Transcript CB077-2.16_NorthShore_Intro to Elect Utility

Section 2
GENERATION
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Capacity
Process
Methods
Fuel Diversity
New Technology
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Sec 2- Generation Capacity
• Generation units use a variety of technologies
convert energy from falling water, coal, natural
gas , oil , nuclear and other sources to produce
electricity
• The majority of electric generators are driven
by hydraulic (water/steam) turbines
• The electric capacity a generator can produce
is usually measured in……… MEGAWATTS
Sec 2-Generation- Capacity
• Customer need for electricity is called demand
• Constant consumer demand is referred to as
BASE LOAD
– Base load is usually served by coal, natural gas or
constant hydro
• Temporary or short term demand is called
PEAK LOAD
– Peak load often served by gas/oil combustion
turbines ….or pumped –storage hydros
Sec 2-Generation- Capacity
• In 2003 total USA nameplate capacity was
1,031,692 MW
• Industry forecasts a need for new generation
428,000 MW by 2025
• Planned generation additions by 2008
115.5 MW……… 88% of which will be
Natural Gas
Sec 2-Generation-Capacity
• Net “availability” of system generation varies
as generators and transmission equipment is
brought on and off line and is always less than
“nameplate” capacity
• Utilities maintain surplus generating standby
generating capacity known as “Capacity
Margins”
Sec 2-Generation-Process
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Fuel is converted to heat
Heat process moves turbines
Turbines turn generators
Generators convert motion/magnetic fields to
create currents of Electricity
Sec 2-Generation-Process
• Generation plants have two types of circuits
• MAIN – Carry power from generator to stepup transformers and to station high voltage
terminals
• ACCESSORY or AUXILIARY- Carry power to
motors used to drive pumps etc. needed for
the particular generating process
SEC 2-Generation- Process
• AUXILIARY CIRCUITS are also needed for
– Control circuits (circuit breakers etc.)
– Lighting circuits
– Excitation circuits to create magnetic fields
necessary for generation
– Instrument and Relay circuits
– Communication circuits
Sec 2-Generation-Process
• RELAY CONTROLLED CIRCUIT BREAKERS
Are used to turn on and off circuits carrying
high voltage and large loads
Circuit Breakers are devices designed to
interrupt power in a manner to reduce the
“arc” of the flow of electricity across the
switching device as the switch opens
Relays are low voltage devices to control
breakers
Sec 2-Generation-Methods
• Steam turbines are the most common method
to generate power
• Steam turbines- three categories
Fossil Fuel 70% USA generation
Nuclear
20% “
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Renewable 9% “
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Sec 2-Generation-Methods
• FOSSIL FUELS
Major Coal
Petroleum
Natural Gas
Other
Petroleum coke, coke oven gas, liquefied
petroleum, peat, oil shale, various industry
wastes
Sec 2-Generation-Methods
• NUCLEAR
Heat is produced by controlled nuclear
reaction in a “containment vessel”
This is done by controlling the reaction
between nuclear fuel (uranium)- fuel tubes
and control mediums (elements that absorb
neutrons)- control rods
Water is commonly used to transfer the heat
to drive the turbine - “light water reactor”
Sec 2-Generation-Methods
NUCLEAR LIGHT WATER REACTORS use the
water to slow down or moderate the neutrons
in the reaction process and as a medium to
transfer heat energy to turn the turbines
• TWO TYPES of Light Water Reactors
-Pressurized Water Reactor- PWR (closed
loop/heat exchanger)
-Boiling Water Reactor-BWR (direct to turbine)
Sec 2-Generation-Methods
• GAS TURBINE
-Works with compressed gas which is ignited
and hot gases then turn the turbine
-Often used for peak, emergency, and reserve
power because of their quick startup
-less cost efficient than steam turbines
-generally 100 MW or less
- can be turned on and off within minutes
Sec 2-Generation-Methods
COMBINED CYCLE UNITS
Hybrid Plants combine both steam and gas
turbines to utilize excess heat byproduct to
increase net plant efficiency
COGENERATION ….aka Combined Heat and
Power (CHP)
Use a generating plant to provide both
steam(for heat or manufacturing process) and
electricity
Sec 2-Generation-Methods
DISTRIBUTED GENERATION
Until recently regulatory and technology
issues meant customer generated power
could not be easily or safely coupled with
incoming grid supplied electricity
The advent of improved electronic control
devices allow for cogenerators to sell back
their surplus generated power to the utilities
The proliferation of distributed generators will
challenge the grid networks ability to manage
the flows
Sec 2-Generation-Methods
MICROTURBINES
Newer technology..usually smaller in relative
size to other types of generator
Can be used in “distributed generation”
schemes
When used in CHP systems efficiencies of over
90% can be achieved
Sec 2-Generation-Fuel Diversity
FUEL DIVERSITY
The variety and proportions of energy sources
used to produce electric power
Primary Sources- Fossil, Nuclear and Renewables
“A sound national energy policy should
encourage a clean and diverse portfolio of
domestic energy supplies. Such diversity helps
to ensure future generations ….will have
access to the energy they need”
……….NEPDG 2001
Sec 2-Generation-Fuel Diversity
The Edison Electric Institute (EEI), a trade group
representing IOU’s, has statistically shown
Electric use in the USA will
increase by 54% by 2025
Sec 2- Generation-Fuel Diversity
RENEWABLE ENERGY SOURCES
-Biomass
-Hydropower
-Geothermal
-Wind
-Solar
Currently the total of above sources is 9% of the
USA fuel mix
Sec 2 –Generation- Fuel Diversity
• BIOMASS —burned to turn steam turbines
-Residues from wood and paper industry
-Residues from food production/processing
-Trees and grasses grown for energy crops
-Gaseous fuels from solid biomass, animal
wastes , and landfills
• BIOFUELS from Biomass
-Ethanol…fermented biomass carbos (corn)
-Biodiesel..oils, fats, algae..cooking greases
Sec 2-Generation-Fuel Diversity
• HYDROPOWER
Turbine turned by kinetic energy of water
Three types
-falling water (dam, reservoir, water conduit)
-run of river (current turns turbines, no
reservoir)
-pumped storage (pump water to reservoirs
during off peak with cheap power for use to
hydro generate during peaks
Sec 2-Generation-Fuel Diversity
• HYDROPOWER -OCEAN ENERGY
Thermal from solar heating- Sun heats surface
and technology uses difference in water
temperature at different depths to supply
energy
Mechanical from tides and by waves
Sec 2-Generation-Fuel Diversity
• GEOTHERMAL
Uses the heat from the earth – various
technologies
-Heat exchanger types from shallow depths
-Direct heat/steam from geologically active
areas
-Inject water to deep depths to dry/rock heat
at core and retrieve heat via the circulated
water
Sec 2-Generation-Fuel Diversity
• WIND
– turns Wind Turbines to generate power, charge
batteries or pump waters
– Usually needs towers over 100 ft tall
• Wind farms of multiple towers supply grid
• Individual tower units for local use
Sec 2-Generation-Fuel Diversity
• SOLAR
Photovoltaic (PV) Technology
-Semiconductor PV cells (sunlight knocks loose
electrons from semiconducting material and
electrons produce a charge captured for
electrical use
-Cells combined into Modules
-Modules combined into Arrays
Sec 2-Generation-Fuel Diversity
• SOLAR(cont)
Concentrated Solar System
Sunlight collected and focused by mirrors
to concentrate heat to create steam of
mechanical energy to generate
Sec 2- Generation-New Tech
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Nuclear revival
Clean Coal Technology (CCT)
Fuel Cells/Develop Hydrogen Economy
Develop Wind Technology
Enact renewable Energy Standards (RES)
Laws to mandate use by utilities of alternative
fuel mix technologies
Sec 2- Generation-New Tech
NUCLEAR REVIVAL
– Newer Safer Smaller Designs
• PEBBLED MODULAR REACTORS (PBMR)
– fuel pebbles encapsulated in carbon
– reactor cooled by Helium gas
•Sec 2- Generation-New Tech
CLEAN COAL TECHNOLOGY (CCT)
Reduction of SO2,NOx,CO2 and Heavy metal
emissions
Combustion - combine coal with other
substances to make it burn cleaner
Post combustion-use scrubber technology to
clean emissions before they leave the plant
Conversion- convert to a gas or liquid to be
further refined so as to burn cleaner
Sec 2- Generation-New Tech
FUEL CELLS
– Use chemical energy of hydrogen to generate
electricity with waste products of pure H2O and
heat
– DOE (Department of Energy) program is focused
on Polymer Electrolyte Membrane type of fuel
cells primarily for transportation
Sec 2- Generation-New Tech
FUEL CELLS- Hydrogen Economy
• Research ongoing to develop hydrogen fuel
production and distribution in conjunction
with fuel cell improvements
– Purpose to reduce fossil fuel dependence in
internal combustion engines and motors thus
reducing the overall dependence on fossil fuels
into the next century
Sec 2- Generation-New Tech
WIND
– NTWC (National Wind Technology Center
Capacity for generation of all US demand
Limited by Transmission Grid
– Industry growth dependant on development
of “deep water”, offshore facilities
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Higher wind quality- less turbulence
Load proximity
Increased Transmission options
Reduced land use and landbased aesthetics
Relaxed size constraints (transportation/installation
Sec 2- Generation-New Tech
RENEWABLE ENERGY STANDARDS (RES)
Legislative mandates (State)
• Primary driver of new renewable energy
generation in the USA
• Existing RES as of 2003 will result in CO2
reductions of 64.3 million metric tons
equivalent to
– 9.6 million cars off the road
– Planting 15.4 acres of trees
• National RES legislation is inevitable