System selection for Stand-alone S

System selection for Stand-alone S alone PV-DG Hybrid system 2th Annual Solar Energy South East Asia Dr. Wuthipong Suponthana, PhD. Leonics Co., Ltd. Thailand. Phone: +66 8 1815 3787/ Email: wuthipong@leonics.com

Agendas -DC and AC coupling PV energy systems -Efficiency of each type -Which one is better, DC or AC coupling? -Load profile impact performance and energy cost -What is the best solution? -Real performance from system in operation -Conclusion

General Electrical Power System Urban Area Power System Remote Area Power System AC coupling Stand Alone PV-WT Hybrid System DC coupling Stand Alone PV-WT Hybrid System AC SHS Stand-Alone PV Hybrid Mini-Grid Stand-Alone PV Hybrid Stand-Alone PV Hybrid Stand-Alone PV Stand-Alone PV

Stand-alone alone Hybrid Mini-Grid System Stand-alone alone -System is not connected to utility power network Hybrid -The system has more than one type of energy sources - Diesel fuel by Diesel generator - Solar energy by PV - Wind energy by wind turbine - Hydro energy by Hydro turbine - Biomass / Biogas energy Mini-Grid -There are group of users or villages who consume power from the system via local distribution line

Why the Hybrid System should be considered to implement?

Why the Hybrid System should be considered to implement? - There are people in remote area live without electricity Source: Southeast Asia Energy Outlook 2013, IEA

Simple Stand-alone alone Hybrid Mini-Grid System One Inverter, One Diesel Generator From 5 kw to 300 kw

Stand-Alone PV system Design Concept using DC Coupling : PV energy goes into system at DC Bus

Stand-Alone PV system Design Concept using AC Coupling : PV energy goes into system at AC Bus Grid Connect Inverter AC Bus Bi-Directional Inverter AC Load

AC Coupling VS DC Coupling Day time system efficiency when PV supply Load Efficiency from PV to supply load = 96% Efficiency from PV to supply load = 93.1% AC coupling Stand Alone PV-WT Hybrid System DC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter Charge Controller Inverter 96% 95% AC Load Bi-Directional Inverter AC Load 98% Real Load = Load + BDI Loss

AC Coupling VS DC Coupling Day time system efficiency when PV charge battery Efficiency of PV energy path to charge Battery = 82.08% Efficiency of PV energy path to charge Battery = 88.2% DC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter Charge Controller 96% 98% Inverter AC Load Bi-Directional Inverter AC Load 95% 90% 90% 82.08%from 100% of PV output 88.20% from 100% of PV output

AC Coupling VS DC Coupling Night time system overall efficiency when battery supply load Efficiency from PV to battery and Back to supply load = 74.07% Efficiency from PV to battery and Back to supply load = 79.6% DC coupling Stand Alone PV-WT Hybrid System Grid Connect Inverter Charge Controller 98% Inverter 95% AC Load Bi-Directional Inverter AC Load 95% 95% 95% 95% 82.08%from 100% of PV output 88.20% from 100% of PV output

- Both of them are good in different time - DC coupling is better when PV is used to charge battery - AC coupling is better when PV is used to direct supply load System Efficiency Day time charge in to Battery Day time supply to Load Night time round trip supply load DC Coupling 88.20% 93.1% 79.60% AC Coupling 82.08% 96.0% 74.07% - DC or AC coupling which one is better should be effected by Load profile that the PV system operates.

Cost of Energy comparision from using DC or AC Coupling when Load Profiles are different simulated by using HOMER

1. Uses HOMER to simulate cost of energy 2. Same load energy consumption per day 3. Same PV power, Converter, Battery capacity 4. Change Load Profile - Flat Load, - High Day time Load, - High Night time Load 5. Change PV configuration - PV on AC bus - PV on DC bus

PV AC Coupling PV DC Coupling Cost of Energy (USD/kWh)

The Hybrid DC and AC coupling can benefit by using better point of both PV at DC and AC coupling. Balance fluctuation of the Sun 96% Direct Supply load 96% form AC Coupling 98% Direct Charge Battery 98% From DC Coupling

Grid Connect Inverter MPPT Charge Controller Bidirectional Inverter

Grid Connect Inverter MPPT Charge Controller Bidirectional Inverter

The Hybrid DC and AC coupling can benefit by using better point of both PV at DC and AC coupling. Supply Night time Load With efficiency 95% form Battery 95%

MPPT Charge Controller Bidirectional Inverter

HOMER Pro simulation with DC and AC coupling with real village load profile

Hybrid DC-AC design approach Hybrid DC-AC Coupling can improve system efficient 3-7% 3 by Use AC Coupling for Day time Load Use DC Coupling to Charge Battery for Night time Load

Design DC Couple side by using nigh time energy consumption and AC Coupling side using day time energy consumption Load Profile of haminadhoo Night Day Pattern load Real load 0:00 160.14 160.14 160.14 1:00 159.36 159.36 159.36 2:00 159.19 159.19 159.19 3:00 157.34 157.34 157.34 4:00 163.41 163.41 163.41 5:00 172.91 172.91 172.91 6:00 159.77 159.77 159.77 7:00 134.07 134.07 134.07 8:00 136.86 136.86 136.86 9:00 130.50 130.50 130.50 10:00 131.74 131.74 131.74 11:00 122.52 122.52 122.52 12:00 113.62 113.62 113.62 13:00 109.95 109.95 109.95 14:00 124.35 124.35 124.35 15:00 133.20 133.20 133.20 16:00 147.33 147.33 147.33 17:00 162.66 162.66 162.66 18:00 222.78 222.78 222.78 19:00 247.30 247.30 247.30 20:00 222.51 222.51 222.51 21:00 210.96 210.96 210.96 22:00 194.16 194.16 194.16 23:00 182.50 182.50 182.50 kwh 2,709.06 1,150.07 3859.13 3859.2 Ratio 70.20% 29.80% Peak power 247.30 Average Load/h Add Increase factory 40% 160.80 Cal Average 160.8 225.12 kwh per hours

% pf PV % of Fuel Produce CO 2 100.00% 0.00% - kg/day kw 300.00 200.00 100.00 160.1 159.4 159.2 157.3 163.4 172.9 159.8 134.1 136.9 Real load Profile 130.5 131.7 122.5 113.6 110.0 124.4 133.2 147.3 162.7 222.8 247.3 222.5 211.0 194.2 182.5 Irradiation Ambient Temp. 6.37 kwh/m2.day 31.8 o C 0.00 Peak Load 247.30 kw Aver. Load 160.80 kw/h Total Load 3859.20 kwh/day Bidirectiona Inverter Grid Connected Inverter # of Inverter 250 kw 3 Units Units 300.00 1 units Back Up DG Power rating 300.00 kw AC Coupling PV 700.00 kwp Consume Diesel Fuel - Liters/day Installation Area 5967.50 m 2 Fuel Consumption rate 0.28 Liter/kWh MPPT charger Battery 9000.00 Ah 8 480 Vdc Units 240.00 Cells Annual Load Energy consumption 1,408,608 kwh Annual Energy generated form PV 1,901,181 kwh Expect Batt Life 5.95 Years Annual Diesel fuel consumption - Liters Replace fuel @ Energy Price 0.347 IPP 0.340 USD/kWh DC Coupling PV 500.00 kwp Annual Diesel fuel reduction 0 Liters Installation Area 4262.50 m 2 Annual Diesel fuel amount saving 0 USD Total Investment 2,747,641 USD Simple Pay back period 5.62 Years Project Life 18 Year Confidential information, this hybrid minigrid design is property of Leonics Co., Ltd., may not reproduce without prio notice to Leonics Co., Project IRR reduce use of fuel 10.19% IPP 9.69% % Averag daily system operation condition and consumptions Site Name : TG. Labian Project Owner : Site Location (Lat./Long.) : 5.18 o N 119.24 o E Design by Wuthipong S. Version/Rev. : 1A Date 16-Sep-14 Altitude : Meter (ASL)

MW scale Stand-Alone Hybrid Mini-Grid System (PV) = Photovoltaic Module, (I) = BDI + GCI, (B) = Battery, (DG) = Diesel Generator X.xx MW Total Power of INV+DG+PV T&C 14-Nov-12 3.30 MW Kema 850 kwp (PV) 850 kw (I) 4,800 kwh (B) 1600 kw (DG) 3.45 MW T&C 25-Jan-14 Bario 906 kwp (PV) 1,100 kw (I) 3,860 kwh (B) 1,443 kva (DG) 4.93 MW Banggi 1,200 kwp (PV) 2,075 kw (I) 2,880 kwh (B) 1,650 kva (DG) 4.45 MW T&C 19-Nov-12 Tanjung Labian 1,212 kwp (PV) 1,650 kw (I) 4,320 kwh (B) 1250 kw (DG)

Grid Connect Inverter 75kW x 3 = 225kW Grid Connect Inverter 250kW x 3 = 750kW Bi-directional Battery Inverter 300kW x 3 = 900kW Diesel Generator 350kW 500kW 500kW GS GS GS PV on AC Coupling Remote Station 4.93 MW Banggi Battery 480Vdc 720 kwh Battery 480Vdc 2,880 kwh MPPT Charge Controller 70 kw x3 = 210kW

PV-DG Main Power station t Banggi Island, Kudat, Sabah, Malaysia COD on : 25 January 2014

BDI 3 BDI 2 BDI 1 Charge Controller GCI 3 GCI 2 GCI 1

Conclusions -Both DC and AC coupling are good in different time -DC coupling is better when using with high nigh time load -AC coupling is better when using directly supply load at day time -The best performance is using both DC and AC coupling together in a PV system. -Load profile is useful in determining portion of DC and AC coupling to supply energy to PV system -HOMER Pro simulation software has simulation result that Hybrid DC and AC coupling has lower cost of energy than using DC coupling or AC coupling alone. -There are hybrid PV-DG power plants in operation using DC-AC coupling design and have plant performance as design calculation.

Thank you for bring us electricity Children in Papua, Indonesia at the moment that they have electricity, Dec 2012