The necessity for large-scale hybrid renewable energy systems

D. Koutsoyiannis, and A. Efstratiadis, The necessity for large-scale hybrid renewable energy systems, Hydrology and Society, EGU Leonardo Topical Conference Series on the hydrological cycle 2012, Torino, doi:10.13140/RG.2.2.30355.48161, European Geosciences Union, 2012.



Since global economy is dominated by the energy sector, the planning and management of energy systems is a prerequisite for a sustainable future. It is widely recognized that the existing paradigm, based on the intense use of fossil fuels, if far from sustainable and thus a substantial shift is needed, in the direction of energy saving and developing renewable sources. Yet, current energy planning in Europe, while it strongly promotes the penetration of such systems, has failed to account for the significant differences thereof with conventional energy sources. Small scale energy production units are encouraged and even subsidized. In addition, their piecewise view and the lack of an integrated development plan at country scale, results in increased costs and puts significant restrictions on energy management. It is well-known that renewable energy is highly varying and unpredictable, as it strongly depends on the hydro-meteorological conditions. The inherent uncertainty of the related natural processes is directly reflected in energy production, which cannot follow the temporal distribution of the corresponding demand. An additional drawback is the lack of regulating capacity, which makes impossible to store the excess of production. In this context, the concept of a future scene in which renewable sources dominate will be feasible only if renewable energy resources are combined with technologies for energy storage. The proven technique of pumped storage (i.e. pumping of water to an upstream location consuming available energy, to be retrieved later as hydropower) represents the best available technology since it does not emit any by-products to the environment, and is cost efficient, with loss ratios less than 10% (in large scale projects). In addition, hydroelectric energy production does not consume water (only converts its potential energy) while it can also be combined with other water uses (domestic, agricultural, industrial). Hybrid systems, combining multiple sources of renewable energy with pumped-storage facilities, are generally viewed as proven technology to increase renewable energy source penetration levels in power systems. However, such systems have, in general, limited capacity and are mostly implemented in relatively small areas, e.g. to serve autonomous island grids. On the other hand, the dominant ideological views especially in the European Union disfavours the building of new dams and large hydro-projects. However, the issue of scale, which refers to both the size of energy units and their spatial extent, is of major importance, since efficiency (in terms of produced energy to installed capacity) increases with scale, as does reliability (in terms of covering energy demand). For this reason, it is impossible to envisage a future energy landscape without large-scale hydroelectric reservoirs, equipped with pumped storage. To this extent, a holistic planning for large-scale hybrid renewable energy systems, in which water, wind and solar radiation are the sources of energy, with water in an additional integrative and regulating role, becomes plausible and desirable.

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Our works that reference this work:

1. C. Ioannou, G. Tsekouras, A. Efstratiadis, and D. Koutsoyiannis, Stochastic analysis and simulation of hydrometeorological processes for optimizing hybrid renewable energy systems, Proceedings of the 2nd Hellenic Concerence on Dams and Reservoirs, Athens, Zappeion, doi:10.13140/RG.2.1.3787.0327, Hellenic Commission on Large Dams, 2013.
2. 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.

Tagged under: Renewable energy, Water and energy