We were discussing the European electric grid control system; I was asking him whether the Germans were prepared to buy nuclear power from the French once Germany shut down all their nuclear plants, and whether they were OK with depending not only on the French but on the Russians (for gas). We got to talking about Wind power.
He said "We have quite a few wind installations in the Baltic Sea that feed the German grid, and we sell that power to France and Poland when the wind is up. One night, we had the lines to Poland open, when a storm came up in the Baltic, the grid control system was overloaded, and we sent way too much power to Poland over the lines and took down their entire grid."
He chuckled "Again ve haf invaded Poland, but this time on the electric wires!!" He was a funny guy ...