Electric Vehicles and Plug-In-Hybrid Vehicles

http://www.roperld.com/science/ElectricCarsMusings.pdf

L. David Roper
http://arts.bev.net/RoperLDavid/

2 July, 2017

Contents

Electric Vehicles

Electric and Plug-In-Hybrid Vehicles Now or Soon Available in the U.S.

All Electric


1 mpge = 0.0292 miles/kWh

Plug-in Hybrid

Practical Environmentalist 2012 Electric Cars in the USA

There is a large tax credit for purchases of electric and plug-in hybrids.

Plug-In Conversions

Vehicle to Grid (V2G)

Vehicle to Home (V2H)

Batteries

Regeneration

Regeneration converts energy expended braking for slowing down and going down hills to electrical energy to put back in the battery. Usually the electric motor that propels the vehicle also serves as the generator for regeneration.

Regeneration References

Range and MPGe


miles/kWh=0.0292*MPGe

The European calculation of range yields about 1.5 times the USA calculation of range. .

Charging Stations

There are three levels of charging stations for electric vehicles:

  1. Level 1: 120 volts AC @ 12 amperes current.
  2. Level 2: 240 volts AC @ 15 amperes current (3.3 kW charger).
  3. Level 2: 240 volts AC @ 30 amperes current (6.6 kW charger).
  4. Level 3: 480 volts DC @ 80-125 amperes current.

Suppose an electric vehicle has a battery that contains 20 kWh of useable energy; then the charging times for the three levels of charging stations are:

  1. Level-1 = ~14 hours
  2. Level-2 (3.3 kW) = ~6 hours
  3. Level-2 (6.6 kW) = ~3 hours
  4. Level-3 (90 A) = ~0.5 hours

An EVSE for direct connection to standard 120-volts or 240-volts outlets.

Drivers of the Nissan LEAF can upgrade the 120-volt EVSE cable that comes with the vehicle such that it can also be used with a 240-volts NEMA-L6-20R outlet. Drivers of other electric or plug-in-hybrid vehicles that use the J1772 plug (e.g., Ford Focus EV, Mitsubishi i-MiEV, Chevrolet Volt) can purchase the revised LEAF EVSE for $979 + $20 shipping and then sell the EVSE that came with the vehicle. It costs another $48 to change the LEAF EVSE 240-volts from 12 amperes to 16 amperes.

Charging-stations types

http://www.roperld.com/science/chargingstationsbevs.pdf

EV Charger Sharing Protocol

Websites for Charging Stations' Locations

Wireless Charging Stations

Prices for Charging EVs

In southwest Virginia the following prices existed in 2012:

Long Distance Travel by Electric Cars from Blacksburg Virginia

Charging-Stations References

Lower Maintenance

Some of the parts not in an electric car:

Only one reason to drive an electric car!

Gasoline-Prices Projection

This is only one reason to drive an electric car.

Gasoline-Prices References

Less Global-Warming Gases Emissions

Two reasons that electric vehicles produce less Global-Warming-gases emissions than do gasoline cars:

1.      Electric motors use energy more efficiently (about 90%) than do gasoline engines (about 25%) or diesel engines (about 40%).So, even with coal electric power plants at about 40% efficiency, electric vehicles times coal efficiency yields about 36% efficiency, which is better than gasoline vehicles and about the same as diesel vehicles. However, energy efficiency is not the same as carbon-dioxide emissions. A gallon of gasoline contains about 36.6 kWh of energy and produces about 19.4 lbs of carbon dioxide; so, per kWh the relevant number is about 0.53 lbs/kWh for burning gasoline at 100% efficiency. The actual efficiency of about 25% for gasoline engines changes the number for gasoline engines to 2.12 lbs/kWh. Compare this to the coal-fired-power number of 2.25 lbs/kWh. However, the U.S. mix of electric power plants (see below) yields about 1.78 lbs/kWh or lower, which is considerably lower than the 2.12 figure for gasoline engines.
Using natural gas for an electric power plant improves the efficiency to about 60%, yielding a combined efficiency for electric vehicles of about 54%, considerably better than diesel vehicles.
Wind or photovoltaic electric power plants at 100% efficiency, in terms of not requiring fuel, yields a combined efficiency of about 90% for electric vehicles, much better than gasoline or diesel vehicles.
The sources of electrical energy in the U.S. are Coal 50%, Nuclear 20%, Natural Gas 18%, Hydro 7%, Other 5%. Assuming that nuclear electric power generation is as inefficient as coal for producing electricity, when all factors are considered, the average efficiency of U.S. electric power generation is about 0.4(0.5 + 0.2) + 0.6(0.18) + 1.0(0.12) = 0.51 = 51% . Then the average yield for electric vehicles in the U.S. is about 46%. In almost all circumstances electric vehicles are much better than gasoline vehicles and usually better than diesel vehicles. As more and more renewable sources of energy are used to produce electricity, electric vehicles will be much better than fossil-fueled vehicles in not emitting Global-Warming gases.

2.      It is easier to sequester the Global-Warming gases at a power plant than from the tail pipes of millions of vehicles. See http://electric-cars-are-for-girls.com/electric-powered-cars.html .

Less Money Emissions

A gallon of gasoline contains about 36.6 kWh of energy and a gallon of diesel contains about 40.6 kWh of energy. (http://www.bpa.gov/Corporate/KR/ed/energyaudit/chapter1/chap1.htm)

 

If you pay $.08 per kWh for electricity:

·         The equivalent price of the energy content of gasoline would be $2.93 per gallon.

·         The equivalent price of the energy content of diesel would be $3.25 per gallon.

 

However, electric motors are about 90% efficient, gasoline engines are about 25% efficient and diesel engines are about 40% efficient. Allowing for those efficiencies:

·         The equivalent price of gasoline would be $0.81 per gallon.

·         The equivalent price of diesel would be $1.44 per gallon.

 

To calculate the approximate equivalent price per gallon for a gasoline vehicle and a diesel vehicle for a price P per kWh of electricity to charge the batteries of an electric vehicle:

 Gasoline: 36.6(0.25/0.90)P, Diesel: 40.6(0.40/0.90)P .

USA Car Commuting Distance Traveled

USA EV Sales

Global plug-in sales

One often reads laments that electric car sales are not increasing very fast in the US. However, they are increasing much faster than early Toyota Prius sales did:


The electric data includes plug-in hybrids, such as the Chevrolet Volt and the Toyota Prius Plug-In.

The exponential time constant for the Prius is 2.00 years and the exponential time constant for electric cars (including plug-in hybrids) is 0.916 years. If the electric-cars growth continued at that same exponential rate, it would exceed the current number of cars in the U.S in ten years!

New technologies usually grow exponentially for many years.

Of course, only two data points can be equally well fit by a straight line, which fit also is shown in the graph above. The projections for the next five years for both fits for electrics are:

Reality will probably be somewhere between the two projections, say 500,000 electrics by year 2015.

References

Go to top.

L. David Roper interdisciplinary studies
http://www.roperld.com/science/ElectricCarsMusings.pdf
When will all cars be electric?: http://www.roperld.com/science/ElectricCarsTotal.htm

L. David Roper, http://arts.bev.net/RoperLDavid/
2 July, 2017