Starship (Power and Subsystems)
In the game subsystems for a starship are split into four sections: Weapons, Engines, Shields and Auxiliary. These subsystems share an overall basic amount of 200 subsystem power that all starships have, and increasing the power level of one subsystem will reduce it in another. Players are able to use presets to quickly reconfigure the ships power levels to focus on specific areas or balance power between more than one subsystem, even whilst in combat.
The highest a player can manually set any of their subsystems is 100. The lowest a player can set these systems is 25. The exception to this rule is running at Full Impulse which will lower all systems except engines to 5.
 Subsystems, Power and Abilities
The Weapons subsystem affects the potency of your starships energy weapons. Increasing or decreasing power into this subsystem will have either a positive or negative effect on the damage modifier of the energy weapon. This subsystem does not affect Torpedo Launchers or Mine Launchers.
If a player has 50 power in this subsystem it will allow each of your ships energy weapons to cause 100% of their natural DPS. Every additional point of power applied to this subsystem will increase overall DPS by 2% per weapon. As an example, running 100 weapons power will yield a 100% bonus to weapon DPS giving an overall amount of 200% of the energy weapons base damage. However, every point under 50 in this system will lower overall DPS of each energy weapon by 2%. This means that if a player uses 25 power in the weapons subsystem then every energy weapon on the ship will only cause 50% of their original DPS.
The weapons subsystem power levels are capped at 125 power. Any extra power to this subsystem will not increase damage or buffer power loss further. The only exception seems to be with Beam Array type weapons, where stacking power past 125 will continue to increase the damage dealt. It is unclear if this is bonus is intended or not, as no other energy weapons benefit in this manner from extra power past 125.
The Shields subsystem controls how effective your Shield Array is at regenerating shield power every six seconds. It does not affect how much shield strength your shield facings have.
50 power into this system represents 100% shield regeneration as given on your Shield Array tooltip. Every additional point of power applied to this subsystem will increase your shield regeneration value by 4%. Every point of power under 50 will reduce your shield regeneration by 4%.
Higher shield power also improves shield resistance. At 125 power, shields gain an innate resistance of 35%. 
Power into the Engines subsystem will modify your starship's speed. Having 50 power in this subsystem will allow the ship to move at its base speed. Every extra point of power applied to this subsystem adds an additional 2% speed. As an example, running 100 power into engines will increase your base speed by 100%. For every point of power below 50, your base speed will be reduced by 2%.
Additional power to engines does not appear to affect warp travel.
Every point of power above 50 into the Auxiliary systems will increase your Perception stat by 2% and increase the potency of Science abilities by 2%. Every point of power under 50 in the Auxiliary subsystem will do the reverse and drop the modifier of abilities, perception and cloak effectiveness by 0.6% and 2% respectively.
In addition, Engineering abilities that use the Auxiliary subsystem, such as Auxiliary to Structural, are affected by the power level in the Auxiliary subsystem.
 Abilities affected
- Gravity Well
- Transfer Shield Strength
- Feedback Pulse
- Tachyon Beam
- Subnucleonic Beam
- Tyken's Rift
- Tractor Beam Repulsors
- Evasive Maneuvers
- Fermion Field
- Multidimensional Graviton Shield
- Quantum Field Focus Phaser
- Quantum Focused Shield Bubble
- Auxiliary Power to the Structural Integrity Field
- Auxiliary to Dampeners
- Auxiliary to Battery
 Efficiency and Performance skills
The skill tables for each profession of player houses multiple skills that can improve both the efficiency and performance of your ship power levels in all subsystems. There is also an Efficient Captain trait will do the same as the efficiency skills but on a weaker level.
Performance skills give a direct increase to the ship subsystem power levels. Unfortunately the mathematical calculations for performance skills are not known, however they appear to provide 1 additional power for every rank of the skill. Such as having 9/9 into Starship Shield Performance would yield, roughly, +9 power to the Shields subsystem.
Efficiency works by increasing your subsystems power based on how much power is already in that subsystem. If a player has the efficiency skill for engines and decided the run the engines at a flat 25 power, the efficiency trait and skills would boost this. Efficiency provides a much larger bonus to power when the subsystem is ran at a low power levels. See the following table, which uses the engine subsystem, the Warp Core Training, the Engine Efficiency, and the Engine Performance skills to demonstrate their effectiveness.
 Power Customization
Players are able to manually alter these presets if they wish using the power section of the GUI (graphical user interface) and switching the view mode to "3". In this view mode, players can move the sliders up and down to change power levels. The additional green bar present at the top of the some of the subsystems is the bonus power granted to that subsystem through the Efficient trait, performance skills and efficiency skills.
To lock a preset so it cannot be moved when changing other subsystems power, click the small lock button at the top of the bar. To save the present, click the save button, and to restore defaults click the restore button.
 Full Impulse
When a player enters into full impulse mode (default key: Shift + R) your starship automatically routes all available power to your engines and drastically reduces power to the rest of your subsystems.
- Weapons: 5
- Shields: 5
- Engines: 100
- Auxiliary: 5
Full Impulse also receives a bonus modifier to speed, and attaining 100 power into your engines without full impulse active will still be slower than if the player was at full impulse. The speed at which the power is rerouted, and therefore the quicker it takes you to reach the maximum speed you can attain at full impulse, is affected by your EPS which is explained below in the Regeneration and EPS section of the article.
It is highly recommended that players do not use full impulse to enter combat due to how drastically it reduces your Weapons and Shields subsystems. If a player enters combat at full impulse they will only be causing 10% of their energy weapons base damage (excluding Mine and Torpedo Launchers) and will have little or no shield regeneration.
Until power is rerouted the players damage caused at 10% of their original value will be negligible and all enemy ships shields and hull will be able to out-repair the damage caused by the player. There is a small delay before subsystem power is rerouted back to the original values the player had them set to before entering full impulse. This delay does not appear to be affected by EPS consoles.
 Regeneration and EPS
The rate at which power is transferred between the subsystems is defined by the EPS (Electro Plasma System). Players are able to use an "EPS Flow Regulator" Engineering console to increase the rate at which the power is transferred between subsystems and how fast it is regenerated once spent. Engineering Captains can also use their career specific EPS Power Transfer ability to increase the power transfer rates for a short period.
This only affects power being transferred from one subsystem to another, and will not recharge weapon power lost to weapon drain faster than normal.
 External Links and References
- Some of the information is this article references, with permission, work done by BigBagD from his blog The Engines Cannae' Take It!