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| Titel |
Trade-offs Between Electricity Production from Small Hydropower Plants and Ecosystem Services in Alpine River Basins |
| VerfasserIn |
Philipp Meier, Robin Schwemmle, Daniel Viviroli |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250109096
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| Publikation (Nr.) |
 EGU/EGU2015-8973.pdf |
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| Zusammenfassung |
| The need for a reduction in greenhouse gas emissions and the decision to phase out nuclear
power plants in Switzerland and Germany increases pressure to develop the remaining
hydropower potential in Alpine catchments. Since most of the potential for large reservoirs is
already exploited, future development focusses on small run-of-the-river hydropower plants
(SHP). Being considered a relatively environment-friendly electricity source, investment in
SHP is promoted through subsidies. However, SHP can have a significant impact on riverine
ecosystems, especially in the Alpine region where residual flow reaches tend to be long. An
increase in hydropower exploitation will therefore increase pressure on ecosystems.
While a number of studies assessed the potential for hydropower development in the
Alps, two main factors were so far not assessed in detail: (i) ecological impacts
within a whole river network, and (ii) economic conditions under which electricity is
sold.
We present a framework that establishes trade-offs between multiple objectives regarding
environmental impacts, electricity production and economic evaluation. While it
is inevitable that some ecosystems are compromised by hydropower plants, the
context of these impacts within a river network should be considered when selecting
suitable sites for SHP. From an ecological point of view, the diversity of habitats, and
therefore the diversity of species, should be maintained within a river basin. This asks
for objectives that go beyond lumped parameters of hydrological alteration, but
also consider habitat diversity and the spatial configuration. Energy production in
run-of-the-river power plants depends on available discharge, which can have large
fluctuations. In a deregulated electricity market with strong price variations, an
economic valuation should therefore be based on the expected market value of
energy produced. Trade-off curves between different objectives can help decision
makers to define policies for licensing new SHP and for defining minimum flow
requirements. The trade-offs are established using a multi-objective evolutionary
algorithm.
A case study on an Alpine catchment is presented. The position of water intake and outlet
and the design capacity of SHP, and different environmental flow policies are used as decision
variables. The calculation of complex objectives, as described above, relies on an accurate
representation of the physical system. The river network is divided into segments of 500
meters length for each of which the slope is calculated. Natural incremental flows are
calculated for each segment using the PREVAH hydrological modelling system. Trade-offs
are established on the basin scale as well as on the sub-basin scale. This allows the
assessment of the influence of different configurations of SHP on ecosystem quality across
different spatial scales. |
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