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400kW charger - how many of these on a typical local network ?

Discussion in 'Electrics UK' started by SimonH2, 16 Dec 2018.

  1. JohnW2

    JohnW2

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    That would obviously help. However, I think that the over-riding issue is the total amount of energy we're talking about - no matter how it its use is spread/shared over time and space.

    I am often reminded that there were very serious concerns being expressed about the adequacy of UK electricity generation and distribution, in the medium-term (and long-term), long before the prospect of large-scale appearance of EVs appeared as part of the equation.

    Kind Regards, John
     
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  2. JohnD

    JohnD

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    Yes indeed.

    We have had successive governments whose policy has been to not have an energy policy.

    Perhaps when generation and distribution are next in public ownership, policy will be created that takes into account the good of the nation.
     
  3. reds42

    reds42

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    Theres also the ability to feed energy stored in cars back into the grid when there are demand spikes. Vehicle-to-grid
     
  4. JohnD

    JohnD

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    yes.

    local spikes can be managed out.

    But I wonder how many kWh of energy are in all those gallons of petrol and diesel that are sold on an average day.

    UK grid demand is usually around 20GW to 35GW, but on some days hits 40GW peaks

    We could run existing plant for more hours per day, and we could use storage to manage round spikes, but I don't know what capacity is needed to replace the hydrocarbon.

    I wonder if it would be possible to create some kind of public transport system that people would be willing to use.
     
  5. ivixor

    ivixor

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    Let's see... 1 litre of diesel is apparently equivalent to 10kwh.

    125 million litres of diesel/petrol sold per day. So that is equivalent to 1.2 bn kwh needed. Aka 1.2 TWh.

    We generate 6 TWH per day.

    So we need to generate 20% more electricity.

    Is my maths wrong?
     
  6. reds42

    reds42

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    The efficiency of internal combustion engines vs electric would need factoring in.
     
  7. reds42

    reds42

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    A quick google ( not double checked multiple sources) suggests following efficiencies.

    "EVs convert about 59%–62% of the electrical energy from the grid to power at the wheels. Conventional gasoline vehicles only convert about 17%–21% of the energy stored in gasoline to power at the wheels."
     
  8. Harry Bloomfield

    Harry Bloomfield

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    That was part of the remit for Smart Meters, so load shedding could be selective, rather than entire areas blacked out.
     
  9. Harry Bloomfield

    Harry Bloomfield

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    There a fuel grid in the UK, you don't see as many fuel tankers as you would otherwise because of the grid. It was initialised prior to WWII.

    Diesel and petrol are a relatively compact form of fuel, for the amount of energy which can be released from them.
     
  10. JohnW2

    JohnW2

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    I realise that it depends very much on ones political views and inclinations, but the history of 'taking things into public ownership' seems to be that it often tends to make things go from bad to worse!

    Kind Regards, John
     
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  11. JohnD

    JohnD

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    So we divide that by (about) 3 for the efficiency difference? So we would use 0.4TWh per day more than we currently use? Be generous and say, use 10% more than we currently use?

    looking at the daily demand graph, it drops down between 10pm and 8am. How much slack do we need, if most charging is done overnight?
     
  12. JohnW2

    JohnW2

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    Is there not a crucial part of that equation missing - namely the efficiency of conversion of the source fuel (where appropriate) to electricity?

    Kind Regards, John
     
  13. Harry Bloomfield

    Harry Bloomfield

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    So, you plug one in to charge it up overnight, ready for next morning - only to find that rather than being charged, it has been discharged by the network.

    EV's sound good in principle, until you look at the practicalities of massive numbers of them needing to be charged each night.
     
  14. JohnD

    JohnD

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    Like the railways, you mean?

    And the CEGB? I don't think either used to be such a shambles as we have today.

    Anyway, lots of Britain's train companies, generation and other utilities are state-owned. It's just that the states that own them are foreign ones. The British taxpayer is subsidising the foreign taxpayer.
     
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  15. JohnD

    JohnD

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    have a look at the time of day of demand spikes, and of slack capacity.

    Which of them happens during the night, when you want to charge your car?

    http://www.gridwatch.templar.co.uk/

    Not every car needs to be fully charged every night.
     
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