Energy is one of two resources in Supreme Commander; the other is mass. Energy is primarily produced by any type of power generator. Alternatively, some is obtained from reclaim, or the resource allocation system (RAS) implemented in ACUs and SCUs.
As a resource, Energy is primarily required to build all structures and units; it is also used to fire the ACU overcharge cannon, load artillery structures, and drained to maintain shields and intel capabilities (such as radar and stealth fields).
Importance[]
It is useful to know how to make it, spend it, grow it, and dump it. Managing generator count, avoiding power stalls, upgrading to new generators, and avoiding waste are all important parts of balancing the energy resource economy.
Energy is not especially difficult to get by, and is usually not the limiting resource. This is because if you need energy, the solution is to build power generators, and that is all. This has some mass cost and consideration from a few engineers, but as long as there is nearby space it is possible to build more generators over time until the energy requirement is satisifed. Unlike mass extractors, power generators are not upgradeable (as each different type has a different size), so the main way to grow power supply is to slowly build more of the generators over time. For example, it is possible to queue an engineer to create a line of generators by dragging the ghost structure over the terrain.
While there is an opportunity cost in overspending mass on power generating structures, the main problem is that running out of power (a "power stall") can have devastating consequences. All of your intel structures will go offline, not only leaving you in the dark, but losing the units you identified in the past too. Your shields will deactivate, leaving your base vulnerable, but also your shield generators and your shielded units especially vulnerable (they have very low HP, usually). Your mass extractors will also cease to function, lowering your mass income. Finally, getting out of this situation is especially difficult, as power generators mainly cost energy to produce, the resource you currently don't have. As much as you can, try to never run out of power.
Power generation is linked quite strongly to advancing in tech level. When enough generators have been created to make it possible to construct the next level of power generator without stalling, it is wise to do so and reclaim the lower tier generators, as they are less mass efficient per unit of power produced. In fact, higher generators are more efficient in terms of space and build time too. 1-2 Energy storage can be useful to give more buffer time when performing the upgrade process, but remember that each storage costs almost as much as two generators. Another expensive cost are ACU upgrades (as an example, the gun upgrade such as the UEF Zephyr Amplifier costs 24k energy), which often causes energy stalls if not enough T1 generators have been created (say about 10 or so). However, note that the T2 ACU engineering suite can be used to produce power generators as an alternative to having to invest in a T2 factory and engineers. Finally, it is also not possible to upgrade mass extractors without having several generators of the previous level to support them while they upgrade.
Because as of Forged Alliance Mass Fabricators are not very efficient, the main way to balance an excess of energy production is either to spend it, or to reclaim the mass from the generators. Air tends to be high energy low mass units, and tend to cost more energy than their land counterparts. When producing from an air factory it will be quite useful to have an adjacency bonus from generators to improve spending efficiency of the factory. For example a tank costs a few hundred energy, but a T1 Interceptor costs up to 10x as much at a whopping 2k energy, and a T2 Bomber will cost nearly 50x at 10k energy. Another big step up is from T2 to T3 land which also costs several thousand energy per unit and can be up to 5x the cost of T2 land, requiring more efficient power generation to sustain it.
See also[]
For information about the second resource in Supreme Commander, mass, visit the mass page.