Microsoft Word 2012, Källén, M.,-Energy Efficiency Opportunities within the Heat Treatment Industry

3.3  Current Energy Consumption 

The only energy source for the process equipment in the plant is electricity. The workshop 

area is heated by recycled process heat. A small amount of district heating is used for heating 

the offices and for the tap water heater, see figure 10. During 2011, 9 590 MWh electricity 

and 120 MWh district heating was consumed in the plant. 

 

Figure 10. The energy consumption for 2011 in MWh. 

The process is operated continuously day and night, seven days a week. The energy 

consumption during an average day can be seen in figure 11. 

 

Figure 11. The energy consumption during an average day in kWh/h.  

The production rate is equal for weekdays and weekends. The operating staff works in three 

shifts during weekdays and two shifts during weekends. The plant operates unmanned two 

nights during the weekend with ordinary production rate.  

The energy consumption distribution over one year can be seen in figure 12. The production 

is stopped during two weeks in summer for vacation and partly decreased during Christmas 

time. Even though the production is stopped in summer, not all equipment is turned off. For 

example, pumps and the compressor need to be operating so that the equipment does not get 

damaged. 

9590

120

Electricity

District heating

0

200

400

600

800

1000

1200

1400

1600

1

3

5

7

9

11

13

15

17

19

21

23

kW

h/

h

---

 

 

19 

 

 

Figure 12. The energy consumption during one year in MWh/week. 

 

The specific energy usage for the plant can be seen in table 2. The numbers are based on the 

production rate and energy consumption in 2011. 

Table 2. Specific energy usage in the plant. 

Energy use/Production time 

(MWh/h) 

Energy use/Turnover 

(MWh/kSEK) 

Energy use/Amount goods  

(MWh/ton) 

1.16 0.18 

2.93