General: Using electricity when carbon intensity is lowest

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- CommentAuthorEd Davies
- CommentTimeNov 16th 2021
From the departments of “what if everybody did that?” and “grandmothers need egg-sucking advice” could I suggest it would be good manners not to start and stop electricity use nicely NTP synchronised to the half hours but rather to add some sort of (pseudo-)random offset?
- CommentAuthorphiledge
- CommentTimeNov 16th 2021
Cant seem to be able to quote from the previous page so........

Posted By: philedge-the country is definitely all sharing the national generation mix we have from the principle generators

Posted by John Walsh-To be clear, the above statement is simply wrong

In respect of adding the Western HVDC link to the nations supergrid, heres what Scottish Power have to say about the link-
"This achievement has been a decisive part of the project, a joint operation between SP Energy Networks and the National Grid, involving an investment of £1.3billion which will secure electricity for the whole of the UK, allowing electricity to flow north and south, taking low carbon energy to where it is needed"

Pretty unambiguous statement, to me anyway
- CommentAuthordjh
- CommentTimeNov 16th 2021
Posted By: philedgeCant seem to be able to quote from the previous page

No, it's a 'feature' of the forum software
- CommentAuthorfostertom
- CommentTimeNov 16th 2021
You can fake it by quoting something from the current page, then pasting in (substituting) the text from the previous page - and the name as well if nec.
- CommentAuthorEd Davies
- CommentTimeNov 16th 2021 edited
Some useful background reading: https://en.wikipedia.org/wiki/National_Grid_(Great_Britain)

Particularly:

Power flow

In 2009–10 there was an average power flow of about 11 GW from the north of the UK, particularly from Scotland and northern England, to the south of the UK across the grid. This flow was anticipated to grow to about 12 GW by 2014.[33] Completion of the Western HVDC Link in 2018 added capacity for a flow of 2.2 GW between Western Scotland and North Wales.[34]

Because of the power loss associated with this north to south flow, the effectiveness and efficiency of new generation capacity is significantly affected by its location. For example, new generating capacity on the south coast has about 12% greater effectiveness due to reduced transmission system power losses compared to new generating capacity in north England, and about 20% greater effectiveness than in northern Scotland.
So, yeah, it's basically all one grid (and has been since about 1938) but losses and capacity limitations mean it's close to, but not quite, uniform and needs tweaking as generation and demand move around. Adding a 2.2 GW link is a significant tweak but doesn't change the basic situation all that much.
- CommentAuthorJohn Walsh
- CommentTimeNov 16th 2021 edited
Two issues here, both true:

1. As philedge notes, Scottish renewable electricity is distributed and consumed around the UK, as will be other v large generation sources including the 2GW coal-fired source in the East Midlands. In that sense, as Ed Davies says, "it's basically all one grid".

2. For the purpose of using electricity when carbon intensity is lowest, National Grid publish carbon intensity forecasts for each region. The forecasts are much more accurate than the UK average as they reflect local conditions regarding the balance of generation sources.
- CommentAuthorWillInAberdeen
- CommentTimeNov 16th 2021 edited
Like this:
Posted By: me on the previous pageDiagram here:
https://data.nationalgrideso.com/backend/dataset/cf3cbc92-2d5d-4c2b-bd29-e11a21070b26/resource/bb6d6ec6-16d9-4be5-b32c-1a70c09fd871/download/network-diagram-ew.png
If John had opened the link, he'd have found that his area is supplied by a major east-west connection running from the Scottish HVDC wind turbine link in N Wales, via Birmingham across to Humberside, with a second connection to/from the NW London area.

(Edit: to be clear, I cross posted with John who is now completely correct!)

To be fair, NG also had to ignore their own network map to get their API to work with postcode areas.

The problem they have in N Scotland region, is that there is usually more intermittent wind and hydro power than the inhabitants can use, so their method almost always says that our intensity is zero. But we rely on the English gas and coal stations for grid frequency stability and calm weather backup. So is it fair to say that the neighbours of those English gas/coal stations have high intensity, while ours is always nil? In that case, I can run fan heaters in the garden at whenever time I like. Or is it actually the case that we all share the grid and so our intensity is the same - I think so.
- CommentAuthorJohn Walsh
- CommentTimeNov 16th 2021 edited
EDIT: tone of post above now toned down. Thank you.
- CommentAuthorJohn Walsh
- CommentTimeNov 16th 2021 edited
Posted By: Ed DaviesFrom the departments of “what if everybody did that?” and “grandmothers need egg-sucking advice” could I suggest it would be good manners not to start and stop electricity use nicely NTP synchronised to the half hours but rather to add some sort of (pseudo-)random offset?

For clarity, I'm not a grandmother and neither do I run cron jobs on the hour!

While it's necessary to abide by the NG's half-hour forecast periods in the python script, (as you suggest) it would seem best practice to run cron jobs offset from the hour. That said, I'm not claiming to be a purist in these matters.
- CommentAuthorEd Davies
- CommentTimeNov 16th 2021
Posted By: WillInAberdeenThe problem they have in N Scotland region, is that there is usually more intermittent wind and hydro power than the inhabitants can use, so their method almost always says that our intensity is zero. But we rely on the English gas and coal stations for grid frequency stability and calm weather backup. So is it fair to say that the neighbours of those English gas/coal stations have high intensity, while ours is always nil? In that case, I can run fan heaters in the garden at whenever time I like. Or is it actually the case that we all share the grid and so our intensity is the same - I think so.
I think so, too, almost. Every kW used in the north of Scotland is one less kW available to send south to displace higher-intensity generation there unless all the lines south are running at capacity (which I understand doesn't happen most of the time).

There are transmission losses (as noted in the Wikipedia text I quoted above) but still a spare kW of wind in the north is worth something like 800 W on the south coast so should be counted at maybe 80% of the south's intensity, not the tiny fraction that it seems come from that National Grid regional intensity API. E.g

https://api.carbonintensity.org.uk/regional/postcode/KW3 Lybster, Caithness, current intensity 0 g/kWh
https://api.carbonintensity.org.uk/regional/postcode/HP12 High Wycombe, Buckinghamshire, current intensity 307 g/kWh

One should usually not be less than about 80% of the other.
- CommentAuthorJohn Walsh
- CommentTimeNov 16th 2021
Posted By: Ed DaviesThere are transmission losses (as noted in the Wikipedia text I quoted above) but still a spare kW of wind in the north is worth something like 800 W on the south coast so should be counted at maybe 80% of the south's intensity, not the tiny fraction that it seems come from that National Grid regional intensity AP

There's an explanation of the formula NG use here:

https://raw.githubusercontent.com/carbon-intensity/methodology/master/Regional%20Carbon%20Intensity%20Forecast%20Methodology.pdf
- CommentAuthorEd Davies
- CommentTimeNov 16th 2021
Yes, but it's this bit which doesn't seem to make much sense:

It is then possible to calculate the carbon intensity of electricity in each region. If the region is exporting
power, then that region consumes electricity equal to its carbon intensity of generation. If the region is importing power, then the carbon intensity of the power that it consumes is equal to the weighted sum of its regional generation plus the power flow from the lines it is importing from.
It's as if they think there are different coloured electrons, green through black, and it actually matters which particular ones you're using.

As previously discussed, I think the whole thing is somewhat misguided but here it's just bonkers.
- CommentAuthorJohn Walsh
- CommentTimeNov 16th 2021 edited
Posted By: Ed DaviesYes, but it's this bit which doesn't seem to make much sense:

I've previously quoted that para from the report - this is where the report made sense to me!

I wonder if the point at issue is how the grid is balanced. In Figure 2 of the report ('Electrical representation of reduced GB network') what do the horizontal lines represent? For example, is this where balancing happens? Is it that the flow of electricity into a 'region' for consumption in that region is one control and the flow of electricity through the region and onto another region is another control?

I feel that taking this up with the authors - Dr Alasdair R. W. Bruce, Lyndon Ruff, James Kelloway, Fraser MacMillana, Prof Alex Rogers - would be a way of definitively resolving this. In the absence of that, I would tend to take the authors' opinion. That's just me trying to balance what's in front of me.
- CommentAuthorEd Davies
- CommentTimeNov 16th 2021 edited
Posted By: John WalshIn Figure 2 of the report's pdf what do the horizontal lines represent?
They represent a bus (in the electrical sense of the word) standing for that part of the grid which is in a region.

For example, is this where balancing happens?
Yes, basically the sum of generation - demand + flow in - flow out has to be zero. (Note, they get the formula back-to-front in Step 3 vs the text description above it.)

Is it that the flow of electricity into a 'region' for consumption in that region is one control and the flow of electricity through the region and onto another region is another control?
Once they've predicted the generation and demand in each region they then solve for the flows into and out of the regions along each of the lines between them in step 4, so they aren't really controls as such, more like outputs of the model.

In the absence of that, I would tend to take the authors' opinion.
That's up to you, of course, but if it's giving obviously nonsensical results others can be a bit more sceptical.

E.g., at least late this afternoon it was giving an intensity of 0 g/kWh for northern Scotland. I ran my washing machine during the afternoon (because it was windy). Do you really think total emissions for Great Britain were not at all affected by that? I think emissions were increased but not quite as much as they would have been if I'd run it in my old house in High Wycombe.
- CommentAuthorJohn Walsh
- CommentTimeNov 16th 2021
Posted By: Ed DaviesThat's up to you, of course,

I've emailed Lyndon Ruff (address on the API front page) - fingers crossed there's a response.

Hi Lyndon,

A small-scale end-user query about the Grid's Carbon Intensity API - how usable is the regional forecasting data?

I'm using the data to control space and water heating and have shared this on 'Green Building Forum'. There is, however, scepticism about the validity of your data, even questioning whether it is accurate to consider the grid at a regional level.

I hope you are able to respond - it's small-scale but arguably important to developing end-user engagement with your data.

Thread here:
http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=17281&page=1#Item_0

Thanks for your time
John Walsh
- CommentAuthordjh
- CommentTimeNov 16th 2021
Posted By: Ed DaviesE.g., at least late this afternoon it was giving an intensity of 0 g/kWh for northern Scotland. I ran my washing machine during the afternoon (because it was windy). Do you really think total emissions for Great Britain were not at all affected by that? I think emissions were increased but not quite as much as they would have been if I'd run it in my old house in High Wycombe.

Yet another way to look at this is to ask where you buy your electrons from? i.e. does your supplier buy electricity from nominated generators or do they buy it wholesale? Or some percentage in between?

(of course in reality I don't buy electrons from anybody. I bought a load in the wire when I built the house and I loan just enough of those every 100th of a second to balance those that the network loans to me for the next 100th of a second. And yes, I very carefully timed switching on my electricity the very first time )
- CommentAuthorJohn Walsh
- CommentTimeNov 17th 2021 edited
People on here are very sure that it isn't possible/viable/reliable to forecast *regional* carbon intensity. The argument is that intensity is the same everywhere on the grid at any one time and so regional forecasting is "misguided" and when described in the Grid's 'Regional Carbon Intensity' doc (linked to above) it's "bonkers".

While it's entirely feasible (if unlikely) that the six authors of the Grid doc are stretching what is possible, for example in order to make green claims, is it also feasible that the electricity grid industry in Europe is also 'bonkers'?

Europe has the world's largest electricity grid - the Continental Synchronous Area - with 400 million customers in 24 countries, and with detailed carbon intensity data for each country. For example, average intensity for consumed electricity is almost double in Germany what it is in neighbouring Austria. So, unless someone can come up with an explanation for why the UK's national grid with regions is somehow different from Europe's grid with countries then, sorry, but the unsubstantiated claims from e.g. WillInAberdeen and Ed Davies are going to need retracting.

My feeling is (I'm no expert here) the misunderstanding stems from an understandable lack of a technical understanding and thus a distinction between transmission and distribution. One thing for sure though - there's lots of people around the world working on providing accurate carbon intensity data, given the data is crucial for planning a greener future, and two guys on here don't cancel out all that work.
- CommentAuthorWillInAberdeen
- CommentTimeNov 17th 2021
John, right now the NG forecast says that electricity in N Scotland will have an intensity of 0g/kWh for every hour over the next three days.

If the public were credulous enough to believe that, they would conclude they could all run their electric patio heaters guilt-free for the next three days and emit 0g of carbon. There's no carbon reason why they would need to switch them off overnight.

However, the NG forecast says that intensity in S Wales will be so high through tomorrow, that the public there would be better advised to heat their water by burning coal, rather than by using electric immersions.

Now wouldn't you agree that, if the public acted like that, the overall outcome would be "misguided" or even "bonkers"?

That's despite there being a grid of big wires sharing the electricity supply between Scotland and Wales, to divert it out of the Scottish patio heaters and into the Welsh immersions. When someone answered your question about this in good faith, you accused them of "climate-change-denialism". Perhaps that's "an unsubstantiated claim" that's "going to need retracting"?
- CommentAuthorEd Davies
- CommentTimeNov 17th 2021
Posted By: John WalshPeople on here are very sure that it isn't possible/viable/reliable to forecast *regional* carbon intensity.
I, for one, said nothing about the reliability of the *forecasting*. I don't think WiA did, either. All my criticism applies equally to the values they give after the fact.

As should be clear from my comments, I think there is a reasonable notion of regional intensity which varies across the country. What I don't think is reasonable is their method of just looking at the flows in and out of regions in the way they do as it seems to ignore the opportunity cost of consumption of electricity in low-intensity regions when that electricity could otherwise have been exported to higher-intensity regions, thereby reducing their intensity (albeit, with some transmission losses).
- CommentAuthorWillInAberdeen
- CommentTimeNov 17th 2021
Posted by: me on the previous page:
>>>> "With the increasing connections between UK, Norway, Netherlands, Belgium, Ireland, a time will come when we have to consider UK generation as part of the European continental generation mix. Which will make it even harder to define the marginal carbon intensity, or even the average intensity."

It would be interesting to consider: when exactly would that time come, such that a single intensity figure applies across Europe? Possibilities are:

A) when 'significant' electricity flows across frontiers - in 2020 GB imported 3% of electricity supply from France and 1% each from Belgium and NL. I can't find 2020 figures, but earlier years' figures for Germany/Austria were similarly very low. So Europe-wide interconnection is still quite limited.

B) when the UK/European transmission system becomes managed as a single grid with shared dispatching decision-making, rather than a system of independent national grids with limited cross border interconnections (as it is at present in GB, Ir/NI and the independent national grids within the CSA).

Without reopening the 'marginal intensity' discussion, it's already the case that saving the marginal 1kWh of electricity in Scotland, means that England needs to import 1kWh (almost) less from France, who can then supply 1kWh (ish) extra to Germany, so displacing 1kWh from Poland. So the marginal intensity in all those countries is linked, if not the same.
- CommentAuthorJonti
- CommentTimeNov 18th 2021
Isn't it the overall carbon intensity that counts???
- CommentAuthorJohn Walsh
- CommentTimeNov 18th 2021 edited
Posted By: JontiIsn't it the overall carbon intensity that counts??

That would depend on what your purpose was:

1. make no changes, carry on as normal - then overall, national average carbon intensity is all you need.

2. understand that the generation mix is rapidly changing to very low carbon intensity, but this will increase the problem of matching generation and demand - then, you might be interested in finding new ways to adapt your energy use to coincide with low carbon generation. And to help with that WWF, Environmental Defense Fund Europe and the University of Oxford department of Computer Science have partnered with the National Grid to produce regional carbon intensity forecasts.

I'm not going to even read what the likes of WillInAberdeen and Ed Davies have written because it has tended towards personal insults.

Suggestion for GBF: provide a channel dedicated to 'scepticism'. Any of the above unsubstantiated or just abusive "the National Grid are bonkers" can be shunted over to the scepticism channel. I'm serious here - people just looking (and not posting) will be put off by the tone and attitude of the sceptics. Sure, it's probably best to provide a space for scepticism but can we find a way of preventing it from dominating and therefore detracting from the purpose of GBF?
- CommentAuthorEd Davies
- CommentTimeNov 18th 2021 edited
Posted By: John WalshEurope has the world's largest electricity grid - the Continental Synchronous Area - with 400 million customers in 24 countries, and with detailed carbon intensity data for each country. For example, average intensity for consumed electricity is almost double in Germany what it is in neighbouring Austria.
Given the longer distances and presumably limited inter-country transmission (WiA: “I can't find 2020 figures, but earlier years' figures for Germany/Austria were similarly very low.”) a 2:1 ratio seems quite plausible. This doesn't support the idea that a 307:0 ratio within a well-connected area makes much sense.

I'm not going to even read what the likes of WillInAberdeen and Ed Davies have written because it has tended towards personal insults.
For anybody else still reading, then, I've just re-read all my own posts on this thread and don't think I've written anything which can be described as personal insults. I've described the outputs of that model as “nonsensical” and “bonkers” but I think that's legitimate kick-the-ball-not-the-player comment.
- CommentAuthordjh
- CommentTimeNov 18th 2021
Posted By: WillInAberdeenIt would be interesting to consider: when exactly would that time come, such that a single intensity figure applies across Europe? Possibilities are:

A) when 'significant' electricity flows across frontiers - in 2020 GB imported 3% of electricity supply from France and 1% each from Belgium and NL. I can't find 2020 figures, but earlier years' figures for Germany/Austria were similarly very low. So Europe-wide interconnection is still quite limited.

I expect, although I don't know, that exports/imports take place on a pretty-much price driven basis. If it's cheaper to import than generate then if I'm the person responsible on the day, I'll do it.

There's an obvious national security issue about not being dependent on imports, so the price signal needs to be 'influenced'. I'd suspect that there are artificially high charges for the cross-border interconnects in order to stop the price driven person in charge using them and to ensure that each country builds and maintains its own power stations.

All pure speculation of course. Roll on the day that fusion in orbit makes it all too cheap to meter.

B) when the UK/European transmission system becomes managed as a single grid with shared dispatching decision-making, rather than a system of independent national grids with limited cross border interconnections (as it is at present in GB, Ir/NI and the independent national grids within the CSA)

I can't see that happening until after political union.
- CommentAuthorMike1
- CommentTimeNov 18th 2021 edited
Seems sensible to me to use regional emissions. Transmission losses are a factor, but more particularly only a limited amount of electricity can be moved between regions because the transmission capacity between them is limited. And there is apparently a charging mechanism to encourage companies to keep transmission local too (TNUoS... means that users will pay more if they source or send their electricity over large distances).

For a more sophisticated model, you'd need access to the data to be able to model it.
- CommentAuthorJonti
- CommentTimeNov 18th 2021
Posted By: John Walsh
Posted By: JontiIsn't it the overall carbon intensity that counts??

That would depend on what your purpose was:

I would have thought the main goal would be to reduce the carbon intensity of all electrical generation and though what you are pushing will do a small amount towards that I still believe that it is more a policy driven solution that will be successful rather than consumer habits.

Ed,

I to am at a loss as to where you have made any personal insults.
- CommentAuthorWillInAberdeen
- CommentTimeNov 18th 2021
The Germany/Austria situation actually turned out quite interesting (IMO, others may disagree!). Apparently until a few years ago, Germany and Austria were trying to operate a single power market zone. But unfortunately Poland and Czechia were finding that their grids were being loaded up with a lot of power that was nothing to do with them, it was in transit between Germany and Austria. So they were asked to disconnect from each others' market and they operate separately for now.
https://www.cleanenergywire.org/news/german-austrian-power-zone-split-eu-no-plans-tighten-co2-goal/higher-prices-austria-germany-first-auction-after-power-price-zone-split

but there are longer term plans to reconnect them with HVDC links running across Germany, similar to the Scotland-Wales one, but over land (so upsetting folk living nearby). The aim is that Austrian hydro power could one day complement German offshore wind, bringing down the intensity in the grids at both ends, similar to the Norway-GB and Scotland-Wales HVDC links.
- CommentAuthorJohn Walsh
- CommentTimeNov 19th 2021
Brilliant educational tool for getting over the hump of believing "carbon intensity on the national grid is the same everywhere at any one time".

https://www.entsoe.eu/data/powerflow-tool/

I guess you could liken the hump to "the national economy is like a household budget" myth: electricity is the same everywhere around my house and so that must also be the case on the national grid? In HE the hump might be called a threshold concept or 'troublesome knowledge', where students are confronted with a seemingly counter-intuitive concept. Once over the hump of understanding the concept though, students see the world differently and are able to take on board further new knowledge.

Recommend grid plan #5 of the power flow tool, which includes North Sea wind turbines. The visualisation helps with thinking about power flow across the *transmission* network. That, if in a region such as Northern Scotland where more power is being generated than consumed there will be measurable power flow south along the *transmission* lines. And this is the important bit - in the region, the *distribution* network will only be taking electricity from local generation, which will be a proportion of what is generated with the rest going south over the *transmission* lines. As with yesterday, this meant 0gCO2/KWh carbon intensity for part of the day for Northern Scotland.

Hope that helps.
- CommentAuthorfostertom
- CommentTimeNov 19th 2021 edited
Looks fun - and thanks for distilling the essence of the 'lesson'.

Posted By: John Walshthreshold concept or 'troublesome knowledge', where students are confronted with a seemingly counter-intuitive concept. Once over the hump of understanding the concept though, students see the world differently and are able to take on board further new knowledge.
See
https://www.amazon.co.uk/Deficit-Myth-Modern-Monetary-Economy/dp/1529352568/ref=sr_1_1?keywords=the+deficit+myth&qid=1637319079&sr=8-1
- CommentAuthorJohn Walsh
- CommentTimeDec 8th 2021
National Grid have a new region-based carbon intensity smartphone app - search for 'WhenToPlugIn' on your app store. Good to see NG continuing to develop this tool.

https://www.nationalgrid.com/cop26/when-to-plug-in-app

Access to the data: https://api.carbonintensity.org.uk/

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