Chapter 10
Structure of the Utility Industry
Managing Energy Demand
Electrical Charges and Currents
Batteries and Electric Vehicles
Hybrid Vehicles
Ohms Law
Energy in the News
Electrical Generation vs Time
Sources and amount of electricity generation in the United
States from 1950 to 2000 (for units see figure 10.1 in your
Book. Purple (top): coal Green: Petroleum and natural gas
Aqua: Hydroelectric power Blue: Nuclear power.
General Trends
Coal provides most of the power for electrical generation
Need for electrical power in the 1970s, doubled every 10 years
Rate of growth in demand has slowed to about 2% per year
(implied doubling time??)
Energy use overall: largest rate of growth is in electrical consumption
Use of Coal, Natural Gas and
Petroleum by Utilities
Nonutility producers of
Energy: use proportionately
more renewable energy,
Don’t use nuclear at all.
Do use some fossil fuels.
Restructuring of the Utilities
Deregulation of the utilities:
Goals:
1) To make electricity cheaper by promoting competition
2) Promote increased efficiency of power plants
3) Allow consumers choice of renewable energy sources
Historical Perspective: Why a utility monopoly?
1) Smoothing of demand: promotes efficiency
2) Power plants are expensive
Utilities: Why Change?
1) Facilities already built
2) Profit guaranteed: no incentive for change
3) Power plant efficiencies: historical trends
4) Renewable energy sources (other than hydro)
Deregulation History
PURPA: Public Utility Regulatory Policy Act: 1978
1) Must buy power from independent producers at avoided cost
(about 6 cents per kWH), typical cost of electricity from existing
Power plants (about 3.5 cents per kWH).
Avoided cost: cost of constructing new power plants
Cost of wind generated power: about 5.5 cents per kWh
Cogeneration: typically cheaper than wind power
Result: promotion of cogeneration and wind power:
Increased energy efficiency and renewable power.
Problems with Deregulation
Stranded costs
Utilities divided up:
Generation, transmission and distribution all separate
If a utility sells a power plant: who should get the profits?
California: regulated charges from utilities to consumers
But not charges from fossil fuel brokers to utilities
Transmission lines: incentive to modernize?
Good Aspects of Deregulation
Number of independent power producers increased,
Therefore more power generated from renewables
Efficiency of power plants now increasing rather
Than stalling; newer plants 40% efficient
Could be 60% efficient with best technology
Consumers in some states can choose to pay more
To buy power generated from renewables:
Increases the market for renewables
Energy Trends
Times of high demand: electrical costs $10 per KWH
Vs typical price?
Peak power use closer and closer to total capacity
Big plants no longer most efficient power generators:
New technologies like microturbines important
Transmission lines: need modernization
(What happened in California power crisis?)
Times of high demand: utilities pay big energy users
To shut down. (What types of companies use the most power?)
Electrical Charges and Currents
Electricity= moving electrons
Conductors: metals with electrons able to move easily
(outer shell of electrons in the atom)
Electron: negative charge
Proton: positive charge
Unit of Charge: coulomb
6.25E18 electrons = 1 Coulomb
Like charges repel: unlike charges attract
Semi-Conductors and Insulators
Semi-conductors: electricity is conducted but less
Easily than in conductors (What uses semi-conductors?)
Insulators: don’t conduct electricity. PCBs are insulators
PCB = polychlorinated biphenols Hudson river and PCBs
Why did General Electric manufacture PCBs in large amounts?
Electrical Force
Potential Energy: Applies to electrical force
Electrical Potential= Potential energy embodied
In electrical charges: unit of potential = volt
One volt = 1 Joule per Coulomb
Potential Difference: Electrical potential energy
Derived from difference in energy between positively
And negatively charged parts of electrical device
Electrical current flows from negative to positive
Why??
Electrical Current
Electrical current: movement of electrons from
Area of electron excess (negative charge) to
Area of electron deficit (positive charge)
Unit of current= amp or ampere
Types of current: direct current (DC)
Alternating current (AC)
Alternating current: has a frequency in hertz (Hz)
USA: 60 Hz
Europe: 50 Hz
Most devices run on AC because generators produce AC
Solar homes run on DC (why?)
Battery Driven Electrical Motor
Where is the circuit
In this picture?
What do you need to
Know to determine
The direction of
Current flow?
Batteries
Inside of a flashlight with two batteries:
Where is current flowing in this device?
In what part is current flowing to the right?
In what part is current flowing to the left?
Components of a Battery
1)Two electrodes (or terminals)
2) Submerged in an electrolyte
Electrolytes allow a chemical
Reaction to occur. This
chemical energy is converted
Into electrical energy by the
Battery
Do batteries get warmer when
they operate: why or why not?
Pb-acid
Dry Cell
Pb-acid batteries
Chemical reactions:
Negative electrode
Pb= Pb 2+ +2ePb2+ +SO4 2- = PbSO4
Positive electrode: PbO2
PbO2 + SO4 2- , 4H+ + 2e- =
PbSO4 + 2H20
Electrolyte is providing H+ and SO4 2Both are needed for the chemical reaction
Where does PbSO4 end up?
Pb acid battery: car battery stores about 2% of the energy in 1 gallon
Of gasoline (seismometers in Iceland)
Important Battery Characteristics
Overall voltage
Battery Life
Rechargable?
Energy Density (Watt hours per kilogram)
Toxicity of components
Battery Design
First battery: invented by Volta
Zinc and Silver plates
Blotting paper moistened with
Salt water.
What are the electrodes?
What is the electrolyte?
What compounds are being formed?
(Make an educated guess)
Lemon Power Runs a Calculator
Why does this work?
What part of the battery are
The lemons functioning as?
What else needs to be
Present?
Battery Characteristics (for electric
cars)
What is the range derived from? Why don’t the batteries with
The highest energy density always have the greatest range?
Types of Batteries
Range is for an electrical car with that battery. Why doesn’t the
Battery with the highest energy density have the largest range?
Electrical Vehicles
Not new: first speeding ticket for a car-given to
An electrical car
(how fast was it going?)
Electric powered vehicles (Evs)
Mostly powered by Pb acid batteries
Batteries take 6 to 8 hours to recharge
Range of 60 to 160 miles between charges
(sound too short a distance? 75% of private cars
Are driven less than 50 miles per day)
How an Electrical Vehicle Works
Electrical Vehicles:Why?
Big incentive: California law requiring that 10% of
all new cars sold in California be zero emission
vehicles (ZEVs) by 2003.
Only two types of zero emissions vehicles: bicycles
and electrical cars
Are there zero emissions of CO2 when an electrical
Car is used? Why or why not?
Electrical Cars: Pros and Cons
Against: are not truly zero emissions vehicles
Emissions are just moved to the power plant
Pb acid batteries: production and use generate Pb
Pollution-so far other batteries much too expensive
At present power plant efficiencies overall level of pollution
Produced by electrical cars: more than by hybrid cars
Pro: as power plant efficiencies improve (60% possible)
Electrical vehicles will outperform present hybrids
In terms of overall emissions
Reduce urban air pollution
Hybrid Vehicles
Hybrids are not just cars: a hybrid is any vehicle
That uses two forms of energy for propulsion
Name three types of hybrid vehicle.
Two Hybrids on the Market
Toyotas Prius: 52 mpg city, 45 mpg highway
Hondas Insight: 61 mpg city, 70 mpg highway
How Insight gets 70 mpg!!
This is a new record!!
Combination of electrical motor and gasoline engine: thus
gasoline engine smaller, runs at maximum efficiency
Gasoline engine shuts off at a stoplight
Energy from braking used to charge the battery that runs the
electrical motor.
Unique aerodynamic design of car
Emissions Reduction
Insight emits 84% fewer hydrocarbons and
50% less NOx than a typical car.
Note that the Prius gets better mileage in the
City than on the highway. Why?