IEEE Electrification Magazine - June 2014 - 16

U.S. Electrical
Energy Production (gWh)

6,000
5,000
4,000
3,000
2,000
1,000
0
2010

2015

2020

2025

2030

2035

Year
Coal

Petroleum

Natural Gas

Nuclear

Renewable Source

Figure 1. U.S. electrical energy production. [Source: Annual Energy Review 2010, DOE/EIA-

U.S. Electrical Energy Price (US$/kWh)

0384(2010) (Washington, D.C., October 2011) and supporting databases.]

0.12
0.1
0.08
0.06
0.04
Residential

0.02

Transportation

0
2010

2015

Commercial

Industrial

Average
2020

2025

2030

2035

Year
Figure 2. The projected price of electricity in the United States. [Source: Annual Energy Review
2010, DOE/EIA-0384(2010) (Washington, D.C., October 2011) and supporting databases.]

Petroleum and Biofuels
(Conventional and Alternative Sources)
Electricity and Hydrogen
(Zero Emission Energy Source)

Light
Electrification

HEV
PHEV

ExtendedRange Electric

Battery
Electric

Increasingly Electrified Propulsion System

Conservation

Displacement

Figure 3. The level of electrification in an automotive propulsion system.

I E E E E l e c t r i f i c ati o n M agaz ine / j un e 2014

economy, resulting in some level of
petroleum conservation. some
options listed in Figure 4 include
continuously variable transmission
(Cvt), downsized turboengine, variable lift, multispeed transmission,
vehicle start-stop, etc. however,
most petroleum displacement is
achieved with an increasing level of
electrification. Battery energy is
increased with an increasing level of
electrification. For mild and full
hybrids, roughly 10% and 25% of
energy, respectively, comes from the
battery. this number is roughly
increased to 40-50% for plug-in
hybrids. For erevs, battery energy is
100% when the car is operating in
pure ev mode while the battery
energy drops in the extended-range
mode when the internal combustion engine (iCe) is added. obviously
for Bevs, the battery energy is 100%.
the higher the level of electrification, the higher the vehicle fuel
economy. the improvement of fuel
economy with the increased level of
electrification is achieved because of
several reasons:
x
improved engine/transmission
efficiency with reduced engine
and transmission losses
x fuel cut-off during deceleration
x stop-and-go operation
x
regenerative braking (by capturing energy released during
vehicle deceleration).
in pure evs, the equivalent vehicle fuel economy improvement is
achieved because of the overall higher efficiency of the electrical propulsion system and battery charging
(from utility), regenerative braking,
and energy diversification of the
electricity generation, among others.
the battery ev is widely accepted to be the automobile of the
future. government regulations in
the united states and other nations
effectively demand the production
of Bevs whose sole source of propulsion energy is electricity. today,
battery technology is still challenged
to supply sufficient energy by itself
for vehicles that customers will purchase in the numbers required by

Table of Contents for the Digital Edition of IEEE Electrification Magazine - June 2014