48550 Electrical Energy Technology
Energy Resources
Electrical Energy Systems
Energy
The capacity for doing work. The SI unit for energy is Joule.
Main Energy Forms
* Electrical
* Mechanical
* Chemical
* Solar
* Geothermal
* Nuclear
Energy Resources
Energy resources are the various material that contain energy in
usable quantities. These are present in any of the various energy
forms that are transformable to other forms.
Expendable Resources:
fuels (e.g. coal, oil, & natural gas)
Renewable Resources:
water, wind, solar, tide, and biomass
Energy Resources
Electrical Energy Generation
Utilisation of Electrical Energy
System Design Examples
Electrical Vehicles
Remote Area Power Supply
Grid Power Supply
Electrical Energy Generation
Electrical Energy Generation
- Conventional Methods: Hydroelectric
- Conventional Methods: Hydroelectric
Electrical Energy Generation
Electrical Energy Generation
- Conventional Methods: Thermoelectric
- Conventional Methods: Thermoelectric
Electrical Energy Generation
Electrical Energy Generation
- Conventional Methods: Thermoelectric
- Conventional Methods: Nuclear
Electrical Energy Generation
- Conventional Methods: Nuclear (Cont.)
In a nuclear power plant, the heat energy released by nuclear fission is
used to produce the steam that rotates the turbine that drives the electric
generator.
Electrical Energy Generation
- Non-conventional Methods
Thermionic Converters Biomass
Electrochemical Cells Ocean Power
Solar Power
Geothermal Power
Solar Cells
Wind Power
Solar Thermoelectric
Hybrid Power Systems
Solar Power
- Solar Cells
Very high growth predicted
Recent European Commission
white paper on renewable energy
sources
Rooftop programs in Europe,
USA, Japan
5.5% renewable generation by
2010 in USA
2% renewable generation by
2010 in Australia
25% average growth rate
Solar Power
- Solar Thermoelectric
Biomass
Geothermal Power Plant
Ocean Power
Ocean Power
Oceans cover three quarters of the
earths surface and represent a vast
natural energy resource in the form
of waves
The World Energy Council estimates
that 2TW of energy could be
harvested from the worlds oceans,
the equivalent of twice the worlds
electricity production
If less than 0.1% of the renewable energy within the oceans could
be converted into electricity it would satisfy the present world
demand for energy more than five times over
(from www.wavegen.co.uk)
Energy density
Figures in kW/m
Source: Wave Energy paper, IMechE, 1991 and European Directory of
Renewable Energy (Suppliers and Services) 1991
Ocean Power
Wind Power
- Facility
Fuel Cells
Wind Generators
- Fundamental
Electricity
Hydrogen
Installed world-wide end 1997 7700 MW
Generated energy
19 TWh p.a.
Germany has largest capacity 2002 MW
Market is growing
22 % p.a.
Average size 600 kW, doubling in last 5 yrs
FUEL CELL
Heat
Oxygen
Water
2e-
Load
Fuel In
Oxidant In
H2
Positive Ion
O2
H2O
Negative Ion
H2O
(Snowy Hydro 10,000 GWh = 10 TWh p.a.)
Depleted Fuel and
Product Gases Out
Depleted Oxidant and
Product Gases Out
Anode
Electrolyte
Cathode
(Ion Conductor)
The electrolyte provides a physical barrier
to prevent the direct mixing of the fuel and
the oxidant, allows the conduction of ionic
charge between the electrodes, and
transports the dissolved reactants to the
electrode.
The electrode structure is porous, and is
used to maximise the three-phase interface
between the electrode, electrolyte and the
gas/liquid, and also to separate the bulk
gas phase and the electrolyte.
The gas/liquid ionisation or de-ionisation
reactions take place on the surface of the
electrode, and the reactant ions are
conducted away from or into the threephase interface.
Fuel Cells
Fuel Cells
- Structures
- Principle
Control
Oxidant
Fuel
Management
Unit
Fuel
Oxidant
Reactants
Fuel Cell
Stack
Heat
DC Power
Power
Conditioning
Unit
Application
Heat
Unprocessed
Fuel
Control
Control
Unit
Anode reaction H 2 2H + + 2e
Cathode reaction 12 O2 + 2 H + + 2e H 2 O
Overall reaction 12 O2 + H 2 H 2 O
Heat
Management
Unit
Control
Fuel Cells
Fuel Cells
- Classifications
- Fuel requirement
CLASS
ABBREVIATION
Solid Oxide
SOFC
Polymer Electrolyte Membrane
PEMFC
Phosphoric Acid
PAFC
Molten Carbonate
MCFC
Alkaline
AFC
Gas species
H2
CO
CH4
CO2 and H20
S (as H2S and
COS)
PEMFC
Fuel
Poison(>10ppm)
Diluent
Diluent
Unknown
AFC
Fuel
Poison
Diluent
Poison
Unknown
PAFC
Fuel
Poison(>0.5%)
Diluent
Diluent
Poison
MCFC
Fuel
Fuel
Diluent/Fuel
Diluent
Poison
(>0.5ppm)
SOFC
Fuel
Fuel
Diluent/Fuel
Diluent
Poison (>1ppm)
Fuel Cells
Fuel Cells
- Electrochemical
- Applications
TYPICAL
APPLICATIONS
Portable electronics
equipment.
Cars, boats, and
domestic CHP.
Distributed power
generation, CHP,
and buses.
M AIN
ADVANTAGES
Higher energy
density to batteries,
faster recharging.
Potential for zero
emissions, higher
efficiency.
Higher efficiency,
less pollution, quiet
operation.
POW ER (W )
APPLICATION
RANGE FOR
FUEL CELL
CLASS
10
100
1K
10K
100K
1M
ACF
10M
M CFC
SOFC
PEM FC
PAFC
Fuel Cells
- Advantages and disadvantages
Advantages
Efficiency - Fuel cells are generally more efficient than combustion engines
as they are and are not limited by temperature as is the heat engine.
Simplicity - Fuel cells are essentially simple with few or no moving parts.
High reliability may be attained with operational lifetimes exceeding 40,000
hrs.
Low emissions - Fuel cells running on direct hydrogen and air produce only
water as the by-product.
Silence - The operation of fuel cell systems are very quiet with only a few
moving parts if any. This is in strong contrast with present combustion
engines.
Disadvantages
Relatively high cost of the fuel cell, and
to a lesser extent the source of fuel.
Hybrid Power
Systems
Electrical Power Transmission
Electrical Power Transmission
- Substation
Utilisation of Electricity
Industrial Applications
Motor drive systems, e.g. machine tools
Electrical furnaces
Domestic Electrical Appliances
TV, air conditioning, and washing machine, etc.
Computer Peripherals
Disk drives (floppy, hard disk and CD), printers,
etc.
Solar powered submersible water pump
CSIRO-UTS project
brushless DC,
NdFeB, 4 pole,
surface magnet
water filled
>1000 produced
300, 600, 1200 W
sensorless, current
impulse starting
MPPT
Brushless DC Transmission
Drives for Electric Cars
Electrical Vehicles
Electric Lotus Elise - Zytek
Ethos 3 EV - Pininfarina & Unique Mobility
EV Plus - Honda
Prairie Joy - Nissan
RAV-4-EV - Toyota
In-wheel Motors - Solar Cars
CSIRO-UTS / Aurora - 5.5 kW, 50 Nm peak for 72 s
Direct-drive, axial flux
Solar-Wind Hybrid Ferry
Solar Sailor/UTS - 2x40 kW, 400 Nm
Direct-drive, PM brushless DC motor
Green House
Effect
The concentrations of
green house gasses in
the atmosphere have
increased over recent
year and are still
increasing.
The increased
concentrations of green
house gasses will have
some effect on the
earths climate.
How to Reduce CO2 Emissions?
Use clean energy source for electricity generation, e.g.
solar, wind, hydro, geothermal, and nuclear (?)
Reduce power loss in power transmission lines
Use high efficiency electrical appliances in households
and industry
Since motors account for 65% of the electric energy
consumed in industrial applications, it is important to
Select right motor size (motor selector software package)
Use high efficiency motors, e.g. PM motors
Use high efficiency electric drive techniques, e.g. variable speed, direct
drive
Kyoto Protocol
- Japan, December 1997
55 nations agreed to implement measures to
reduce emissions to stabilize the global
environment
38 industrialized nations agreed to reduce their
1990 level greenhouse emissions by 8% in 20082012
European Union committed to reduce with 8%
The US by 7%
Japan by 6%
Australias eventual target of 8%
Australian
Electrical Energy
Total annual consumption 50,000 GWh =
50 TWh
Average household in Sydney consumes
20 kWh per day, 7,300 kWh p.a.
Snowy Hydro 10,000 GWh = 10 TWh p.a.
Largest wind farm (to be) Crookwell 5
MW power maximum, 10 GWh p.a.
energy generation
Australian Greenhouse commitment
requires extra 2% = 10 TWh p.a. electricity
generated by clean energy source by 2010
For best available
now, 28 TWh, 3%
of motor
consumption, 62%
from motors in the
0.75-7.5 kW range
increase of
efficiency from
80 to 86%
large number of
units (83% of
the total)
30
D esired e ffic ien cy
25
Man dato ry
B est ava ilab le no w
20
Annual
saving
(T W h)
15
10
5
0
0.7 5-7.5
>7.5-3 7
>37-75
M otor power (kW )
Integrated VVVF Drive for 750
W Evaporative Cooler Fan
(a)
>75
750 W Evaporative Cooler Fan
Energy Consumption
200 W power saving at 600
rpm
50,000 units p.a., 25%
duty cycle
22 GWh saved p.a.
$50 per unit = 11.4c per
kWh saved p.a.
Crookwell 5 MW wind farm
10 GWh p.a.
$2000 per kW
$1.00 per kWh saved p.a.
Fan motor input power
1200
1000
Power in (W)
Energy Saving from Induction Motor
Efficiency Improvement in Europe by 2010
800
Triac variable
voltage
600
Inverter
drives
400
200
0
0
500
1000
Triac V V control
Inverter 1
Integrated VVVF Drive for 750
W Evaporative Cooler Fan
(b)
The Drive PCB
a) attached to a heat sink for testing
b) Mounted in the motor end plate with other required components
1500
Speed (rev/min)
The assembled prototype
motor and drive
Inverter 2
Efficiency of 750 W Evaporative
Cooler Fan Drives
Future Direction
- PM brushless DC and SR motors
Efficiency (%)
Specified
Speed
70.00
Triac Drive
VVVF Drive
60.00
Comparison of efficiency
between a commercial 750 W
triac controlled fan drive and the
prototype inverter VVVF drive
50.00
Single Phase
AC Supply
40.00
AC/DC
Converter
C
DC Link
30.00
20.00
10.00
0.00
0
200
400
600
800
1000
Speed (rev/min)
1200
1400
1600
maximum energy levels for
refrigerators, e.g. 732 kWh/year for a
570 L refrigerator-freezer
to be lowered further by around 30%
in 2001
Position
Sensor-less
Electronic
Commutator
PM
Motor
3 Ph Square
Wave Voltage
PM brushless DC motors are more efficient (typical efficiency 90-95%) than induction
motors, but more expensive.
The cost can be reduced by using position sensor-less drive techniques and when PM
materials become cheaper.
The switched reluctance motors can be both more efficient and cheaper, but sensorless drive still needs more work.
Refrigerator Efficiency
Denmark: Variable speed PM
motor compressor gave 40%
reduction in energy use (Pedersen
and Andersen EPE97)
USA: 1993 National Appliance
Energy Conservation Act
Refrigerator
Efficiency
Mandatory energy
labeling in NSW
could reduce energy
used by up to 50%
