3.4 Energy Saving Potentials and Energy Efficiency in Manufacturing
63
For this work, the following focus arises with regard to realization of
optimization potentials:
• Energy Consumption Optimization via timing of machine states
By determining maximum duration times for non-value-adding machine states
(on line and factory level), it is possible to achieve an energy-optimal timetable and necessary recommendations for action with regard to the switching
behavior of machines during production interruptions.
• Energy Consumption Optimization via scheduling of machine starts
The exact calculation of machine starts as a function of the machine states
and processing times of previous production machines leads to the avoidance
of unnecessarily early availability of downstream production machines. This
eliminates the lingering of machines in non-productive but energy-consuming
machine states and thus increases the energy efficiency.
• Energy Cost Optimization via peak consumption avoidance
Early or delayed machine starts as well as timed machine state changes can be
used to reduce load peaks in the power consumption profiles and thus have
a direct impact on the energy cost component “electricity costs for power
demand”.
The following section briefly describes how optimization measures can be
presented and evaluated using key figures.
3.4.2 Energy Performance Indicators
A key performance indicator (KPI) system is supposed to track a development in
a respective field of activity. To better illustrate the development of energy consumption and to track the success of optimization measures, energy performance
indicators (EnPI) can be defined [Ge+2015, p. 33; DS2008, p. 150]. Generally,
a distinction between absolute values and ratios has to be made. While absolute
values (e.g., the total energy consumption per year, peak demand, …) are relevant
to follow up on energy supply contracts, ratios (e.g., specific energy use per production volume) can facilitate comparisons and statements about energy efficiency
[Au2009, p. 48].
A classic key indicator is the yearly energy consumption of a production,
tracked from the actual conditions and used to draw conclusions for the future
[Sc2006, p. 42]:
63
For this work, the following focus arises with regard to realization of
optimization potentials:
• Energy Consumption Optimization via timing of machine states
By determining maximum duration times for non-value-adding machine states
(on line and factory level), it is possible to achieve an energy-optimal timetable and necessary recommendations for action with regard to the switching
behavior of machines during production interruptions.
• Energy Consumption Optimization via scheduling of machine starts
The exact calculation of machine starts as a function of the machine states
and processing times of previous production machines leads to the avoidance
of unnecessarily early availability of downstream production machines. This
eliminates the lingering of machines in non-productive but energy-consuming
machine states and thus increases the energy efficiency.
• Energy Cost Optimization via peak consumption avoidance
Early or delayed machine starts as well as timed machine state changes can be
used to reduce load peaks in the power consumption profiles and thus have
a direct impact on the energy cost component “electricity costs for power
demand”.
The following section briefly describes how optimization measures can be
presented and evaluated using key figures.
3.4.2 Energy Performance Indicators
A key performance indicator (KPI) system is supposed to track a development in
a respective field of activity. To better illustrate the development of energy consumption and to track the success of optimization measures, energy performance
indicators (EnPI) can be defined [Ge+2015, p. 33; DS2008, p. 150]. Generally,
a distinction between absolute values and ratios has to be made. While absolute
values (e.g., the total energy consumption per year, peak demand, …) are relevant
to follow up on energy supply contracts, ratios (e.g., specific energy use per production volume) can facilitate comparisons and statements about energy efficiency
[Au2009, p. 48].
A classic key indicator is the yearly energy consumption of a production,
tracked from the actual conditions and used to draw conclusions for the future
[Sc2006, p. 42]: