[londons_explore]

Did they consider connecting to both grids at the same time making a bigger 'supergrid'?

If there is insufficient connectivity between the grids and the connections all disconnect due to overload, you just end up back in the two-grids situation that they have planned anyway.

[sidewndr46]

The goal of this is to economically and politically isolate Russia and prevent anything in Russia from affecting the Baltic states

[lvlvlv]

BRELL ring is a tool to manipulate the baltics energy system and pressure them politically. Namely, it is used as a “last resort” balancing system where fast response river Volga cascades are able to eat the surplus (stop producing) or provide enough in case of shortages. Balancing energy is the most expensive and there is really no good way to bound/hedge the costs. Hence a tool to manipulate the baltics. In addition to that, this will allow the baltic countries to finally move onto more liquid and cheaper 15min day-ahead, intraday markets.

[pjc50]

The political situation is not favourable to that.

[amenghra]

This would require both grids to be exactly synchronized.

[HPsquared]

It's possible to transfer power between two grids at different frequencies (even between 50 and 60 Hz), it just requires more expensive equipment.

[kzrdude]

There's by now a lot of DC links in Europe for example going from the European continental grid to the Nordic grid. Denmark is split between the two so it has a country internal DC link too.

[cf100clunk]

There are several DC links in Canada too, i.e. the underwater link between the Lower Mainland of British Columbia and Vancouver Island, which uses only one conductor and the water itself as the other. The North American grid is also DC linked betwen Alberta and Saskatchewan at one point.

DC links solve a myriad of synchronization problems.

[cf100clunk]

At one site in a jungle, my employer had an electrically driven flywheel built that ran on that country's mains grid, paired with an AC alternator on the flywheel that fed the building. This solved a variety of frequency and voltage problems, including mains outages. If the mains went dark, a diesel generator would kick in to boost the flywheel RPMs on an as-needed basis rather than constantly run.