In the fusion tech there is a technology to boil water using liquid lead to generate 1000 degree steam. But there is no turbines or generators able to use the steam. I'm really confused why should this recipe be there.

(1 year necroreply)

Some mods add turbines with higher maximum temperatures. Space Exploration for instance has 5000 degree turbines, so you could run them at 1/5 power with that.

However, even vanilla turbines can benefit from steam mixing. The turbine max is 500 degrees. So, if you mix three parts 165 steam from a boiler and two parts 1000 steam from the recipe, you get 499 degree steam, just shy of the turbine's maximum power output, without having to use a nuclear heat exchanger. Mixing does come at the cost of some complexity though.