風力發電應用於海水淡化機組之個案研究與成本效益評估

Cost Benefit Analysis for the Integration of Wind Power and Desalination Technology

郭章賢(Chang-Hsien Kuo)

指導教授 ： 張四立

國立臺北大學/公共事務學院/自然資源與環境管理研究所在職專班/碩士(2014年)

摘要

海水淡化具有開發時程短、不受水文變異之影響等優點，應是因應氣候變遷導致缺水危機的選項之一，但因製水過程會消耗較高能源，相對增加CO2排放量，因此本研究以風力發電應用於海水淡化技術為探討，藉由採用潔淨能源之風力發電，來降低使用化石燃料使用及CO2排放量，同時運用成本效益分析(Cost Benefit Analysis)，將CO2減量效益予以量化，依據各項CO2減量及空污減量成本，推估風力發電所產生外部效益，合計每度電約為0.17~1.70元/度。
經參考國內民營企業所投資之海水淡化機組，及選擇台灣中部之風力示範系統作為個案探討，計算其投資效益及回收年限，結果為：
一、在傳統海水淡化廠以250噸/日規模設計，實際運轉結果每噸產水之平均耗電4.7度/噸，再加計其他變動成本及設備固定成本後，每噸產水成本為41.97元。
二、將660KW風力發電應用於上述海水淡化機組後，考量風力發電不穩定，經以容量因數25.89%計算，僅可取代海淡機組之73.8%用電，將其環境效益內部化及風能高峰多餘產電效益計算後，得知結合風力發電機組的海水淡化廠比傳統海水淡化廠的成本，可由41.97元/噸降低至32.89元/噸，省下約21.6%，較具競爭利基，並可促進海水淡化及風機相關產業之發展及符合國家再生能源發展政策。
三、假設不同的折限率、設備補助費用、電價費率、合理水價及環境效益等參數，進行本個案的敏感度分析，以計算各情境的差異性，依據敏感度分析結果，若以缺水嚴重及風場充沛之離島地區為例，以由台灣本島運水供應成本每噸水160元計算，海水淡化加上風力發電的設備回收年限為5年，已具投資的條件，可優先推廣應用。

關鍵字

敏感度分析 ； 環境效益 ； 成本效益 ； 風力發電 ； 海水淡化

並列摘要

Desalination has many advantages, including short lead-time in planning and installation, and unaffected by variation of hydrological. It should then be considered as one of the options to tackle the future possible water shortage problem caused by climate change. But desalination process itself is an energy intensive process and may result in increasing emission of CO2, if the electricity used is fossil fuel based of power generation. Therefore, the purpose of the study will be focused on the feasibility of combining renewable power with the desalination process to explore its possible costs and benefits. Specifically, wind energy is considered as the source for power generation to substitute part of the fossil fuel (mainly coal) based electricity. Cost-benefit analysis is applied as the research method to identify as well as quantify various possible costs and benefits derived. It is estimated that the cost of wind power is about NT $0.17 to 1.70/KWh according to the effects of CO2 reduction and the reduction of air pollution.
A privately owned desalination unit combined with wind power generation unit under planning is used as the case for the cost-benefit analysis to calculate the investment returns and payback period. The results are as follows:
1.The capacity designed for the traditional desalination unit is 250 CMD. Based on actual operating record, the average electricity used for one ton of water produced is 4.7 KWh. With the additional variable and fixed costs taken into account, the water production cost is NT $41.97 per ton.
2.After 660KW wind power is added with the above stated water desalination units, only 73.8% of electricity used could be replaced by the desalination unit, due to the variability of wind resource and the capacity factor of 25.89%. After internalizing wind power environmental benefit, the cost saving from desalination can be 21.6%, compare with conventional desalination plant (from NT $41.97/ton down to $32.87/ton). This result obtained shows that there may exist a competitive advantage, and may contribute to the development of desalination, wind power-related industries, and consistent with the development policy of the National Renewable Energy.
3.By changing the scenario set for the BAU (Business As Usual) case, the study then performs a set of sensitivity analysis to show the resulting changes in net present values derived by the changes of the following parameters, which includes subsidies provided for purchasing wind power equipment, electricity price and water price. According to the sensitivity analysis and assuming that water demand is satisfied by importation of water from Taiwan, the cost generated will be about NT $160 per ton. It is because the quality of wind is higher, while the water resource is less abundant in the offshore islands, so the combined use of wind power and water desalination, the payback period will be shortened to 5 years. This scenario is therefore more preferred than the case of BAU scenario.

並列關鍵字

Environmental Benefits ； Cost Effectiveness ； Wind Power ； Desalination ； Sensitivity Analysis

參考文獻

4.李珣琮、施勵行，2010年，碳經濟第十九期，論述我國再生能源發展政策之效益評估模型架構。

7.陳明煌，2010年，台灣推廣設置小型風力發電機之個案研究與效益評估，國立台北大學自然資源與環境管理研究所碩士論文。

13.郭世勳，2008年，台灣地區離岸式風力發電成本效益分析，國立台北大學自然資源與環境管理研究所碩士論文。

26.Dua, M., Manwell, J. F. and J. G. McGowan., 2008. Utility Scale Wind Turbines on a Grid-Connected Island: A Feasibility Study, Renewable Energy, 33, 712-719.

27.Fulya Verdier., 2011. MENA Regional Water Outlook Part II Desalination Using Renewable Energy, Germany.