First-gen district heating was steam, then moved to hot water. It didn't go away...

First-gen district heating was steam, then moved to hot water. It didn't go away [1] but there's regional differences. In cold climates there are oil based simpler backup plants that can cover for the normal CHP[2] and elctric+heat pump based generation. It's a good way to buffer and use cheap energy in periods of cheap electricty from eg high wind production[3].