Does making the battery for a hybrid car take more energy than the car saves?

Posted in Green, Random, Tech on April 13th, 2011 by Andy
A Humvee

Some folks on the internet have actually tried to claim that a hybrid car uses more energy than a Hummer. Lol!

I recently heard someone trot out a factoid i’d heard before a couple of times:

The battery on hybrid cars takes so much energy to produce that it’s actually greener to drive a normal car.

As a Prius owner myself I wondered; could this be true?

Toyota have been rather tight-lipped about the exact details of Prius battery manufacture, although this is probably just because they consider their Hybrid Synergy Drive technology commercially sensitive (at least while they’ve got such a lead in the hybrid market over their competitors)

So let’s take a guesstimate at some numbers and see how it stacks up:

A new Prius starts at about £20,845. Let’s be generous to the sceptics and say that making the battery is a whopping 20% of the sticker price of the car (it’s likely much less than this). That means it costs £4169 to make a battery. Again, lets humour the sceptics and say that 90% of the cost of the battery manufacturing process is energy and that Toyota pays the equivalent of 5p/kWh. That puts the energy consumed during manufacture at 270GJ. That amount of energy is equivalent to a little over 1800 gallons of petrol. Toyota rate the hybrid drive as offering an improvment of about 25mpg over a standard drivetrain (using figures from the Auris vs Auris Hybrid), even if that’s only 15mpg in reality then a Prius would only take 27,200 miles to make back the energy used making the battery. Remember, those numbers I chose are extremely pessimistic, it’s likely that the real break-even point was much sooner.

Toyota’s warranty on their hybrid batteries is eight years, so unless you don’t think you’re going to put 27,000 miles on the clock in that time, a hybrid will reduce the amount of energy your driving consumes.

So bottom line: even a rough calculation of the energies involved does not support the claim that building batteries for hybrid cars is more wasteful than driving a conventionally powered car.

If you want to play around with the numbers, you can download this spreadsheet.

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Why “The Singularity” is bollocks

Posted in Random, Tech on February 20th, 2010 by Andy
A graph of the number of blades per razor over time

The logic behind the "singularity" applied to razor blades. Personally I think there might be something in this one...

There’s a lot of nonsense talked about the supposedly looming “technological singularity“. For the uninitiated, this is based on a principle called Moore’s Law. Broadly speaking, Moore’s Law states that every couple of years, computers get twice as fast for the same cost. The impressive thing is that in the 40 years or so since Gordon Moore first cooked it up, it’s been remarkably accurate, even though the tech has gone through changes he could never had foreseen.

What gets all the singularity nuts excited is the idea of what happens next. According to Moore’s “Law”, computers will get smarter and smarter, until eventually they’re smarter than us, and begin (according to the singularity folks) designing themselves at a rate we couldn’t match. The machines take over, humanity becomes irrelevant, etc, etc.

Except that’s a load of bollocks, and here’s why:

In the real world stuff never continues to grow exponentially forever. Projections based on unbridled exponential growth are the mathematical equivalent of perpetual motion machines. It’s called a Malthusian growth model, after a bloke who made some very dire predictions about world population back in the 19th century. Lucky for us, the complete lameness of this type of model meant that the world didn’t implode under the combined weight of humanity, and the mathematicians went back to the drawing board. The result was a new, better model they called the Logistic model, which acknowledges the idea that even if something can grow at an exponential rate for a while, eventually forces that may have been too small to notice begin to slow the growth rate. This model has been far more successful at accurately modeling real-world processes.

Sure the idea of the singularity is fun, but the less sexy reality is that your wrist watch is unlikely to ever be able to out-smart you, let alone usurp your position at the top of the food chain by creating it’s own army of super-intelligent wrist watches. Moore’s Law will eventually break down, machines will stop getting smarter so quickly, or even stop getting smarter at all.

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Why I have enough light bulbs for the next 404 years

Posted in Random on January 18th, 2010 by Andy
A human skeleton

A picture of me the next time I buy light bulbs

UK electricity companies are in the habit of sending out packs of free energy saving lightbulbs to their customers. It’s one way they satisfy their climate change obligations to government. During the course of a couple of house moves i’ve ended up getting sent 3 packs of four bulbs each, so 12 bulbs in total.

Now, I already had five spare bulbs, so that means i’ve got 17 spares kicking around now. We currently use eight low-energy bulbs around the house, and i’ve yet to have one die in about three years of use. If one blew tomorrow, that would put my usage at 0.042 bulbs per year. If they all blew, that would mean 2.67 bulbs per year. So in the very worst case scenario I have 6.37 years before I have to buy stock up on bulbs again. If you take the lowest estimate, i’ve got enough for 404 years.

I mean, free stuff is great, but I think i’m pretty much sorted for light bulbs now. If you’re listening power companies: you can stop sending them now. If you feel you have to send us free stuff, alcohol will do nicely.

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The Mathematics of Pulling

Posted in Random, Stupid trivia on April 17th, 2009 by Andy

I’ve recently been brushing up on some basic maths as part of a degree course. Which is fine. But the more evil number magic you do the more it creeps into your brain and changes the way you think about things.

Take, for example, the oft repeated Rule of Non-Creepiness when it comes to partners. According to common wisdom, the minimum non-creepy age for anybody you’re shagging is half your own age, plus seven. Or in geek:

y=0.5x+7

Which, any maths knob will tell you, graphs as a straight line. Now, it occured to me that this rule works both ways, and that your prospective partner also has to satisfy a similar non-creepiness equation. So the upper age limit of your partner is bounded by:

y=2x-14

So what you ask? Well it occurred to me that these two straight lines diverge.

Range of Eligible Partners

This means that as you age the number of eligible partners increases. I actually found that a rather encouraging thought. Most things get steadily shittier with age, but your chance of finding some loving (assuming you aren’t sold off into wedlock already) actually improves over the years.

But just how much better do they get? We need some hard figures. So I went to statistics.gov.uk and got some population stats for the UK.

Their nice .svg graph comes with hard numbers as well. This allows us to calculate, for any given age, the total number of people of the opposite sex within your upper and lower non-creepiness limits. Of course, only looking at the opposite sex completely overlooks the love that dare not speak it’s name. If anyone wants to track down some hard stats and redo the numbers adjusting for gayness, be my guest.

So this brings us to our second graph:

Total Number of Available Partners

Total Number of Available Partners

Lo and behold, we can see that for both sexes the number of eligible partners increases stridently well into our 30’s and 40’s. From the raw data we can see that it doesn’t level off until age 47 for males and 49 for females. Eventually the rot does set in, but not until the surprisingly late age of 51 (for both sexes) and even the then only declines at a maximum rate of 2% per year until death.

Note for pedants:
These figures involve a certain amount of fudge. First of all, the population data for 2009 is a projection, latest official figures are 2007.
Also, due to the fact that the non-creepiness rule produces ages such as 23.5, and we only have data for ages that are whole numbers i’ve had to average the numbers between whole number ages to keep the things relatively sane.
If that bothers you, then +10 maths geek points. Now shut up.

On a roll, I decided to make another graph, this time showing how our fortunes change over the years.

Rate of Change in Available Partners

Rate of Change in Available Partners

Sure enough, although the raw numbers of actual partners is low, it’s the young ‘uns that are experiencing the fastest rates of growth in the eligible partner numbers. Good for them. But the graph does also show that it takes a long time for the line to crash down to zero, and even then doesn’t dip too far into the negatives.

At this point, it occurred to me that the next step was to get more data. How would marriage (and divorce) figures affect the shaggable population? And what about getting some numbers from Hot or Not and introducing some kind of munter factor? However, enough is enough. If I carried this maths lunacy any further I was going to have start flushing my own head down the toilet for being a weedy poindexter.

So i’ll leave it there, and will hand over this important line of research to the faceless geekosphere. Stride on, my nerdy brothers!

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