경제성 있는 육상 풍력발전사업을 위한 최소 평균풍속의 결정

Abstract

A study on economic feasibility analysis of a wind project was carried out to find the "marginal mean wind speed" which means the minimum average wind speed for profitable operation of general utility-scale onshore wind farms. A flow chart showing the overall process was proposed to determine marginal mean wind speeds under various financial conditions. The procedure at the flow chart is as follows: Rayleigh wind speed distribution with the mean of 4.5 m/s to 8.0 m/s was assumed as wind condition for this study. The average power curves for wind turbines with power ratings of 1.5, 2.0, 2.5 and 3.0 MW were derived, and gross annual energy production (AEP) and capacity factor (CF) were calculated using each wind distribution. Then, 10 % and 15 % loss of AEP was applied to gross AEP for estimating net AEP at real wind farms. Next, economic feasibility analysis were performed using Net Present Value (NPV), Benefit Cost Ratio (BCR) and Internal Rate of Return (IRR). The parameters for determining the cost and the benefit of a wind project were carefully chosen on the basis of the Korean wind market. In particular, it was very hard to estimate System Marginal Price (SMP) and Renewable Energy Certificate (REC) price so that they were assumed based on some references. Accordingly, it should be noted that the results of this study highly depended on variation in SMP and REC price. Finally, BCR was regarded as a main factor for determining marginal mean wind speed, and the marginal mean wind speeds were estimated when BCRs were 1.0, 1.15 and 1.25, respectively. The result showed that when the BCR was 1.0 and REC sales were not included in the economic analysis, the marginal mean wind speed needed from 5.6 m/s to 6.1 m/s (median: 5.9 m/s). In the case of including REC sales, the marginal mean wind speed ranged from 4.8 m/s ∼ 5.1 m/s (median: 4.9 m/s). In addition, when the BCR was 1.15 and REC sales were not included in the economic analysis, the marginal mean wind speed was from 6.1 m/s to 6.7 m/s (median: 6.4 m/s). When REC sales were included, the marginal mean wind speed ranged from 5.1 m/s to 5.5 m/s (median: 5.3 m/s). Furthermore, when the BCR was 1.25 and REC sales were not included, the marginal mean wind speed ranged from 6.5 m/s to 7.2 m/s (median: 6.9 m/s). With REC sales, the marginal mean wind speed was from 5.4 m/s to 5.8 m/s (median: 5.6 m/s). That is, the marginal mean wind speed for profitable operation of a wind farm greatly depended on REC sales. Additionally, sensitivity analysis was carried out for 1.5 MW wind turbines. The economic feasibility in a wind project was sensitive to mainly SMP, CF and Capital Expenditure (CAPEX). When REC sales were applied, changes in SMP had the most effect on NPV, IRR and BCR.