Last week, driving around Alpine Europe, we crossed the borders of Germany, Austria, Liechtenstein, Switzerland, and Italy, sometimes more than once. Nowadays, the border guards are gone, and even the roadside signs marking borders are very modest, but you can tell you’re in Germany by one simple clue: everything is covered by solar panels. There are fields of photovoltaic cells, like crops, and they cover every other roof. That’s not just my impression, but a significant national phenomenon, driven (natürlich!) by policy:

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Data come from here. Interesting explanatory report here. (Liechtenstein, with just 35,000 people, doesn’t count.)