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Eirgrid figures during night time EV charging

  • 26-08-2017 5:48pm
    #1
    Registered Users Posts: 11,226 ✭✭✭✭ KCross


    There have been a few posts lately about the Irish grid and how environmentally friendly it is (or isn’t!).

    I pulled the data from their website for the last 30 days to see how it stacks up.

    I then averaged the daily values for the time period 4-8am as this is the time where most EV’s would be charging.

    Wind generation provided, on average, 28% of the demand for the 4-8am period. It varied from 0-58%

    The CO2 intensity figure averaged 365gCO2/kW (range 288-433)

    Wind generation provided 24% of the demand over the entire 30 days(24/7).


    Room for improvement, but an average of 28% isn't bad at all.

    I'll repeat the analysis for some other months to see if the figures go up or down. I presume (maybe wrongly) that winter would have more wind?


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Comments

  • Registered Users Posts: 992 jamesthepeach


    KCross wrote: »
    There have been a few posts lately about the Irish grid and how environmentally friendly it is (or isn’t!).

    I pulled the data from their website for the last 30 days to see how it stacks up.

    I then averaged the daily values for the time period 4-8am as this is the time where most EV’s would be charging.

    Wind generation provided, on average, 28% of the demand for the 4-8am period. It varied from 0-58%

    The CO2 intensity figure averaged 365gCO2/kW (range 288-433)

    Wind generation provided 24% of the demand over the entire 30 days(24/7).


    Room for improvement, but an average of 28% isn't bad at all.

    I'll repeat the analysis for some other months to see if the figures go up or down. I presume (maybe wrongly) that winter would have more wind?


    Most EVs start charging at the minute the cheap rate kicks in.
    So.if it's 11 to 8 then practically all EVs plugged in will start charging at 11 and finish at different times according to how much they have left to charge when they start. I would think that 11 would be peak charging and 8 would be minimum as a hell of a lot of them would have finished earlier and not be charging when it comes to 8.

    Adjust for the 12 - 9 time accordingly. Though then you have commute start times into the equation.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    Most EVs start charging at the minute the cheap rate kicks in.
    So.if it's 11 to 8 then practically all EVs plugged in will start charging at 11 and finish at different times according to how much they have left to charge when they start. I would think that 11 would be peak charging and 8 would be minimum as a hell of a lot of them would have finished earlier and not be charging when it comes to 8.

    Adjust for the 12 - 9 time accordingly. Though then you have commute start times into the equation.

    Not necessarily true. I have mine setup to finish at 8. The car decides when to start so it would always be in the 4-8am range.

    Some people may start at 11pm and thats fine too. I'm sure the figures wouldn't change that much as an average so I still think the analysis is valid. Im not trying to cover everyones scenario here. Some people charge by day. The 4-8am figure as an average is a good representation of what EV's are doing.


  • Registered Users Posts: 992 jamesthepeach


    KCross wrote: »
    Not necessarily true. I have mine setup to finish at 8. The car decides when to start so it would always be in the 4-8am range.

    Some people may start at 11pm and thats fine too. I'm sure the figures wouldn't change that much as an average so I still think the analysis is valid. Im not trying to cover everyones scenario here. Some people charge by day. The 4-8am figure as an average is a good representation of what EV's are doing.

    I would say you are unusual though. So you are only covering your own scenario.
    Maybe the figures wouldn't change at a, but to get the times more accurate.
    Most people set it to start at 11. That way you get 100% of the night rate whether your charged to full or not. But if you start at 4 then then the max you will ever get of the night rate is less than half of it.

    That's just my take on it. Others may disagree though.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    I would say you are unusual though. So you are only covering your own scenario.
    Maybe the figures wouldn't change at a, but to get the times more accurate.
    Most people set it to start at 11. That way you get 100% of the night rate whether your charged to full or not. But if you start at 4 then then the max you will ever get of the night rate is less than half of it.

    That's just my take on it. Others may disagree though.

    To be honest, I dont think it matters whether you take 11-3 or 4-8. The figure I'm giving is an average for a 4hr period during night rate (when most people charge) so you will just find that some hours will be higher and some lower and you will end up with the same average at the end.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    Most people set it to start at 11. That way you get 100% of the night rate whether your charged to full or not. But if you start at 4 then then the max you will ever get of the night rate is less than half of it.

    Just to clarify on this point.... if you set the Leaf to finish at 8am you get the full night rate. The car will start at whatever time it deems appropriate to ensure it is at 100% by 8am so one night it will start at 4am, another night 2am etc depending on how low the battery is.


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  • Registered Users Posts: 992 jamesthepeach


    KCross wrote: »
    Just to clarify on this point.... if you set the Leaf to finish at 8am you get the full night rate. The car will start at whatever time it deems appropriate to ensure it is at 100% by 8am so one night it will start at 4am, another night 2am etc depending on how low the battery is.


    True, but I think most would start it at the beginning of the tariff rather than target the end of it. But, as you say, I'm.sure it makes no difference at all.


  • Registered Users Posts: 16,162 ✭✭✭✭ Sleeper12


    KCross wrote:
    Wind generation provided, on average, 28% of the demand for the 4-8am period. It varied from 0-58%

    KCross wrote:
    Room for improvement, but an average of 28% isn't bad at all.


    I don't have an ev yet but when they do really take off I think you will find that wind won't cover more than 1 or 2 %. The more that change to electric the more fossil fuel they'll have to burn.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    Sleeper12 wrote: »
    I don't have an ev yet but when they do really take off I think you will find that wind won't cover more than 1 or 2 %. The more that change to electric the more fossil fuel they'll have to burn.

    You're assuming the extra requirement would have to be fulfilled by fossil fuels. There is no reason why it can't be more wind.

    Other countries are also attaching Solar PV and battery to their grids so that could also be part of the solution. Basically, fossil fuel doesn't have to be the only answer and I dont think it will. It will be a mix.


  • Registered Users Posts: 16,162 ✭✭✭✭ Sleeper12


    KCross wrote:
    Other countries are also attaching Solar PV and battery to their grids so that could also be part of the solution. Basically, fossil fuel doesn't have to be the only answer and I dont think it will. It will be a mix.


    I love the idea of pv but sadly there's no selling to the grid in Ireland. ESB or the government need to cop on here. I'd have every inch of my roof covered in pv panels when the do cop on.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    Sleeper12 wrote: »
    I love the idea of pv but sadly there's no selling to the grid in Ireland. ESB or the government need to cop on here. I'd have every inch of my roof covered in pv panels when the do cop on.

    I agree. The only Solar PV they are entertaining is the big Solar PV farms and there is quite a bit of that in plan.


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  • Registered Users Posts: 1,502 ✭✭✭ macnab


    The grid bring on gas plants at around 6am to get ready for the morning peak. That will reduce the ratio of wind/renewables so your figures will probably be affected.


  • Registered Users Posts: 8,287 ✭✭✭ n97 mini


    Ours starts charging just after midnight (nightsaver is currently 12am-9am... 11pm and you're still on day rate). Washing machine etc comes on at 8am.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    macnab wrote: »
    The grid bring on gas plants at around 6am to get ready for the morning peak. That will reduce the ratio of wind/renewables so your figures will probably be affected.

    Interesting.

    It might affect the CO2 intensity figure but not the ratio figure as it is based on the demand figure, not generation.


  • Registered Users Posts: 3,270 ✭✭✭ cros13


    We've also had a particularly bad year for wind speeds so far.


  • Registered Users Posts: 13,702 ✭✭✭✭ BoatMad


    Sleeper12 wrote: »
    I don't have an ev yet but when they do really take off I think you will find that wind won't cover more than 1 or 2 %. The more that change to electric the more fossil fuel they'll have to burn.

    based on what data

    given the goal is very high levels of renewables and coupled with home micro generation , the likelihood is future EV charging might be entirely " green "


  • Registered Users Posts: 13,702 ✭✭✭✭ BoatMad


    n97 mini wrote: »
    Ours starts charging just after midnight (nightsaver is currently 12am-9am... 11pm and you're still on day rate). Washing machine etc comes on at 8am.

    we bring the dishwasher and washing machine on at midnight and the car at 2 am ( 32A EVSE) . The house can actually support both domestics and the car on at night ( just dont have a power shower at 4 am !! )


  • Registered Users Posts: 1,008 ✭✭✭ ei9go


    Always set the timer to start at 00.15.

    car usually stops charging between 3 and 4 am

    7 kWh charger


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    All,
    I understand people charge at different times. I dont think its relevant to the point of the thread though, which is how much of the demand is met by wind on the Irish grid.

    I've taken a 4hr average during night rate to calculate that. That average won't change significantly if you shift the time window a few hours. Its not like the wind always blows more or less from 12-4 vs 4-8. Its swings and roundabouts.

    If people feel it is relevant in some way I'll run the numbers again from 12-4 and see if I get much the same answer.


  • Registered Users Posts: 1,502 ✭✭✭ macnab


    KCross wrote: »
    All,
    I understand people charge at different times. I dont think its relevant to the point of the thread though, which is how much of the demand is met by wind on the Irish grid.

    I've taken a 4hr average during night rate to calculate that. That average won't change significantly if you shift the time window a few hours. Its not like the wind always blows more or less from 12-4 vs 4-8. Its swings and roundabouts.

    If people feel it is relevant in some way I'll run the numbers again from 12-4 and see if I get much the same answer.

    I would like to see the figures for 12 to 4, if you have the time.


  • Closed Accounts Posts: 12,451 ✭✭✭✭ pwurple


    KCross wrote: »
    All,
    I understand people charge at different times. I dont think its relevant to the point of the thread though, which is how much of the demand is met by wind on the Irish grid.

    Wind doesn't change, but the system demand does. Typically demand upswings from 6am onwards, so the % wind drops.

    Hard to know what % of EV's charge that way also, but it's a nice to know for people.

    Alongside my EV driving colleagues, I charge during the day, at work. The site is powered by a wind turbine.


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  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    pwurple wrote: »
    Wind doesn't change, but the system demand does. Typically demand upswings from 6am onwards, so the % wind drops.

    Hard to know what % of EV's charge that way also, but it's a nice to know for people.

    Alongside my EV driving colleagues, I charge during the day, at work. The site is powered by a wind turbine.

    Thats a good point. I'll run the numbers again for 12-4.


  • Registered Users Posts: 16,162 ✭✭✭✭ Sleeper12


    BoatMad wrote: »
    based on what data

    given the goal is very high levels of renewables and coupled with home micro generation , the likelihood is future EV charging might be entirely " green "

    Not on night rate they won't. All you'll have is wind at that hour of the night. Then it's burning fossil fuel


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    KCross wrote: »
    All,
    I understand people charge at different times. I dont think its relevant to the point of the thread though, which is how much of the demand is met by wind on the Irish grid.

    I've taken a 4hr average during night rate to calculate that. That average won't change significantly if you shift the time window a few hours. Its not like the wind always blows more or less from 12-4 vs 4-8. Its swings and roundabouts.

    If people feel it is relevant in some way I'll run the numbers again from 12-4 and see if I get much the same answer.
    macnab wrote: »
    I would like to see the figures for 12 to 4, if you have the time.
    pwurple wrote: »
    Wind doesn't change, but the system demand does. Typically demand upswings from 6am onwards, so the % wind drops.

    Hard to know what % of EV's charge that way also, but it's a nice to know for people.

    Reran the numbers for 12-4. Its the "same" (marginally better).

    29% of demand is met by wind (Min 1, Max 63) from 12-4 over the last 30 days.
    CO2 Intensity averaged 363gCO2/kWh (Min 265, Max 469).


    Just to be clear. This is just one month of the year. I suspect these numbers have a reasonably large seasonal variation.


  • Registered Users Posts: 1,502 ✭✭✭ macnab


    KCross wrote: »
    Just to be clear. This is just one month of the year. I suspect these numbers have a reasonably large seasonal variation.

    Yes seasonal variation is a factor. There is much more wind in the winter months, but then again demand is higher too.


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    I've a question for anyone in the know.

    Typical day last week was 2000MW’s demand around 4am and then peaking to 3700MW at 12pm and 6pm.

    Interesting is that as the morning peak occurs I’ve noticed that the wind generation seems to follow the demand curve. If it was just one day I'd say it was a coincidence but it seems to happen alot (most days last week)

    Do the grid restrict/reject wind power based on market price or is there some other reason for this?

    Anyone on here know how ESB ramp up/down the various plants and wind.

    DATE & TIME ACTUAL GENERATION(MW) ACTUAL WIND(MW) ACTUAL DEMAND(MW)
    20/08/2017 04:00 2288 206 2044
    20/08/2017 04:15 2292 213 2046
    20/08/2017 04:30 2312 224 2041
    20/08/2017 04:45 2325 233 2046
    20/08/2017 05:00 2343 263 2051
    20/08/2017 05:15 2356 286 2056
    20/08/2017 05:30 2363 295 2054
    20/08/2017 05:45 2356 333 2059
    20/08/2017 06:00 2314 375 2078
    20/08/2017 06:15 2312 396 2065
    20/08/2017 06:30 2273 395 2041
    20/08/2017 06:45 2249 403 2047
    20/08/2017 07:00 2180 389 2068
    20/08/2017 07:15 2222 402 2131
    20/08/2017 07:30 2270 445 2173
    20/08/2017 07:45 2314 480 2230
    20/08/2017 08:00 2311 458 2298
    20/08/2017 08:15 2473 490 2376
    20/08/2017 08:30 2621 513 2442
    20/08/2017 08:45 2644 530 2527
    20/08/2017 09:00 2633 544 2587
    20/08/2017 09:15 2639 568 2666
    20/08/2017 09:30 2639 569 2719
    20/08/2017 09:45 2707 589 2771
    20/08/2017 10:00 2786 576 2833
    20/08/2017 10:15 2926 566 2892
    20/08/2017 10:30 2931 521 2925
    20/08/2017 10:45 2930 480 2953
    20/08/2017 11:00 2906 507 2972
    20/08/2017 11:15 3011 591 3000
    20/08/2017 11:30 3054 642 3039
    20/08/2017 11:45 2996 628 3053
    20/08/2017 12:00 2996 633 3070


  • Registered Users Posts: 13,702 ✭✭✭✭ BoatMad


    Do the grid restrict/reject wind power based on market price or is there some other reason for this?

    CER told me that wind is regularly " switched off" in periods of low demand as conventional power generation is online anyway


  • Hosted Moderators Posts: 7,485 ✭✭✭ Red Alert


    Has anyone wired up their EVSE to the night-saver control pair to ensure that charging only happens in the off-peak period?


  • Registered Users Posts: 13,702 ✭✭✭✭ BoatMad


    Red Alert wrote: »
    Has anyone wired up their EVSE to the night-saver control pair to ensure that charging only happens in the off-peak period?

    The car has a timer, thats all thats needed. its the same with your dishwasher


  • Registered Users Posts: 11,226 ✭✭✭✭ KCross


    BoatMad wrote: »
    CER told me that wind is regularly " switched off" in periods of low demand as conventional power generation is online anyway

    That makes sense.

    And since I've seen this happen regularly it suggests there is spare wind capacity at night if there is an increase in EV uptake... how much spare is another question entirely but they seem to be able to add 100s of MW's of wind in a step like fashion so it is significant (as long as the wind is blowing of course).


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  • Registered Users Posts: 13,702 ✭✭✭✭ BoatMad


    KCross wrote: »
    That makes sense.

    And since I've seen this happen regularly it suggests there is spare wind capacity at night if there is an increase in EV uptake... how much spare is another question entirely but they seem to be able to add 100s of MW's of wind in a step like fashion so it is significant (as long as the wind is blowing of course).

    yes, this was a major point in my recent meeting with the CER, they were very enthusiastic that EVs could soak up unused green energy , especially night time energy , ( and more wind is coming online ) . They opined that in fact such energy could be much cheaper then current night time rates and this would be facilitated by the smart meter rollout program , that is due to start next year

    ( mind you I was reminded of the comment when nuclear was first introduced in the UK )


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