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on the circumstances in which the electricity is produced –
besides efficiency, this aspect also influences the ecological
performance like CO 2 emissions or airborne pollutants.
Basically, electric motors with a nominal power of more than 1
kW have efficiencies of around 90% while modern spark ignition
engines achieve a maximum of 30%. Electric motors realise a
more than 3 times higher efficiency, which is a major advantage
for this technology. The comparison of different technologies for
electric power generation reveals that performance differs
widely (from about 35% to more than 90% taking cogeneration
into account). The energy available for end-use, i.e. electric
mobility, compared to the energy input by fossil fuels, ranges
from about 30% to 80%, strongly depending on the technology
of electric power generation. Concerning the 80% energy
efficiency it has to be stressed that the non-electric use of heat
is considered.
Besides the impacts concerning climate change, the level of
pollutant emissions would also be reduced in the case electric
vehicles were implemented widely. At present millions of
vehicles equipped with their own exhaust gas treatment unit -
operating in transient conditions - are produced in an effort to
limit pollutants. In contrast to this, power plants have high
standards for exhaust gas treatment in a comprehensive way –
their centralised and stationary operation conditions could
achieve better performance, regarding both ecological and
economical aspects. Therefore fossil fuels burnt in power plants
tend to emit fewer pollutants and, in addition, be more costefficient.
Today’s technologies for renewable generation of electricity are
at different stages of maturity, as can be seen in the following
overview:
Hydropower
Fundamentally, this is a mature technology. There is still some
potential for optimisation potential for small-scale hydropower
plants. The current share of domestic electricity generation is
58%, and it seems possible to increase this to some extent,
taking ecological requirements into account.
Wind power
Wind power plants have reached a high technological standard
in the last decade. Wind potential is only exploited to around
30% of capacity in Austria. Under high wind conditions, it is
necessary to apply temporary limitations on available grid
capacity. The extension of pumped hydro storage capacities
from the present level of 2,000 MW to about 5,000 MW in the
next decade will solve the problems of balancing demand and
storage to a large extent. The problem of grid capacities will still
be predominant.
CHARGING INFRASTRUCTURE AND SUSTAINABLE ENERGY
FOR ELECTRIC PROPULSION
Photovoltaic power
This technology has been further developed in recent years, but
it is not yet fully mature. There is insufficient knowledge with
regard to lifetime and degradation. The potential for developing
large collector fields is high if a significant reduction in
investment cost can be achieved in the future.
Generation of electricity from biogas
The technology is mature, although consideration is being given
to increase the electric efficiency (around 35% using gas
engines) through additional downstream thermal conversion
units (e.g. ORC).
Generation of electricity from solid biomass
Electricity generation from biomass combustion in the range
above 5 MW is mainly based on the traditional steam turbine
process. In the lower power range the ORC process will have a
greater perspective for implementation. In the power range
below 100 kW, implementation of the Stirling motor is being
considered.
All these technologies are already deployed in combined heat
and power plants with an electrical efficiency below 30%. In
case of gasification of biomass, there is the possibility of
increasing the efficiency of the combustion motors or gas
turbines used by incorporating additional thermal converter
technologies (see above). The additional cost of these measures
makes economic operation unviable at present.
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