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Something I've wondered for a while: if the whole continent is on a synchronized grid, how can countries tell to or from whom they're exporting and importing electricity. I can see how they can measure their total imports or exports by comparing generation to consumption, but how do they figure out which neighbour they're getting electricity from / sending it to?

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For completeness - that's just one grid included in this viz, for the map of the different european grids see: https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta...

(Russia is another big chunk of Europe but not included in the above map, though I think it may be the same grid with the Baltics)

For the question, measuring the flow of electricity is just normal power engineering, your home electricity meter does it as well. It's not so much the countries doing it though.

The Baltics are disconnecting from the Soviet era BRELL grid with Russia and Belarus in two months [0].

https://www.reuters.com/world/europe/baltic-countries-leave-...

Additional info: https://spectrum.ieee.org/baltic-power-grid

You can measure the flow of power by calculating the vector product of the current and voltage in the power line. EEVblog has a very good explanation video how this is done in an (analog) domestic watt-hour meter: https://www.youtube.com/watch?v=P_3DXcB9-xE

It's a fair question. Energy charts has both the physical flows and trading charts for Germany.

E.g. trading https://www.energy-charts.info/charts/energy/chart.htm?l=en&...

Physical flows https://www.energy-charts.info/charts/energy/chart.htm?l=en&...

And it's not the same, so sometimes there is just "transit", although transit here should I guess be understood very loosely. I also assume they just know who paid for what.

Edit: although upon re-reading I think you probably asked something else. Sorry in that case.

Disclaimer: I'm working for an actor in the electricity market, although not on the business side so I don't know everything about it.

They do know who paid for what. And actually anyone is able to know. It's a very regulated market, and most of its data is published, although I have to admit that if you don't know how to fetch it and read it, it's a bit hard to figure out by yourself.

You should be able to find published data on the ACER Remit Portal (https://www.acer-remit.eu/portal/home), ENTSO-E Transparency Platform (https://m-transparency.entsoe.eu/) and JAO website, Market Data tab (https://www.jao.eu).

By measuring current flows across the wires.

Each country works as a free market (inside a rails defined by their national agencies), where energy providers aim to offer a price low enough to be among the cheapest to cover the energy consumption forecast.

For those countries connected, those providers can participate in other markets. France power plants can sell energy to Spain, but not to Portugal.

The trick here is that the price each opperator's offer is somewhat calculated based on opportunity cost. Wind turbines has no opportunity cost, since not selling the energy generated from the wind now does not make them able to sell it in the future (that energy can not be stored at industrial level). Then, all the accepted offers for a given forecast are paid at the price of the most expensive offer among them.

There are five synchronous areas in Europe, the largest one being the synchronous grid of continental Europe [1].

Each national grids has interconnections with other grids and you can measure the flow of power through these interconnections to know who is sending electricity or getting electricity from neighbours.

[1] https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta...

> how can countries tell to or from whom they're exporting and importing electricity.

In terms of market deals, TSOs can't really do that. What can be done is measure the power flowing in lines connecting two grids, and summing them you get the total power exported from one grid to another.

Do you mean, for example, that the UK is importing energy from France, but where are they importing it from?

You don't. You guess based on generation, consumption and where the power lines are hooked up.

Absolutely false. Current flow is metered using current transformers.

full disclosure: I install high voltage switchgear for a living.

Seeing current flow through switches isn't the same as seeing specifically where your power is coming from.

Like, if power from several different sources flows into a single substation before it goes to your home, you know exactly which source created the electricity you're using?

And if I purchase power from a 100% renewable company, is it always only electricity from their generators, never ever mixed in with power from other grid sources during downtime?

No, it's just best estimates based on generation, consumption and flow.

That's like taking a bucket of water out of the ocean and saying you know where it came from. Sure, it might have come from the nearest estuary, but odds are it got mixed in with water that originated somewhere else.

I don’t understand what anything you wrote has to do with the topic at hand,

But I can tell you, each line is measured closely and billed accordingly. There is no guessing.

Electricity transmission is a bit like water pressure and distribution. You're not going to get the same electrons (or water molecules) that you subscribed to from various producers in the distribution network put in, the flow causality and the physical embodiments of production are different though related things.

Since your supply is alternating current, the electrons aren't net moving at all.

The question isn't even well-formed. It's like playing tug-of-war and asking exactly which player on the other team you're pulling against.

Kirchoff's laws applies though. It should be possible to calculate where the power in your outlet comes from for the power line operators.

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