Energy Systems and Technologies for the Coming Century ...

ing down the cost of solar PV modules from $600/Wp to $5/Wp while overallefficiency improved three fold (Erickson and Chapman, 1995). The cost of solar PVsystem has been come down with the technological learning-by-doing and economies ofscale (Ferioli et al., 2009). The technological learning rate of solar PV modules over thelast 20 years varied from 18% to 23%, which means that there has been a reduction in thecost of the module by 18%–23% per doubling of cumulative installed capacity (Sanden,2005). So with the increase in the learning rate, the LCOE of solar PV system is alsoexpected to go down. The LCOE for wind home system is varying significantly (0.46-3.2USD/kWh) depending upon the wind speed. The wind energy market in Nepal is on thevery primitive level and there are very few companies that manufacture the wind turbineat the local level. This cost also could go significantly down in case of the expansion ofthe market in the future. So, some initial support in terms of technical and financialassistance deemed necessary for the wind sector to form the market infrastructure.3.2 Levelized cost for Micro Hydro (MH) PlantsMicro hydro is very site specific technology and the cost may vary a lot depending uponthe physical features of the major components namely civil components like water way,electromechanical equipment like turbine, generator, load controller, protection systemand electrical transmission distribution system. In general, the study has shown that costof the MH projects decrease with the size of the plants (Mainali and Silveira, 2011).The average installation cost of typical 25 kW and 50 kW size micro hydro projects wereadopted for the reference for both the case of Nepal and Afghanistan. Operation andmaintenance cost (O & M cost) has been assumed 5% of the installation cost. Small andminor replacement may be needed in the power plant during its life span, but small hydropower can be operated its full life span without any major replacement cost (Lako, 2010).These small replacement cost are taken into account in the regular operational andmaintenance cost. Normally, construction of micro hydro may take 1.5 to 2.5 years. Inthis analysis, we have assumed that the construction period is 2 years with equaldistribution of the investment for both two years. The other assumptions regarding plantavailability factor, load factor for islanded mode and life span of the projects arementioned in Table 2.Table 2: Information on cost and other parameters for different size MH projects (2010)Countries Nepal AfghanistanDescription /Plant Size 25 kW 50 kW 25 kW 50 kWInstallation cost per kW 2.8-3.5 2.5-3.0 3.0-4.0 2.5-3.5in 000 USDYearly O & M cost interms of total project cost5% 5% 5% 5%Availability factor 0.9 0.9 0.9 0.9Load factor 0.3 0.3 0.2 0.25Life span 20 20 20 20Levelized cost in USD/kWh 0.28-0.35 0.25-0.30 0.50-0.67 0.34-0.47Data Source: RRESCs, ESAP, Nepal and MRRD/UNDP, Afghanistan.Risø International Energy Conference 2011 Proceedings Page 368