The 11 th international Energy Conference (IEC 2016)

Transcription

1 ArticleCode : FES_918 Dynamic Financial Modeling for One MW Photovoltaic Plant with Improved Technology and New Financial Resources: University of Kashan, a Proposed Case Study Abstract 1,*Mohammad Nazififard, 2 Seyed M. Taheri, 3 Alain Corcos * Dept of Energy Systems Engineering, Energy Research Institute, University of Kashan, , Iran 2 Elektra Technologies International, Ltd (RAK) 3 SED (China) *Corresponding Author nazifi@kashanu.ac.ir The objective of this paper is to investigate the economic feasibility of a solar photovoltaic (SPV) plant given the latest developments in the SPV plant technology and financial models available. A One MW capacity SPV plant has been proposed as an invesment today, under the PPA available through the MOE, with the potential to meet the future energy demands of the campus of University of Kashan. Two financial models are considered for financial analysis of the SPV power plant project viz (i) with PPA scenario, (ii) with no PPA using open market startegy. In each scenario a 100% equityt option and a 25% equity option is analyzed. For the scenario using the PPA the financial evaluation was done over 20 years to be coterminus with the PPA. For the Open Market scenario the full 25 years of uefull life was accounted for. Keywords: Solar Energy, Grid-connected, solar photovoltaic plant, Feasibility study, Techno-economic analysis, Payback period. 1. Introduction The use of solar power to generate electricity has been on the rise over the past decade as the efficiency of panels has improved and the cost has been declining while the cost of electricity generation from fossil fuels has been on the increase. Therefore, the technical and economic feasibility of solar electricity generated form solar power has increased allowing a larger number of players both in the industrialized and developing nations to take advantage of this rising technology. Recently many industrialized nations have injected significant solar power capacity into their grids to supplement or provide an alternative to conventional energy sources, to generate electricity, while an increasing number of less developed nations have turned to solar power to reduce dependence on expensive imported fossil fuels. Table (1) list is the top 10 countries using solar power as of the end of

2 United Kingdom Belgium Australia France Spain United States Japan Italy China Germany Figure 1. Total solar radiation on a fixed surface south facing tilted at latitude angle (Right) [1] and approximate footprint of proposed SPV plant (Left). Table 1. Top ten countries using solar power in the word by end of Country Total Capacity (GW) Among the developing countries, Iran has been slowly exploring the potentials of solar power as a source of electricity generation over the past several decades but with noticeable acceleration over the past 2 years. Solar energy (irradiation) is abundantly available in most of Iran, especially in the central and southern regions. The first solar photovoltaic plant (SPV), with a peak capacity of 5 kw DC, was established in the central region of Iran in Doorbid village Yazd in Since then, a small number of PV projects were implemented in Yazd, Semnan, Khorasan, Tehran and Taleghan. However, the capacity of these projects is miniscule compared to the country s total potential [1]. The advances in efficiency and economic feasibility of solar power as well as the government supports in place shall be the subject this analysis for a 1MW solar power plant for the campus of The University of Kashan. Several research and technical analysis have been performed globally in order to evaluate the feasibility and performance of different SPV plants and it can be concluded that the SPV power plant is a viable and feasible option to meet the power requirements at present and in the future [2-9]. In a recent study, the analysis of harnessing solar radiation in fifty different cities of Iran showed that the highest capacity factor is estimated at Bushehr and lowest at Anzali, i.e. 26.1% and 16.5% respectively with a mean capacity factor of 22.27% [1]. The importance of SPV power plants is going to increase with the rising electricity tariffs [1-2]. Recently in order to promote extensive utilization of renewable energies in Iran, Minister of Energy of Iran announced the guaranteed purchase tariffs on

3 Table 2. Guaranteed photovoltaic electricity purchase tariffs [10] Item Technology and Capacity Guaranteed Purchase Price 1 Solar farms over 10 MW 5600 (Rials/kWh) 2 Solar farms of 10 MW or less 6750 (Rials/kWh) 3 Solar energy of 100 KW or less* 8730(Rials/kWh) 4 Solar energy of 20 KW or less* 9770 (Rials/kWh) *Only for consumers and limited to their connection capacity. Table 2 presents the guaranteed photovoltaic electricity purchase tariffs in Iran [10]. For this study, a one MW grid connected SPV plant was designed with the latest technology and the financial analysis was performed using the newest financial models available for the University of Kashan. The financial analysis was done considering 25 years of SPV power plant life and the 20-year PPA currently available. 2. Design Methodology and Performance Evaluation of SPV Plant Kashan is located in latitude of N, longitude of E, and 1672m above sea level and has capacity factor of 23.50%. Kashan has very good conditions for the development of photovoltaic solar power systems due mainly to the high mean daily radiation and the high number of sunny days. The SPV plant is mainly composed of the solar modules, DC lightning protection, junction box, DC distribution systems, inverter, transformer, AC power distribution systems and communication, weather station & monitoring system (Fig. 2). A solar cell is an electronic device that catches sunlight and turns it directly into DC electricity. Solar cells are bundled together to make larger units called solar modules, themselves coupled into even bigger units known as solar panels which are connected to an Inverter. The Inverter and related equipment converts the DC electricity to AC electricity that can then be injected into the grid. This entire system is monitored and controlled from a local or remote operation center. The design methodology and technical specifications of the SPV power plant are discussed in this section. Figure 2. Solar plant and grid integration 3

4 2.1 Solar PV Panels Configuration The PV module sizing and performance estimation of SPV plant is carried out with PVsyst software [2]. For the purpose of simulation, available Meteo data are imported from software data library. The PV panels, 250W PV panel from Elektra Technologies International are selected due to their proven reliability and superior value/performance ratio to enhance the financial feasibility of the project. To achieve one MW solar power (nominal power) a total number of 4000PV panels is required. Figure 3 shows the perspective of the PV-field and surrounding shading scene. SPV plant consists of 21 modules in parallel and 200 strings. The total module area is about 6500 m² but considering the panel spacing and shading, total land area required is about 1 Hectare. Table 3. Characteristics of 250WPV module [13]. Parameter Units Values Maximum power (Pmax) W 250 Optimum operating voltage (Vpm) V Max. power current (Ipm) A 8.29 Open circuit voltage (VOC) V Short circuit current (ISC) A 8.86 Operating temperature C -40~+85 Output power tolerance % 0~+0.3 Maximum system voltage Vdc 1000 Module efficiency % Fire rating - Class C Application class - Class A Note 1: Standard test conditions: air mass 1.5, irradiance=1000 W/m 2, Temperature=25 C. Note 2: The values in the above table are nominal. 2.2 Inverter Sizing The main function of the inverter in the SPV plant is obviously to convert the DC power of the SPV arrays into AC power compatible with the grid requirements. The size of the inverter depends on the total SPV peak power requirement. Equinox 1MW Inverter [12] is considered for the SPV plant which has an inbuilt maximum power point tracking (MPPT) system. MPPT is a fully electronic system that varies the electrical operating point of the modules so that the modules are able to deliver maximum available power. Note that additional power harvested from the modules is then made available as increased current. Table 4 represents the characteristics of Equinox 1MW inverter [12]. 4

5 Parameter Table 4. The Equinox 1MW inverter characteristics [12]. Value Input voltage range VDC Maximum array input voltage 600 VDC Maximum operating input current 3206 (2x1603) ADC Maximum short circuit input current 4800 (2x2400) ADC Nominal power 1.0 MW Native output voltage, low voltage 200 VAC Native output voltage range, [-12%/10%] VAC Nominal medium voltage output (Dependent on MV Transformer) Maximum output current/phase 2886 A Standby consumptions 325 W Maximum harmonic distortion <3% THD Power factor, full load >99% Dynamic power factor control +/- 0.8 Efficiency 98.5% Power curtailment 0-100%, 1% steps Operating temperature range -20 ºC to +50 ºC Figure 3. Perspective of the PV-field and surrounding shading scene. 5

6 2.3 Efficiency Analysis PVsyst calculates several loss parameters during the simulation, as shown in the Fig. 4. The loss diagram provides a quick look and insight into the quality of the SPV plant, by identifying the main sources of the power loss. The array losses start from the evaluation of the nominal energy (1915 kwh/m 2 ), using the global effective irradiance and the array MPP nominal efficiency at standard test condition (STC). Then it gives the detail of the PV model behavior according to the environmental variables. Note that In Kashan city region, the array losses due to dirt on the PVmodules and thermal behavior of the PV array are the main concerns of designers. The array losses, including thermal, wiring, module quality, mismatch and IAM losses, shading, dirt, MPP, regulation losses, as well as all other inefficiencies\ The dirt on the PV-modules may be defined in 1% of STC, yearly or in monthly values. The thermal loss is calculated following the one-diode model [11]. For crystalline silicon cells, the loss is about -0.4 %/ C at MPP. For fixed voltage operating conditions, the temperature mainly affects the I/V curve voltage, and effective losses are strongly dependent on the array overvoltage with respect to the operating voltage. In order to evaluate the PV installations, JRC (European Joint Research Center) introduced the Performance Ratio (Fig. 5) and Normalised Performance Production indexes (Fig. 6). These efficiency indicators are related to the incident energy in the collector plane, and are normalized by the Pnom = Array nominal installed power at STC, as given by the PV-module manufacturer [kwp]. Therefore, they are independent of the array size, the geographic situation and the field orientation. Performance Ratio (PR) represents the ratio of the effectively produced (used) energy, with respect to the energy that could be produced by a "perfect" system continuously operating at STC under same irradiance. The PR includes the array losses (Shadings, IAM, PV conversion, module quality, mismatch, wiring, etc.) and the system losses. PV panels are very sensitive to shading. When shade falls on a PV panel, the shaded portion of the PV panel cannot collect the high-energy beam radiation from the sun. The Iso-shading diagram of SPV plant is depicted in Fig. 7. It is a graphical expression of the shading factor table and shows lines of some given shading factors, superimposed on the sun paths. Blue lines also indicate the tangential limits of the plane (i.e. when the sun rays are parallel to the plane). This diagram gives a synthetic evaluation of the shading distribution according to the season and the timeof day during the year. The irregular look of the lines is due to the interpolations across discrete calculation points. Note that this loss factor applies to the beam component reaching the PV plane. When the incident angle is high, even high loss factors will act on very low irradiance component, giving rise to reasonable effects on the overall efficiency. 6

7 Figure 4. Loss diagram over the whole first year of SPV plant. Figure 6. Normalized Productions Figure 5. Performance Ratio 7

8 Figure 7. Iso-shadings diagram of SPV power plant. 3. Financial Analysis An economic evaluation of the SPV plant was performed on the basis of the defined parameters and the simulation results. The net investment is derived from the gross investment by subtracting eventual subsidies and adding a tax percentage (VAT). The operating and maintenance costs depend on the type of system. For a grid-connected system, usually very reliable, they are limited to an annual inspection, eventually some cleaning of the collectors and the insurance fees if any. Some Inverter suppliers provide a long-term payable warranty, including replacement, which are equivalent to an insurance. The total annual cost is the sum of the annuities and the running costs divided by the effectively produced and used energy, it gives an evaluation of the energy cost (price of the used kwh). For grid-connected systems, the long term profitability may be estimated according to different consumption or feed-in tariffs conditions. As discussed before the feed-in tariff is set by a long-term contract, the PPA (usually 20 years), at a level determined at the system commissioning time, and fixed for the whole contract period and adjusted for inflation. The second scenario ignores the PPA rate and uses the currently available open market rates with all other variables remaining the same as the PPA scenario. For the purposes of this study a very conservative approach was taken by using the export rate for electricity sold to neigboring countries such as Iraq and adjusted for a trasmission surcharge of approximatley 15% anticipated to be paid to the grid operator. Both scenarios were also evaluated for IRR and pay back period using a 100% and 20% equity models. 8

9 For the pruposes of this paper and to gauge as accurately as possible the economic feasability of the one MW solar power plant the following input parameters were gathered: 1. The PPA for a 1MW solar plant is 6750 Rials adjusted annually for inflation (see MOE Memeo) 2. Adjustments for inflation shall continue at the official government declared rates,currently at 15% (although this rate is widey belived to be underestimated by at least 5% based on Bank CD deposit dividends) 3. The land cost (lease) is negligable. A nominal expense of $4000/year is accounted for leashold expenses 4. Insurance, mainly for equipment is estimated at.2% of the initial installed cost 5. Maintenance is.5% of the initial installed cost (derived from industry standards). 6. All financial calcualtions were done in PVCal online calculator ( Two financial models are considered for financial analysis of the SPV power plant project viz (i) with PPA scenario, (ii) with no PPA using open market startegy. In each scenario a 100% equityt option and a 25% equity option is analyzed. The financial analysis is based on the effective plant life of 25 years Table 5. Financial analysis for proposed SPV power plant (Price in US dollar). Analysis With PPA With no PPA using open market startegy Annual Yield per kwp (kwh/kwp) Degradation (%/year).5.5 Percent of own consumption (kwh/year) 0 0 Energy Price Inflation (%/year) 15% 15% Feed in tariffs IRR (%) 100% Equity 30.1% 20.2% IRR (%) with 25% Equity 39.1% 25.8% Simple payback period (years) 100% Equity Simple payback period (years) 25% Equity Conclusion This study has been carried out to assess the technical feasibility and economic viability of a one MW capacity solar photovoltaic power plant as an investment for the University of Kashan. The total number of 4000 PV modules of 250W are required. The total land area required is about 1 Hectar. The net energy injected into the grid grid is 1727 MWh electricity in the first year and over 25 years, considering cumulative degradation of about 20%, electricity generation from the plant will be i.e GWh. For the scenario using the PPA the financial evaluation was done over 20 years to be coterminus with the PPA. For the Open Market scenario the full 25 years of uefull life was accounted for. Analysis shows SPV power plant project with PPA is quite attractive. 9

10 Acknowledgement It is with great regrds that we appriciate the Energy Research Institute of the University of Kashan and Elektra Technologies for thier support and forsight through the MOU that was the cornerstone for this study. Refrences [1] S.M. Besarati, R.V. Padilla, D.Y. Goswami, E. Stefanakos, The potential of harnessing solar radiation in Iran: generating solar maps and viability study of PV power plants, Renew Energy, 53 (2013), pp [2] M. Chandel, G.D. Agrawal, A. Mathur, Techno-economic analysis of solar parabolic trough type energy system for garment zone of Jaipur city Renew Sustain Energy Rev, 17 (2013), pp [3] M. EL-Shimy, Viability analysis of PV power plants in Egypt, Renew Energy, 34 (2009), pp [4] H. Radhi, On the value of decentralized PV systems for the GCC residential sector, Energy Policy, 39 (2011), pp [5 N.W. Alnaser, R. Flanagan, W.E. Alnaser, Potential of making over to sustainable buildings in the Kingdom of Bahrain, Energy Build, 40 (2008), pp [6] T. Pavlovic, D. Milosavljevic, I. Radonjic, L. Pantic, A. Radivojevic, M. Pavlovic, Possibility of electricity generation using PV solar plants in Serbia, Renew Sustain Energy Rev, 20 (2013), pp [7] T. Muneer, M. Asif, S. Munawwar, Sustainable production of solar electricity with particular reference to the Indian economy, Renew Sustain Energy Rev, 9 (2005), pp [8] S. Gupta, Scope for solar energy utilization in the Indian textile industry, Sol Energy, 42 (1989), pp [9] Kumar, B. S., & Sudhakar, K. (2015). Performance evaluation of 10 MW grid connected solar photovoltaic power plant in India. Energy Reports, 1, [10] [11] [12] [13] Elektra Technologies Company 10