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Discussion > Different National Demand Curves

I had one of my usual glances at http://www.gridwatch.templar.co.uk/ to see what the status was. I note that he has added a French Grid page.

What I find interesting is the very different daily profile to the UK daily power demand curve.

UK goes up at 0800 (approx) level all day, then risies to an eveing peak at 2000 then declines.
The French curve has a distinct morning peak then declines to an afternoon dip with a bit of an evening bumb.

So I would suggest that each nation has a differnt curve according to its climate and culture.

I now speculate that the Spanish curve would show a distinct drop at 1300, reflecting the lunch time close down or siesta followed by a bigger and longer evening demand than one would see in the UK curve - they stay up later after their afternoon nap and dine later. (Typically shops are shut 1300 to 1800 and open 1800 to 2100).

The implication for solar power (PV) in Spain is maximum supply at the time of minimum demand - about the best way of screwing up a grid and baseload that any man could devise.

Has anyone got any data (accurate or anecdotal) on different national demand curves ?

Have I noticed anything interesting about how a "one size fits all approach" might not work ?

Apr 5, 2014 at 4:56 PM | Unregistered CommenterNic

It is also noticeable how the French pattern has a smaller range, proportionally, between max and min demands.

Others who live there will know more about it but it has always been my understanding that they had to make major efforts to smooth their demand pattern when they went for their huge nuclear programme to cut back on oil imports. Nuclear plants work best at high and constant loads. They will turn down but, counter-intuitively, there are no savings. Indeed the fuel can become poisoned which reduces output and shortens the life cycle.
So they went nearly all-electric for their domestic requirements and brought in a split-tariff system as standard. Hot water tanks are automatically heated at off-peak times with an option to boost during peak times, if needed. This also encourages folk to run heavy users like washers and cookers during the off-peak hours.
It seems to have worked. They use quite a bit more electricity than we do for similar populations, despite their more benign climate. Also their base load is around 75% of peak demand where ours is more like 50% (using Mark I eyeball on the graphs). Last, but not least, power is much cheaper there (domestically, I don't know about the industrial tariffs).

Seeing what has been achieved in France, it is clear we are missing the boat with our "smart meters". It is such an opportunity to increase the use of (cheap) off-peak power and smooth the demand curve. Instead all we will get is the "feature" allowing our power to be rationed when the supply crunch bites.

Apr 6, 2014 at 4:52 PM | Registered Commentermikeh

I think I noticed from Gridwatch that the typical total power level in France (with roughly the same population as Britain) is typically around twice the GB level. I think electric heating is widely used in France but is perhaps a rarity in Britain which might explain some of the difference.

Some years back I did some analysis prior to renovating a house in France. I compared the cost of:

- liquid gas
- fuel oil
- daytime electricity
- night-time electricity

To my surprise, liquid gas cost around the same (per kWh output) as daytime electricity. Fuel oil cost about the same as night-time electricity. Piped gas was not available and wood was ruled out for its inconvenience, other than as an emergency source of heat. I have not compared prices recently, so I don't know if that would still apply. Those results pretty well decided it for me.

Electric heating costs almost nothing to install and (barring power cuts) is reliable and maintenance-free. My neighbour pointed out that the cost of installing an oil or a gas central heating system would pay for several year's worth of electricity. It's flexible - each room can have its own programmer so that it's heated automatically to be warm when normally needed. The main hot water tank is heated exclusively by nightime electricity and is adequately large for all daytime needs.

Apr 6, 2014 at 5:28 PM | Registered CommenterMartin A

Nic, below is the demand for Spain.

https://demanda.ree.es/demandaEng.html

Apr 7, 2014 at 4:14 PM | Unregistered CommenterDavid Porter

And I should have added that if you want more information, such as capacity and breakdown of energy types, then you can find it here: http://www.ree.es/en/activities/realtime-demand-and-generation

Apr 7, 2014 at 4:22 PM | Unregistered CommenterDavid Porter

Nic, why ask the question if you don't want to know the answer?

Apr 10, 2014 at 9:08 PM | Unregistered CommenterDavid Porter

huh?

Apr 10, 2014 at 9:50 PM | Unregistered Commentersplitpin

In this part of the Limousin many people have invested in non electrical heating. Perhaps because power cuts are fairly frequent although better these days. The main alternatives are wood burners, gas or oil in large tanks, or gas or oil room heaters. Bottled gas is used for cooking, and is available at almost all filling stations. Oil is available at supermarkets and DIY stores during autumn and winter.

Wood burners are not a low cost investment and come with their own risks, we know of three house fires in the last two years caused as a direct result of wood burners. Domestic electricity is not straight forward, as I recall there are various limits you can choose for maximum power demand. The higher the limit the greater the charges, but I could be wrong on that. There may be cultural difference as the people round here go to great efforts to use water collected as rainfall or from wells rather than connecting a hose to a tap and using mains water at a few centimes a cubic metre, putting in a bit of effort to save a few pennies seems no longer part of the British make up but is very strong here, foraging is an all year activity and seasonal crops and where to find them as talked about as the weather.

I don't have any demand information though.

Apr 10, 2014 at 11:34 PM | Unregistered CommentersandyS

sandyS - You are right on the standing charges depending on your maximum load.

Here are the current EDF standing charges for 'tarif bleu' (the normal tarif that most people use). I've rounded the figures to whole numbers.

kW Annual standing charge €
6........................91
9......................122
12....................198
15.....................229
18.....................258
24.....................541
30.....................639
36.....................736

daytime cost 0.15 € per kW hr
nightime cost 0.10€ pe kW hr

The EDF circuit breaker is set to the tarif you have opted for. If you exceed the set limit for more than a very short time, the house is abruptly disconnected. Many people who use electric heating therefore have installed 'energy management' units which disconnect some of the heating when the total load approaches the subscribed limit.

I simply hooked up some relays on the circuit breaker panel so that the heating in the main rooms takes turns getting access to power. With 6kW heating per room, this means that a room will warm up quickly, yet 9kW supply is adequate for the house.

It makes sense for EDF to charge in this way as, EDF has to make a greater investment in local equipment (transformer, cable) to provide for customers with a higher limit.

Using well water instead of mains water for watering the garden can save enough money to make it worth doing - the cost of a pair of tyres perhaps. Mains water here in Normandy costs around 2 ½ euros per cubic metre - more than just 'centimes'.

Apr 11, 2014 at 9:08 AM | Registered CommenterMartin A

David,

Thank you for that link.
I am just an ordinary curious man - I am not researching for a paper or article but you have very kindly placed a data source where others can find it.

The siesta (as I hypothesised) is clearly visible !

Is this not the scientific process -
Casual observation (an apple falling from a tree, for example)
Leads to a hypothesis
Then data gathering
and the proof or disproof of the hypothesis.

You link proves that the Spanish do not work in the afternoon !

Apr 11, 2014 at 10:03 PM | Unregistered CommenterNic

Further to my observation of the Spanish trend,

After a casual scan of some random dates, the afternoon dip is less in the mid summer. Air conditioning ?

The afternoon dip appears to most pronounce in the temepreate months (Spring, Autumn) where one uses neither heating nor conditioning.

I just find this delightful trivia.

Another thought; There is a one hour time difference between France & Spain and the UK. If the UK was to change to CET (central European Time) , What strain would this place on the Channel connector that feed French power to the UK ?
Or conversely - if Spain was to use GMT/BST (as Portugal does and Spain logically should) would there be a benefit to European power transmission ?

Apr 11, 2014 at 10:10 PM | Unregistered CommenterNic

Nic

Thanks for coming back. Sorry about my third comment, I was beginning to think I had wasted my time.

I have viewed their site many times without realising the demand downturn during the afternoon. So your theory appears correct.

If you are interested in delving further into the Spanish electricity industry the link below goes to their system report for 2013 and is in English. Apart from all the renewables in the system I think the most interesting detail is the capacity (102GW) verses maximum demand (40GW). Compare that with our own measly excess capacity of about 5GW.

http://www.ree.es/sites/default/files/downloadable/preliminary_report_2013b.pdf

Well worth a read, especially from the renewables perspective. It gives pause for thought.

Apr 12, 2014 at 10:35 AM | Unregistered CommenterDavid Porter

Martin A
Not being blessed with a well, but 1000 litres is about 100 of my watering cans, an few centimes a day at 5 cans per day or three weeks worth; supplemented by water from rain capture and domestic use.

We only have a single heated towel rail as heating, and avoid using an electric kettle or running anything major when the oven is on. Most lighting is LED now, the old halogen 50W spotlights in the kitchen consumed a lot during winter months. In the last 12 months we've only exceeded 9kW once. I suspect most French households rarely venture into 12kW territory and beyond.

I agree with your assessment of the reason as EDF spent a couple of days upgrading the supply to our hamlet after months of random power cuts. Even in rural France people want the latest labour saving white goods. Whereas EDF need to smooth the load a bit. It's perhaps a model some of the UK big 6 should consider following.

Not sure this answers Nic's question but it is interesting, for me at least, getting other views on aped ting to a different regime.

Apr 12, 2014 at 2:17 PM | Unregistered CommentersandyS

Thanks to all for your comments.

I am just an ordinary man having a bit of casual musing and conversation.
However I think there might be something in your kind responses that would be of interest to those that consider these matters for a living.

For me, I have leads to a more interesting conversation in the pub.

Thanks again for comments. There is something here worthy of study.

Apr 12, 2014 at 11:14 PM | Unregistered CommenterNic

SandyS -

"Most lighting is LED now, the old halogen 50W spotlights in the kitchen consumed a lot during winter months."

Lighting is essentially free in winter (assuming the room is being heated anyway by a means whose cost is roughly comparable with that of electricity) since nearly every watt that goes into a lamp finishes up as heat in the room - even the small fraction that is actually emitted as light. Each joule of heat delivered by the lighting is a joule less that the heating needs to deliver.

Yes, if you do your watering by hand, the cost is going to be very small. I bought Brico Depot's cheapest pump and it happily lifts water about 8 m. It can empty my well in an evening - perhaps 3 cu m of water. Enough to keep a good area well-watered thoughout a drought. The well has replenished itself by the next evening. Using mains water that much would quickly run up a hefty bill.

Apr 13, 2014 at 9:39 PM | Registered CommenterMartin A