Friday, 25 May 2012

Some thoughts


Kettles
Recently there has been a move to improve energy efficiency, particularly here in the UK, where you can no longer buy filament lamps over 60W in power consumption. So for my contribution, when I boil a kettle for coffee or Tea, I tend to take the kettle off the power base a second or so before it automatically switches itself off.  This is not entirely altruistic, it saves me money too. 
I have found that the residual heat in the heating element in my kettle is sufficient for the kettle to come to the boil up to around three seconds after removal of the power, if you time it right.  In this way I am saving almost three kilowatt seconds every time I make a hot drink.  This does not sound like much, but if my idea catches on and only 3,600 people in the UK do the same, between us we will be saving three kilowatt HOURS every second we all do this.  It does not need to be all at the same time, because the power efficiency saving will still be the same in total even if it is spread over the day.   TBH and I make coffee or tea at least three times a day and more if we have visitors, then on average a little over 9kw will be saved per second in a day by us.  If more people do it the savings will increase in proportion, so come on all you energy savers, take the kettle off the power base or switch the wall switch off just as the kettle changes from a heating up sound to the quieter bubbling of water about to come to the boil.  A sound change you must all be familiar with. 
For those of you who have bought a power hungry coffee maker, chuck it away you energy wasters and if you really cannot stand instant coffee, buy a cafetiere, so that you can use an ordinary electric kettle and save the world.

A fair wind and calm seas
Whilst on the subject, we hear a lot about sustainable energy sources and wind power.  Wind power has become the de facto thing for our government but to my mind there are a number of snags to this form of energy.  Whilst it is fine when it is working and we are getting energy apparently for free, there are a few factors that are never made much of.
First, how much power is consumed in the manufacture of these things? These massive machines do not spring out of the ground ready formed.  They consist of highly refined materials which need to be mined, smelted and precision engineered.  All these stages are high energy processes, the smelting alone using hundreds of Megawatt hours of energy.  They have a life expectancy of twenty-five years I have been told, so do they produce as much energy that it took to build them in this rather short lifetime?
Only if the wind blows consistently - and it doesn’t.    Anyone who sails for a hobby can tell you that there is a strong chance you won’t always be able to indulge in your sport just whenever you feel like it, it depends on the weather.
On cold frosty mornings, when we all need a bit more power, where is the wind? This kind of calm and very cold winter weather happens quite regularly in the UK.  Likewise when gales rush in off the Atlantic, the turbines have to be feathered down so that they do not overload and sustain damage, they are not able to produce electricity under these conditions either.
So when the weather is at its worst, they do not produce any power so we need some conventional backup power generators to fill in for those times when there is no wind power, but the demand is going to be at its highest.
 You cannot just switch on a one hundred Megawatt generating station in an instant when the wind power falls off, it needs to run up in stages which takes several hours, so in order to compensate for lack of wind power you either need some very accurate long range weather forecasting, which does not happen, or you need to keep the backup generators running on standby.  This will waste power all the time wind power is available, but it must be available or there will be a serious brown out if the weather changes suddenly. 
So how much power have we gained so far from wind power?   Some maybe, but not a lot.
Lastly, many wind farms have been built on the West coast of the UK, because we receive our prevailing winds regularly from the west, so other than dead calms and gales we stand a fair chance of getting a reasonable amount of power from these offshore farms.   However, I have been asking this question for some years and no one seems to have an answer.  Based on the universal fact that you cannot get something for nothing, if you take energy from the prevailing winds, what does that do to the weather?
Since these farms have been in existence we have had several years of very dry winters.  This may just be a coincidence and have nothing to do with the wind farms, but looking at this long term, as more and more wind farms are built, it must have some effect.  You really cannot take energy out of a system and expect it to make no difference, so what will be the result long term?
I have no answer and it seems that no one else does either.  Should someone be looking into this?  A nice subject for an under grad’s thesis perhaps.

2 comments:

  1. Snafu, I have not yet figured out how your mind works in some of these things - not sure if you are completely serious or a little tongue in cheek :)

    I do doubt that I could be disciplined enough to accomplish your kettle energy saving project. Often I forget I actually turned the kettle on, and the water ultimately gets cold until I remember again. I know - it's a horrific waste of energy. But I AM super-good at turning off unnecessary lights.

    Your wind farm theory is a good one - I wonder if anyone in governemt actually ever thought about that!

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  2. I regularly turn the oven off a few minutes before what ever is baking is done. As for turbines and wind farms, I hear they want to build one on Flamborough Head. I'll be doing a blog on it shortly.

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