/ Published on:
Fri, 02/01/2013 - 17:25
With a 75% share, hydroelectricity is by far the main contributor to electricity generation from renewables in Europe[1].
In 2011, it accounted for 16% of total electricity production and more
than 20% of the total installed generation capacity. With 220 GW of
installed capacity[2], hydroelectricity still dwarves wind power that stands at 96 GW.
Despite its dominance, hydroelectricity is seldom discussed as a
renewable energy resource of significance or importance. Policy makers
and the media tend to focus their attention on wind and solar probably
because the latter are fast growing markets with promises of new jobs
and export markets despite serious setbacks in the last few years. Hydro
is also overlooked because it is seen as a mature technology which
potential has been largely exploited.
A geographical mismatch between hydro and wind resources
Technically speaking, hydroelectricity and wind complement each other
well. Hydroelectric plants are highly flexible and can be ramped-up or
ramped-down at very short notice (seconds) without the efficiency losses
of thermal plants. Hydroelectricity can therefore mitigate wind
variability in a very efficient way. The seasonal match is equally
fairly good. Winds are generally stronger and more regular in the
winter, at least in Northern Europe. The contrary is true for hydro,
which reaches its maximum potential capacity in late spring or early
summer, after snow has melted and filled the reservoirs.
Share of hydro and wind in total electricity generation (in %)
Source: Enerdata - Global Energy & CO2 Data
Despite the good technical match between hydro and wind, the
correlation between installed capacities in both technologies at country
level is low or rather, unidirectional. On the one hand, countries with
a very high share of hydro (i.e. above 30%) tend to have little or no
installed wind capacity. On the other hand, countries with a very high
share of wind have either a sizeable domestic hydro industry (Portugal,
Spain and to a lesser extent, Ireland) or access to their neighbour’s
hydro (Denmark).
The absence of a strong link between hydro and wind can be explained
to a large extent by the fact that the geographies of hydro and wind do
not match well as shown in the map below. Rather than the raw wind
energy potential, this map published by the EEA in 2008 gives an
indication on the full cost of wind electricity across regions. It is a
good techno-economic indicator of the future location of new wind power
developments.
Generation costs for wind energy in Europe, 2005
Source: EEA, “Europe's onshore and offshore wind energy potential”, 2008
Countries with a good economic wind potential − such as the British
Isles, Northern European countries with a coastline on the Channel, the
North Sea or the Baltic Sea − do not necessarily have a good or direct
access to a significant hydro resource. The best hydro resource is
generally found in mountainous or hilly regions (the Alps, the Iberian
Peninsula, Norway, the Balkans, etc.) and is often poorly connected with
windy regions.
Scandinavia is an exception as its vast hydroelectric capacities
contribute significantly to the balancing of the Nordic synchronous
electricity area. This has made high wind penetration in the Danish
electricity system possible.
In Europe, hydroelectricity is currently a low growth market
Hydro is hardly growing anymore. In the EU, less than 10 GW of hydro have been added between 2000 and 2011 compared with 82 GW of wind and 52 GW of solar. With approximately 10 GW of new capacity added every year, wind is catching up fast and could overtake hydro by the mid-2020’s.
EU net electricity capacity additions between 2000 and 2011 (in GW)
Source: Enerdata - Global Energy & CO2 Data
The potential for new hydroelectric capacity in Europe is often said
to be limited. However, some estimates put the untapped potential of
economically feasible yet-to-develop capacities at 165 TWh/year in
Western Europe[3]i.e.
a third of the current production level. The residual potential in
Southern Europe and Central Eastern Europe is estimated at respectively
145 and 6 TWh/year.
These estimates include new developments, upgrades and the
rehabilitation of older facilities. The median age of hydroelectric
capacities in Europe is 41 years. This and barriers to new builds
explain why electric utilities in Western Europe tend to focus on the
repowering of existing plants with modern turbines and equipment rather
than greenfield projects.
New hydroelectric potential in the three main European regions (in TWh/year)
Source: WEC; EUROSTAT; UCTE; CESR; Hydropower & Dams World Atlas 2007
With approximately 13 GW, small hydro[4]
is also a significant renewable energy resource. Its potential has been
largely developed in Western Europe, more than 80% in the EU-15
according to the ESHA[5. The remaining small hydro potential is found primarily in Eastern and Southern Europe.
Hydroelectricity remains attractive but faces many barriers
Hydroelectricity is hampered by a number of hurdles, with opposition
from local inhabitants and environmentalists probably the most difficult
to overcome. Large hydro has a significant impact on the environment as
it literally transforms landscapes and disrupts local ecological
systems.
Gone are the days when the State could impose the construction of
large hydro infrastructures to local communities. Developers now have to
contend with lengthy planning and permitting procedures as well as more
stringent environmental or water rights constraints. These barriers can
increase up-front capital costs but also reduce the technical
flexibility of hydro plants.
In this context, rehabilitation looks attractive. It is a good
opportunity to increase the performance and revenues of a hydro plant
while increasing its availability and safety levels. This can be done at
a fraction of new build costs, shorter lead times and lighter
environmental procedures.
SWOT analysis of hydroelectricity
Strengths
|
Weaknesses
|
|
|
Opportunities
|
Threats
|
|
|
Source: Enerdata
Despite these barriers, Austria, Switzerland, Germany, Norway, Spain,
Portugal, have all completed or started developing at least 1 GW of new
hydroelectric capacity over the last decade, as show in the chart
below. A significant share of new builds is made of pumped storage
facilities, a consequence of the search for new sources of flexibility
in electricity markets.
New build and under construction hydroelectric plants in a selection of European countries
Hydro is the ideal back-up technology for wind
Future European electricity systems will undoubtedly be characterised
by a higher level of variable energy generation. Wind generation is
characterised by ample stochastic fluctuations and it is not
dispatchable. Its average load factor is fairly low and production can
sometimes drop to zero when it is most needed. Its capacity contribution
to the system is therefore not guaranteed. As a consequence, the higher
the share of wind in a system, the higher the reserve of flexibility
needed by Transmission System Operators (TSOs) to maintain in order to
be able to cope with unexpected frequency events.
Thanks to their rapid ramp-up and ramp-down properties, hydroelectric
dams and pumped storage facilities can be considered as an indirect way
of storing electricity. These properties make hydro the ideal back-up
technology for wind[6].
Of course, hydro is only one solution among many to provide the
systemic flexibility required when the share of wind or PV increases.
Other technologies such as CCGTs, gas peakers, smarts grids and other
storage technologies (CAES[7],
batteries) have the potential to deliver part of the required
flexibility. Interruptibility, demand response and market coupling are
market arrangements that can also introduce additional flexibility.
Europe could facilitate the integration of wind through better use and sharing of its hydro resource
So far TSOs in countries with a lot of wind power capacity such as
Denmark, Spain or Portugal have been able to manage the situation pretty
well. A key concern is the ability of continental synchronous area
countries to replicate the Scandinavian experience and collectively
leverage their hydro base to introduce much more wind into the European
generation mix.
A further concern is that hydro is still largely used in a national
context to balance national electricity systems. Lack of market
integration and congestion issues limit a pan-European utilisation of
hydro as a source of flexibility. In theory, hydro-rich countries or
utilities should benefit from better market integration by having access
to a larger and deeper market and the new revenue maximisation
opportunities this offers. From their part, wind-rich countries would
benefit by accessing flexibility at the best possible price. They could
also see an advantage by limiting the recourse to high CO2 emitters such as conventional peakers.
Since the building of new interconnectors remains very challenging
and lengthy, priority should be given to encouraging further coupling of
European electricity markets. By authorising an implicit auction of
interconnection capacity, market coupling is a low cost solution to
optimise rapidly electricity exchanges between countries and ensure
price convergence.
The ability of a pan-European “supergrid” to smoother the variability
of wind production by linking distant wind farms has seemingly been
overstated. The benefits of the geographical spread of wind farms across
Europe to smoother fluctuations through aggregation exist but are most
probably too low to justify the construction of a supergrid.
Nevertheless, if you also add the benefits given by an integrated use
of all European hydro resources and the advantages of a deeper
electricity market, then the rationale to invest in new or reinforced
interconnections is undeniable. This will in turn make hydropower even
more valuable and may very well revive the interest as a main source of
renewable electricity.
[1] EU countries plus Albania, Bosnia-Herzegovina, Croatia, Iceland, Macedonia, Norway, Serbia, Switzerland, Turkey
[2] 20% of which is run-of-river
[3] Including Norway and Switzerland
[4] Plants of less than 10 MW
[5] European Small Hydropower Association
[6]
Small hydro is less attractive than large hydro when it comes to
providing back-up for wind power. Small and low head hydro plants not
only lack the storage capacity of large dam and pumped storage
reservoirs, they also need some form of support (e.g. subsidies or a
feed-in tariff) to be financially attractive.
[7] Compressed air energy storageHydro and Wind: Freiend
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