I have an idea for reworking hydroelectric power. It seems kind of silly to me that the total amount of hydroelectric power you can generate is capped. I guess the idea is that it's meant as an easy tutorial resource, and the player is supposed to run out in later levels and will have to rely on more complex resources. However, I think hydroelectric can be more complex long-term, while still being easy to get started with, like this:
The blue meter on the hydroelectric plant presumably represents the water level in the reservoir. It should fill up at a fixed rate, representing the flow of water into the reservoir. A rate of 4 or 5 units would be perfect. This means that if the turbines are off completely, the level will rise slowly - and if only one of the 3-power turbines is on, then the level will still rise very slowly. However, if the player is generating 6 or more units of hydro power, they'll be using the water faster than it's increasing.
In the first few levels of the game (i.e. the part of the game that's already complete), the player needs to generate a lot of hydro power to meet demand, and nothing about that would change. After the first few days, the player is likely to be running low on water. In the long run, the player can never average more than 4 units of hydro power, which will make this resource less relevant as the game progresses, especially as the city grows larger. A smart player will try to avoid using hydro power as much as possible, to let the reservoir fill up, in case they need an extra boost later on.
Some upgrades later in the game that could interact with this system:
- There might be later upgrades to increase hydro turbine power, but since these would drain the reservoir even faster, they would only be practical for short-term emergency power.
- There can be upgrades later on that reroute rivers to increase the reservoir fill rate, so that hydro power doesn't become totally useless in later levels.
- Later levels might have drought conditions (fill rate drops to 0) or flood conditions (fill rate increases significantly, but train tracks intermittently flood, blocking coal refills). The player might get 2-3 days warning about these conditions in daily "news briefings" that take place each game night. These briefings could also indicate other events, such as a mine accident increasing the cost of coal for a day, and might also indicate how much sun the player can expect that day for their solar power generation.