CESI RICERCA Italian Electrical System Research Fund
Evaluation of the residual potential hydropower production in italy Julio ALTERACH, Máximo PEVIANI, Alessandro DAVITTI, Milena VERGATA Cesi Ricerca SpA
Gervasio CIACCIA - Italian Authority for Electricity and Gas (AEEG) and “Sapienza” University of Rome
Fulvio FONTINI - University of Padova
International Conference on Small Hydropower. Hidroenergia 2008: "On the Crossroads“ Bled, Slovenia 11th-13th June 2008
Maximum hydropower potential in Italy • methodology for the development of the Italian maps of the maximum and the residual hydropower potential • highlight areas in which hydropower potential is still available or not totally exploited. • the residual potential hydropower energy takes into account the current water resource exploitation (irrigation, drinkable water, existing hydro power, etc). • the model applied to the Italian territory uses a numerical technique coupled with a GIS • the maps demonstrate to be quite helpful tools to support administrations, decision makers and stakeholders in general, to make Energy Master Plans, or assess and implement small scale hydropower plants. 2
Land and hydrological basic data elaboration
1,500 Sub-basins Italian structure
The rainfall distribution over each elementary basin is the main parameter to determine the natural flow and as a consequence to calculate the potential hydropower.
ITALY DEM Digital Elevation Model 90x90 m
mean rainfall Italian map, from 1950 until 2004, processed by the �spline� interpolation method. 3
Characterization of the actual water uses •Irrigation: normally this kind of withdrawals has no restitution, so all the volume taken off is used; •drinkable water: it is assumed that usually there is a restitution, even if the returned volume is less than the withdrawal volume;
Withdrawals Restitutions
•industrial: like drinkable water withdrawals, the industrial ones generally has a restitution, lower than the withdrawal; •hydroelectric: all the water volume drawn for hydroelectric generation purposes is also given back in the river at a downstream section. 4
Basin hierarchicalization: hydrologic and anthropical discharges Current Basin Afferent discharge: Qaff = A · p · cd natural hidrological river discharge, without any water use consideration. A basin area p annual mean rainfall cd rainfall-runoff coefficient Hydrological discharge: Qhyd = Qaff + Qup_hyd total natural discharge evaluated in the closure point of the current basin, Qup_hyd discharge coming from upstream Anthropical discharge: Qant = Qaff + Qup_ant - j q j discharge in the closure point of current basin taking into account the upstream flow and the human effect on the natural flow withdrawal “+q” or restitution “–q” 5
Hydrological discharge
m3/s
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Calculation of the maximum potential hydroelectricity Eown_max = Conv ∙ g ∙
∙ Qaff ∙ (Hmean – Hclosure)
maximum annual potential hydropower related to the current watershed without considering upstream flow contributions, calculated with the total theoretically available own flow [GWh/year]
Eup_max = Conv . g.
Hupstream_clos
. Qup_hyd .(Hupstream_clos – Hclosure)
maximum annual potential hydropower related to the flow which comes from the upstream watersheds, calculated with the total theoretically available flow [GWh/year]
Etot_max = Eown_max + Eup_max
Hclosure 7
Calculation of the residual potential hydroelectricity Eown_mif = Conv . g. . (Qaff – MIFaff).(Hmean – Hclosure) maximum annual potential hydropower related to the current watershed without considering upstream flow contributions, calculated taking into account the MIF (Minimum Instream Flow) respect [GWh/year] MIF = Minimum Instream Flow
Ewith = Conv . g.
.
Hupstream_clos
j q j.(h j – Hclosure)
annual potential hydropower related to the actual withdrawals in the current watersheed [GWh/year] Eup_res = Conv .g. .(Qup_ant–MIFups).(Hupstream_clos – Hclosure)
Etot_res = Eown_mif + Eup_res – Ewith
Hclosure 8
Maximum potential hydroelectricity in Italy GWh/year
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Maximum specific potential hydropower in Italy Esp_max = Eown_max / A^0,5 + Eup_max / L
GWh/year/km
A= basin area L= distance between the upstream and the downstream basin closure
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Maximum and residual potential hydropower in the Basilicata region
Some basins located in the central and southern part of the region are demonstrated to be interesting from the point of view of a deeper hydropower study in a watercourse scale (particularly those from the Sinni and Basento river). 11
Conclusions • The method demonstrated to be a quite useful tool to produce maps, at a national or regional scale, which gives a first approach for the identification of interest areas with a residual hydropower potential. • These maps may provide the support to administrations, decision makers and stakeholders, to make Energy Master Plans, or assess and implement small scale hydropower plants. • Once a particular sub-basin is identified from the point of view of the residual specific potential, a GIS tool may allow to evaluate the potential hydropower along selected watercourses, taking into account the relationship between the full costs of the mini-hydro power and the benefits from selling the generated power.
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Thank you for your attention ! Julio A. Alterach CESI RICERCA ITALY
Julio.alterach@cesiricerca.it 13