There are three main methods of generating power. Romulans, ever on
the cutting edge, use a pocket black hole , while most comparable
powers use antimatter engines to fuel warp powered vessels. Fusion is
generally preferred for civilian or low-demand applications, ranging
from deep space telescope arrays to colonists' houses to signal
flares and androids; fusion reactors are also present as secondary or
backup systems on board starships.
Rechargable batteries are also used; fairly compact batteries may
provide many gigajoules of energy. Shuttles make use of krellide
storage cells.
Ships are sometimes described as having extraordinarily low amounts
of energy or power on hand; we must either assume that conservation
of energy no longer applies, dismiss this evidence, dismiss many more
episodes, or find a method by which the figures apply to some figure
other than the actual energy reserves or total power generation of
the vessels in question.

There are
some more compatible power and energy references, both explicit and
implicit; these may be carefully used to produce a generally
consistent picture of exawatt range power systems.

On the
other side, occasional feats performed require vastly greater amounts
of energy or power.

There are
complications, but the only reasonable conclusion is that starships
like the
Enterprise commonly
use exawatt range power, once all of these are considered.

Assorted
references still place the warp core as relying on antimatter;
however, in
"The Battle,"
reference to
"emergency storage
cells" and
"fusion
generators" aboard the
Stargazer reaffirm the presence of
fusion generators and batteries. The
Enterprise has many fusion
reactors, and typically does not use all of them at once, as detailed
in
"Final Mission;" there
are at least nine, and probably at least twelve such. Fusion reactors
seem preferred groundside; they are in use in
"Survivors" as well as
"Legacy," and mentioned in
"Galaxy's Child." They
power the subspace telescope (Argus Array) seen in
"The Nth Degree." Data has
microfusion cells with which he is powered, and in
"Liasons," we hear of
microfusion flares. Diverting fusion reactors
"four through
nine" to the shield array doubles its power from standard.
Warp power may then further be diverted. Normal shields are therefore
powered with the equivalent power to six of these reactors; as
shields do not normally consume warp power, the Enterprise has at
least a dozen fusion plants on board, assuming a standardized size.
Microfusion thrusters on shuttles burn deuterium, per
"In Theory."
Romulans, always on the cutting edge, use an artificial (sometimes
referred to as
forced, as
in
"Face of the Enemy")
quantum singularity as their primary power plant. Once started, it
cannot be shut down, as noted in
"Timescape," and behaves in
many ways like a natural singularity. Quantum singularities are
better known by their common name of black holes.
Aside from normal Hawking radiation, emitted in great quantities by
small black holes, fine manipulation of the gravitational constant of
a singularity produces controlled energy releases. A centimeter wide
black hole with the normal gravitational constant G - roughly the
size of that seen onscreen, if only the very brightest central core
is the singularity - would have a mass roughly equal to Earth. If
already under the influence of a warp field as intense as the one
seen in
"Deja Q," this
could easily represent twice the mass of the moon.

In
"The Dauphin," Riker states
that a terawatt is
"more power
than our entire ship can generate" when faced with a terawatt
comm signal. It is difficult to reconcile this with a massive
starship that is capable of leaving a star system in a hurry, but
remains one of very few explicit power rates given.
This is echoed in "The
Masterpiece Society," in which Geordi describes the power
output as being in the terawatt range. In the same episode, however,
the Enterprise shifts a neutron star fragment larger than itself by
routing warp power to the tractor beam. The explicitly stated density
of 1014 T/m3 combines with a terawatt figure to
produce an acceleration that might be generously described as nearly
a nanometer per second squared that could be applied to the fragment
- another evident contradiction. If a Galaxy class vessel's overall
bulk density was half that of water, it would take nearly a month for
a terawatt engine operating at perfect efficiency to move from Earth
orbit to 2 AUs out from the Sun. This would render nearly every
extrasystem transit seen in Star Trek impossible.
As an additional note, in "Disaster," at least "half a million" amps are
arcing across a conduit, filled with air. In order to arc through 2
meters of air, roughly 1.5 million volts of potential are required,
giving an intermittant power flow of three quarters of a terawatt; it
is not plausible that three quarters of the entire power grid of the
ship happens to be leaking through a stray conduit.
After a failed transport of two in "The Outcast," a shuttle is
down to 34%, using 10 megajoules. After a successful transport of
two, 9%. They then tap other systems for power to beam out four
humanoids. This suggests energy reserves of 40 megajoules - 56.4
including the other drained systems - and 5 megajoules per
humanoid-sized transport item. As this is not enough to lift a
kilogram mass - let alone a person - out of Earth's orbit, it is
inconceivable that this is equal to the shuttle's total maximum fuel
energy in a universe where conservation of energy is maintained.
We may attempt to preserve continuity while accepting this evidence
by adding unwritten provisos - e.g., that the terawatt reference of
"The Dauphin" refers
strictly to the comm systems of the Enterprise, the "terawatt range" described by
Geordi is, in fact, thousands or millions of terawatts, and that the
shuttle's reserve power in "The
Outcast" includes only readily tapped battery power.
In "True Q," Data gives a figure
of 12.75 exawatts being generated "per [second]." The phrasing
is curious, but the order of magnitude given (1019 watts)
is much closer to the physical requirements of warp drive than the
terawatt references, making this quote - minus the grammatically
improbable "per" - the
most plausible explicit reference to warp core power output in the
series.
In "Peak Performance,"
Wesley's science project is used to provide 2 seconds of warp 1 power
to a Constellation class starship. If the globule of antimatter in
question (roughly a fist sized sphere contained in a larger ball) is
slush antideuterium, roughly half liquid and half solid by volume,
then it has a mass of ~83 grams. Warp 1 therefore requires an average
power of ~7.5 petawatts for a Constellation class starship. Wesley's
science project, if released into the environment, would have a yield
of ~3.6 megatons; a few fragments of dilithium crystal are sufficient
to channel this reaction. The greater size and high warp factors
available to a Galaxy class make the two figures roughly
compatible.
In "Deja Q," the
Enterprise reduces the gravitational constant of a small eccentric
moon with its warp field. The moon's final mass is several million
tons, but is creating ten meter tides, suggesting a mass of tens of
trillions of tons (40 trillion tons is a reasonable guess). The moon
is just short of smashing into the surface.
By conservation of gravitational binding energy, this means that a
couple yottajoules need to be supplied to put it in a stable high
orbit. This could be done via seven hours at warp nine power fed
through the tractor beam (700 exawatts) or the very quick application
of a warp field (multiple zettawatts).
If the mass of the Enterprise is between 5 and 25 million tons,
the trip taken under its own power via an advanced modification of
warp drive in "Where None Have
Gone Before" would require a similar consumption of energy on
this reasoning (3-15 zettajoules). An engine that can output 12.75
exawatts is up to this task; it would also be able to escape from a
skimming orbit of a Sunlike star within a matter of minutes, as seen
in "Half a Life" as well
as "Relics." We may
therefore wisely consider GCS output to be at least 12.75 exawatts,
with a peak consumption of roughly 100-1,000 exawatts being quite
reasonable during the application of a warp field.
In "Descent," the
Enterprise is in dire straits and trying to hide from the Borg
in the outer layers of a star. Among the methods considering of
evading the Borg is going directly to warp at the surface of the
star; assuming the star to be of similar size and mass to our own
Sun, the Enterprise to have a mass of 5-25 million tons, and
the initial warp speed used being c, 400-2,000 exawatt power
is required based on the rate of change in gravitational
potential.
In "Who Watches the Watchers," the
Enterprise is sent to send
down a 4.2 megawatt generator, enough for a subspace relay, small
phaser array, or holographic generator. The station has three hours
of battery power left when signalled; thus, we may estimate that the
station had about 15 GJ of energy left in their battery backup. "In Theory" notes that shuttles
make use of krellide storage cells; batteries also provide backup
power for the Enterprise and Stargazer, as noted in "The Battle." In "Liasons," Picard holds a power
cell that may hold "one
more charge" to reactivate the shuttlecraft
engines.
"New Ground" - an
out-of-control soliton wave, intended to efficiently transport a
small vessel at what is cited as 98% overall efficiency. When
amplified by a factor of twelve and having a predicted final energy
of two hundred times its original energy, the wave poses a threat of
destroying not only a colony three light years away, but
"taking most of the planet with
it." That this is considered a more efficient method of
travel than normal warp drive suggests that the requirement of
largely reducing a planet to rubble with 200 times the energy to
transport a small vessel. Depending on the degree and mechanism of
destroying the planet (as well as the precise nature of the planet,
which could readily be somewhat smaller or larger than Earth), we may
suggest that the original wave had an energy of between 50-1,000,000
yottajoules (5x10
25-1x10
28J). The nature of the
system being more efficient than normal warp drive and the Enterprise
being every bit as large as other ships intended for such use (if not
larger) suggests that the Enterprise can probably generate similar
quantities of energy within the span of a three light year trip. If
we call this one day's travel, and go with the lower estimate, this
gives a somewhat reasonable 580 exawatts. However, at the highest
speeds exhibited by the Enterprise, and the higher end of the range
of wave energies, this would suggest a power generation into a range
not reasonable for a vessel powered by slush antideuterium. The lower
figures are therefore preferred.
The only other plausible method of fitting
"New Ground" with the most
consistent scales of power generation and warp travel is to
substantially shrink the planet Lemma 2 down to a small planetoid
rather than assuming it to be a nearly Earth-sized planet.

In
"Allegiance," Geordi states
that operating engine efficiency is 93%. This is improved during the
episode to 96%. In a notably similar example in "New Ground," Data
notes that the low energy loss of the soliton wave (<2%) makes it
450% more efficient than the warp drive of the Enterprise. This could
refer to the efficiency of the warp engines at either a bit over 91%,
which would lie closely in line with the above figures, although it
could also be interpreted as placing warp drive efficiency at ~21.8%.
In
"Chains of Command,"
Jellico demands a 15% increase in warp coil efficiency, suggesting
engine efficiency below 85%. The highest efficiency figure mentioned
in the series is 99%.
These efficiencies are too high to allow a single order of
magnitude's gap between base system output and use... and too low to
be the entire story.
Assuming efficiency between 80-99% and a normal generation level of
12.75 exawatts, this means the
Enterprise must annihilate 143-177
kg of matter per second normally, and produce 0.13-3.2 exawatts of
waste heat normally. This also means the Enterprise must somehow sink
or radiate waste heat/energy at a rate comparable to a world-wide
nuclear war while the warp core is in operation - dozens to hundreds
of megatons every second.
We may suggest that this waste energy is somehow recycled into
another form, e.g., trilithium, which is known to be highly volatile
and a waste product of the
Enterprise's warp drive, as noted
in
"Starship Mine;" it is
also possible that some portion of this represents energy loss
through the generation of neutrinos while converting matter into
energy or back into matter. The ability of cloaked ships to remain
undetected at warp while ships have sensitive neutrino detectors
suggests this is not a significant source of energy loss.
The problem of fuel capacity is easier to solve. The
Enterprise has, after all, Bussard
ramscoops that can be used to suck interstellar hydrogen; if these
may be operated at warp speed, the 10
-21 kg/m
3
of interstellar hydrogen typically present can be taken partial
advantage of. By reconverting energy gained from matter/antimatter
reactions back into antimatter, the
Enterprise can breed its own
antimatter stores from collected matter.
A ramscoop with a cross section roughly equal to the
Enterprise's front end would need
to travel roughly 10 billion times the speed of light. In order to
avoid consuming fuel too quickly, the ramscoop would need to be
extended tens or hundreds of kilometers outward. As this does not
exceed the limits to which the deflectors can be extended, it is
quite possible that the
Enterprise is largely
self-sustaining so long as it can keep cruising peacefully.