Microsoft Word 2012, Källén, M.,-Energy Efficiency Opportunities within the Heat Treatment Industry
Economic and Environmental Assessment
Download 1.18 Mb. Pdf ko'rish
|
energy efficiency maqola
|
5.4 Economic and Environmental Assessment
The energy saving measures described in section 5.3 all need an investment to be realised. The investment costs for measure 1-6, which are used for the economic assessment are listed in table 8.
Measure
Investment Cost (SEK) 1. Low energy lighting 1 081 000 5 700 3. Move intake to compressor 10 000 4. Heat exchange furnace gas/washing water 150 000 5. Heat exchange compressor/offices 570 000 6. Install new piping for heat exchange in three ventilation aggregates 350 000
The above listed measures have all been evaluated both by the payback period method and by the net present value method, see section 4.5. The results from the economic assessment can be seen in table 9. The payback period should mainly be used as a risk analysis, since it only regards the present value of an investment. The net present value is based on all costs and cost savings during the next ten years after the investment is made, and is a better measurement of the profitability. The net present value ratio can be used to compare the investments with each other.
Measure Annual savings (SEK/year) Payback period (year) Net present value (SEK) Net present value ratio (-) 1. Low energy lighting 120 300
8.99 2 666 600 2.7 2. Insulation of door hoods 77 400 0.07
2 406 200 422.1
3. Move intake to comp. 11 100
0.90 336 300
33.6 4. HX furnace gas/wash 89 000 1.69
2 622 100 17.5
5. HX compressor/offices 100 500
5.67 2 560 600 4.5 6. New piping in ventilation 278 400 1.26
8 321 500 23.8
37 As can be seen in table 9, all the investments can be considered profitable over a ten year period since all net present values are positive. The heat exchange between the waste heat from the compressor and the heating of the offices and the low energy lighting have much longer payback periods than the other investments. The payback period for the heat exchanging is over five years and this investment has a low net present value ratio. The payback period for the low energy lighting is nine years and has the lowest net present value ratio. These investments could be regarded as a high risk due to the long payback periods. When comparing the net present value ratios, it is found that the insulation of the door hoods is the most profitable investment. However, the much longer life time of low energy lighting is not included in the annual cost savings for the low energy lighting investment. If these were included, the payback period would be shorter. A sensitivity analysis based on increased energy prices has been carried out. The results are presented in table 10. It was assumed that the energy prices will increase linearly over the next ten years and reach levels of 25% above the current price for electricity and 15% above the current price for district heating. As can be seen in table 10, including increasing energy prices in the calculations results in more profitable investments.
Measure Annual savings (SEK/year) Payback period (year) Net present value (SEK) Net present value ratio (-) 1. Low energy lighting 135 300
7.99 3 135 000 2.9 2. Insulation of door hoods 87 100 0.07
2 707 700 475.0
3. Move intake to comp. 12 500
0.80 379 600
38.0 4. HX furnace gas/wash 100 100 1.50
2 968 600 19.8
5. HX compressor/offices 108 000
5.28 2 795 400 4.9 6. New piping in ventilation 299 300 1.17
8 971 900 25.6
Download 1.18 Mb. Do'stlaringiz bilan baham: 
|