Frostpunk: Edition

I was able to get this easily by playing on 'easy' on 'The Refugees' level. If I remember correctly, the temperature doesn't dip below -50°C for the entire game, so you can get away with the generator at max power and efficiency and only tents around the generator. This area will be full of tents toward the end, so keep the area clear of all buildings and build tents outward as the groups come in (~100 people each group = 10 tents and hundreds of stock piled meals).

I suggest researching the next generator level as each group comes in. This way you're ready for them when they enter the city with tents, heat, and food.