Powering your iPad costs $1.36 per year If you charge your fully depleted iPad every other day, it'll cost you a buck thirty-six per year, according to a just-released study by the Electric Power Research Institute (EPRI) of Palo Alto, California. "At less than a penny per charge these findings bring new meaning to the adage, 'A penny for your thoughts'," said the …
I don't think this follows from the stated figures!
12KWh * £0.12354 * 1.05 = £1.56. If you'd like the standing charge included, for me that adds £0.015/KWh, making it more like 12KWh * £0.139 * 1.05 = £1.75.
You'd be paying something like £0.54/KWh to make it £6.80! - perhaps it costs that much in the Shetland Islands, but this is out of line for most of the UK. You can pay more than £0.12354/KWh, but not THAT much more. I'd advise shopping around.
http://www.decc.gov.uk/en/content/cms/statistics/energy_stats/prices/prices.aspx
http://en.wikipedia.org/wiki/Electricity_pricing
"The 60W CFL is really the 7 or 8 W model with the lifespan of a mayfly and the receipt written in invisible ink so you cant even waste time going to the shop to get your money back."
Sigh.
I've still got some of the original CFLs bought for my first flat in 1997. I've also bought ones that failed within 2 weeks, just like - hey! - incandescents.
In a temperate (alright, cold) country like the UK I'm agnostic about the benefits of CFLs, but I don't like to see the usual tripe peddled about them being whale killing, ozone zapping eco nightmares. In warm climes they make a much better case for themselves.
Hm.
The iPad has a 25 Wh battery, which is 25*60*60 = 90kJ. Assuming we charge it from flat every two days, that's 90kJ * 180 = 16.2 MJ. Assume charging efficiency of (wild guess here) 10:1, that's 160 MJ over a year.
Electricity cost is about 10p per kWh, so that's 10 / 1000*60*60 = ~3x10^6 pence per joule.
So over the year, our 160MJ is costing roughly (*very* roughly!) 480 pence.
Given how many numbers I made up, the fact it comes out at the same order of magnitude as the poster does suggest that their figures are at least plausible.
The energy cost of replacing the batteries when they eventually wear out needs to be included in the "energy consumption". After all, people aren't running their their iPads off the charger.
Probably though, the attention span of iPad consumers is shorter than the lifetime of the batteries. In other words even discussing power consumption through the charger is irrelevant outside of the original engineering concerns.
There is a lot of evidence to suggest that many people will not get to the stage of needing a replacement battery for their portable computing device as they have a contract (in the case of a phone) which entitles them to upgrades, or they buy the newest version of the gadget when it's released every 1-2 years anyway.
So really shouldn't the whole cost of the device be included into the study?
I've been experimenting with LED lighting, in this case those 5 meter 300x 5050 sized LED strips that are great for whole room lighting once installed right (pointing at the walls/ceiling instead of directly down works well).
I found that the normal white LEDs are too 'cold' and blue in colour whilst the 'warm white' ones are almost too yellow, but if you use an equal mix of the two types you get a really nice daylight-ish white. Throw in some dimming circuitry and you can fade between the two types of white to get the 'perfect' blend.
My iPad is powered by biogas given off by smug ecotypes who would buy an iPad, and then think "I know what will make this tech device efficient - I'll use expensive solar panels to charge it, panels that I'll mostly keep idle so as to make the process even less efficient".
The environmental cost of the solar panels will massively outweigh the 'savings' from not plugging your iPad into the mains.
A Watt is a unit of power (1 Joule per second). The SI unit of energy is the Joule. Take your pick from:
kilo Watt hours (Energy supplied by an electricity company): 1kWh = 3.6MJ
British thermal unit (Energy supplied by a gas company): 1BTU = 1.055kJ
Foot pound force (A unit of energy - honest): 1ft·lbf = 1.356J
Calorie (Energy spent while exercising): 1cal = 4.2J
Calorie (Energy content of food): 1Cal = 4.2kJ
Electron Volts (Energy per particle in a particle accelerator): 1eV = 1.602E-19J
Litre (1/1000 of a cubic metre) of petrol: 34.2MJ
Kiloton (Energy in 1 ton of TNT): 1kt = 4.184GJ
The units of power are just as bad. The most common is:
1Windturbine = electrical energy used by 10billion homes with gas hot water, cooking and heating, petrol driven transport, food from high energy content fertilisers, candles for lighting and the average number of gadgets for a family living in a remote corner of a rain forest.
Is likely flawed, as whilst a TFT based telly uses a backlight that draws a constant power regardless of picture content, on a plasma there is no backlight, the power consumption is based almost entirely on what's being displayed. A dark scene will draw very little, a light scene lots, but unless you only ever watch your skiing holiday movies on your plasma, the liklihood is the AVERAGE power consumption will be close to that of a TFT (LCD/LED)
At the end of the day, there is little difference between modern plasmas and TFTs, unless you have an agenda, in which case, you can manipulate tests to make TFT seem more energy efficient.
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