Corporate Technology - Rolf Hellinger

Power & Sensor Systems
With its approximately 200
employees, the Power & Sensor
Systems team is researching
a range of innovative and
environmentally-friendly
solutions for applications in
energy, automation, building
management and medicine.
Masters of
Energy Efficiency
Oil and gas have become expensive commodities.
Their prices are a source of concern
for automobile drivers and home owners as
much as for operators of factories and power
plants. In this state of affairs, many people are
once more turning their attention to coal, which
has remained relatively stable in price and will be
available in sufficient quantities for a long time.
The drawback is that per kilowatt-hour generated,
the carbon dioxide (CO2) emissions from
coal-fired power stations are almost twice as
high as those from natural gas-fired combined
cycle power plants. The solution may lie in carbon
capture and storage (CCS) techniques in
which carbon dioxide from power plants is separated
and securely stored.
One such technique is the post-combustion
capture process, with which the CO2 in coal-fired
power plants can be separated after combustion.
In this case, approximately 90 percent of the CO2
in the flue gas binds to a special CO2 scrubbing
agent in an absorber and is thereby removed. So
far, however, this technique has reduced power
plant efficiency by about ten percentage points.
Using modeling and simulation tools, experts at
Corporate Technology’s Power and Sensor Systems
Division are therefore analyzing the complete
separation process and trying to optimize it
in close collaboration with Siemens Fossil Power
Generation Division and its units.
Another way to reduce energy consumption
and CO2 emissions is to optimize the electrical
grid by cutting load peaks and normalizing the
utilization of the network. Whenever possible,
such an optimization should avoid situations in
16 Corporate Technology
which power plants operate at less efficient partial
loads or even at no load in order to be able to
react quickly to an increase in demand. In the future,
however, it will become even more difficult
to balance supply and demand, because the proportion
of fluctuating power generators — such
as wind turbines and solar systems — will continue
to increase. With this in mind, a team of experts
at CT PS is studying a wide variety of energy
storage methods.
Focusing on Energy Storage
Air compression is a case in point. Here, excess
energy is used to compress air and store it under
high pressure. Then, if an energy bottleneck occurs,
the compressed air can be used to generate
electricity, which is fed into the grid.
Surplus energy can also be used to decompose
water into oxygen and hydrogen. In its
stored state, the energy density of the latter is
ten times greater than that of compressed-air
reservoirs. Here too, researchers at the Power
and Sensor Systems Division are working on
strategies for realizing economical energy storage.
In the process, they are relying on Siemens’
extensive experience in developing fuel cells and
electrolysis systems.
The same applies to a different technology
known as “supercaps” — double-layer capacitors
that have a very high energy density of 2,000 to
10,000 watts per kilogram and can be charged
and discharged in a few seconds. These marvels
of energy storage can absorb the braking energy
of a train, for example, and release it again when
the train starts up.
Another example of an energy saving system
is a ship propulsion system developed by CT PS in
cooperation with Siemens’ Marine Solutions and
Large Drives Groups. The propulsion system will
be used for the first time in 2012. Thanks to its
use of high-temperature superconductivity
(HTS), the rotor in this propulsion system incurs
no electrical losses, which increases its efficiency
compared to conventional electrical drives. At
the same time, the superconducting rotor coils
have a current density 100 times greater than
that of conventional copper coils. This makes it
possible to reduce the weight and volume of the
propulsion system by up to 50 percent, which
cuts raw material and energy requirements.
In the Russian region of Siberia, on the other
hand, raw materials prices play a minor role. This
comes as no great surprise, considering that this