Energy crisis inevitably brings nearer, because fossil
fuels run low. Companions of the crisis will be problems
with fuels for cars, heating and power generating. Political
and social chaos comes. Even nowadays some countries
try to blackmail other countries with stopping delivery of
some fuels. Hence, there is an idea of local balancing of
power production and consumption. All power consumed
in selected small area should be produced only using
primary power carriers available within the area. The
primary carriers need to be inexhaustible. Practically,
there are not too many such energy carriers - only
renewable energy resources (RES) as solar irradiation,
wind, water, and various forms of biomass.
Unfortunately practical usage of RES is limited by
theirs changeability and seasonal occurrence. Hence,
power generating systems composed of few units based on
different primary carriers were developed. They are called
hybrid power systems (HPS) . More often than not
UPS' units are located close to each other and to load, so
link resistance can be omitted. The best examples of HPS
are supply system for isolated, far located load as
telecommunication equipment, mountain hostels,
forester's lodges etc.