Hydropower potential
Hydropower potential denotes the potential of the possible use of hydropower that would be possible at full capacity. In order to be able to quantify hydropower potentials, potential analyzes are necessary. The calculation of hydropower potential can basically be assigned two different motivations. On the one hand, it is important for energy policy to identify the hydropower potential of a region (union, state, federal state, etc.) in order to incorporate this form of energetic use in future strategies and to define expansion scenarios. On the other hand, potential analyzes also serve as a basis for project evaluation and location analysis for economic decision-making in specific hydropower projects.
Determination of potential
The following approaches can be distinguished for determining potential:
- Precipitation potential - drawing on the potential energy of the precipitation taking into account the existing topographical conditions and the precipitation load in the catchment area .
- Drainage area potential - Approach of the potential energy of the rainfall that affects the runoff over the topography of the catchment area.
- Discharge line potential - determination of the potential via the potential energy of the channel via discharge load and length section of the watercourse
The discharge line potential provides the most detailed description of the existing hydropower potential. Due to the current situation with regard to data situation, data availability and user software, current studies almost exclusively focus on the potential of the drainage line. The use of GIS programs in particular leads to high-quality estimates of existing potential. The long-term level observations available in Central Europe, which are often available in a very dense observation network, allow hydrological regionalizations of good quality. By using digital terrain models, the elevation of the lines (length section of the flowing water) can be displayed and the hydropower potential estimated in good quality in connection with an existing hydrological database.
Concepts of potential
When determining the hydropower potential, various potential definitions that build on each other are used:
Theoretical potential
The theoretical potential is determined from the amount of precipitation falling on a river catchment area. Taking into account the factors evaporation and infiltration, runoff amounts result from which the upper limit of the hydropower potential can be determined as the product of gravitational acceleration, water throughput and height of fall.
The theoretical hydropower potential of the earth was estimated at approx. 2,800 GW (excluding the locations of small hydropower plants). In the year 2000 only 694 GW, that is 24.8% of the global potential, were used. Asia, South America and Africa have the largest usable hydropower potential (approx. 62%); China alone has a theoretical hydropower potential of 700 GW. In Asia, only 22%, in Latin America 20% and in Africa 7% of the economically usable hydropower has been developed.
Technical potential
The technical potential represents the work that can be performed on average over the course of a year on the respective water body through the use of hydropower. The determination is made by multiplying the theoretical potential with the number of full load hours. The number of full-load hours essentially depends on the water flow in the body of water and the expansion capacity of the power plant.
Technically usable potential
The technically usable potential takes into account the system efficiency of the generator and turbine and is referred to as the net discharge line potential due to the consideration of the loss.
Development potential
In order to analyze the existing possibilities of hydroelectric energy generation in potential studies, further terms are used:
- Developed hydropower potential - Quantifies the already developed potential developed by the existing power plant park and is differentiated from the developed raw potential. The raw potential is the potential that defines the use of the entire available runoff using the gross head.
- Line residual potential - Describes the difference between technical and developed potential. On the one hand, it is divided into potentials that can be developed through the construction of new power plants, and on the other hand into potentials that become available through optimization of existing systems.
- Technically usable residual hydropower potential - Is the portion of the residual line potential that can be developed from a purely technical point of view.
- Residual hydropower potential worth expanding - Part of the technically usable residual hydropower potential that can be developed from economic aspects.
- Expandable residual hydropower potential - Is the portion of the hydropower residual potential that can be developed for legal and ecological reasons as well as socio-political aspects.
Potential studies
Hydropower potential studies serve to demonstrate the area-specific hydropower potential. These studies are mostly politically motivated and are intended to provide a transparent representation of existing and already used potential. On the one hand, they provide a basis for decision-making with regard to the further expansion of hydropower , on the other hand, such studies are often published in the media and offer population-relevant input for assessing this energetic resource. Hydropower studies are of varying quality in different countries. In general, it can be stated that an already high developed potential in the area under consideration requires a correspondingly high level of detail in the potential studies. In countries with already heavily used hydropower potential, the expansion of small hydropower tends to have a higher share. The mapping of small hydropower potentials, however, requires high-resolution potential studies in order to map hydropower locations with outputs <10 MW (Austria and Switzerland) or <5 MW (Germany).
Austrian hydropower cadastre
The publications of the hydropower register were published by the Federal Ministry for Trade and Reconstruction from 1945 to 1966 and comprised 31 volumes.
The statements of the hydropower register concern the line potential. In addition to the representations of the potential analyzes with comprehensive map material, the hydropower cadastre also contains detailed hydrological information on precipitation and runoff behavior in the time series that has been prepared with great care and accuracy.
Hydropower potential study by Schiller
In 1982 Schiller published a comprehensive potential study for almost the entire federal territory of Austria. It was divided into the main catchment areas Rhine, Lech, Inn, Drau, Salzach, Mur, Enns and Danube. The calculation was carried out for rivers whose discharge at the confluence with the main receiving water is greater than 1 m³ / s. The hydropower cadastre served as the essential hydrological basis. The longitudinal sections of the side streams were created from the ÖK 1: 50,000 or ÖK 1: 25,000, whereby these were assumed to be linearly simplified due to the high effort at the time (often only source and mouth). The receiving waters were divided into sections in order to represent the gradient conditions in a higher quality. The results were illustrated in tabular form and supplemented by the corresponding longitudinal sections and overview maps. The net line potential was determined taking into account a system efficiency of 85%. In the Verbundgesellschaft, the so-called “hydropower potential that is worth expanding” was continuously carried out, based on the existing hydropower plants in Austria, supplemented by the known hydropower projects.
Hydropower potential study Austria of the Pöyry
The discharge line potential published in Schiller 1982 was adapted by a current hydrological data set and a survey and analysis of the power plant stock for systems with a bottleneck capacity ≥ 10 MW was carried out. The technical-economic total and residual potential is determined, i.e. H. the potential that would be realizable in Austria if only technical and economic boundary conditions were considered. The survey of the Austrian power plant fleet for systems with a bottleneck capacity ≥ 10 MW provided an expanded potential of 33,200 GWh (net drainage line potential 75,000 GWh). For small hydropower the expanded potential was put at 5,000 GWh. The overall technical and economic potential was determined by defining class utilization rates for equivalent (topographical and hydrological) areas, which estimate the accessible share of the drainage line potential. After deducting the potential that has already been used, there remains a technical and economic residual potential of 17,900 GWh. [1]
Potential study Tyrol
In 2011 a potential study was published for the state of Tyrol . The GIS-based study aimed to identify hydropower potentials by determining the potential of the discharge line, with a system output of> 1 MW being defined as the threshold value. In a specially developed GIS system, the technical and economic potential was determined, assuming excess water, residual water, losses and costs. A storage model was also developed to determine storage size, storage area and storage length at fictitious locations. On the basis of the criteria catalog, which provides the basis for the evaluation of hydropower projects in the state of Tyrol, a basis for the identification of the integrative-meaningful potential was developed with the involvement of experts from the individual specialist areas. Under the exemplary assumption that 50% of the technical and economic potential is to be understood as an integrative-sensible expansion in hydropower, a development of 3.4 TWh was determined for the state of Tyrol.
Due to the rather high threshold values of Austrian potential studies (> 10 MW or> 1 MW), small hydropower potentials are neglected in these studies or shown only insufficiently sharply. Due to the methodology used in the Pöyry study, an underestimation of the hydropower potential v. a. with regard to small hydropower.
Hydropower potential in Germany
In a study from 2011, the technical-economic potential was concluded based on the net line potential. The study assumed that around 60% of the line potential can be used in large systems and only 20% in small and medium-sized systems. The study was GIS-based and took into account both the revitalization and new building potential. Plants with an output> 1 MW were defined as the threshold value for the level under consideration. With regard to the exploitable potential, large, medium and small bodies of water were considered separately. The hydropower plants in operation in Germany were identified as the starting point for the investigation. The net line potential was put at 33,200 to 42,100 GWh. After deducting the used potential of 20,900 GWh, the remaining hydropower potential worth expanding was calculated to be 12,300 to 21,200 GWh. The feasibility of this potential was put at 4,000 GWh. Of these 4,000 GWh, 2,550 GWh can be achieved through revitalization at existing locations (P ≥ 1 MW) of large bodies of water. The construction of new power plants with a capacity ≥ 1 MW on existing transverse structures could be shown at 120 GWh. In the large bodies of water, around 2,700 GWh can be achieved through the use of existing transverse structures and conversion measures. The remaining 1,300 GWh can only be achieved by building new barrages with hydropower plants in previously unused stretches of water. However, such new buildings are assessed as rather unlikely due to the existing boundary conditions, uses and restrictions. As a result of the study, an expandable residual potential of 400 GWh was shown for medium-sized and small bodies of water.
Section 35 (2) of the Water Resources Act stipulates that the competent authority should check whether the barrages that existed on March 1, 2010 can be used for hydropower. The result of the examination should be published. A threshold value is not mentioned. However, there are restrictions if, for example, existing hydropower uses do not meet the requirements of fish protection .
Small hydropower study in Switzerland
This study is a high-resolution GIS-based study, in which, using complex GIS tools in combination with hydrological data, the considered water sections were discretized in 50 m sequences in order to identify the potentials located there. In order to also take account of ecological criteria, so-called killer criteria (floodplains of national importance, raised bogs of national importance, flat bogs of national importance and amphibian spawning areas) have been identified, which exclude the use of these sections. Limiting factors were also taken into account, which do not categorically rule out hydropower expansion, but make use more difficult. The sharpness of detail of this study also allows the designation of waters with an energetic potential <30 kW, these are quantified with a theoretical potential of 148.5 MW. This study, which takes into account existing power plants as well as ecologically sensitive areas, is intended to provide the basis for further work, including socio-economic factors, in the sense of an integrative assessment of hydropower.
Individual evidence
- ↑ a b c Leimegger , accessed on September 7, 2015
- ^ Neurohr info Eduard Neurohr , accessed on September 7, 2015.
- ↑ PÖYRY (2008): hydropower potential study Austria. VEÖ, Vienna
- ↑ STIGLER, H. et al. (2005): Energy management and economic evaluation of the potential effects of the implementation of the EU Water Framework Directive on hydropower. Study by TU Graz - self-published, Graz.
- ↑ SCHILLER, G. (1982): The use of hydropower in Austria - hydropower potential as of 1982. Verbundgesellschaft, Vienna.
- ↑ ILF BERATENDE INGENIEURE (2011): Hydropower in Tyrol - Potential Study, Innsbruck
- ↑ SEIDL, G. & B. PELIKAN (2012): Estimation of the discharge line potential of Austrian tributaries, Hydraulic Construction Symposium 2012, Verlag der TU Graz, Graz
- ↑ Anderer, P. ET AL. (2011): The hydropower potential in Germany, 34th Dresden Hydraulic Engineering Colloquium 2011, Dresdner Wasserbauliche Mitteilungen, Dresden
- ↑ SCHRÖDER, U. & Y. WEIDMANN (2008): Survey of small hydropower in Switzerland - Determination of the hydroelectric potential for small hydropower in Switzerland, Swiss Confederation, Bern