C analysis and is based on a stochastic computational tool that analyzes brightness fluctuation in images. The 2D-C tool is used to measure the degree of variability and in particular the change in variability vs. scale. The application of the tool provides (a) input on the qualitative efficiency of mainstream methods used in landscape-impact analysis, (b) insights into the expression forms of the examined artists and historical periods, and finally (c) evidence that can be used in the search of the originality of an artwork of disputed authorship.
N. Mamassis, A. Efstratiadis, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, and D. Koutsoyiannis, Water and Energy, Handbook of Water Resources Management: Discourses, Concepts and Examples, edited by J.J. Bogardi, T. Tingsanchali, K.D.W. Nandalal, J. Gupta, L. Salamé, R.R.P. van Nooijen, A.G. Kolechkina, N. Kumar, and A. Bhaduri, Chapter 20, 617–655, doi:10.1007/978-3-030-60147-8_20, Springer Nature, Switzerland, 2021.
The fundamental concepts in the field of water-energy systems and their historical evolution with emphasis on recent developments are reviewed. Initially, a brief history of the relation of water and energy is presented, and the concept of the water-energy nexus in the 21th century is introduced. The investigation of the relationship between water and energy shows that this relationship comprises both conflicting and synergistic elements. Hydropower is identified as the major industry of the sector and its role in addressing modern energy challenges by means of integrated water-energy management is highlighted. Thus, the modelling steps of designing and operating a hydropower system are reviewed, followed by an analysis of theory and physics behind energy hydraulics. The key concept of uncertainty, which characterises all types of renewable energy, is also presented in the context of the design and management of water-energy systems. Subsequently, environmental considerations and impacts of using water for energy generation are discussed, followed by a summary of the developments in the emerging field of maritime energy. Finally, present challenges and possible future directions are presented.
R. Ioannidis, and D. Koutsoyiannis, The architectural and landscape value of dams: from international examples to proposals for Greece, Proceedings of 3rd Hellenic Conference on Dams and Reservoirs, Zappeion, Hellenic Commission on Large Dams, Athens, 2017.
Dam architecture has been an issue that has not significantly concerned Greek organizations engaged in research, design and construction of dams. This research paper explores the need to raise the awareness of these organizations on issues related to the architecture of dams and produces relevant proposals. Initially, the current situation is investigated in relation to the architecture of Greek dams and the impact of these projects on the Greek landscape is evaluated. Then, international examples of architectural interventions on dams are examined leading to the creation of database of techniques and ideas that could be implemented in Greece or worldwide. At last, a case study examining the architectural design of a Hardfill dam is conducted, in which the technical, construction-process, architecture and cost aspects of the proposed architectural interventions are analyzed.
D. Koutsoyiannis, and R. Ioannidis, The energetic, environmental and aesthetic superiority of large hydropower projects over other renewable energy projects, Proceedings of 3rd Hellenic Conference on Dams and Reservoirs, Zappeion, Hellenic Commission on Large Dams, Athens, 2017.
Full text: http://www.itia.ntua.gr/en/getfile/1745/1/documents/2017SynedrioFragmatwn5.pdf (3948 KB)
E. Manta, R. Ioannidis, G.-F. Sargentis, and A. Efstratiadis, Aesthetic evaluation of wind turbines in stochastic setting: Case study of Tinos island, Greece, European Geosciences Union General Assembly 2020, Geophysical Research Abstracts, Vol. 22, Vienna, EGU2020-5484, doi:10.5194/egusphere-egu2020-5484, 2020.
Wind turbines are large-scale engineering infrastructures that may cause significant social reactions, due to the anticipated aesthetic nuisance. On the other hand, aesthetics is a highly subjective issue, thus any attempt towards its quantification requires accounting for the uncertainty induced from subjectivity. In this work, taking as example the Aegean island of Tinos, Cyclades, Greece, we present a stochastic-based methodology for evaluating the feasibility of developing wind parks in terms of their aesthetic impacts. At first, a field analysis is been conducted along with photographic surveying, 3D representation and the opinion of the target population regarding the development of wind parks across the island. Subsequently, the landscape transformations that will be caused from the wind turbines are assessed according to the theory of aesthetics, which are depicted by using suitable spatial analysis tools in GIS environment. The 3D representation images along with the maps are finally assessed through stochastic analysis, in order to quantify the visual impacts to the landscape and the nuisance to local community.
Other works that reference this work (this list might be obsolete):
|1.||Vlami, V., I. P. Kokkoris, S. Zogaris, G. Kehayias, and P. Dimopoulos, Cultural ecosystem services in the Natura 2000 network: Introducing proxy indicators and conflict risk in Greece, Land, 10(1), 4, doi:10.3390/land10010004, 2021.|
M. Karataraki, A. Thanasko, K. Printziou, G. Koudouris, R. Ioannidis, T. Iliopoulou, P. Dimitriadis, C. Plati, and D. Koutsoyiannis, Campus solar roads: a feasibility analysis, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-15648-2, European Geosciences Union, 2019.
We study the possibility of replacing conventional roads and buses with solar powered panel roads and electric buses fueled by solar energy within a closed system at a university campus. We also examine an alternative option of using solar buses equipped with panels on the rooftop. We review the recent advances in the technology of solar roads and buses and examine the modeling challenges and uncertainties of a transportation system powered by solar energy. We evaluate the economic aspects as well as the advantages and limitations of the proposed systems.The feasibility of this project is examined in terms of its application in the NTUA campus and possible directions for further research are identified.
Full text: http://www.itia.ntua.gr/en/getfile/1959/1/documents/Teliko_poster_egu_1_selida.pdf (1985 KB)
A. Petsou, M.-E. Merakou, T. Iliopoulou, C. Iliopoulou, P. Dimitriadis, R. Ioannidis, K. Kepaptsoglou, and D. Koutsoyiannis, Campus solar roads: Optimization of solar panel and electric charging station location for university bus route, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-10832, European Geosciences Union, 2019.
We explore the prospect of replacing conventional university campus buses powered by fossil fuels with ones using solar energy. The proposed research investigates the emerging technology of solar powered road panels within a stochastic framework in order to optimally determine the corresponding infrastructure requirements for a university circulator line. More specifically, an optimization model is developed in order to determine the optimal locations for solar-powered roadway segments and electric charging stations for the existing university campus bus route. Since the availability of solar energy is linked to sunshine levels, we explore the possibility of using hybrid buses, powered by electricity and storing the energy to batteries in order to allow operation in days with no sunshine. As an alternative we study the use of solar buses equipped with panels on the rooftop. In order to account for the uncertainty associated with the system inputs, the transportation demand for the campus route and the availability of solar energy over the campus area are simulated using stochastic methods. The capital cost and energy consumption of the selected buses, charging stations and solar panels are also investigated in a case study for the NTUA campus.
Full text: http://www.itia.ntua.gr/en/getfile/1957/1/documents/EGU-Solar-Roads-FINAL.pdf (1082 KB)
Μ. Sako, E. Tsoli, R. Ioannidis, E. Frangedaki, G.-F. Sargentis, and D. Koutsoyiannis, Optimizing the size of Hilarion dam with technical, economical and environmental parameters, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-15297, European Geosciences Union, 2019.
The construction and operation of large dams has been questioned in recent years as, despite their positive effect on the economy, they are regarded as negative to the environment. The size of a dam, in particular, is an important aspect of this debate as it is thought to increase its economic benefit but also its environmental impacts. We investigate the dam scale issue based on a case study for the Hilarion dam, located in Kozani, Greece. More specifically, in an effort to examine the problem of optimal project scale, we quantify selected technical, economic and environmental parameters of the Hilarion dam for different hypothetical scenarios of dam size including its original size. The various scenarios are compared on a cost-benefit basis to provide a first approximation of the exact relation between dam size and its technical, environmental and economic characteristics.
This research has been supported by the OptArch project: "Optimization Driven Architectural Design of Structures" (No: 689983) belonging to the Marie Skłodowska-Curie Actions (MSCA) Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2015.
R. Ioannidis, P. Dimitriadis, G.-F. Sargentis, E. Frangedaki, T. Iliopoulou, and D. Koutsoyiannis, Stochastic similarities between hydrometeorogical and art processes for optimizing architecture and landscape aesthetic parameters, European Geosciences Union General Assembly 2019, Geophysical Research Abstracts, Vol. 21, Vienna, EGU2019-11403, European Geosciences Union, 2019.
Stochastics help develop a unified perception for natural phenomena and expel dichotomies like random vs. deterministic, as both randomness and predictability coexist and are intrinsic to natural systems which can be deterministic and random at the same time, depending on the prediction horizon and the time scale. The high complexity and uncertainty of natural processes has been long identified through observations as well as extended analyses of hydrometeorological processes such as temperature, humidity, surface wind, precipitation, atmospheric pressure, river discharges etc. All these processes seem to exhibit high unpredictability due to the clustering of events. Art is a mix of determinism (e.g., certain rules have to be followed) and stochasticity (e.g., creativity and inspiration). However, in this analysis we analyse each artistic work in a stochastic approach, and attempt to identify their degree of intrinsic uncertainty. The stochastic analysis includes the investigation of possible Hurst-Kolmogorov behaviour in the art of different periods (visual arts, music, poetry) and of relationships with natural processes. Based on the stochastic analysis of different artworks, we make an image analysis of architectural elements in the landscape in order to formulate an indicator that can be used in engineering.
This research has been supported by the OptArch project: "Optimization Driven Architectural Design of Structures" (No: 689983) belonging to the Marie Skłodowska-Curie Actions (MSCA) Research and Innovation Staff Exchange (RISE) H2020-MSCA-RISE-2015.
G.-F. Sargentis, R. Ioannidis, G. Karakatsanis, and D. Koutsoyiannis, The scale of infrastructures as a social decision. Case study: dams in Greece, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-17082, European Geosciences Union, 2018.
Organized societies require specific infrastructures, among which hydraulic projects are most important. Thus, for the functioning of a society, the water supply and drainage are prerequisites, while a new modern society also needs renewable energy in addition to, and in connection with, high quality water. Dams are key infrastructures in this process. Modern economic and social conditions do not define the limits of what we call "development". In this research we are mapping the limits of the development based on the capacity of the landscape, the water resources, the finances, the political aspects and the criteria of a city’s development.
G.-F. Sargentis, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, and D. Koutsoyiannis, Stochastic investigation of the Hurst-Kolmogorov behaviour in arts, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-17740-1, European Geosciences Union, 2018.
The Hurst-Kolmogorov (HK) behaviour (i.e. power-law decrease of the process variance vs. scale of averaging) has been already identified in numerous geophysical processes highlighting the large uncertainty of Nature in all time scales. In this study, we investigate through the climacogram whether or not some art works (such as paintings, music pieces and poems) also exhibit this behaviour and try to interpret the results in terms of (un)predictability in works of art.
S. Sigourou, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, A. Skopeliti, K. Sakellari, G. Karakatsanis, L. Tsoulos, and D. Koutsoyiannis, Comparison of climate change vs. urbanization, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-18598-2, European Geosciences Union, 2018.
Urbanization has long been identified as one of the major human impacts on the micro-climate of urban areas and has been linked to large (and often disastrous) changes into several hydroclimatic processes such as temperature, humidity and precipitation. However, climate change studies have rarely separated the urban local-scale influence from the global one. In this study, we thoroughly investigate and compare the changes in the variability of the above hydroclimatic processes in urban regions and in the ones with small or negligible human impact. The analysis includes global historical databases of the above processes as well as of the urbanization impact through land-use change.
Full text: http://www.itia.ntua.gr/en/getfile/1810/1/documents/EGU2018-18598-2.pdf (31 KB)
S. Sigourou, P. Dimitriadis, T. Iliopoulou, R. Ioannidis, A. Skopeliti, K. Sakellari, G. Karakatsanis, L. Tsoulos, and D. Koutsoyiannis, Statistical and stochastic comparison of climate change vs. urbanization, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-18608-2, European Geosciences Union, 2018.
Urbanization has long been identified as one of the major human impacts on the micro-climate of urban areas and has been linked to large (and often disastrous) changes into several hydroclimatic processes such as temperature, humidity and precipitation. However, climate change studies have rarely separated the urban local-scale influence from the global one. In this study, we thoroughly investigate and compare the changes in the variability of the above hydroclimatic processes in urban regions and in the ones with small or negligible human impact. The analysis includes Monte-Carlo experiments to assess how the aforementioned variability can be simulated through a stochastic model.
Full text: http://www.itia.ntua.gr/en/getfile/1809/1/documents/EGU2018-18608-2.pdf (31 KB)
E. Klousakou, M. Chalakatevaki, R. Tomani, P. Dimitriadis, A. Efstratiadis, T. Iliopoulou, R. Ioannidis, N. Mamassis, and D. Koutsoyiannis, Stochastic investigation of the uncertainty of atmospheric processes related to renewable energy resources, European Geosciences Union General Assembly 2018, Geophysical Research Abstracts, Vol. 20, Vienna, EGU2018-16982-2, European Geosciences Union, 2018.
Renewable energy resources, e.g., wind and solar energy, are characterized by great degree of uncertainty and in general, limited predictability, because of the irregular variability of the related geophysical processes. A simple and robust measure of the inherent uncertainty of a process is the Hurst parameter. Specifically, the more complex a process is, the larger the introduced uncertainty (unpredictability) and the larger the Hurst parameter. This behaviour (called Hurst-Kolmogorov, HK) has been identified in numerous geophysical processes. Although there are several methods for estimating the Hurst parameter, the climacogram (i.e. variance of the averaged process vs. scale of averaging) is one of the most powerful ones, with a lower statistical estimation uncertainty compared to the autocovariance and power spectrum. We apply the climacogram method to timeseries from processes related to renewable energy systems (wind, solar, ocean etc.) with the aim to characterize their degree of uncertainty and predictability across different timescales. We compare results among the different processes and we provide real-world examples of renewable energy systems management to illustrate the technical relevance of our findings.
P. Dimitriadis, L. Lappas, Ο. Daskalou, A. M. Filippidou, M. Giannakou, Ε. Gkova, R. Ioannidis, Α. Polydera, Ε. Polymerou, Ε. Psarrou, A. Vyrini, S.M. Papalexiou, and D. Koutsoyiannis, Application of stochastic methods for wind speed forecasting and wind turbines design at the area of Thessaly, Greece, European Geosciences Union General Assembly 2015, Geophysical Research Abstracts, Vol. 17, Vienna, EGU2015-13810, doi:10.13140/RG.2.2.25355.08486, European Geosciences Union, 2015.
Several methods exist for estimating the statistical properties of wind speed, most of them being deterministic or probabilistic, disregarding though its long-term behaviour. Here, we focus on the stochastic nature of wind. After analyzing several historical timeseries at the area of interest (AoI) in Thessaly (Greece), we show that a Hurst-Kolmogorov (HK) behaviour is apparent. Thus, disregarding the latter could lead to unrealistic predictions and wind load situations, causing some impact on the energy production and management. Moreover, we construct a stochastic model capable of preserving the HK behaviour and we produce synthetic timeseries using a Monte-Carlo approach to estimate the future wind loads in the AoI. Finally, we identify the appropriate types of wind turbines for the AoI (based on the IEC 61400 standards) and propose several industrial solutions.
R. Ioannidis, Architecture and the aesthetic element in dams: From international cases to proposals for Greece, Diploma thesis, 247 pages, Department of Water Resources and Environmental Engineering – National Technical University of Athens, 2015.
Dam architecture has been an issue that has not significantly concerned Greek organizations engaged in research, design and construction of dams. This thesis explores the need to raise the awareness of these organizations on issues related to the architecture of dams and produces relevant proposals. Initially, in the first part of this thesis, the current situation is investigated in relation to the architecture of Greek dams and the impact of these projects on the Greek landscape. Then, international examples of architectural interventions on dams are examined leading to the creation of database of techniques and ideas that could be implemented in Greece or elsewhere. Thereafter, general arguments for and against the inclusion of the aesthetic element as a design parameter of dams are produced. The second part of this thesis includes a set of proposals for architectural interventions in FSHD (Faced Symmetrical Hardfill Dam) dams, using the designs of the most recently constructed dam of this type in Greece (Filiatrinos dam) and setting the Aegean Islands as the proposed area of construction. Finally, the technical, construction process, architecture and cost aspects of those proposals are analyzed, proposing in the meantime a suggested planning process for similar interventions in the future.
Full text: http://www.itia.ntua.gr/en/getfile/1624/1/documents/ThesisIoannidis1.pdf (19257 KB)