Energy Monitoring
I was given an energy monitoring device which we have been using at my office. Without being tooooo much of an anorak (which we were:>) we established that we could make five mugs of tea from a full kettle at a cost of 0.018p, whereas cooking a couple of burgers on the grilling machine cost 0.025p.
If our desktop PCs were working flat out all day (which, of course, modern ones don’t as they have energy saving options) they would cost 0.31p per day. So, although the kettle draws 2Kw it is in such short bursts that the PC usage is much higher. OK, we can all guess that but it’s good to see how much.
Correction: see comments
bromley said,
November 14, 2007 @ 5:20 pm
Admirable energy monitoring, but those costs seem incredibly low… I’m guessing that either you have some very cheap energy source (e.g. an on-site wind turbine), or there’s an error somewhere. Or I might have it wrong, of course! Anyway, I’m calculating that boiling a 2 kW kettle would cost at least 0.66p:
a 2kW kettle running for 1 hour uses 2kWh of electricity;
so a 2kW kettle running for, say, 2 minutes (2/60 hours), uses 2*(2/60) kWh of electricity, which is 0.066kWh;
if 1kWh costs around 10p (approximately typical), that means that running the kettle for 2 minutes costs 0.66p.
Donna said,
November 14, 2007 @ 5:42 pm
Thanks for pulling me up on this, Martin. Maths and I were never the best of bed pals :>)
Anyway, we checked the full kettle (2.5Kw) boiling time on the gadget and it came to .29Kwh in total. This we calculated at 12p per Kwh to be £0.0348.
This also means that the burger was £0.026.
Phew!
bromley said,
November 14, 2007 @ 6:25 pm
Ah that sounds about right
Incidentally, if your office has a big energy bill (£30k or more per year), there’s a pretty good chance you’ll be able to get half-hourly electricity data from your energy supplier. If you get that half-hourly data, and download the free trial of Energy Lens ( http://www.energylens.com/ ), you’ll be able to learn a lot more about your energy consumption at different times of the day and days of the week.
I should admit: Energy Lens is something that my company makes, making the above advice something of a shameless plug. Nevertheless, it is a pretty useful bit of software for energy saving, in my wholly biased opinion!
Keep up the good work,
Martin