Design and techno-economic analysis of a 15 kWp grid-tied net-metering solar photovoltaic power plant utilizing half-cut monocrystalline-PERC Si modules with elevated rooftop structure

doi:10.21203/rs.3.rs-5296779/v1

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Research Article

Design and techno-economic analysis of a 15 kWp grid-tied net-metering solar photovoltaic power plant utilizing half-cut monocrystalline-PERC Si modules with elevated rooftop structure

https://doi.org/10.21203/rs.3.rs-5296779/v1

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The declining cost of photovoltaic (PV) power generation makes on-grid PV plants suitable for residential and commercial applications. The elevated rooftop PV plant installation is an example of a solar plant that generates electricity without disturbing the terrace area. The paper presents the techno-economic analysis of a 15 kWp on-grid power plant placed on the rooftop of Vardhman Hospital with a net-metering scheme located at Durg, Chhattisgarh, India (21°11' N, 81°17' E). The plant rests on an elevated galvanized iron (GI) structure, using half-cut monocrystalline-passivated emitter and rear contact (PERC) cell-based PV modules. The plant's performance parameter and the system losses were calculated using PVsyst simulation software using PVGIS meteorological data. The annual plane of array (POA) irradiation is approximately 2230 kWh/m² at the plant location. The PV energy generation of the plant is 27727 kWh/year, and 27271 kWh/year of energy is injected into the grid. The annual performance ratio of the plant is 81.7%. The research article also focuses on plant design, electricity consumption, and the net electricity bill of the premises for three consecutive years before and after plant installation. The installation of the plant will be equivalent to planting 738 Teak trees over the lifetime, and carbon dioxide emissions mitigated is 461 tonnes. The payback period for an elevated structured on-grid PV plant is around six years.

On-grid Solar Plant

Net-Metering Scheme

PVsyst

Utility Bill

Payback Period

Performance Analysis

Energy is essential for economic and social development of a nation, and improved quality of life of the people. India is endowed with abundant solar radiation for the generation of electrical energy, and about 5000 trillion kWh per year of solar radiation is received (4–7 kWh per sq. m. per day) by India, which is much more than its total annual energy generation of 1624 billion kWh [1, 2]. India has set a target to reduce carbon emission intensity of the nation’s economy by 45% by 2030 from 2005 level, achieve 50 percent cumulative electric power installed by 2030 from renewables, and achieve net-zero carbon emissions by 2070. India aims for 500 GW of renewable energy installed capacity by 2030 [3]. India's cumulative module manufacturing nameplate capacity doubled from 18 GW in March 2022 to 38 GW in March 2023. India’s cumulative residential rooftop solar capacity will reach 3.2 GW by the end of the current fiscal year FY 2022-23, nearly a 60% increase from 2 GW as of FY 2021-22 — according to a new report by the Institute for Energy Economics and Financial Analysis (IEEFA) and JMK Research & Analytics [4].

Solar projects in India use various solar mounting technologies and designs, like rooftop solar, ground-based solar, carports, elevated rooftop PV, and sun tracker mounting structure solutions. The elevated rooftop PV plant installation is an example of a solar plant that generates electricity without disturbing the terrace area, and one can use the terrace area for other residential or commercial purposes. Elevated rooftop structures provide an attractive energy solution to residential and commercial consumers. The design, installation & commissioning, the techno economic analysis is one of the major aspects of in view with the payback period for the consumers throughout the life time of the plant. The plant design considers the tilt angle, the row spacing and the PV module facing towards the sun to grasp the maximum incident sun radiations. The proper choice of tilt angle and inter-row spacing for the installation site are two essential parameters for capturing maximum incident radiation falling over the surface of the PV module to maximize the energy yield [5]. Shah et al. [6] compared the varying output from two 100 MW solar PV power plants located in close vicinity of each other in the Bahawalpur desert region of Pakistan. It evaluates the reasons for the mismatch in energy generation. It presents area-specific recommendations for designers to cater to the ground cover ratio (GCR), tilt angles, and sun charts in designing their PV systems optimally.

The plant's outdoor performance also depends on the lifetime expectancy of the PV modules. The Mid-life degradation evaluation of polycrystalline Si solar photovoltaic modules in a 100 kWp grid-tied system in east-central India investigates and shows the various types of visible degradation and their effective degradation rate [7]. The performance comparison of monocrystalline and polycrystalline Si solar photovoltaic (SPV) modules under tropical wet and dry climatic conditions in east-central is given [8]. The grid-connected solar PV system is more economical than the standalone PV system and grid-connected solar PV with battery storage due to the enormous initial storage cost. The effective design method of solar PV power plants investigated and proposes a reliable backup system for uninterrupted power supply with storage batteries in the base unit in parallel with the existing grid to maintain supply stability and reliability [9]. Another study investigated the performance and operational challenges of six functional PV-based mini-grids of capacity 15 kW to 19 kW in the Indian state of Jharkhand [10].

The outdoor performance of a 2.25 kWp pilot grid-tied solar power plant in the southern region of Algeria was also investigated by researchers. The plant has been operating for seven years in the harsh desert climate of North Africa. The PV plant uses micromorph thin-film solar modules (a-Si/µc-Si) technology [11]. Mudgil et al. [12] analyzed a 12 kWp grid-connected PV plant installed on a rooftop under the net metering regulation of the State Electricity Regulatory Commission in Delhi, India. The plant's total annual energy generation and capacity utilization factor is 1147 kWh/kWp and 13.1%, respectively. Kalke et al. present the complete financial analysis of a 10 kWp grid-tied rooftop solar photovoltaic system employing a net-metering scheme [13]. They also compared the results of the economic study of 10 kWp system using the Capital expenditures (CAPEX) model for the residential sector and renewable energy service company (RESCO) model for commercial users. Al-Zoubi et al. present a feasibility study of utilizing an on-grid photovoltaic (PV) system for the electrification of Cedars Hotel located in Amman in, Jordan as a case study [14]. They calculate the payback period, the annual life cycle savings, and the levelized energy cost for the plant.

The various authors have written research articles that provide information on performance studies and the plant simulation design using PV simulation tools of on-grid solar PV power plants. There is a lagging study by the authors on the on-grid plant design requirements, installation, and commissioning with a net-metering scheme to the local distribution company. This paper presents a detailed design and techno-economic analysis of a 15 kWp grid-tied solar PV plant at Vardhman Hospital, Durg, Chhattisgarh (21°11' N, 81°17' E). The load profile of the premises, the consumption before and after the on-grid plant installation is presented. The simulation results using PVsyst the details of the installation of on-grid power plant with a net-metering scheme are also included. The premises presented a unique problem, in which the consumer did not want any wastage of the rooftop area as it was being used for terrace gardening. We used an elevated structure to fix the PV array and thus saved the entire rooftop area for gardening or for other purposes as usual. The height of the elevated structure was also properly designed by considering the shading effect to ensure that sufficient sunlight was incident on the plants. Additionally, the paper also presents the payback period and the CO₂ emission mitigation of the plant. This research article provides useful data and guidelines for decision-makers, engineers, system integrators and industries in this region (East-Central India) to install and commission such kind of on-grid solar power plant with a net-metering scheme. The study also provides an opportunity to analyze the performance of half-cut mono-PERC PV modules which have been recently introduced in the Indian market.

2.1 Installed Plant Overview / System Design with BoS

The 15 kW on-grid solar power plant with a net-metering scheme has been installed at the rooftop of Vardhman Hospital, Durg, Chhattisgarh (21°11' N, 81°17' E) using an elevated structure. The half-cut passivated emitter and rear contact (PERC) monocrystalline mono-facial photovoltaic (PV) modules technology is used to design the plant. The pictorial representation of the typical on-grid solar power plant design, the actual look of the power plant resting on an elevated structure, the plant side-view, and the Google satellite image, which rests on the building of Vardhman Hospital, is shown in Fig. 1.

Thirty-four (34) PV modules (mono-facial monocrystalline half-cut PERC, make Vikram Solar, 445 Wp) are connected in two strings with seventeen modules in series. The balance of system components of the plant includes inverters, wires (AC/DC), DC distribution box (DCDB), AC distribution box (ACDB), the generation meter, and the net meter. The electrical parameters of the PV module given by the manufacturer at standard test conditions (STC) and the three-phase on-grid inverter are shown in Table 1. The PV string DC cable size of 4 sq. mm bears up to 32 A of current helps connect the DC side of the plant to the DCDB (2-IN-1-OUT). A 16A ACDB connects the inverter output to the local grid.

Table 1 Specifications of PV module (at STC*) and BoS of on-grid power plant

Table 1

**(a)** Specifications of PV Module
Design Parameters	Value
Make	VIKRAM SOLAR
Technology	M6 HALF-CUT PERC
Peak Power Pmax (W_p)	445
Number of cells in Module (N_s)	144
Maximum Voltage V_m (V)	41.5
Maximum Current I_m (A)	10.72
Open Circuit Voltage V_OC (V)	48.9
Short Circuit Current I_SC (A)	11.67
Module Efficiency η (%)	20.01
Tc of Open Circuit Voltage (β)	− 0.28%/°C
Tc of Short Circuit Current (α)	0.057%/°C
Tc of Power (γ)	-0.39%/°C

Table 1

**(b)** Specifications of On-grid Inverter
Input (DC)/Output (AC)/ Efficiency	Value
Model/Make	KSY15KW/KSOLARE
Max. DC Power (KW)	17.5
Max. DC Voltage (Vdc)	1000V DC
Max. MPPT I/P Current(A)	20 A
MPPT Short Circuit Current(A)	26 Amps.
MPPT Tracking Voltage (Vdc)	200-1000V
Min. Start/Shut down (V)	250VDC/150VDC(Low) & 1000VDC(High)
Number of MPPT Tracker	2
strings per MPPT Trackers	2
Nominal Output Power (KW)	15
Max. Output Power (KW)	16.5
Nominal Grid Voltage(V)/Range(V)	320-470V User Defined
Nominal Grid Freq/Range (Hz)	47–55 HZ Auto Selected
Max. Output Current (A)	22
AC Connection (with PE)	3P + N + E
THD (%)	< 2.3%
Power Factor (%)	> 99.99% (User Defined from 0.85 to 0.99)
Max. Efficiency (%)	99

* 1000 W/m² of full solar noon sunshine (irradiance) when the panel and cells are at a temperature of 25 ^oC with a sea level air mass (AM) of 1.5 (1 sun).

The plant location's meteorological data* are presented in Fig. 2. The average May temperature is 35.2°C, with a high recorded 41.4°C. The difference in precipitation between the driest and wettest months is 382 mm. In June, July, August, and September, there is an average of 293.5 mm of rainfall. The months with the highest and lowest relative humidity are August (83.64%) and April (27.32%), respectively. April and May have the highest average sun hours. The data for sun hours and others were obtained from publicly available databases [16].

2.2 Methodology

There is a 15 kWp on-grid solar power plant installed at Vardhman hospital under net-metering scheme with the help of local distribution company's (DISCOM). Figure 3 illustrates a complete methodology for this research article step by step. It covers the load estimation, PVsyst simulation of the plant, on-grid power plant design installation and commissioning, the energy consumption and net electricity bill, comparison of electricity bill before and after the solar plant installation, the CO₂ mitigation, and techno-economic analysis of the plant.

2.3 Load Estimation

The approximate load analysis and the energy requirements of the commercial premises (Vardhman Hospital) are in Table 2. As mentioned in the table, the operating hours of electrical appliances in a day vary and depend upon the number of admitting and discharging patients. Some of the loads' consumption hours are fixed, and others are as per the requirements. So, here we prepare and calculate the average energy consumption of electrical appliances per day after asking the hospital manager.

Table 2

The load estimation of the commercial premises (Vardhman Hospital)
Appliance	Power Rating(W)	Quantity	Total Wattage (W)	No. of hours operated/day
LED Bulb	10	10	100	6 (fixed)
LED Bulb	10	140	1400	As per requirements
Tube-light	20	4	80	4 (fixed)
Ceiling Fan	80	4	320	12 (fixed)
Ceiling Fan	80	21	1680	As per requirements
Exhaust fan	30	5	150	As per requirements
Exhaust fan	250	1	250	12 (fixed)
Room Heater	350	3	1050	As per requirements
Water Heater	700	1	700	As per requirements
Desktop Computer	150	3	450	12 (fixed)
Laptop	100	2	200	As per requirements
Air conditioner	1000	4	4000	6 (fixed)
Air conditioner	1000	10	10000	As per requirements
X-Ray (1.5- Tesla)	3000	1	3000	As per requirements
Mobile Charging Point	10	10	100	As per requirements
Printer	100	2	200	As per requirements
LED TV	250	2	500	8 (fixed)
Wi-Fi modem	40	1	40	24 (fixed)
CCTV + Monitor	80	6	480	24 (fixed)
Miscellaneous	1000	1	1000	As per requirements

2.4 PV plant performance

The performance of a PV plant is evaluated by calculating various performance parameters given by the IEC 61724 standard guidelines (1998). The authors summarized and tabulated the performance parameter [12]. The following formulas have been used for solving these parameters for the PV plant is in Table 3.

Table 3

The description of on-grid plant performance parameters
Performance Characteristics / Months	Definition	Remarks
Reference Yield (Y_R)	$\:{Y}_{R}=\frac{{G}_{POA}}{{G}_{R}}$	It is the ratio of plane of array irradiance to the reference irradiance
PV Array Yield (Y_A)	$\:{Y}_{A}=\frac{{E}_{DC}}{{P}_{R}}$	Ratio of actual array output to the rated capacity of the array
PV Final Yield (Y_F)	$\:{Y}_{F}=\frac{{E}_{AC}}{{P}_{R}}$	Defined as the actual output ac energy to rated capacity of the array
Array Capture Loss (L_C)	L_A= Y_R−Y_A	Difference between reference yield and PV array yield
System Loss (L_S)	L_S = Y_A−Y _F	PV array yield minus PV final yield
Performance Ratio (PR)	$\:PR=\frac{{Y}_{F}}{{Y}_{R}}$	Ratio of PV final yield to PV reference yield

Where,

G_POA = is derived plane of array insolation in Wh/m²

G_R = is reference irradiance at STC (1000 W/m²)

Y_R = reference yield in terms of measured parameters

E_DC = is Actual array output energy in kWh.

P_R = is rated capacity of the array in kW.

E_AC = is Actual AC output energy in kWh.

Y_F = PV final yield in terms of measured parameters

A variety of solar PV simulation tools are developed by different organizations for optimal designing of solar power plants and to estimate the energy yielded. The PVsyst simulation software is use in this research article to find the performance analysis of the plant using various parameters explained below. We have chosen photovoltaic geographical information system (PVGIS) for a typical meteorological year (TMY) at our geographical location to collect weather data. The monthly irradiance, temperature, PV array energy, grid injected energy and the performance ratio detailed in Table 4. The plane of array (POA) irradiance in a year is approximately 2230 kWh/m² falling over the surface of the PV array. The PV array energy generation in a year is 27727 kWh/year and the 27271 kWh/year of energy injected into the grid. The basic performance parameters and the system losses are in Table 5. The average annual performance ratio of the plant is 82.3%.

Table 4

PVsyst simulation balances and main results
Parameters / Months	Global Horizontal Irradiance (kWh/m²)	Diffused Horizontal Irradiance (kWh/m²)	Ambient Temperature (°C)	POA (kWh/m²)	GlobEff (kWh/m²)	PV Array Energy (kWh)	Grid Energy (kWh)	Performance Ratio (PR)
Jan	152.4	47.62	20.56	201	198	2572	2532	0.842
Feb	156.4	45.33	22.31	191.2	188	2404	2368	0.828
Mar	202.6	56.92	28.61	221.4	217.6	2688	2647	0.799
Apr	224.1	60.73	33.28	221.3	217	2620	2579	0.779
May	217.9	74.43	36.69	199.8	195.5	2368	2328	0.779
Jun	195.9	80.75	34.31	174.6	170.7	2117	2080	0.796
Jul	111.7	75.83	26.22	102	99.4	1317	1287	0.843
Aug	149.1	87.47	26.69	143.3	140.2	1834	1798	0.839
Sep	158.6	74.64	26.57	165.2	162.2	2089	2052	0.83
Oct	173.8	59.44	26.16	201.6	198.4	2517	2476	0.821
Nov	159.9	42.68	21.82	207.9	205.1	2629	2590	0.833
Dec	147.8	43.35	20.53	201	198.2	2572	2534	0.843
Year	2050.1	749.2	26.99	2230.4	2190.3	27727	27271	0.817

The monthly global horizontal irradiance, the diffuse horizontal irradiance and the plane of array (POA) irradiance throughout the year at our location is in Fig. 4. The POA is lowest in the month of July and the maximum in the months of March, April and May with comparison to the other months respectively. The monthly generation of the plant and the exported energy to the grid is shown in Fig. 5 the lowest energy generation in the month of July is around 1300 kWh and 2700 kWh in the month of March. The various normalized performance coefficients of on-grid power plant are tabulated in Table 5. The average annual performance ratio of the plant is 0.823.

Table 5

Normalized performance parameters of on-grid power plant using PVsyst software
Performance Characteristics / Months	Reference Yield (Y_R)	PV Array Yield (Y_A)	PV Final Yield (Y_F)	Array Capture Loss (L_C)	System Loss (L_S)	Performance Ratio (PR)
Jan	6.34	5.44	5.36	0.9	0.08	0.844
Feb	6.82	5.7	5.62	1.12	0.09	0.824
Mar	6.78	5.62	5.54	1.16	0.09	0.817
Apr	7.41	5.92	5.82	1.5	0.09	0.785
May	6.45	5.16	5.07	1.3	0.09	0.785
Jun	5.77	4.72	4.63	1.06	0.08	0.803
Jul	3.22	2.79	2.73	0.42	0.06	0.848
Aug	3.97	3.43	3.36	1.54	0.07	0.847
Sep	5.52	4.68	4.6	0.84	0.08	0.833
Oct	6.66	5.61	5.52	1.05	0.09	0.829
Nov	6.9	5.87	5.79	1.03	0.09	0.838
Dec	6.46	5.56	5.48	0.9	0.08	0.848
Year (Avg.)	6.02	5.03	4.95	0.98	0.08	0.823

Figure 6 demonstrates PVsyst software's predicted loss diagram for the entire year. As we can see, the highest losses have happened due to temperature (-12.30%), inverter loss during operation, efficiency (-1.63%), and PV loss due to wires (-1.26%). Most of the losses in production power occur in the PV array, as it is influenced by several parameters such as sun exposure, ambient temperature, ohmic wiring, and manufacturing mismatch. The total PV array losses are 17.69%, resulting in a power drop of 32673 kWh to 27343 kWh.

The expected life cycle of the PV module is around 30 years claimed by manufacturers. Figure 7 provides an explanation and illustration of the CO₂ emissions that the plant mitigates during its 30-years of life cycle. Approximately 600 tonnes of CO₂ are mitigated throughout the plant's lifespan, and in five years, 100 tonnes of CO₂.

Once the simulation study over plant design initiated. This plant is a self-owned system with upfront investment and no subsidy by any of the India's state or central government agency. The actual size of the on-grid power plant is 15.13 kWp, operating since June 2022. The detailed plant design is shown in Fig. 8. The PV module and the inverter technical specifications are given in Table 1. A total of 34 PV modules in the plant are divided into two strings, each of 17 PV modules connected parallel to the 2-MPPT of inverter through DCDB, inside DCDB 16A connector with SPD attached. The output of the inverter is connected to ACDB with a 16A connector with SPD. ACDB output goes to the grid via a generation meter, and the CSPDCL synchronizes the net meter. The net-metering scheme of the state DISCOM is the unit-by-unit reduction of consumed electricity every month. Suppose the energy generation by the solar PV plant is higher than the consumed electricity for a month. In that case, it will be carried forward and adjusted for a whole financial year in the forthcoming month by existing policy CG government. And for the next financial year, this will be repeated in the same manner as before.

4.1 Inter-row spacing of PV module

A significant task in the PV plant installation is determining how much distance you should keep between neighboring rows of PV modules (the pitch). If the pitch is high, the required area will increase; if the pitch is low, there will be significant losses due to inter-row PV module shading. The variation of the sun's path throughout the year at plant location is given in Fig. 9. The sun chart diagram shows the sun's daily, monthly, and yearly path. In our case, the PV array rests on elevated structure around 12 feet from the rooftop and 42 feet from the ground is adequately spaced, and the values of the parameters mentioned clearly in Fig. 10.

To find the pitch distance, we calculate sun angle and sun azimuth for maximum working hours of solar system at our location. This can be picked from sun path diagram Fig. 9 and assume the maximum exposure for solar panel is for 9:00 am to 3:10 pm.

Where,

PV module tilt angle, α = 23⁰

Solar Elevation, β = Changing from morning to evening

Length of the PV module, L = 212 cm

Lower height of the PV Module from surface, h = 15 cm

Upper height of the PV Module from surface, H = 92 cm

Sun angle (According to start time) = 27⁰

Sun Azimuth (According to start time) = 48⁰

d = sin (α) * panel-length * cos (sun azimuth) / tan (sun angle) ………. (1)

Distance between pitch (two rows), d = 113.6 cm

Total horizontal space occupied by two rows of PV modules, D = d + L*cos(α) * 2 = 503.89 cm ………. (2)

4.2 Electricity consumption & solar PV plant generation

The net electricity consumption (kWh) and energy charge (electricity bill) of the premises from April 2021 to March 2024 is given in Table 6. The solar PV plant installation happens in June 2022. The monthly comparison of energy consumption before and after plant installation shows a clear difference in the energy charges paid by consumer.

Table 6

The utility electricity bill from April 2021 to March 2024 showing the consumption and the net electricity bill
Bill Month	Consumption (in kWh)	Energy Charge in ₹ ($)	Electricity Cost (per kWh) in ₹ ($)	Fixed Charge in ₹ ($)	Net Bill in ₹ ($)
Mar-24	870	6568 (79.13)	7.55 (0.09)	5600(67.23)	5600(67.23)
Feb-24	540	4077 (48.94)	7.55 (0.09)	5600(67.23)	5600(67.23)
Jan-24	630	4756.5 (57.10)	7.55 (0.09)	5600(67.23)	5600 (67.23)
Dec-23	540	4077 (48.94)	7.55 (0.09)	5600(67.23)	5670 (68.07)
Nov-23	642	4847.1 (58.19)	7.55 (0.09)	5600(67.23)	5600 (67.23)
Oct-23	1029	7768.95 (93.26)	7.55 (0.09)	5600(67.23)	5600 (67.23)
Sep-23	828	6251.4 (75.05)	7.55 (0.09)	5600(67.23)	5600 (67.23)
Aug-23	711	5368.05 (64.44)	7.55 (0.09)	5600 (67.23)	5870 (70.47)
Jul-23	900	6795 (81.57)	7.55 (0.09)	5600 (67.23)	8350 (100.24)
Jun-23	1110	8380.5 (100.61)	7.55 (0.09)	5600 (67.23)	8640 (103.72)
May-23	1860	14043 (168.58)	7.55 (0.09)	5600 (67.23)	8500 (102.04)
Apr-23	1050	7927.5 (95.17)	7.55 (0.09)	5600 (67.23)	5600 (67.23)
Mar-23	690	5209.5 (62.54)	7.55 (0.09)	5600 (67.23)	5400 (64.83)
Feb-23	630	4756.5 (57.10)	7.55 (0.09)	9000 (108.04)	9100 (109.24)
Jan-23	480	3624 (43.51)	7.55 (0.09)	9000 (108.04)	19390 (232.77)
Dec-22	660	4983 (59.82)	7.55 (0.09)	9000 (108.04)	10140 (121.73)
Nov-22	720	5436 (65.26)	7.55 (0.09)	9000 (108.04)	9960 (119.57)
Oct-22	720	5436 (65.26)	7.55 (0.09)	9000 (108.04)	10070 (120.89)
Sep-22	1050	7927.5 (95.17)	7.55 (0.09)	9000 (108.04)	10450 (125.45)
Aug-22	1110	8380.5 (100.61)	7.55 (0.09)	9000 (108.04)	11930 (143.22)
Jul-22	1170	8833.5 (106.04)	7.55 (0.09)	9000 (108.04)	14250 (171.07)
Jun-22	3419	25813.45 (309.89)	7.55 (0.09)	9000 (108.04)	39090 (469.27)
May-22	3277	24741.35 (297.02)	7.55 (0.09)	9000 (108.04)	35460 (425.69)
Apr-22	3020	22801 (273.72)	7.55 (0.09)	9000 (108.04)	35310 (423.89)
Mar-22	1440	10656 (127.92)	7.40 (0.09)	9000 (108.04)	20540 (246.58)
Feb-22	981	7259.4 (87.15)	7.40 (0.09)	9000 (108.04)	16750 (201.08)
Jan-22	1051	7777.4 (93.37)	7.40 (0.09)	9000 (108.04)	17360 (208.40)
Dec-21	1010	7474 (89.72)	7.40 (0.09)	9000 (108.04)	17090 (205.16)
Nov-21	1023	7570.2 (90.88)	7.40 (0.09)	9000 (108.04)	42390 (508.88)
Oct-21	1907	14111.8 (169.41)	7.40 (0.09)	9000 (108.04)	24820 (297.96)
Sep-21	1882	13926.8 (167.19)	7.40 (0.09)	9000 (108.04)	24610 (295.44)
Aug-21	1915	14171 (170.12)	7.40 (0.09)	9000 (108.04)	24720 (296.76)
Jul-21	1760	12760 (153.18)	7.25 (0.09)	7560 (90.76)	21490 (257.98)
Jun-21	2054	14891.5 (178.77)	7.25 (0.09)	7560 (90.76)	24130 (289.68)
May-21	2492	18067 (216.89)	7.25 (0.09)	7560 (90.76)	21640 (259.78)
Apr-21	5014	36351.5 (436.39)	7.25 (0.09)	7560 (90.76)	72380 (868.91)
*The values in brackets are in USD as per the Rupee-Dollar exchange rates on 06 April 2024

The plant installation and commissioning happen in the month of June 2022. The average net electricity bill in the month of July 2022 and onwards is around Rs. 8425 only.

4.3 Energy demand and net electricity bill

In our case, one of the major advantages of installing the PV plant to the owner is that, they can reduce their maximum demand load as per requirements as well as there is a reduction of fixed charge by reducing the sanctioned load of CSPDCL for the premises. The maximum demand load by the consumer up to 33 kW but just after installation of the PV plant the maximum demand load by the consumer is reduced and varying between 6 kW to 15 kW. The maximum demand load is reduced more than 50% that we can say the customer dependency to the local DISCOM is minimized by 50%. Earlier the sanctioned load of the premises was 56 kW, but after the solar installation, sanctioned load is reduced to 33kW.The customer has to pay 80% of the sanctioned load as fixed charge with a rate of Rs.200 per kW as per electricity board norms for the commercial utility. Earlier the customer used to pay Rs. 9000 on fixed charge and now he does 5600 on fixed charge i.e. the fixed charge of the customer has been reduced by approximately 40%, if we compare with earlier. The detail of electricity bill for the consecutive three years from April 2021 to March 2024 with and without solar PV plant is given in Fig. 11. One can also have the observation from the figure, in the year 2022 -23 and onwards, the energy charge has been suddenly reduced as compared with 2021–2022.

5.1 Solar PV Plant Payback Period

There are many economic performance metrics [17] out of which paper uses simple payback period. The time required to recover the funds expended in a PV plant as an investment calls it a payback period. The actual size of the installed on-grid power plant is 15.13 kWp, and the cost is around ₹ 900000. The solar PV plant's energy in the first year is around 20226 units (kWh). The operation and maintenance of the plant is only for cleaning the PV modules; no other part involved is around ₹ 16000. The electricity bill per unit CSPDCL costs around ₹ 9, including all charges. The consumer indirect benefit tax relief is 40% on depreciation acceleration (Under section 32 of the Income Tax Act., GoI). This installation will be equivalent to planting 738 Teak trees over the lifetime, and carbon dioxide emissions mitigated is 461 tonnes (Data from IISc) [2].

Total plant costs in a very first year = Actual plant cost (₹ 900000) + operation & Maintenance Cost (₹ 16000)

Total plant costs in a very first year = ₹ 916000

The cost of energy generated by the solar PV plant in the very first year = Energy generated by the solar PV plant in a year (20226 units) * CSPDCL Rate (₹ 7.55)

The cost of energy generated by the solar PV plant in the first year = ₹ 152706.

Hence, the payback period is around (~ 916000/152706) 5.9 years for the proposed 15kWp on-grid elevated solar power plant.

This paper presents a detailed analysis of the load profile of premises, the consumption before and after the on-grid plant with a net-metering scheme installed at the rooftop of Vardhman Hospital, Durg, Chhattisgarh (21°11' N, 81°17' E) using elevated structure and the analysis of PVsyst simulation results. According to the objective of this research article, the on-grid plant design, installation, and commissioning was discussed. The energy consumption bill presented by Distribution Company before and after the net-metering scheme to the on-grid solar PV power plant is discussed. From last four months the consumer only pays the fixed charge of ₹5600/- to the local DISCOM Company. The detailed PVsyst simulation result of the plant is discussed. The plane of array (POA) irradiance in a year is approximately 2230kWh/m² falling over the surface of the PV array. The PV array energy generation in a year is 27727 kWh/year and the 27271 kWh/year of energy injected into the grid. The cost of energy generated by the solar PV plant in the first year is approximately ₹ 182034 /-. The payback period for the proposed 15 kWp on-grid elevated solar power plant is around 5.03 years. The PV plant installation will be equivalent to planting 738 Teak trees over the lifetime, and carbon dioxide emissions mitigated is around 461 tons.

This research article is more beneficial and useful guidelines for decision-makers, engineers, system integrators and industrial companies in this region to install and commission such kind of on-grid solar power plant with a net-metering scheme.

Some of the influential factors which will consider by the PV engineer or system integrator (SI) before the plant design, installation and commissioning for maximum energy yield and reduce payback period of the plant are given below:

Type of PV module

A solar cell or photovoltaic cell is a device that converts the sunlight into usable energy. Commercially half cut mono PERC (M10) PV modules are available with 21% efficiency with latest technology. It is better to use the latest technology PV modules with higher efficiency.

Pitch of PV row

Tilt of PV modules

The tilt of the PV array is important at the point of energy generation, and the tilt angle of the PV array approximately the latitude of the site where you want to install your plant.

Array Design and Balance of system (BoS) losses

The on-grid power plant design is totally dependent on the inverter technical datasheet. Proper system design leads to overall very low losses.

Cleaning frequency of PV modules

The cleaning frequency of the PV plant depends on the location of the plant site. In general, the PV modules are cleaned at least once every fifteen days. Use water and a soft sponge or cloth for cleaning, do not use detergent or any abrasive material for panel cleaning. At last, the visible inspection is required to clean the PV module with respect to intensity of dust deposition over the surface of the PV modules.

Author Contribution

SKS contributed to methodology, design, installation, data analysis, writing, original draft preparation, and software simulation. NC contributed to supervision, methodology, and writing—reviewing and editing. AS contributed to the supervision and power plant access to collect the data.

Acknowledgement

The authors thank Dr. Prafulla Jain (Director), Mr. Sachin Jain for his support in accessing the solar PV plant at Vardhman Hospital, Durg. Authors also thank to Mr. Nitish Sinha (Technical Staff, AEPL), Mr. Thandoolal (Technical Staff, TYadoba Solutions Pvt. Ltd.) for their immance support.

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No competing interests reported.

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Design and techno-economic analysis of a 15 kWp grid-tied net-metering solar photovoltaic power plant utilizing half-cut monocrystalline-PERC Si modules with elevated rooftop structure

Status:

Version 1

Abstract

Figures

1 Introduction

2 Materials and methods

2.1 Installed Plant Overview / System Design with BoS

2.2 Methodology

2.3 Load Estimation

2.4 PV plant performance

3 PVsyst simulation

4 Plant design installation & commissioning

4.1 Inter-row spacing of PV module

4.2 Electricity consumption & solar PV plant generation

4.3 Energy demand and net electricity bill

5 Techno-economic analysis

5.1 Solar PV Plant Payback Period

6 Conclusions

7 Recommendations

Declarations

Author Contribution

Acknowledgement

References

Additional Declarations

Status:

Version 1

Performance Characteristics / Months	Definition	Remarks
Reference Yield (Y_R)	\(\:{Y}_{R}=\frac{{G}_{POA}}{{G}_{R}}\)	It is the ratio of plane of array irradiance to the reference irradiance
PV Array Yield (Y_A)	\(\:{Y}_{A}=\frac{{E}_{DC}}{{P}_{R}}\)	Ratio of actual array output to the rated capacity of the array
PV Final Yield (Y_F)	\(\:{Y}_{F}=\frac{{E}_{AC}}{{P}_{R}}\)	Defined as the actual output ac energy to rated capacity of the array
Array Capture Loss (L_C)	L_A= Y_R−Y_A	Difference between reference yield and PV array yield
System Loss (L_S)	L_S = Y_A−Y _F	PV array yield minus PV final yield
Performance Ratio (PR)	\(\:PR=\frac{{Y}_{F}}{{Y}_{R}}\)	Ratio of PV final yield to PV reference yield