PhD Thesis - Energy Systems Research Unit - University of Strathclyde

esponse, high electricity-to-electricity efficiency and one in which the power
output and storage capacity can be specified separately.
The main difference between the Regenesys system and electrolyser/fuel cell
technology is that the electricity is stored as ‘charged’ electrolytes rather than
hydrogen and one central system is used for charging and discharging (receiving
and generating). The ‘charged’ and ‘uncharged’ electrolytes are stored in
separate tanks and the level of charge depends on the ratio between the two.
The storage capacity is limited only by the size of the electrolyte tanks, and the
output does not vary with the amount of charge. As the Regenesys system
technology is modular, the efficiency does not vary with plant size so anything
from 5W to 500MW would be feasible. This flexibility makes it suitable for a
large range of uses from small-scale autonomous renewable generation systems
to use in much larger-scale electricity supply networks to allow greater use of
variable renewable generation.
The engine model described in this thesis could be enhanced to allow more
engines to run simultaneously, in order to increase efficiency and lessen the
impact of outages and downtime for maintenance. The option could also be
given to run the engines at minimum load when the demand is less than this, so
that the demand can be met, and use can be made of the excess electricity and
heat.
9.2.4 Larger Geographical Areas
When considering the use of intermittent supplies whose outputs depend on
weather patterns, it is important to vary their siting to help compensate for their
intermittent nature. As only one climate file is used for the prediction of the
outputs of intermittent sources, this may give misleading results when larger
geographical areas are being considered. To avoid this, some variation could be
introduced in order to allow generation from different locations to be
considered.
270