Standby Power Question

cloudy on 23/05/2016 - 09:03
Last edited 23/05/2016 - 09:28 by 1 other user

I just read this article, and thought it's worth sharing.

Standby energy consumption adds $860 million to electricity bills

And did some quick maths to check my understanding of watts and the cost we pay.

The says we waste around 40w per say and it cost us almost $95 pa.
So I did 40*365= 14600w. So that is 14.6 kW. At $95, I got around $6 per kW, that sounds like a lot more than what I pay. I thought we pay around 20-25c per kW.

Where am I wrong?

Sorry for the rounding in numbers, using my phone and can't remember all the figures to the tee.

• 

  retiredfeline on 23/05/2016 - 09:18

  +1

  Watt is a measure of power but you pay for energy which is power x time. It's actually 20-25c per kWh. So the calculation should be 40 x 24 x 365 / 1000 = 350 kWh giving roughly $90, in the ballpark.

  Aside: the unit of energy is Joule = 1 W x 1 second. 1 kWh = 3600000 J.

  • 

    cloudy on 23/05/2016 - 13:18

    Thanks GP,

    I dunno if you read the article, but it reports it as stand by power consumes an average household 39w per daily. So I thought it had converted it to a daily consumption, instead of what you said being a 39wh. Which now makes sense.

    • 

      retiredfeline on 23/05/2016 - 13:27

      It's not 39W daily, it's just 39W. Watts are a measure of rate of energy consumption so there is no need for a time period. It's like saying 50 km/h per hour. Bloody journalists and publicists.

      As an aside, I'm shocked at how inefficient set-top boxes are. You can feel the heat. I would guess about 10W dissipation so about $20 extra a year left on all the time. Hopefully they are dying off as the TV distribution is more digital and hopefully the standby for those isn't terrible too.

      • 

        cloudy on 23/05/2016 - 16:20

        Yea, I totally get what you mean by the rate of energy. I just assumed the article to be what it says. But it totally makes the math sense when u do look at it per hour (how it generally is supposed to be stated).

        I live in a small town house, and I don't have much appliances, so I'm shocked to see the average household has almost 1kw wasted a day in stand by, coz according to my powershop, I use approx 1.3 units a day, so 1.3 kw per day. Which i know is tiny, but I'm not exactly living in the dark.

• 

  ESEMCE on 23/05/2016 - 10:25

  Your 40W (Wh I'm assuming) estimate is WAAAY off..
  To give you some idea, our 2012 model Panasonic Plasma TV sucks about 300Wh (0.3kWh) overnight alone, about 900Wh/day!

  I have a whole house usage meter and it's fairly accurate at predicting our bills…
  Overnight, let's say 8 hours, we use about 1.5kWh (including fridge, personally I'd classify it as active, not standby power). I've done the tests and turned off everything possible to get our overnight usage down to about 0.7kWh (pretty much just the fridge, clock radio, phone chargers x2 and hardwired oven in standby)..
  So let's say the fridge is consuming 0.7kWh over the 8 hour period, leaving 0.8kWh to genuine standby usage.
  That's 2.4 kWh per 24 hours (assuming we're on holiday and not actively using stuff). Where I live, in SA with expensive electricity ~35c/kWh (Summer Peak rate), that's about $0.85/day of power. ~$305/year.
  Assuming every house is like mine, you need 2.8 million homes at $305/year to make $860 million, which, if anything sounds on the low side.

  I'm not familiar with actual rates for other states, but obviously cheaper rates = more homes required to make up $860 million assuming each home has standby power of 2.4kWh/day.

• 

  mskeggs on 23/05/2016 - 11:11

  I also cringed at the watt per day error, but assume it means 40w continual draw, which is quite likely.
  Like scubacoles, I can monitor my whole house power, and I sit around 200w when idle, including fridge, freezer, bar fridge, router, Tivo, cordless phones, phone chargers, plus all the standby power use!
  So 40w x 24hours =0.96kWh per day, or $87 a year with 25c kWh power bills.

• 

  amkssg on 23/05/2016 - 11:26

  TL;DR:

  $6 / 24 hours = 25 cents per kwh
  which is correct.