Tapping Energy from Buoyancy
Country: United States
Date: August 2008
If I were to place an on demand HHO producing fuel cell at
the bottom of the ocean - creating a situation where all of the gas
production has a mile journey to the surface - Could I utilize the
buoyancy force X distance to create more energy than needed to produce
the original gas. Obviously it would be done with proper
water/electrolyte solution in a partitioned cylinder, not of
particularly large diameter but VERY deep, along with a mechanism to
harness to buoyancy and convert it into mechanical energy, finally
We do not get any net energy from the buoyancy of the gas. It is
easier for me to visualize the mechanical part of the problem
by imagining a mile-long pipe full of water sticking straight up
in the air. To make a bubble of gas at the bottom of the pipe,
we have to raise the water in the pipe. When we allow the bubble
to travel up to the top of the pipe, the water will get lowered by
the same amount it previously was raised. It does not matter whether
the bubble is produced mechanically, or by electrolysis; we still
have to supply the energy to raise the water to accommodate it.
OK, I have glossed over a detail: the water actually gets lowered
slightly more than it got raised, because some water was converted
to gas, after all, and is no longer in the pipe. But this cannot help,
because we would get the same final state whether water at the top or the
bottom of the pipe were electrolyzed.
I would say this idea works better as an energy-storage method, than
as an energy-production method.
If something seems "too good to be true" -- it probably is. I think you run
into trouble with the laws of thermodynamics. There is a major link that
your cycle does not take into account, that is the work that has to be done
by the gas at the bottom of the ocean to form the initial bubble. This is:
W = Pexternal x dV. where "Pexternal" is the hydrostatic pressure at the
bottom of the ocean. Even if the cycle is reversible, that is, there are no
frictional or thermal losses, that work term is the same as the buoyant
force but with an opposite sign. Think of the reverse cycle of taking a
large bubble of gas at the surface being compressed to the size of the
bubble at the bottom of the ocean. The first law of thermodynamics wins
If I understand your question, you are suggesting that water be electrolyzed
in the deep ocean to create hydrogen and oxygen gas, the buoyancy of which
can be harnessed to create energy.
Unfortunately, it takes more energy to electrolyze water at high pressure at
the bottom of the ocean than at low pressure, nullifying any energy you can
recover due to buoyancy.
If you take a class in thermodynamics, you will encounter equations that
take account the pressure at which a reaction takes place. It can be any
reaction: a chemical reaction can be sped up or slowed down with pressure;
freezing points of materials are altered by pressure; solubility is affected
by pressure, and yes, even electrolysis is helped or hindered by pressure
A significant amount of energy is required to split the water to form hydrogen
and oxygen gases -- it is not clear from your description from
where that energy is coming. A fuel cell does not make HHO from water -- in
fact, the opposite, the fuel cell converts the energy of converting HHO to
water into electricity. By HHO, I assume you mean a mixture of hydrogen and
oxygen gases. I have seen in various on-line sources other non-scientific
explanations of "special" hydrogen-oxygen mixtures, but these "special"
formulations do not stand scientific scrutiny. So you have to input
energy -- you do not get any extra out of the process.
However, if you happened to have compressed gas (and it does not have
to be at the bottom of the ocean), yes you can do work with that
compressed gas. It requires work to compress the gas, and the potential
energy of the compressed gas can then be converted into other forms of
energy or work.
The thing to keep in mind is that there is no such thing as an 'energy
creation' device, only energy conversion. Anything that claims to
create more energy than it started with is simply not possible. These
are generally classified as 'perpetual motion machines', and
unfortunately, real, working perpetual motion machines simply do not
Even worse, in any energy conversion, some energy is wasted (converted
to a non-useful form) -- so not only can you not win (no energy can be
created), you cannot even tie!
Hope this helps,
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Update: June 2012