Optimizing energy savings for Taylor’s University electrical distribution system
Cite as: AIP Conference Proceedings 2233, 030006 (2020); https://doi.org/10.1063/5.0001583 Published Online: 05 May 2020
Yen Ling Lai, Chockalingam Aravind Vaithilingam, and Reynato Andal Gamboa
Optimizing Energy Savings for Taylor’s University Electrical Distribution System
Yen Ling Lai
1, Chockalingam Aravind Vaithilingam
1,a), Reynato Andal Gamboa
11Taylor’s University, 1 Jalan Taylor’s, 47500, Subang Jaya, Selangor, Malaysia
a)Corresponding author: chockalingamaravind.vaithilingam@taylors.edu.my
Abstract. In this epoch of modernization, most of the functions and comforts in this world are entirely dependent on electricity and the demand is increasing. Hence, it is almost impossible to imagine our lives without electricity. In consequence, the global warming issue is rising and thus causing an adverse impact to the public health and the environment. Nevertheless, by applying the clean technology like the photovoltaic (PV) system, reduction in greenhouse gases (GHG) and energy efficiency can be achieved for sustainable development in Malaysia. Energy audit was performed by the professionals in Taylor’s University Lakeside Campus (TULC), but the energy savings strategy proposed can be further enhanced by utilizing the PV system which the assessment will be done in this research. Through evaluation of the design aspects like sizing of PV array, layout planning, load profiling, could give us an insight on the technical feasibility of PV system in TULC. The layout design will be configured by using the Helioscope software. Other than that, sizing of the PV array together with the performance analysis and loss diagram will be done by using PVsysts software. In evaluating of business value in adopting the PV technology in TULC, it provides an apprehension on its economic viability, which is essential as it often becomes the key parameter for the management, stakeholder, or potential investors to properly measure the value of the project can deliver to the society. Financial analysis will be conducted in various methods such as estimating the Return of Investment (ROI) and payback period. As a result, it is to be expected that the impact on the energy and cost saving for TULC will be evaluated via the optimization of energy consumption by the PV system.
INTRODUCTION
In the recent years, the rise in energy is directly correlated with the booming population and massive developments, especially in the developed countries as well as the progressive countries. According to the World Green Building Council [1], building sector is one of the major factors that cause global warming and it also consume most energy as compared to the other sectors such as the industry and transport [1]. Global warming is one of the most precarious environmental issues in the world which is instigated by the emission of greenhouse gases (GHG) such as carbon dioxide. In terms of GHG emissions, Malaysia is said to be high among the other developing countries in the Southeast Asia. Research has been done by Shahid [2] and found out that the per capita GHG emission of Malaysia is around 3.5 times of the values of Indonesia and 1.6 times of the value of Thailand. They are emitted as a form of air pollutants and are produced from burning of fossil fuels [3]. Air pollution like this is undoubtedly detrimental to public health and bring negative impact to the environment. Aside from that, Malaysia currently is still highly dependent on the non-renewable energy (NRE) sources such as the fossil fuels and natural gas [4]. However, NRE is still controversial due to the issue of their pricing, environmental impact, and limitation of the source. Imagine as population increases, the building demand increases, and energy demand increases at the same time. If the NRE to conventional sources were to be exploited, there will surely be one day when they are depleted. On the other hand, renewable energy (RE) serves as an alternative energy source. There are currently few types of RE in Malaysia, for instance, hydropower, biomass, biogas, geothermal, and solar.
Solar power is produced by converting the solar energy to electrical energy. It has high potential in providing a cleaner and greener environment with zero GHG emission. Dealing with RE like solar can be an advantage since Malaysia is located in the equatorial region, which bring this strategic location to have high solar irradiation for at least 6 hours sunlight every day even though with the covering of the clouds [5]. Other than that, because there is no
seasonal change in this country due to the geographical factor, the solar irradiation is constant as compared to other countries that have four seasons. This can be proven as there are emerging new large-scale solar projects (LSS) and the residential or commercial rooftop PV installation.
Furthermore, the government is planning some prudent strategies to reduce the emission by encouraging the usage of RE and creating awareness to the public about it. Moreover, incentives were provided by the government in order to support the growth in the renewable energy and energy efficiency. As mentioned earlier, the society has shown more interest to the energy efficient and energy conservation. This is because people realized of the adverse environmental effects caused by the exploitation of NRE. Consequently, people are currently trying to find a cleaner and sustainable option like RE. Taylor’s University Lakeside Campus (TULC) too have gained much concern to the issues raised. TULC is served by 4 distribution transformers with a total maximum demand of 36732 kW. As the subject need to be dealt fairly, energy consumption of TULC in each month of 2017 will be analyzed in detail. Based on the energy bill, the average total electricity consumption is 999.21 kWh per month, starting from January to December. The load curve of the transformers in TULC based on energy audit data which is the maximum active power of each transformer have been plotted as shown in Figure 1.
FIGURE 1. Load Curve of Transformers in TULC
Based on Figure 1, during the period of 12:00 a.m. till 7:25 a.m., the load consumption is the lowest. The load consumption starts to increase gradually at around 7:30 a.m. when the university starts the day and decrease slowly from 8:30 p.m. when there is lesser academic activities. The peak hour of total electricity consumed for the transformers is roughly around 1:30 p.m. In this university compound, it comprises of 6 blocks in total, which are known as the commercial Syopz Mall block, Block A, Block B, Block C, Block D, and Block E. There are 4 transformers in the buildings. The highest proportion of the total energy consumed is usually by the chiller, the commercial block as well as the hospitality block. Based on the monthly electricity bill of TULC, the average maximum demand is 3061kW out of the 12 months in Year 2017. The utmost concerned is that, TULC need to spend the amount of RM476612.10 on average of Year 2017 and RM494,342.43 just for the electricity bill as reference to the latest electricity bill in October 2019.
Although an actual energy audit was conducted at TULC, further optimization of the energy can be achieved by utilizing the PV system. It is not just to save energy, but it is also to save costs at the same time. Potential energy savings can be found in reducing the load consumption through PV system, especially during the peak operating hours together with the consideration of PV panels effective time which is within the estimated time frame of 9:00 a.m. till 5:00 a.m. Financial analysis can be done to justify how cost reductions can be realized through the efficient use of energy. Investing on PV system promises a good ROI as solar energy is a potential cost-effective energy source.
Focusing on the commercial buildings in Malaysia, integration of the energy savings into business practice can be attained via PV system.
By applying the PV system in TULC, it is in fact a cooperative effort to support the government blueprint at the same time. Regardless of being a net oil-exporting country in ASEAN [6], Malaysia is still compelling to pursue for the renewable and sustainable energy alternatives. Utilization of the RE such as solar energy which ensure an adequate
0 500 1000 1500 2000
12:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00
Energy Consumption (kW)
Time
Load Curve of Taylor's University
Transformer 1, T1 Transformer 2, T2 Transformer 3, T3 Transformer 4, T4 Total Transformer
and secure energy sources as it plays a role in the energy cycle to minimize the negative impacts to the environment.
All in all, this paper is mainly to evaluate the viability of the PV system in Taylor’s University from the technical and financial aspects based on the results of PV system design sizing and cost analysis.
Thus, in this research, it is to assess the viability of adopting a PV system in optimizing the energy savings for TULC. There are to objectives to be achieved from this research, which is to conduct assessment on the design requirements and evaluate the impact of PV system in energy and cost savings for TULC. The scope of this project is accentuated to design factors of the PV system on the economic and technical analysis by using the software like PVsysts, Helioscope and AutoCAD.
RESEARCH METHODOLOGY
The energy consumption data can be collected from the energy bill of TNB. The data obtained from the energy audit were analyzed. Load profile of Transformer 1 to Transformer 4 of Monday to Sunday were plotted from the load consumption data. The load profile plotted were further analyzed to optimize the electricity generation. The most suitable transformer will be suggested among the four transformers to be tapped on after analyzing the load curve.
The brand and size of the solar panels and the inverters were determined based on the comparison done. Other than that, in order to identify the suitable location and sizing of the PV system, two software were used in modelling the PV system performance which are PVsyst and Helioscope. This software is commonly used in the industry sectors to predict the performance of the PV system. Helioscope will be used to configure the layout design of the system. It consists of the module model design, inverter model design, racking geometry and layout. The PV array sizing results are based on the simulation of the annual energy estimation by settings of azimuth, tilt, setbacks, row spacing and so on. When the configuration of the layout is completed by using Helioscope, the selected panels and inverter were used as the parameter setting,
In the project design, PVsysts software was used to perform a thorough system design and performance analysis by using the detailed hourly simulations. It was built through the framework of the project that contains the data of the geographical situation and meteorological hourly data. Through few sets of variants that is run as the simulation of different setting of parameter, optimizations and parameter analysis can be performed. PV array sizing is performed by defining the choice of the PV modules in the library and the specification of losses. Loss diagram is the summary of the results as it provides a quick insight into the quality of the design after identifying the main sources of the losses for the whole year. Finally, system simulation by hourly steps will be performed and its results will be a complete engineer report that can be further completed with the economical evaluation.
Upon obtaining the simulated system report from PVsysts, financial analysis can be completed. With the system price and tariff rate, the payback period was calculated. The impact of cost savings and energy savings were calculated and emphasized. The single line diagram of the system design is drawn in AutoCAD for a better overview on the specifications. However, there are some limitations due to this research. Solar energy can only be used during daylight hours in electricity generation. There is uncertainty exists in the system performance because it is still strongly dependable to the environment such as the rain, bird droppings and many other unexpected conditions that may be encountered but their impact are relatively small and can be ignored.
RESULTS
Solar Panel and Inverter Sizing
To begin with the solar design, solar panel and inverter will need to be confirmed. In terms of brand and model, their price and availability in the local suppliers is much concerned. In terms of rating of the panel and inverter, there are a few important factors that need to be considered, including physical space on the roof, and the electrical sizing of tariff. Upon selection, the information on the panel and inverter can be referred from the datasheet or the warranty certificate. There are two most common type of solar panel which are Monocrystalline Solar Panels (Mono-Si) and Polycrystalline Solar Panels (p-Si). Even though Mono-Si cells have slightly higher efficiency of 15-22% than then conventional p-Si cells, Mono-Si is much more expensive than p-Si [7]. From a financial standpoint, solar panels that is made of p-Si can be a better choice due to its cost-effectiveness. There are various PV module brands such as Canadian Solar, Longi, Q cell, Risen, Trina Solar, and many more. It is important to make a comparison of the module brand to select a more suitable brand which is appropriate to be applied in this project.
TABLE 1. Comparison of Panel Brand
Brand RISEN Trina Jinko JA
Power Class 340 340 340 340
Product Name
Polycrystalline Module 340Wp
72 Cells
Polycrystalline Module 340Wp
72 Cells
Polycrystalline Module 340Wp
72 Cells
Polycrystalline Module 340Wp
72 Cells
Model number(s) RSM72-6-340P
PE14A FRAMED 72-CELL MODULE
(1500V)
Eagle 72P-V 340WATT
JAP72S09 340/SC
Panel technology Poly Poly Poly Poly
Company origin Risen Energy Trina Jinko JA Solar
Maximum power (W) 340 340 340 340
Open circuit voltage (Voc) 46.1 46.2 47.5 46.39
Short circuit current (Isc) 9.5 9.42 9.22 9.48
Voltage at max. power
(Vmpp) 37.8 37.8 38.2 37.74
Current at max. power
(Impp) 9 8.99 8.91 9.01
Panel efficiency 17.50% 17.50% 17.52% 17.20%
Panel weight 22kg 22.5kg 22.5kg 22.3kg
Operating temperature -40°C~+85°C -40°C~+85°C -40°C~+85°C -40°C~+85°C Temperature coefficient
(Pmax) -0.39%°C -0.41%°C -0.38%°C -0.4%°C
Product warranty length 12 years 10 Years 10 Years 12 years
Max. system voltage 1500V 1500V 1500V 1500V
TABLE 2. Comparison of Panel Rating
Company origin Risen Energy Risen Energy Risen Energy Risen Energy Risen Energy
Maximum power (W) 340 345 345 350 355
Open circuit voltage (Voc)
46.1 46.3 46.5 46.7 46.9
Short circuit current
(Isc) 9.5 9.6 9.5 9.6 9.7
Voltage at max.
power (Vmpp)
37.8 37.95 38.8 38.95 39.1
Current at max.
power (Impp) 9 9.1 8.9 9 9.1
Panel efficiency 17.50% 17.80% 17.30% 17.60% 17.80%
Panel weight 22kg 22kg 23kg 23kg 23kg
Operating
temperature -40°C~+85°C -40°C~+85°C -40°C~+85°C -40°C~+85°C -40°C~+85°C Temperature
coefficient (Pmax) -0.39%°C -0.39%°C -0.39%°C -0.39%°C -0.39%°C Product warranty
length 12 years 12 years 12 years 12 years 12 years
Max. system voltage 1500V 1500V 1500V 1500V 1500V
Dimension 1956x992x40
mm
1956x992x40 mm
2010x992x40 mm
1956x992x40 mm
1956x992x40 mm
The panel chosen is Risen Energy RSM 144-6-355P[8] due to its availability in Malaysia reliable local supplier and it has high efficiency of 17.80%, long product warranty period of 12 years. The inverter chosen is Sungrow SG- 60KTL due to its availability in the Malaysia local supplier and it provide enough power to the system. Other than that, the brand of Risen is chosen as it is the Top 3 solar module manufacturers in the 1Q 2019 Global PV Market Outlook Bloomberg NEF’s tier 1 criteria[9], and it is available in Malaysia reliable local supplier.
System Capacity Based on Rooftop Sizing
The site location will be at Taylor’s University Lakeside Campus Block A building with the latitude and longitude of 3.064846, 101.617144 respectively or 3°03'53.5"N 101°37'01.7"E that is obtained from Google Map.
FIGURE 2. Site Location
The capacity of the physical roof space of the building on Block A is obtained by using Helioscope software. The different panel rating has different physical dimension and thus it will affect the space available to place the panels.
As for the roof condition, the roof plan is obtained from the chargeman of TULC so that the results that have been analysed through Helioscope software will be more practical. In industrial practice, access to the roof is important to check out the roof condition. There is little useful information that has been extracted from the interview with the chargeman as well as the roof plan provided. It can be summarized in the Table 3.
TABLE 3. Rooftop Information
Specifications Information
Height of the building (m) 15
Type of Roof Metal Deck
Roof Tilt (°) 5
Any shading caused by obstacles?
(eg.exhaust fan) Yes. It has taken into the design consideration.
Any skylight available? Yes. It has taken into the design consideration.
The height of the building of Block A is approximately 15 metres. The type of roof is metal deck and its tilt is 5°.
On the rooftop, there is only one area that is suitable for the application of PV system which is shown in Figure 3.
Shading profile is not required in this case because the skylight and shading are being avoided during design stage.
FIGURE 3. Layout Design using Helioscope
Upon grasping all the necessary information, the design and layout of the solar system are done by using Helioscope software as shown in Figure 3. Module layout is a tool for the description of the panels geometrical arrangement, their interconnections and the strings. Based on the layout, with the total area of 1,693.0m2, 440 modules of solar panels will be placed on the site location rooftop. As an output, 156.2 kWp of capacity based on rooftop is designed. The arrangement of the modules will be 20 in series and 22 in parallel.
Load Curve Analysis
FIGURE 4. Load Curve of Transformer 1 on Thursday 0
100 200 300 400 500 600 700 800
12:00 12:40 01:20 02:00 02:40 03:20 04:00 04:40 05:20 06:00 06:40 07:20 08:00 08:40 09:20 10:00 10:40 11:20 12:00 12:40 13:20 14:00 14:40 15:20 16:00 16:40 17:20 18:00 18:40 19:20 20:00 20:40 21:20 22:00 22:40 23:20
ENERGY CONSUMPTION (KW)
TIME
LOAD CURVE
Transformer 1, T1 Energy Saved
Among the daily load curves of the four transformers in TULC, Transformer 1 is chosen to be further investigated and analysed. It is because of its closest distance to the PV location. Other than that, Transformer 1 has the highest load consumption with an average peak of 700kW as compared to the other transformer. The Thursday load curve is chosen as it simulates the typical operation. 156kW of energy per day will be produced which is also meant that 165kW of energy will be saved daily after applying the PV system in TULC.
Performance Analysis Using PVsysts Software
FIGURE 5. Normalized Productions (per installed kWp)
Estimated performance monthly as shown in Figure 5 can be analysed using the PVsyst software. In normalized performance index, the array nominal installed power at standard test condition (STC) with the global irradiance in outdoor conditions of 1000W/m2 [10] which is obtained from the PV-module manufacturer. Collection loss (Lc) is the array losses which include the module quality, mismatch and soiling, as well as other inefficiencies. System loss (Ls) is the inverter losses in the grid connected system. System Yield (Yf) is the daily useful energy in the system.
FIGURE 6. Performance Ratio PR
Performance ratio (PR) is a crucial parameter of a PV system, particularly for the investor’s focus. As an outcome of using the PVsysts software, the performance ratio is 79.3%, which meant that there are 20.7% energy generated
through the PV panels is lost in the system losses. The energy produced will be 197253kWh/year with a specific production of 1263kWh/kWp/year.
FIGURE 7. Loss Diagram Over the Whole Year
The PV array loss factor such as the array soiling losses, wiring ohmic loss, module quality losses, module mismatch losses and so on is as shown in Figure 8. One of the detailed losses set is called soiling loss, it is due to rain, dust and bird droppings and other environmental conditions on the PV modules. Another loss is the module quality loss that is based on the manufacture’s technical specifications and +0.5% is considered an estimated quality gain.
Light Induced Degradation (LID) is the degradation of the modules at the first exposure to light. Based on the general industry experience, Tier-1 modules commonly has the LID of 0.8% to 1.5%[11]. Inverter loss during operation is the loss of power of the inverter converting its power from DC to AC. AC ohmic losses is the loss in the cable from the inverter to the substation.
FIGURE 8. Single Line Diagram of the PV System
By using AutoCAD software, the single line diagram of the PV system designed is being constructed for better understanding with the visual aid tool as shown in Figure 8. It shows briefly how the 440 modules are connected to 2 inverters as well as into the meter and grid. There will be 11 strings and 220 modules connected in one inverter and the two inverters are in parallel to each other.
Financial Analysis
Cash Modelling is the key to indicate the impact of cost saving in a project. Financial analysis will be conducted in various methods such as estimating the Return of Investment (ROI) which show the efficiency of an investment.
The payback period is also estimated to aid in the estimation of the time taken to cover the initial cost of investment.
TABLE 4. Payback Period
Information Value Unit
System Size 156.00 kWp
Price Per kWp 3,500.00 MYR/kWp
System Price 546,000.00 MYR
Annual Specific Yield 1,263.00 kWh/kWp
Annual Solar Generation 197,028 kWh
Y1 System Performance 100.00% p.a.
Y2 System Performance 97.50% p.a.
Annual Sub. System Degradation 0.70% p.a.
TNB Tariff Rate 0.3650 MYR/kWh
ICPT Rate 0.0255 MYR/kWh
Project Payback Period 7.22 Years
Based on the calculation, payback period for this project is around 7 years. With the designed system size of 156.00kWp and quoted commercial price per kWp which is RM3,500/kWp, the system price will be RM546,000.00.
With the annual specific yield obtained from the PVsysts results based on the system size, the annual solar generation from the system will be 197,028kWh. Based on the Risen Energy warranty certificate, the end-of-first-year rated minimum output power of polycrystalline solar PV modules will not be lesser than 97.5% [12] and at the end of each year after the first year, the power output will not be decreased by more than 0.70% every year.
FIGURE 9. Return of Investment Chart (1,000,000)
(500,000) 0 500,000 1,000,000 1,500,000 2,000,000 2,500,000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
ACCUMMULATE NET SAVINGS (MYR)
YEARS 0 000
Return of Investment (ROI) Chart t - - Cash Model
Accumulate Annual O&M Fees (MYR) - ADD-ON
Accumulate Annual Return (MYR)
TABLE 5. Cost Savings
No of Years
System Performance
Solar Generation
(kWh)
TNB Tariff (MYR)
TNB Bill Savings
(MYR)
KWTB B Savings (MYR)
O&M Annual Fees (MYR)
Yearly Net Savings
(MYR)
Accumulate Net Savings
(MYR)
0 100.00% 197,028 (546,000) (546,000)
1 100.00% 197,028 0.3905 76,939 1,151 - 78,090 (467,910) 2 97.50% 192,102 0.3905 75,016 1,122 (4,423) 71,715 (396,195) 3 96.80% 190,723 0.3905 74,477 1,114 (4,423) 71,169 (325,026) 4 96.10% 189,344 0.3905 73,939 1,106 (4,865) 70,180 (254,846) 5 95.40% 187,965 0.4452 83,676 1,262 (4,865) 80,074 (174,773) 6 94.70% 186,586 0.4452 83,062 1,253 (4,865) 79,450 (95,323) 7 94.00% 185,206 0.4452 82,448 1,244 (5,351) 78,341 (16,982) 8 93.30% 183,827 0.4452 81,834 1,234 (5,351) 77,717 60,735 9 92.60% 182,448 0.5075 92,591 1,407 (5,351) 88,647 149,382 10 91.90% 181,069 0.5075 91,891 1,396 (5,886) 87,401 236,783 11 91.20% 179,690 0.5075 91,191 1,386 (5,886) 86,691 323,474 12 90.50% 178,310 0.5075 90,491 1,375 (5,886) 85,980 409,454 13 89.80% 176,931 0.5785 102,362 1,566 (6,475) 97,453 506,907 14 89.10% 175,552 0.5785 101,564 1,553 (6,475) 96,643 603,549 15 88.40% 174,173 0.5785 100,766 1,541 (6,475) 95,832 699,382 16 87.70% 172,794 0.5785 99,968 1,529 (7,123) 94,375 793,757 17 87.00% 171,414 0.6595 113,054 1,739 (7,123) 107,671 901,427 18 86.30% 170,035 0.6595 112,145 1,725 (7,123) 106,747 1,008,174 19 85.60% 168,656 0.6595 111,235 1,711 (7,835) 105,111 1,113,286 20 84.90% 167,277 0.6595 110,326 1,697 (7,835) 104,188 1,217,473 21 84.20% 165,898 0.7519 124,734 1,928 (7,835) 118,827 1,336,301 22 83.50% 164,518 0.7519 123,697 1,912 (8,618) 116,991 1,453,291 23 82.80% 163,139 0.7519 122,660 1,896 (8,618) 115,938 1,569,229 24 82.10% 161,760 0.7519 121,623 1,880 (8,618) 114,885 1,684,114 25 81.40% 160,381 0.8571 137,468 2,134 (9,480) 130,122 1,814,236 Total 4,623,853 2,479,162 37,860 (156,787) 1,814,236 With the estimated system performance over 25 years, the total cost savings after implementing this system is RM1,814,236.00.
With the accumulate net savings over the 25 years, including the Operation and Maintenance (O&M) cost the ROI chart is plotted to summarize the annualized the profitability over costs.
CONCLUSION
As the manuscript is documented, few analyses are conducted to assess how the PV system will impact the overall performance of the TULC distribution system. Technical feasibility of PV system in TULC is proven with the design and evaluation of the PV array sizing, layout design, load curve analysis, and other aspects. Helioscope software were used to configure the layout of the PV system. The PV array sizing is completed using PVsysts software with the loss diagram shown. As an outcome, 197,028kWh of energy and RM1,814,236.00 will be saved in applying PV system for optimizing the energy consumption of TULC. As for recommendation, the usage of drone can be involved in aerial survey for backup purpose of the data collection of the actual rooftop condition. There are few more losses that could be included such as the system downtime losses and other type of losses that are align with the standard design practices.
ACKNOWLEDGMENTS
The project is supported through the Taylor’s University Research Grant TRGS/MFS/1/2017/SOE/007.
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