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Data and monitoring: CO2 and temperature difference

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  1.  
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      CommentAuthorSteamyTea
    • CommentTimeFeb 17th 2012 edited
     
    Been playing with the data I have been steadily collecting over the last year or so. Have had a few problems with it,but have at long last got some meaningful charts out of it.
    These first two are basic weekly means and one trend line to show a correlation (ducking already but it is a starting point for further investigation).
    My data comes from the National Grid website, a local weather station, my internally collected data and the CO2 stuff is from Damon's excellent site. The many millions of data points (the CC logs every 6 seconds, the ND stuff every 5 minutes, soon adds up) have been condensed down to hourly means. CO2 emissions are calculated from my hourly readings multiplied by the number of hours and multiplied by the CO2 emissions for those corresponding hours.
    When I get time there will be more to come.
      CO2 Image 1.jpg
      CO2 Image 2.jpg
    • CommentAuthorGavin_A
    • CommentTimeFeb 18th 2012
     
    what does the 'temperature difference' data refer to? difference from what?

    It looks like you've produced a graph showing the CO2 emissions go up when it's cold, which would be a fair summary of the situation, as that's generally when more coal fire stations are in use.
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 18th 2012
     
    Difference between inside and outside.
    Not looked at the energy mix by week yet, been playing in a cold muddy field.
    Also going to look at the solar gain thought the year, see what that is worth. should be able to gauge overall levels from the kurtosis and rainfall figures.
  4.  
    I'm interested whether using electric heating during off-peak hours would give the same heat for less CO2 than using it during daytime.

    Can you see that from your data? Does it make much difference?

    Am thinking about storage heating, TS, using DHW cylinder immersion overnight, .....
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 18th 2012 edited
     
    Will
    Yes I can find that out, and pretty sure it will. The reason I started this over a year ago was to see if I would be better off on a different tariff, just it just grew and now I collect weather data, national grid data, and other bits and pieces along the way.
    CO2 is really a function of the energy mix and demand. So it depends on time of year and day.
    Couple of charts to hopefully make it clear. Only based on the six month so of 2011 though (from Week 28)
      CO2 and Demand.jpg
      correlation between CO2 and Demand.jpg
  6.  
    So if we heat water at 4am and leave it in the cylinder for a shower at 8am, we save 20% of the CO2 compared to heating the water instantly at 8am when i need it?

    (accepting that ST heated water used at 8pm would be better)

    If I stored heat overnight with my ASHP which has realworld CoP 2.5-2.7 (by my rough measure), using off-peak electric at .40 kg/kWh, the CO2 would be 0.4/2.5 = 0.16kg/kWhth which is a bit better than gas.

    But if I do the same at peak time, 0.48kg/kWhe, 0.19kg/kWhth which is no better than gas.

    All academic as I'm off gas grid and have no heat storage (yet)!

    How did CO2 kg/kWh correlate with times-when-your-heating-was-on, did you find your heating was on mainly at times of high-CO2-per-kW? I think mine is, but got no data.
    • CommentAuthordickster
    • CommentTimeFeb 20th 2012
     
    I'm a bit confused, whereabouts are the monitors ?
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 20th 2012
     
    External temp is from weather station, internal temp is in the kitchen, where I tend to live, 3 electrical circuits monitored (now), Ringmain, Water and Heating.
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 21st 2012
     
    Will
    Does this help. It is variations of the means. Though I think January this year may have been a bit odd.
      Variation.jpg
    •  
      CommentAuthorDamonHD
    • CommentTimeFeb 21st 2012
     
    There have been some very odd things going on with the cold weather on the continent meaning that we've been exporting to the max and have actually at times (for days in a row) seen the relative lowest carbon intensity for the day at peak UK demand times.

    http://www.earth.org.uk/note-on-UK-grid-CO2-intensity-variations.html#20120208

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 21st 2012 edited
     
    It is strange for us, does show that we have a fair bit of spare capacity and we are not so reliant on imported electricity as people think. Some days were were generating 60GW, needs a big fuse that does.
    I think from your figures that nuclear was a little down with with a few 8 and 9 GW, that seems to have gone up to 11 and 12 GW now.
    The Zeros coudl be no data
      NonCO2 Generation.jpg
      Weekly Non CO2 generation.jpg
  12.  
    Thanks Steamy, good stuff! And respect as ever to earth.org.uk.

    I get that UK grid-wide CO2/kWh correlates with times of high grid-wide demand (normally). What i'd like to understand is to what extent my own house heating usage coincides with times of high CO2/kWh.

    EG my heating comes on for a good blast about 5am (coincides with a time of low CO2/kWh, this is good)
    then ticks over through the day (high CO2/kWh)
    then ramps up a bit in the evening 6-9pm (coincides with highest Co2/kWh, this is bad)
    then goes off overnight, which paradoxically is when CO2/kWh is least

    But I have no hard data on how much heating in kW my house is drawing at different times-of-day (my Efergy doesnt record) so dont know where to start with shifting these heating peaks to times of lower CO2/kwh .

    Could you plot your house heating demand data on the same chart as grid CO2/kWh, with time-of-day on the x-axis? Or even plot [house heating demand] against [CO2/kWh] to see if they correlate?

    regards Will
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 22nd 2012 edited
     
    Right
    This is the hourly annual (sounds odd that) household demand and CO2 intensity over 2011, CO2 is only from week 28 though, so not entirely accurate.
    The second chart describes it better as it shows the Standard Deviation of the CO2 intensity. Basically, 1 SD is a nats under 70% of the data. So as this shows the spread of Standard Deviations, if you pick just one data point that shows the middle value, plus or minus 35%. Easy.
      Hourly Annual Demand and CO2.jpg
      Annual CO2 and StDev.jpg
    • CommentAuthorbrig001
    • CommentTimeFeb 23rd 2012
     
    SteamyTea, on your graph of correlation between temperature difference and carbon dioxide emmisions, do you get a better correlation if you slip the temperatures by a month? I have found that for a given temperature in spring and autumn, we use less gas in autumn. I imagine this is to do with the ground warming up during summer, and some of this heat is helping during autumn.

    Brian.
    •  
      CommentAuthorSteamyTea
    • CommentTimeFeb 23rd 2012
     
    Not looked yet, but intend to do a full years worth of analysis when I have the time.
    One thing that interests me is how much difference does a sunny (little cloud cover), as oppose to just daylight makes.
    •  
      CommentAuthorDamonHD
    • CommentTimeFeb 24th 2012 edited
     
    Just for all you stats-heads...

    I've just updated my carbon-intensity page to accommodate flows from the East-West Interconnector (IE--GB) due to come on line this year (code INTEW as I understand it).

    EirGrid already provides a spiffing intensity graph: http://www.eirgrid.com/operations/systemperformancedata/co2intensity/

    So I may in the future be able to take a like intensity feed from them into my page, though the flows will remain small (500MW max towards GB so Wikipedia tells me), so it's probably below the noise levels of the rest of the calculation.

    Rgds

    Damon

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