Lenze's new international sales structure

26
In pursuit of energy efficiency
As a magazine for drive and automation technology customers, we wanted to cast a little more light
on the subject of “energy efficiency in mechanical engineering”. With that in mind, we interviewed
Professor Dr. Wilfried Hofmann, who holds the chair for “Electrical Machines and Drives” at the Elec-
trotechnical Institute of the Technical University of Dresden.
Dr. Hofmann, how important is the contribution of the
industry to energy efficiency or climate protection?
In a highly developed country such as Germany, the
industry consumes 50 % of the electrical energy that is
generated. With the current energy mix, electricity gen-
eration is responsible for 30 % of total CO 2 emissions,
which makes the industry responsible for 15 %. The indus-
try’s contribution becomes relatively less significant
when you consider other serious climate sinners such as
agriculture and private transport. Only a comprehensive
climate protection plan based on increased efficiency,
therefore, will prove effective. But because the industry
also provides components and equipment for power
generation and other segments such as households,
transport and trade, it occupies a position of direct and
indirect responsibility on both sides.
Where are the technical limits here at this time?
If we go by the latest current figures before the financial
and economic crisis of 2007 – compiled by AG Energiebilanzen/VDEW
and IfE TU München – 63 % of generated
electricity went to energy conversion through electrical
drives, 26 % to processes, 5 % to lighting, and 4 % to
information and communications. In concrete terms, this
means that energy amounting to 143 TWh (32 % gener-
ated power) was converted in electrical drives alone. Of
these 143 TWh, at least a third, or 50 TWh, could be saved
through energy efficiency measures, which is equivalent
to the energy use of ten fossil fuel power station units.
What economic disadvantages does energy efficiency
bring?
For the vendors of drive technology, manufacturing
highly efficient industrial motors entails added costs
because of the more sophisticated technology and
increased expenditure for materials. The customer is
going to have to be willing to pay more for energy efficiency
in the future as well. But when set off against
operating costs, the result is a plus for the customer. For
the manufacturer, it can even become a competitive
advantage.
Where is there future potential, generally and specifically,
for savings?
The general savings potential for drive technology are
currently estimated at 20 % from process optimisation,
10 % from the use of variable speed drives, and 3 % to 5 %
from improving the effectiveness of motors. While the
smaller values can be predicted fairly accurately, the
potential savings from process optimisation always have