Partial truths

As a retired electrical engineer, I find it hard to accept claims by people appearing on television news telling us that we are wasting a lot of electricity when we leave our cell phone chargers plugged in all the time. 

The claim is that these chargers still use electrical energy even when not in use and that cumulatively, these chargers use enough electricity to require more thermal electric generators on line.  If we only unplug these chargers, we can shut down some coal burning generators and help our environment.


Most technical people know that unused or wasted energy most often show up as heat. Cell phone chargers are typically cool when not charging even if plugged in and get slightly warm when charging.

One recent television news show with that claim finally motivated me to do some calculations.

The result is that the claims are true, but only partially true.

Typical cell phones use about 2-5 watts when charging and .1 to .2 watts when not charging.  This agrees with my intuition that not much energy is used when plugged in.  Almost all chargers are "switching power supplies" meaning that they turn on to let power through when there is something to charge.  When there is nothing to charge, there is a little bit of power used just to keep the circuits activated and transformers magnetized.

Assuming one cell phone each for the 30 million Canadian population, if we all plug our cell phones in at the same time, it will demand 60 Megawatts from a generator.  This is small in terms of utility power plants but large for independent power producers.

However, if we take the 300 million US population, then the total demand is 600 Megawatts.  Now we can point to that figure and say "see, that is the size of a decent coal burning thermal power plant that can be eliminated if we don't charge cell phones".

But we don't all charge our cell phones at the same time.  So if we use the power usage with the charger plugged in but not used, it is one tenth of this figure.

Now a much smaller power plant of 60MW capacity for the whole US population.

Perhaps we have an iPad, iPod, and a few other chargers.  So triple the figure and we have 180MW.

Still seemingly a big number and still the truth.

However, what is not mentioned up to now is that there are 6,997 power plants in the US with a capacity larger than 1 MW.  The total generation capacity is around 600,000MW.

So the cell phone chargers demand around 0.1% of the generation capacity when charging and around 0.01% of capacity when plugged in but unused.

It cost around 50 cents a year to run a cell phone charger per year.  http://energyusecalculator.com/electricity_cellphone.htm

Note that it is true that if we all unplug our chargers and stop charging our cell phones, that we can indeed shut down a generation plant or two in the US.

It is not that the claim is not true, but that it paints a picture that is not true.

Someone compared it to bailing the sinking Titanic with a teaspoon.  It is true that it helps but it is not the right use of our attention and energy.


Most of us do not have a grasp of the number of generation plants there are and the overall size of the system so we are impressed with large numbers resulting from multiplying with large populations.

Shutting down a power generation plant is a vivid image.  So long as we don't see it as one among several thousand.

Our book club is currently reading Joseph Heath's "Enlightenment 2.0".  It highlights how we need rational thinking and analysis to resist our intuitive feel.

Here is an example of that.

In our modern interconnected life where division of labor narrows us to our own specialties, we depend on experts to for advice.  Unfortunately, these experts often have their own agendas to promote and it is not always easy to judge the validity of their expertise. To make matters worse, mass media is no better at selecting experts than we do and the wrong people get media exposure all the time.

So we have partial truths and it is up to us to decide what else we should know that we have not been told.

How are we suppose to know what we don't know?

May 14 Living the dream

Next week at the Ideas Cafe, we will discuss the idea of "living the dream".



I came across this phrase while looking at my physiotherapist's website.  It lists one of their previous physiotherapists as in Mexico "living the dream".  Presumably, he is retired and doing what he always wanted, living in a warm place, with few cares that previously came with work life.

It reminds me of the ending of children's books "......and they live happily ever after."

I am retired and many in the group are. Are we living the dream?  Does it feel like we are ?  Not having to wake up to the alarm clock and join in the rush hour traffic,  not having to deal with people and situations because they are in the way of our desired goals.  It all sounded like we are living the dream.

Except that it does not always feel like we are.

Ask anyone who has retired for a while and they will tell you that life is better than before but it is still a routine, not the utopia that working people think of.

If you have trouble believing this or think that we are just a bunch of hard to please people, just think of your previous situations.

Remember when you were in grade 9. Did the grade 12 students seem super cool?  They seem free.  They even get to choose what they are going to study! Lucky for them, school will be over soon. No more homework, unreasonable teachers.

But did you feel that way in Grade 12?  Maybe for a week, but soon, it is the fear of the uncertainties of college or the work world, the prospect of starting all over again from the bottom after being the most senior class in high school.  Why did you not enjoy what your grade 9 self thought you would have ?

It seems that we all have dreams of what we rather be instead of the present.

We work towards that but quickly develop dreams of something else that we rather be instead of enjoying the moment that we reach our previous dream.

Is this the inability to live in the present, that of mindfulness so popular today?

Can we ever be content if we seem to be forever chasing dreams, going for the grass that is greener elsewhere?

However, if we are able to appreciate the present, to savoir the moment, let it be, then what of tomorrow?

Should we stay in the world of grade 9 because that was what we wanted when we were in grade 6?

How long should we dwell on our previous dream before we explore new territories?

When should contentment give way to new explorations?

Can contentment ever become too much of a good thing?

Where is the balance?

Maybe that is the secret of the most popular leisure activities like golf. There is the satisfaction of achieving a better score but it soon gives way to wanting an even better score and the progression gets more and more difficult but still possible.

Without consciously knowing it, we are moving through life through one challenge after another, enjoying the thrill of success from time to time, only to be urged on to a new objective from the perspective of the new starting point.

Boredom is the motivation to search for new challenges, launch new expeditions.

We shall never rest.  Not for long in any case.

I am offended....(part 2)

This coming Wednesday at the Ideas Cafe, we will be discussing another source of offense, that related to gender and sex.

Should men compliment women on their beauty without worry about being accused of treating women as sex objects?

What is the difference between an appreciative versus a leering glance? It is apparently very obvious but impossible to quantify.

Flirtation or sexual harassment?  What are the elements that differentiate one from the other? http://www.theguardian.com/commentisfree/2014/apr/09/everyday-sexism-condemns-sexual-advances-mysogynist#comment-34150155

Are all sexual advances "misogynist" ?  http://www.theguardian.com/commentisfree/2014/apr/09/everyday-sexism-condemns-sexual-advances-mysogynist#comment-34150155

Why is it difficult to discuss a proposition for sex?

Can sexual advance ever be respectful and courteous?

To quote the second article, "As such, there is nothing inherently sexist, or threatening or harassing, about making a direct, unambiguous sexual advance to another person. We are conditioned to find such propositions taboo because an expression of straightforward, unencumbered desire transgresses prevailing ideology."

" Sexual pleasure pursued purely for its own sake runs counter to what Freud called the "reality principle" and social philosopher Herbert Marcuse later adapted as the "performance principle" – ie the restraints placed on us by the demands of civilised society, whereby sexual gratification has to be earned through social "performance". Such performance is manifested through some or all those things – money, social status, property, marriage, procreation – that underpin capitalism and ultimately civilisation. In short, such a principle seeks to ensure that the pursuit of sexual pleasure occurs initially within a framework of spending and consumption, being ultimately directed towards a monogamous, patriarchal, potentially procreative relationship."

" The behavioural codes of contemporary society already make it extremely difficult for both men and women to approach strangers with a view towards making sexual advances. This should be a source of regret to us all. There is no shame in feeling and expressing sexual attraction, and we should be promoting conditions that give rise to as much mutual sexual pleasure as possible. After all, it's one of the greatest pleasures life offers. And it's free! Of course, this very freedom exemplifies why unencumbered sexual pleasure presents such a problem for those who would support the sexually repressive ideologies that still prevail today."

The amount of comments on these two articles from the Guardian shows the intense interest and yet opposing view on these topics.

Should beautiful women (or men) use their good looks to their advantage in advancing their objectives, while being offended by other admirers who do not fit their purpose?

Should powerful men (or women) use their influence and be offended by others who are attracted to them?

But I digress, there is so much to discuss on just the courtship dance and how it affect our lives even for those of us who may not be in the dance.

Read the articles and let's discuss Wednesday on how courtship is in modern day society!