hybrid power plant

1

Hybrid Controller for Renewable Energy Power Plant

in Stand-alone sites

Prof. M.L. AzadHOD

Electrical & Electronic Engineering Department, Amity University, Greater Noida

1

Outline

Introduction

Technology aspects

Benefit to the Industry

Commercialization prospective

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

2

Introduction

Uncontrolled Renewable energy sources essentiallyhave random behaviors. eg: Solar, Wind, etc.

Power production from Uncontrolled sources isindependent of human intervention

Hybrid power systems may contain controlled anduncontrolled energy sources and energy storageelements with appropriate control systems

Stand-alone hybrid power systems take advantage ofthe complementary nature in profile of the renewableenergy sources

Hybrid power systems ensure continuous and reliablepower production


3

Hybrid Controller for Renewable Energy Power Plant in Stand-alone sites 4

Model of

Hybrid Power Generation System

Possible Renewable Hybrid Energy Systems

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

5

Wind and solar power generation are two of the most

promising renewable power generation technologies.

5


DG/Battery Hybrid Solution: Merits

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)

6

6


DG based Hybrid Solution : Demerits

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


Hybrid Renewable Energy Systems

On the other hand, the proposed renewable energy based system helps in:

Decrease environmental pollutionReduction of air emission

Energy savingReduces production and purchase of fossil fuels

Abatement of global warmingCO2 and other green house gases are not produced

Socioeconomic developmentDevelops employment opportunities in rural areas

Fuel supply diversityDiversity of energy carriers and suppliers

Distributed power generationReduces requirement for transmission lines within the electricity grid


Challenges

Site dependence of renewable sourcesSite survey with long term data acquisition & forecasting

Hybrid renewable energy system designConfiguration 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

9


Challenges

Economic viabilityCost-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


10

10

Technology aspects


11

Introduction

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


12

A typical stand-alone PV-Fuel cell-Battery hybrid energy system:

13


System Development

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.


14

SPV-FC-BATTERY-DG HYBRID ENERGY POWER PLANT

Discharging

Charging

Supply to Load

PV Power

FC Power

DG Power

SOLAR PV ARRAY (Primary Source)BATTERY BANK ( Back Up Source)

FUEL CELL SYSTEM (Back Up Source)

CONTROLLER

DIESEL GENERATOR (Back Up Source)

LOAD

H2 storage

H2

Supply

Experimental Test Results

0

10

20

30

40

50

60

Vo

ltag

e (

V)

Time of the day (hr)

SPV Module-1Voltage (V)

FC Module-1Voltage (V)

DG Module-1Voltage (V)

System Voltage(V)

Battery-3 Voltage(V)

Load Voltage (V)

FC Operation

Battery Operation

DG Operation

Battery Operation

SPV Operation

SPV Operation


16

Load 0.75 kW

Load 1 kW

-40

-30

-20

-10

0

10

20

30

40

50

60

Cu

rren

t (A

)

Time of the day (hr)

SPV Input Current (A)

SPV Module-1 Current (A)

FC Input Current (A)

FC Module-1 Current (A)

FC Module-2 Current (A)

DG Module-1 Current (A)

DG Module-2 Current (A)

System Current (A)

Battery Current (A)

Load Current (A)

SPV OperationBattery Operation

FC Operation

DG Operation

SPV Operation

Battery Operation

Experimental Test Results


17

Load 0.75 kW Load 1 kW

Excess CurrentBattery ChargingBattery Charging

Merits of Topology

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, FuelCell, Battery Bank and the load

◦ Battery reaches a high state of charge under all operatingconditions

◦ Work in tandem with the SMPS based power plant tooptimize the charging capability of the FC/SPV andprotect the batteries from overcharge


18

Important Features of Topology

◦ Use of solid-state devices to control the charging current tothe battery and supply power to the load simultaneously

◦ Blocking devices to prevent reverse current flow from thebattery to the FC/SPV during cloudy days or other chargingmodes

◦ Lightning / transient protection to protect the control circuitryfrom damage due to excessive voltage

◦ Programmable charging capacity, change over settings andpeak power point

◦ Programmable maximum power point tracking (MPPT) logicwith the built in embedded logic controller


19

Solar resource assessment (SRA) system


20

•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

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

Remote Monitoring System


Sensors

Hybrid Controller

cRIO-9073, Data acquiring, Generating and logging

Monitoring StationRemote PC

Benefit to Industry


Market potential

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

Commercialization prospective


Cost-benefit analysis

Net present value = Total lifetime savings –Total lifetime investment

Savings include revenue generated from thehybrid PV system by replacing the DG-batterysystem, the carbon tax benefit and savings inthe operational cost of the system.

Investment includes the extra first cost which isthe difference between the Capex of the hybridPV system and the Capex of the DG-Batterysystem


Cost-benefit analysis

CAPEX for hybrid PV system to meet 4kWpeak load will around 50Lakh INR

The lifetime of both the systems consideredto be 30 years.

Economic analysis for different scenariosgives payback period between 5-10 years


Real world application

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


Component size and price

Component Pricing

PV (per Wp) 70

Battery (per kwh) 7,000

H2 tanks(per m3) 400

Fuel cell(per kW) 2,00,000

Diesel Generator (per kW)

33,000

Diesel (per litre) 40

Component Size

PV (Wp) 16500

Battery in hybrid PV system(kwh) 57.6

DG in hybrid PV system (kW) 5

H2 tanks (m3) 120

Fuel cell (kW) 4.56

DG in DG-Battery system (kW) 25

Battery in DG-Battery system( kWh)

105

Financial Assumptions Hybrid PV system:

• CAPEX is the total initial cost of the system.

OPEX in case1 =1% of CAPEX+ 100% of Battery cost in every 5years+100% of FC cost every 10,000 hours of operation+operating cost of FC @Rs 417/hr +operating cost of DG @Rs50/hr.

OPEX in case2 =1% of CAPEX+ 100% of Battery cost in every 5years+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 5years+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 %

Capex and Opex comparisons

3,060,000

8,973,982

Longer DG operation

Capex

Opex

3,683,200

23,600,932

Longer FC operation

CapexOpex

1,810,000

26,436,200

DG-Battery

Capex

Opex

Hybrid PV/FC/DG/Battery

system

DG/Battery system

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

25,217,247

27,284,132

Longer FC operation

Savings

Investmen

ts 37,400,995

12,657,182

Longer DG operation

Savings

Investmen

ts

NPV and Payback PeriodLonger FC operation Longer DG

operation

With carbon tax benefit 23,344,047 35,527,795

Net present value

Without carbon tax benefit

16,463,765 29,068,754

With carbon tax benefit

5 4

Payback period

Without carbon tax benefit

7 6

hybrid power plant

Documents

renewable energy power

energy storageelements

solar power generation

dghybrid controller

sitesdgbattery hybrid

limited lifetime

low cost

long cycle life