I thought it was an oblique critique of renewable energy.

Fridolin the mouse talks about the warm sun rays and the mice imagine this and becoming happy.

He also talks about smells and the blue sky etc.

He lifts the mood and does his part in the community with this.

Wow I very much did NOT know where you were going with that. I thought he was tricking the prepared mice into being eaten by cats so he could take their resources.

Me too haha I thought this was one of those creepy old books.