I had quite a lot of fun playing this, and it was definitely a tense experience!
The different mechanics for the power plants were really interesting and gave me a lot to think about when managing the power. Being able to see when the power demands are about to rise also allows for some strategic planning.
My main criticism relates to UI and presentation in general. From a technical standpoint, I had some non-responsive buttons (I failed on level 3 and couldn't click replay, and the biomass upgrade button took several clicks to work). I'm not sure if this is something to do with the WebGL player, or me playing on a mac, but have a look into it.
In terms of UI/world design though, the game itself has some issues. The town is static and basically non-interactive for the duration of the level, so unless there's stuff that happens there later on, the game would play exactly the same without it.
So as a visual, it's okay to have it there, but it does mean that the UI that the player spends 99% of the time with is pushed to the edges of the screen. This also means that the toggle buttons for the power plants are a bit small and difficult to hit. From what I played, the game could take place entirely from the point of view of a person in front of a big console, and you could potentially do some awesome stuff with filling the screen with nifty UI controls.
If there is stuff that happens in the town that I missed, then this feedback isn't relevant, but I didn't see any in the 3 levels I played.
Alternatively, maybe the town could sort of represent the rising and falling power demand graph, so the player has to really keep an eye on what's going on in the town to figure out if the demand is about to spike. If snow starts falling, everyone begins turning on their heaters, indicating that the demand is about to shoot up. A neighborhood could suddenly spring up, and people quickly start moving in, so you know it will rise. Or alternatively, a storm could cause 2x production from your dam power plant.
Anyway, I think the management game in there is a lot of fun, but I'd just like to see something done with the town.
Looking forward to seeing more of this