Environmental Engineering Reference
In-Depth Information
Figure 4.51
Photograph of a Fuel Cell Stack Prototype
The electrical efficiency
(4.112)
is obtained from the electrolysis efficiency
η
Ely
, transport losses
f
Tr
, storage
losses
f
St
and the electrical efficiency of the fuel cell
η
FC,el
. The electrical
efficiency
η
el
of further-improved systems could be about 50 per cent.
Assuming a thermal efficiency
η
th
of 20 per cent provides a total efficiency
η
tot
of 70 per cent.
Owing to the relatively poor electrical efficiency of the hydrogen storage
chain, the direct use of electricity is preferred, even if the electricity must be
transported over very large distances.
Other storage concepts
There are other possibilities for storing electrical energy apart from
electrochemical storage in batteries or hydrogen storage. However, most of the
other storage concepts are rarely used today. Other methods, such as pumped-
storage plants, can be only used for very large applications. Other storage
concepts are:
•
capacitor banks
•
storage in superconducting coils
•
flywheel storage
•
pumped-storage hydroelectric power plants
•
compressed air storage.
