Fusion

Fusion research improves positive energy output and gives the Fusion Reactor an extra Fuel Cell production bonus. It also unlocks the Fusion Reactor at level 1.

Quick Stats

Property	Value
Main unlock	Fusion Reactor
Energy bonus	+10% positive energy output per level
Extra Fusion Reactor bonus	+5% Fusion Reactor Fuel Cell output per level
Research Lab requirement	4

What Fusion Improves

Fusion applies to positive energy output sources.

Global Energy Bonus

positive_energy_output
  = base_output × (1 + 0.10 × Fusion level)

In practical terms, that boosts:

Solar Plant output
Solar Satellite output
Fusion Reactor output before Fuel Cells are charged from it

Extra Fusion Reactor Bonus

Fusion Reactor output gets an additional reactor-only multiplier:

fusion_reactor_output
  = base_output
    × (1 + 0.10 × Fusion level)
    × (1 + 0.05 × Fusion level)

So Fusion is especially strong if your empire depends on Fuel Cells.

Cost Formula

Metal = 2,000 × 2^(level - 1)
Crystal = 1,000 × 2^(level - 1)
Deuterium = 1,000 × 2^(level - 1)

Example Costs

Level	Metal	Crystal	Deuterium
1	2,000	1,000	1,000
2	4,000	2,000	2,000
5	32,000	16,000	16,000
10	1,024,000	512,000	512,000

When Fusion Is Worth It

Fusion becomes more valuable when:

you run large Solar Plants or Solar Satellite fields
you depend on Fuel Cells
you use Sensor Phalanx, Jump Gates, or Fuel Cell mission boosts often
you want the best possible return from Fusion Reactors

It is much less urgent if your empire is still focused only on basic economy growth and has not yet committed to the Fuel Cell loop.