HYBRID VEHICLES

Honda Civic Toyota Prius

•Small and fuel-efficient gas engine•Electric motor to assist underpowered gas engine•Regenerative braking•Engine shutdown at stops

CHEVY VOLT - First “plug-in hybrid”•able to drive 35 miles using only battery-powered electric motor•unlimited range with gas engine (and refillable gas tank)

•Electric drive motor: 150 hp – turns the wheels•1.4L Gasoline engine: 80 hp – turns the wheels and recharges the batteries which power the electric motor

•Commute (~35 miles/charge) gas-free and tailpipe emissions-free for about $1.50 of electricity per day.•On-board gas-powered generator creates enough electricity to power the Volt for up to 344 miles/tank of gasoline.

CHEVY VOLT – First plug-in hybrid

•Regenerative braking captures energy of forward motion and converts it into electricity.•Volt can reach a top speed of 100 mph in all-electric mode in near silence.

CHEVY VOLT – First plug-in hybrid

•16-kWh lithium-ion battery pack is backed by an 100,000 mile/8-year warranty•Lithium-ion cells outperform nickel metal hydride cells (found in today's hybrids) in life cycle•Batteries fully charge in ~10 hours with 120-volt line, or ~4 hours using a 240-volt line

CHEVY VOLTFirst plug-in

hybrid

Plug-in hybrid gas-electric vehicles are about to reach the market, eg., the Chevy Volt. The Volt can travel 35 miles electric only using its battery, and with its gas engine can travel another 344 miles on 9.3 gallons of gasoline in its fuel tank. The batteries recharge in 4 hours at 240 volts, and use 36 kWh to move the car 100 miles. One gallon of gasoline (costing $3.75) contains energy equivalent to 33.7 kWh of electricity, and electricity costs an average of 10 cents/kWh.

A) Estimate the reduction in gallons of gasoline burned per year that you would achieve by switching to a plug-in hybrid gas-electric car, i.e., the Volt, assuming the following: (1) you will drive your Volt 30 miles per day on weekdays, 75 miles on Saturday and 30 miles on Sunday; (2) your present vehicle gets 25 MPG, the average mileage for a car in the U.S.; and (3) you drive your current gas-only car the same number of miles as you will drive your Volt.

B) How much more or less would it cost in one year to drive the Volt compared to the “average” U.S. automobile?

A) VOLT: weekdays - 30x5=150; Sat. – 35 electric, 40 gas; Sun. – 30 electric 215 electric (no gas), 40 mi on gas 344 miles/9.3 gal = 36.99 mpg 40mi/36.99 mpg = 1.1 gal/week x 52 = 56.2 gal/yr GAS CAR: 255 miles/25 mpg = 10.2 gal/wk x 52 = 530.4 gal/yr 530.4 – 56.2 = 474 gal/yr SAVED

B) VOLT: 100 miles/36kWh = 2.77 mi/kWh 215 mi/2.77 = 77.4 kWh/wk x 52 = 4024.8 kWh/yr x $0.10 = $402.48/yr electricity 56.2 gal/yr x $3.75/gal = $210.75 gasoline TOTAL COST = $613.23 GAS CAR: 530.4 gal x $3.75/gal = TOTAL COST = $1,989.00 SAVE $1375.77/yr

C) There is a concern that switching to electricity for our transportation fuel will produce as much or more CO2 than burning gasoline since 67% of our electricity

comes from fossil fuels. If burning one gallon of gas produces 20 kg of CO2, and assuming that the current

mix of fuels burned to make electricity emits 0.6 kg of CO2 per kWh delivered, determine whether or not driving

a Volt as described above would increase or reduce your carbon footprint (and by how many kg of CO2) if you

were currently driving the “typical” U.S. automobile described in (A).

C) Determine difference in CO2 emissions between Chevy Volt plug-in gas-electric hybrid and standard gas-only car getting 25 MPG.ASSUMPTIONS: Volt – driven 30 miles per weekday and on Sunday, driven 75 miles on Saturday, goes 35 miles per charge, uses .36 kWh per mile, can go 344 miles on 9.3 gallons in gas tank, charges overnightStandard car – driven same total miles per week as Volt, gets 25 MPGGasoline – burning one gallon of gas produces 20 kg of CO2

Electricity - producing and delivering one kWh of electricity releases 0.6 kg CO2

VOLT: electric - drives (6x30) + 35 = 215mi x 52 = 11,180 mi 11,180 mi x .36 kg CO2/mi = 4025 kWh x .6 kg CO2/kWh = 2415 kg CO2

gas – drives 40 miles at rate of (344mi/9.3gal=) 37 MPG, uses 1.08 gal1.08 gal/wk x 52 = 56.2 gal/yr x 20 kg CO2/gal = 1124 kg CO2

total CO2 produced in one year = 2415 + 1124 = 3539 kg CO2/yr.GAS CAR:

drives (6 x 30) + 75 = 255mi/wk x 52 = 13260 miles/25 MPG = 530.4 gal/yr.530.4 gal x 20 kg CO2/gal = 10,608 kg CO2/yr.

DIFFERENCE: 10,608 kg – 3,539 kg = 7,069 kg CO2/yr. SAVED