Just completed the light house then rec’d energy from it a few hrs later. Does it give this on a..

When complete the Lighthouse generates 1 energy every 40 minutes. It stops increasing when it reaches a maximum of 15 energy after 10 hours. You can collect it at any time and it will just start filling again until it fills up stopping at 15 energy. Then it starts again after it was collected.

The same thing happens when you have completed the other landmarks. The next one you will work on is the Wedding Chapel. It will provide the same amount of energy as the Lighthouse once it is complete.