Because electricity is difficult to store, but because of how the grid works you always have to generate exactly as much as is used. Not electricity generation fluctuates (obvious with wind and solar; all plants need maintenance; nuclear often has to shut down in the summer either because rivers don't carry enough water or are so hot that feeding warm cooling water back into them endangers fish). Demand also heavily fluctuates both over the course of a day and with the seasons.
Trading electricity over geographically large areas smoothes out some of these fluctuations and gives you more options to deal with planned outages
> nuclear often has to shut down in the summer either because rivers don't carry enough water or are so hot that feeding warm cooling water back into them endangers fish).
I don't believe this has much impact on Germany's export patterns: in fact, summer is usually the time scheduled maintenance is planned in France, because electricity usage is much lower during summer than during winter. So there's still a lot of wiggle room before France ends up being forced to import in the summer because of that phenomenon.
The main driver for import/export patterns are different consumer patterns (not all countries have the same daily load curve - for instance, France and Spain both benefit a lot from trading because France's peak use time is an hour ahead of Spain's) and renewables availability.
Say it's a super sunny day, Germany generates more solar power than they use themselves (Germans don't usually have aircon at home anyway), Poland is happy to import and use it since it's basically free since it has no input costs of fuel, so they can idle their coal plants and use less fuel. Now it turns to night and the sun goes down and Germany generates 0 solar power. Then they can import coal power from Poland.
Expand this over a whole content and you get flows of electricity between companies depending on how the grid interconnect loads look and the prices of the various power sources. If Polish coal costs more then French nuclear, then Germany can sell their cheap wind power to Poland for something in between polish coal costs and French nuclear costs, and then buy nuclear from France and pocket the difference. Assuming the grid interconnects can't handle Poland importing direct from France.
Again none of these examples are real, just an explanation of why you would want to trade electricity and why you have a big market like the EU power market.
If you look at the electricity map at various times of day or over a week, you'll see the import arrows flip direction depending on the weather and time of day.
The UK exports wind power at night, but imports power during the day. Scandinavia often exports hydro power.
Taxes on carbon emissions mean Poland will import green power if it's available, as it will be cheaper than burning their own coal.
wongarsu|1 year ago
Trading electricity over geographically large areas smoothes out some of these fluctuations and gives you more options to deal with planned outages
pyrale|1 year ago
I don't believe this has much impact on Germany's export patterns: in fact, summer is usually the time scheduled maintenance is planned in France, because electricity usage is much lower during summer than during winter. So there's still a lot of wiggle room before France ends up being forced to import in the summer because of that phenomenon.
The main driver for import/export patterns are different consumer patterns (not all countries have the same daily load curve - for instance, France and Spain both benefit a lot from trading because France's peak use time is an hour ahead of Spain's) and renewables availability.
kalleboo|1 year ago
Say it's a super sunny day, Germany generates more solar power than they use themselves (Germans don't usually have aircon at home anyway), Poland is happy to import and use it since it's basically free since it has no input costs of fuel, so they can idle their coal plants and use less fuel. Now it turns to night and the sun goes down and Germany generates 0 solar power. Then they can import coal power from Poland.
Expand this over a whole content and you get flows of electricity between companies depending on how the grid interconnect loads look and the prices of the various power sources. If Polish coal costs more then French nuclear, then Germany can sell their cheap wind power to Poland for something in between polish coal costs and French nuclear costs, and then buy nuclear from France and pocket the difference. Assuming the grid interconnects can't handle Poland importing direct from France.
Again none of these examples are real, just an explanation of why you would want to trade electricity and why you have a big market like the EU power market.
Symbiote|1 year ago
The UK exports wind power at night, but imports power during the day. Scandinavia often exports hydro power.
Taxes on carbon emissions mean Poland will import green power if it's available, as it will be cheaper than burning their own coal.
https://app.electricitymaps.com/map
pyrale|1 year ago