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3
Pumped hydro storages are the most efficient storage technology
Pumped
hydro
storage
● Retrofit in Alpine storages
● Limited potential for new
construction
Competitors in the
electricity market
Compressed
air storage
(CAES)
● Requires salt caverns –
potential in northern Europe
● Attractive where network
congestion arises
Conclusion
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Umwandlungsverlust
("round trip")
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Transformation
losses
H2-gas
turbine
AA-CAES
Retrofit
D-CAES
Zebra-
NaNiCl
Methanisation
New built
Lead-acid
battery
Flow
battery
Sodium-
sulfur
Cost degression
until bis 2020
0 200 400 600 800
Depends on lifetime, size of
the storage etc.
Kapitalkosten [€/kw/a]
Capital costs [€/kw/a]
Fuel cell
Li-ions
Size = typical plant
size
Hydrogen
● Might make sense on the
long-term
● Mobile, i.e. appropriate for
„power- to-transport“
Competitors also in
the transport
market
Batteries
● Potential depends on
learning effects
● May be viable decentrally
● Mobile
Source: Frontier Economics
● Pumped hydro storages best combine investment costs, lifetime and
efficiency
● However, the technical potential for PHS within the EU is limited -
this makes it even more important to use the existing potential