Fairly easy to unlock in the early game, but does not work in the campaign.
You need to play Utopia and the starting city needs to have a Geothermal Spring for steam power.
Next you need the tier 1 Adaptation generator, an Extraction district over the Geothermal Spring and a Geothermal plant. When you use 300 steam power and have less than minor squalor the achievement will unlock.
If you don't want to wait until you get an Adaptation faction you can start with Machinists and Foragers.
You can also use Emergency Shift on the district to reach 300 power. Generator overdrive might also work.
It's fine if you also have coal and oil, steam is used first.