Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

1. Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites Dr. Prabodh Bajpai Assistant Professor Electrical Engineering Department, IIT Kharagpur 1

2. Introduction • Technology aspects • Benefit to the Industry • Commercialization prospective Outline Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

3. Uncontrolled Renewable energy sources essentially have random behaviors. eg: Solar, Wind, etc. • Power production from Uncontrolled sources is independent of human intervention • Hybrid power systems may contain controlled and uncontrolled energy sources and energy storage elements with appropriate control systems • Stand-alone hybrid power systems take advantage of the complementary nature in profile of the renewable energy sources • Hybrid power systems ensure continuous and reliable power production Introduction Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

4. 1) Wind/PV/FC/electrolyzer/ battery system 2) Micro-turbine/FC system 3) Microturbine/wind system 4) Gas-turbine/FC system 5) Diesel/FC system 6) PV/battery 7) PV/FC/electrolyzer 8) PV/FC/electrolyzer/battery system 9) FC/battery, or super-capacitor system 10) Wind/FC system 11) Wind/diesel system 12) Wind/PV/battery system 13) PV/diesel system 14) Diesel/wind/PV system 15) PV/FC/ SMES system Possible Renewable Hybrid Energy Systems Wind and solar power generation are two of the most promising renewable power generation technologies. Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites 4

5. Easy to install and low cost on site construction • Highly integrated intelligent hybrid power system for control and protection • Inclusion of battery back up reduces the DG size • Saving in diesel and reduction in maintenance of diesel generator • Reduced operating time and enhanced DG life • Specially designed deep cycle battery available in market • Rechargeable in a short time, • Long cycle life under STC, • High DoD (Depth of Discharge) DG/Battery Hybrid Solution: Merits Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites 5

6. DG as energy source has problems of : • Pollution • air, noise, heat • Dependence of fuel • world-wide increase of oil prices; limited resources in future • Transport to the sites • long distances and cost intensive transports • Storage of the fuel at site • safety problems - explosions, vandalism • No unattended operation is possible • high personnel cost • High maintenance cost and limited life-time of DG DG based Hybrid Solution : Demerits Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

7. On the other hand, the proposed renewable energy based system helps in: • Decrease environmental pollution • Reduction of air emission • Energy saving • Reduces production and purchase of fossil fuels • Abatement of global warming • CO2 and other green house gases are not produced • Socioeconomic development • Develops employment opportunities in rural areas • Fuel supply diversity • Diversity of energy carriers and suppliers • Distributed power generation • Reduces requirement for transmission lines within the electricity grid Hybrid Renewable Energy Systems Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

8. Site dependence of renewable sources • Site survey with long term data acquisition & forecasting • Hybrid renewable energy system design • Configuration and sizing of the hybrid system components with the objectives: • Supplying the power reliably under varying atmospheric conditions • Minimizing the total cost of the system • Maximizing the system efficiency by efficient energy flow management strategies • Optimization through simulation studies under real operating conditions for a reasonable tradeoff among conflicting design objectives Challenges Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

9. Economic viability • Cost-benefit analysis of hybrid system for reasonable payback period • Real world application • Design of power conditioning devices with maximum power point operation of energy sources • Optimal energy management strategies and their testing with laboratory prototype hybrid controller • Development of hardware and associated software for field-implementation Challenges Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites 9

10. Technology aspects Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

11. Solar PV based renewable power plant with FC, Battery and DG as backup sources • Hybrid controller to implement the energy sources changeover logic based on optimal energy management strategy. • Automatic mode of operation in the hybrid controller for FC and DG changeover operations. • Laboratory prototype of hybrid Solar PV-Fuel Cell-Battery-DG system for upto 5 kW load Introduction Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

12.  A typical stand-alone PV-Fuel cell-Battery hybrid energy system: Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

13. Robustness of the controller to fluctuating weather conditions and load demand is being rigorously tested, monitored and documented. • Hybrid controller comprises of: • Solar DSCAM (master controller) and two slave controllers, the Fuel Cell DSCAM and DG DSCAM • Individual power conditioning units for SPV, Fuel Cell and DG system to provide regulated DC output on the DC bus. • The master and slave controllers interact to provide switching and control signals for the converter units. System Development Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

14. SPV-FC-BATTERY-DG HYBRID ENERGY POWER PLANT SOLAR PV ARRAY (Primary Source) BATTERY BANK ( Back Up Source) Discharging LOAD PV Power FUEL CELL SYSTEM (Back Up Source) Supply to Load Charging DIESEL GENERATOR (Back Up Source) FC Power DG Power H2 Supply CONTROLLER H2 storage

15. Load 1 kW Load 0.75 kW Experimental Test Results Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

16. Battery Charging Battery Charging Excess Current Load 1 kW Load 0.75 kW Experimental Test Results Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

17. Merits of solar PV charge controller and Fuel Cell charge controller • Optimal charging of the batteries and maximum power extraction from solar PV and FC • Supervisory functions to prevent damage to the battery • Effective interface to inter connect Solar PV modules, Fuel Cell, Battery Bank and the load • Battery reaches a high state of charge under all operating conditions • Work in tandem with the SMPS based power plant to optimize the charging capability of the FC/SPV and protect the batteries from overcharge Merits of Topology Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

18. Use of solid-state devices to control the charging current to the battery and supply power to the load simultaneously • Blocking devices to prevent reverse current flow from the battery to the FC/SPV during cloudy days or other charging modes • Lightning / transient protection to protect the control circuitry from damage due to excessive voltage • Programmable charging capacity, change over settings and peak power point • Programmable maximum power point tracking (MPPT) logic with the built in embedded logic controller Important Features of Topology Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

19. Necessity of weather monitoring • Inspecting the feasibility of a site for a solar energy project • Site comparison and selection based on weather data • Long term energy assessment helps in effective system sizing and cost minimization • Helps to predict the performance of SPV • Measures weather parameters like • solar insolation (W/m2), • ambient temperature (0C) and • relative humidity(%) • Weather data at defined intervals is measured using sensors • Data is sent continuously to a central server through GPRS and is monitored online Solar resource assessment (SRA) system Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

20. Sensors Hybrid Controller Monitoring Station Remote PC cRIO-9073, Data acquiring, Generating and logging Remote Monitoring System Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

21. Benefit to Industry Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

22. Extendable to a generalized solution for any kind of stand-alone site. • Independent of continuous availability of the renewable source as well as grid power availability. • Power converters are modular in nature • For any kind of critical load in stand-alone site • Telecom towers, • Cold storage plants, • Hospitals, • Military establishments • Fuel stations • ATMs Market potential Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

23. Commercialization prospective Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

24. Net present value = Total lifetime savings – Total lifetime investment • Savings include revenue generated from the hybrid PV system by replacing the DG-battery system, the carbon tax benefit and savings in the operational cost of the system. • Investment includes the extra first cost which is the difference between the Capex of the hybrid PV system and the Capex of the DG-Battery system Cost-benefit analysis Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

25. CAPEX for hybrid PV system to meet 4kW peak load will around 50Lakh INR • The lifetime of both the systems considered to be 30 years. • Economic analysis for different scenarios gives payback period between 5-10 years Cost-benefit analysis Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

26. Proof of concept verified with a laboratory prototype • Field site testing with stand-alone load application needs to be done • The Technology Transfer may take place as per One Time License Payment or Revenue Sharing Model or any other criteria mutually agreed Real world application Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

27. Thank You Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites

28. Component size and price

29. Hybrid PV system: • CAPEX is the total initial cost of the system. • OPEX in case1 =1% of CAPEX+ 100% of Battery cost in every 5 years+100% of FC cost every 10,000 hours of operation+ operating cost of FC @Rs 417/hr +operating cost of DG @Rs 50/hr. • OPEX in case2 =1% of CAPEX+ 100% of Battery cost in every 5 years+100% of DG cost in every 15 years + operating cost of FC @Rs 417/hr+ operating cost of DG @Rs 50/hr. • DG/Battery system: • CAPEX is the total initial cost of the system. • OPEX =2% of CAPEX+100% of Battery cost in every 5 years+100% of DG cost in every 8 years + operating cost of DG @Rs 50/hr. • The lifetime of both the systems was considered to be 30 years. • The present diesel cost was assumed to be Rs 40/litre. • The annual escalation in diesel cost was assumed to be @ 10 % Financial Assumptions

30. Hybrid PV/FC/DG/Battery system DG/Battery system Capex and Opex comparisons

31. Comparison of savings & investments for hybrid PV/FC/DG/Battery system

32. NPV and Payback Period