This is an analysis on the many different kinds of energies flowing within the Matoran universe and through the bodies of its inhabitants.
It draws on the body of knowledge contained in the published story and promotional material, as well as numerous Greg Farshtey conversation topics. Take this topic as a synthesis of all the provided information and as an explanatory material detailing everything we know. The aim is to make obscure distinctions more clear and perhaps shed light on some of the questions you might have raised in the past.
I find it appropriate to preface this by highlighting the fact that the Matoran universe or the Bionicle story as a whole, does not posses a single central “power system” or “energy type” like many other series do (think Transformers - energon; Star Wars - the force; etc.)
Instead, the MU posseses several kinds of energy with different uses and properties.
We shall take a Toa as our model MU representative, as they posses most of the main energy types.
First, here is a list: 1) physical energy, 2) elemental energy, 3) toa power, 4) life force, 5) kanohi energy.
I am going to dicuss these one by one.
1) Physical energy
We start with perhaps the most important, but most overlooked energy type. It has several names, but all of them are valid and accurately describe the energy flowing through the bodies of ALL the MU inhabitants:
Personal, physical, internal energy, is the energy required for everyone to function. It can be replenished by eating and/or by recharging in the approprietly designed power station (like the Matoran feeding points in Metru Nui). Power-costly activities such as hard work or combat deplete this energy faster. Beside the bodily functions the physical energy also empowers all of the non-elemental abilities a character might have. Toa do not have many, but examaples of these include kraata powers, Skakdi abilities, Shadowed One’s eyebeams, and just about any special power you can point to except the elemental powers or Kanohi usage.
A notable example are Rhotuka spinners, which are formed exclusively from physical energy. It is here we see another property - that it is tied to/contains the essence of the morals and character traits of the individual. This makes sense as it permeates the mind.
The amount of physical energy the individual has is directly proportional to their physical size. Time and time again we see smaller characters like Matoran being depicted and described as weaker, or incapable of handling certain objects of power - that is because their capacity is relatively low. This increases after they become Toa and decreases again once they become Turaga. That is also the reason why while the Matoran can produce Rhotuka, they would quickly tire out if they attempted more than one or two. Some of the most powerful beings like Brotherhood of Makuta or Order of Mata Nui members have immense physical energy, so much so that lesser beings struggle containing it, potentially suffering adverse effects (Conjurer, Thok, Hakann).
When made visible, the physical energy manifests itself in a sinister black appearance such as the black lightning which shot out of Brutaka or black flames of the Maxilos’ sword, which directly manipulates robot’s physical energy.
The true nature of this power is intentionally left unclear, but it is not electricity.
2) Elemental energy
Unlike the previous one, the elemental energy only takes root in the select species of the MU (Toa, Bohrok, Makuta, etc.) It feeds the true elemental powers with extremelly wide application range and free control. It forms a separate energy pool unrelated to the physical energy. The main halmark of elemental powers is that they draw upon the elemental energy instead of the internal physical energy of the user, so its usage does not tire you out.
Elemental energy is constantly generated in the bodies of the elementaly powered beings. If they run out they have to wait for it to recharge to substantial levels before they can access its power.
When released, the energy quickly solidifies into its given element or its protodermic equivalent if it exists. Likewise, existing element can be transfomed into elemental energy of its flavor. This can be used to replenish elemental energy pool, but there is a limit to how much extra energy a Toa can absorb. Exceeding the natural maximum elemental capacity is possible, but it is similar to carrying heavy weight - the more you carry, more difficult it gets and at high levels can even be mentally taxing. If a Toa exceed their limit by a large enough margin, they risk losing control of the power unless it’s expelled elsewhere.
Different beings have differing amounts of elemental power: Matoran have trace amounts, Turaga a substantial but relativelly small amount, and Toa have a very large capacity. Toa Nuva are higher in this regard and Makuta are even higher up the rank. The Element lords have a nigh inexhaustable amount of elemental energy because they are linked to all of the existing element in the environment on a fundamental level.
Elemental energy seems to be affected by toa power, but it is not completely contingent upon it. For example increase or decrease in Toa power results in increase or decrease in maximum elemental capacity, but a complete absence of toa power does not necessitate the absence of elemental energy.
Also, the Rhotuka abilities of Toa Hordika happened to match their elements, but these still used physical energy (as all Rhotuka do). What was special about Hordika is that their new tools allowed them to acces their elemental energy pool and charge the spinners with that instead of using their physical energy. They could reach very high power levels using this method and could even charge up other objects (the gate).
3) Toa power
Only found inside Toa, this unique energy is very powerful, but finite. Once used up it cannot be replenished. The only way to create more toa power is to stimulate the latent toa power of a destined Matoran with a pre-existing power of another Toa. This Matoran is “inoculated” with the toa power which multiplies until it reaches a full capacity. This amount is all the Toa will ever get, unless one uses an external battery of toa power like the Nui Stone.
The power in appearance ranges from invisible, light of various colors, to blue-white lightning discharge. Nui Stone produces crimson red aura when activated, but it is unclear whether this is pure toa power or just an effect of the stone. The multiple depictions would indicate latter.
Toa power can be used to create toa stones and similar objects, or to create new Toa directly. It can heal mortal wounds and clear infections, as well as energize objects or individuals - awakening beings from a coma-like state. It is also a neccessary component of a Toa Seal placed on top of protodermis cage. We have not yet seen the full extent of toa power application.
4) Life force
Life force is the type of energy keeping the characters alive and it seems to be the same for MU inhabitants and Spherus Magna natives (as evidenced by the effects of the Ignika and the fact that Squids can leech life force out of MU denizens). It is extremely difficult to create new life force, the only things known to have this ability are the Matoran creation machines (and any equivalnets for other species), machines on the Red Star, Ignika, Great Beings and their equipment, Artakha if provided with extra GB equipmement, Rahi creation process and creation process for other species. Mutation done to inanimate objects can also sometimes result in new life force (Roodaka’s spinner).
The life force is tied to the spirit (AI) of the being. It is also somehow proportional to the size, but this is less clear cut than in case of physical energy. For example, Teridax has more life force than Matoran Jaller, but Toa Matoro was still able to use his life force to revive GSR (a possible amplification mechanism due to Ignika). It is easier to make more of existing life froce than to create it de novo. Depleted life force regenerates over time. Only a sufficiently functional body can house life force.
5) Kanohi energy
Kanohi masks contain their own type of energy. This goes for Kanoka disk too. The energy determines the power level and power type of the mask/disk and is dependent on the properties of the protodermis mask/disk is made from. The effects of this energy are more “wild” and less stable in case of disks, and more focused and controlable in case of masks. When a disk is converted into a mask, this energy leaks out, which is the reason only the disks of higher power levels retain some after the process. Once in mask form, the energy stabilizes even more so than what was possible in disks.This energy is finite and cannot be replenished, but the capacity of a mask is huge (Helryx’s mask existed since before the dawn of MU and has been in heavy use all the time, yet did not run out of power) This is not true for disks for afformentioned reasons (kanoka on Mata Nui lost their powers in less than 1000 years). Thus Kanohi seem to be around 100X more stable than disks.
The Kanohi energy can be visible in rare circumstances such as Eliminator extracting the Kanoka energy and forming it into lighting-like blasts, or Great Disks acting on their own to destroy Morbuzahk with a yellow-white energy sphere.
So far we talked about the energy that gives the mask/disk its power. But there seems to be another energy type within, the one that vitalizes a Kanohi user and enables them to function. It is not clear whether this is truly a different kind or the same type. Since the masks are often described as batteries and are cited as objects enabling Kanohi-dependent species to function without much external recharging, it is entirely feesible that at least a portion (or even all) of this energy is actually physical energy. The dependence on masks varies even between mask-wearing species and one could perhaps imagine that the extra power creates a sort of positive feedback loop amplifying users physical energy.
Intra-species variability in mask dependence also exists. Maskless Toa operates at 50% efficiency, Turaga at some undisclosed lower value and Matoran enter a coma-like state if the mask is not replaced within certain time.
So this is it for now! There are of course many more energy types, but these are the mot important ones and anytime you need to know more about them, you can refer back to this topic