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In praise of electric light.

 
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adam2
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Joined: 02 Jul 2007
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Location: North Somerset

PostPosted: Wed Feb 21, 2018 2:36 pm    Post subject: In praise of electric light. Reply with quote

It is well to be prepared with alternatives to mains powered electric lighting, making your own electricity or non-electric alternatives both have their merits, but whilst times are normal it is worth remembering just how cheap is mains power for lighting.

Taking all the costs into account, it is doubtful if any artificial lighting is cheaper than grid supplied electricity.

Here are some examples.

Costs vary a lot so no great accuracy can be claimed, but here are some approximations of costs for a total of 10,000 hours use.

60 watt incandescent lamp.
10 replacement lamps at 50 pence each-------------£5
600KWH of electricity at 15 pence a unit------------£90
Total cost per 10,000 hours--------------------------£95

15 watt CFL.
One replacement lamp-------------------------------£5
150KWH of electricity at 15 pence a unit-----------£22-50
Total cost per 10,000 hours--------------------------£27-50
(note that I have assumed a 15 watt CFL, this will give slightly MORE light than a 60 watt incandescent, a greater saving would result from use of an 11 watt CFL, but that will be a bit dimmer. I have also assumed a purchase cost of £5 for a reputable branded lamp such as Phillips or Osram. Cheaper alternatives exist but may not last as long)

10 watt LED.
One replacement lamp at--------------------------- £6
100KWH of electricity at 15 pence a unit-----------£10
Total cost per 10,000 hours-------------------------£16.
(note that I have assumed a purchase price of £6, for a good quality lamp from a reputable maker, much cheaper alternatives exist but may have a shorter life or lower light output than claimed)


Non electric lighting, consider a Tilley lamp for example it gives a similar light to a 60 watt incandescent bulb and is most useful for emergencies or premises without electricity, but see just how expensive it is !

Paraffin consumption, 0.1 L an hour for 10,000 hours is 1000 litres
At say £1 a litre that is---------------------------------------------------£1,000
10 replacement vapourisers at £15 each----------------------------------£150
10 replacement mantles at £1 each-----------------------------------------£10

Total £1,160 for 10,000 hours use, and I have assumed very low prices for fuel and replacement parts, you could easily pay double the above.

Or what about candles ? about 120 candles will give about the same light as a 60 watt incandescent bulb.
If each candle burns for about 8 hours, then for 10,000 hours use
about 100,000 candles will be needed.
That will cost at least £25,000. Possibly twice as much.
To keep 120 candles burning neatly, and to replace them when needed may well need a servant, at a cost of another £75,000 presuming payment of the minimum wage.

Other examples to follow.
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woodburner



Joined: 06 Apr 2009
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PostPosted: Wed Feb 21, 2018 10:34 pm    Post subject: Reply with quote

That’s ok if people just used the light they needed. Unfortunately there is too much light around in many places in the world and the cheaper it gets the more people waste it.
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adam2
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Location: North Somerset

PostPosted: Thu Feb 22, 2018 11:51 am    Post subject: Reply with quote

Or worth considering home produced electricity perhaps.
For 10,000 hours use of a 10 watt 12 volt LED lamp, similar in output to a 230 volt 60 watt incandescent.

In 10,000 hours, 100KWH have been consumed, that will wear out about one large deep cycle battery at a cost of about £100.
So with the lamp costing £10, the total cost is about £110.

The capital cost of the PV or wind turbine has not been allowed for, that could amount to about £500, but will of course last a lot longer than 10,000 hours use. it might be reasonable to set say £50 of the capital cost against each 10,000 hours use, making the total cost about £160.
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