One correction about poserLX's post:
We energize `urban buildings', not `cities'. City is a whole area, with a specific color, like Praha, Leizpig, etc.; Urban buildings are the square tiles on our playerboard. We need to distinguish these two concepts clearly so that we won't be misleaded when trying to fulfill some contracts.
In conclusion (about energizing):
1. You choose a power plant.
- You may transport any amount of coals to the city that contains the power plant, using your own and/or other player's railways.
- You may transport at most (number of turbines built in the city + 1) uraniums to the city, using your own and/or other player's railways, if the power plant in the city has an Nucleum.
2. Calculate the electricity you produce.
You get 1 energy for each coal you use and 2 energy for each uranium you use. If you use uraniums, you need to check the turbines in the city. The Nucleum can process 1 uranium; each turbine can also process 1 uranium. If you use your own turbine, nothing else happens; if you use other player's turbines, you need to pay the player 1 thaler for each turbine used.
For example,assume the city has 1 Nucleum, 1 your turbine, 1 turbine belongs to other players. You can transport at most 3 uraniums to the city and produce 6 energy, and you need to pay the other player that build the turbine 1 thaler. However, if you only transport 2 uraniums, you do not need to pay that 1 thaler.
You may also get energy from action tiles or turbine effects. They are automatically calculated. For example, you built your 3rd and 4th turbine, then you would gain 2+1=3 extra free energy in each energize action, regardless of whether the corresponding turbine is used.
Sum up all these energy. That is the energy you produced.
3. Check if the energy can be transported to the city that your urban building lies in, and if the amount of energy is not less than the requirement. Producing more energy than the requirement does not give any bonus. If energy can be transported and is enough, you flip the urban building and get the rewards. (Achievement tokens(stars), Technology, income steps, etc.)