You didn't see the size of the city. It didn't represent seasons, so in winter more people will be using heaters and lights whilst in summer people will need less heaters and lights on at night.
The resources don't run out so quickly in real life. The game seemed biased to renewable energy.
I think that the flaws were that there weren't different seasons as the amount of energy produced could be determined by the weather. It was also biased as the most energy was produced by things that produced renewable energy.
When asked how they would improve the app the responses were:
Use different scenarios for the seasons. It didn't show clearly that the renewable resources don't... (unfinished)
The app could use numbers and measurements instead of bars.