For those who have been wanting to do "Kingmaker in Space" our group has been doing that to determine that we divided the charges by 10 for reactors and by 5 for the laboratories to determine the BP value (limit of one reactor per city district). Unlike several buildings, reactors and labs are not upgradeable.
Fission Reactor - 100 BP (4 lots) 1000 charges
Fusion Reactor - 50 BP (2 lots) 500 charges
Geothermal Reactor - 20 BP (1 lot) 200 charges
Graviton Reactor - 80 BP (4 lots) 800 charges
Solar Generator - 5 BP (1 lot) 50 charges
Laboratories work the same way except they are divided by 5:
Cybernetics Lab - 20 BP (1 lot) 100 charges
Graviton Lab - 50 BP (2 lots) 250 charges
Medical Lab - 4 BP (1 lot) 20 charges
Military Lab - 20 BP (1 lot) 100 charges
Nanotech Lab - 30 BP (2 lots) 150 charges
Production Lab - 10 BP (1 lot) 50 charges
Robotics Lab - 40 BP (2 lots) 200 charges
Spaceship Lab - 90 BP (4 lots) 450 charges
Each generator provides power for an entire district. For example, the new kingdom district has a Solar Generator. It can power either 2 medical labs or 1 production lab. A fission reactor can support a robotics lab (200), a graviton lab (250), a production lab (50), a cybernetics lab (100), a medical lab (20), a military lab (100), a nanotech lab (150). All excess power can be utilized to charge items, etc.