A heatpump needs power to operate, but will generate at least 3x more heat than the electricity to power it.

The article describes how there will be a water battery.

So it can be thought of as a part of a bigger countrywide or europe-wide plan and grid?

Sure, but if you build a nuclear reactor suitably close to your city (!) it produces hot water directly in addition to electricity. It's just a much bigger pain to ship hot water over long distances than electricity.

Sweden's first commercial nuclear plant[0] was built right next to a newly constructed suburb precisely so that it could be used for district heating too. And also for producing small quantities of weapons grade plutonium, for... research purposes. Waste not, want not!

(It didn't last very long and was shut down in the mid 1970's, for somewhat obvious reasons.)

[0]: https://en.wikipedia.org/wiki/%C3%85gesta_Nuclear_Plant

It was Philippsburg was 30km to Mannheim, Could have send 3GW of thermal energy over.