Introduction to
Electronic Circuits
Energy Consumption
Consumer Electronic Circuits
Sustainability in Electronics
An important practical piece of electronic circuit analysis and design is supporting the
Sustainability of the designs we produce and the modifications we make to those designs.
In this introductory course in electronic circuits, we are looking at supporting
sustainability from two perspectives:
1.  The Three Pillars of Sustainability – Social, Economic, Environmental
2.  The Four Pieces of Sustainability in Engineering– Person, Parts, Purpose, Plan
In previous lectures, we have looked specifically at Parts (how to reduce the number of
components and toxicity of those components that make up circuits) as a means to
improve the sustainability of the many electronic devices available on global markets.
Today, we look at one component of the Plan: how designing and using electronics
with lower power consumption in mind can increase the sustainability of those
products.
Social Equality Pillar:
Reducing power consumption in critical
electronics (e.g. cell phones) decreases the
gap in accessibility to technology between
developed and developing countries
Environmental Pillar:
Decreasing global power consumption
lessens energy demand and the burden
of producing energy from both
renewable and non-renewable sources.
Energy/Power Consumption
in the United States: Overview
Reviewing the kilowatt-hour:
One kWh = 1000 watts of power over a single hour
One watt = One joule/second
Therefore:
One kWh = 1000 watts (one joule/second)(3600 seconds/hour)
One kWh = 3,600,000 Joules!
And:
One kg of oil generates about 11.6 kWh
How much energy is consumed in the U.S.?
10,932 kWh in Electricity per Capita (U.S. 2014)
7,032 kg of oil equivalent per Capita (U.S. 2011)
for an impressive total of:
92,503 kWh TOTAL per Capita (U.S. 2011)
Graphic of person
consuming goes
here ... using
phone while driving
Residential Energy/Power Consumption
in the United States: Electricity
Where does it all go?
10,932 kWh in Electricity per Capita (U.S. 2013)
840 kWh per year or 7.7%
397 kWh per year or 3.6%
420 kWh per year or 3.8%
Residential Energy/Power Consumption
in the United States: Electricity
Where does it all go?
10,932 kWh in Electricity per Capita (U.S. 2013)
1500 kWh per year or 13.7%
1854 kWh per year or 17%
1192 kWh per year or 11%
Residential Energy Consumption
over Time
Year
Consumption
(Thousand
Megawatthours
2003
1,275,824
2004
1,291,982
2005
1,359,227
2006
1,351,520
2007
1,392,241
2008
1,380,662
2009
1,364,758
2010
1,445,708
2011
1,422,801
2012
1,374,515
2013
1,394,919
Despite the introduction and use of energy saving
appliances in U.S. households and the shift in
population to warmer, drier states (which require
less heating and air conditioning), residential
energy usage has remained essentially the same.
Consumer Electronics = the reason why
Residential Energy/Power Consumption
in the U.S.: Consumer Electronics
What role does Consumer Electronics play in all this consumption?
About 12% is occupied by consumer electronics
(which is equal to about 4.4% of total U.S. electricity consumption)
Residential Energy/Power Consumption
in the U.S.: Consumer Electronics
What role does Consumer Electronics play in all this consumption?
163 TeraWatt hours are used by consumer electronics every year.
About 12% is occupied by consumer electronics
(which is equal to about 4.4% of total U.S. electricity consumption)
Which consumer electronics are the major consumers of electricity?
Out of 163 TeraWatt hours:
1.  Analog Televisions: 53 TWh or 32.52% of total CE Energy Consumption
2.  Desktop Computer: 21TWh or 12.88%
3.  Digital Television: 16 TWh or 9.82%
4.  Set-Top TV Box: 9-10TWh or between 1.47% and 6.13%
5.  Compact Audio: 6 TWh or 3.68%
6.  Cordless Phone: 5 TWh or 3.07%
7.  VCR: 5 TWh or 3.07
8.  DVD Player: 4.4 TWh or 2.70%
9.  Laptop Computer: 2.8 TWh or 1.72%
10. Video Game Players: 2.4 TWh or 1.47%
Residential Energy/Power Consumption
in the U.S.: The Cell Phone
Not very much energy?
iPhone 5: about 3.5 kWh per year to recharge
Galaxy SIII: about 4.9 kWh per year to recharge
Should we conclude
that our cell phones
are nothing in the
grand scheme of our
energy consumption?
This is insignificant compared to over 10,000
kWh consumed every year on average by each
person in the United States
Residential Energy/Power Consumption
in the U.S.: The Cell Phone
Looking again at the Smartphone energy consumption:
A smartphone consumes anywhere between 2kWh and 19kWh per Gb of
data transmitted. For an average between 1Gb and 2Gb of data
transmitted per month for the average Verizon or AT&T subscriber, the
"cloud" energy involved in smart phone use can add up!
A cell phone tower
consumes about
3.5kW. Operating all
the time, that adds
up to over 30,000
kWh per year per cell
phone tower.
The energy involved in wirelessly transmitting data and voice can add up to
between 24kWh and over 400 kWh per year depending on how the data is
transmitted – at the upper end, this is more than a refrigerator consumes!
Residential Energy/Power Consumption
in the U.S.: Hidden Energy Usage
What role does Consumer Electronics play in all this consumption?
About 12% is occupied by consumer electronics
Over 30% of this 12% is consumed when the device is not in use!
While 70% of this total is used in the
"Active" mode of operation, 23% is used in
the "Off" mode (the device is turned off, but
still drawing power).
Electricity consumed in "off" mode is
decreasing faster than electricity
consumed in "active" mode in most
consumer electronics, but still represents a
significant source of "waste"
While consumer electronics that are actively used are maxed out on power
savings created by low power design techniques, big "wins" can be made by
improving sleep and off mode power consumption!
Residential Energy/Power Consumption
in the U.S.: Vampire Power Draws:
Exposing the Vampire:
Electronics that remain
plugged into AC outlets
in the home draw
power even when turned
“off” or when operating
in "sleep" mode.
This vampire draw is
small on a per device
basis, but due to the
increase in the number
of electronics in a
household, the total
amount of power in
vampire draws now
exceeds 30% of
consumer electronics
power usage.
What are the
advantages and
disadvantages of
each of these
approaches?
Vanquishing the Vampire
•  Unplug: physically unplug
consumer electronics devices
when they are not in use.
•  Kill switch: a simple switch
or switches installed in the
home which turn off everything
in a particular floor or entire
house.
•  Top Down: consumer
electronics products are
designed to draw less power in
off or sleep mode.
•  Off means off – Products are
designed to fully turn off, no
electrical draw, rather the put
into a standby mode when
turned off.
Energy/Power Consumption in
Consumer Electronics: Summary
Despite
significant
advances in
energy efficiency
associated with
household
appliances, the
U.S. continues to
consume an
immense amount
of electricity on
a global scale.