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Buoy Seawater Batteries , how do buoys get power ? magnesium at the anode


Br Dan Izzo

Jan 1, 1970
Seawater Battery

magnesium at the anode

The power for all the NEREID system is supplied by the SWB system,
which consists of three SWB1200 (Kongsberg Simrad, Norway) cells
(Hasvold et al., 1997), a DC/DC converter, and an accumulator. The
cell is a magnesium/oxygen battery based on a magnesium anode
(negative electrode) that uses seawater as the electrolyte and oxygen
dissolved in the seawater as the oxidant.

The chemistry of the cell is the dissolution of magnesium at the
anode, given as

2Mg = 2Mg+ + 4e-, (1)
and consumption of oxygen at the cathode,

O2 + 2H2O + 4e- = 4OH-, (2)
which is written in a simplified form

2Mg + O2 + 2H2O = 2Mg(OH)2. (3)
The formation of an alkaline at the cathode surface may lead to the
formation of a calcareous deposit as follows:

4Ca2+ + 4HCO3- + 4OH- = 4CaCO3 + 4H2O. (4)
The alkaline reaction products need to be removed from the cathode
surface by sea current because the calcareous formation disturbs the
reaction (Equation 2) at the cathode.

The anodes are AZ61 magnesium alloy rods with a diameter of 184 mm and
a length of 2200 mm, including the anode connector device. The anode
can be replaced by ROV and is surrounded by the cathodes suspended
from the titanium frame (Fig. F19). The weight (in air) of each anode
is 110 kg and that of the titanium cathode frame is 62 kg. The cathode
element consists of a titanium wire core with carbon fibers oriented
radially (Fig. F20). The carbon fibers allow rapid material transport
and high current density. The cathode collector lead is connected to
the titanium frame, which is also part of the cathode. The titanium
frame allows seawater to pass easily through the cells so that
oxygen-rich seawater is supplied to the cathode and the products of
the cell reactions are removed.

The obtainable cell voltage is ~1.6 V, although this depends largely
on the conductivity of the seawater, which may vary with temperature
and salinity. The catalytic effect of bacteria colonizing on the
cathode surface, which was observed on all seawater cells in previous
deployments of the system, is another of the many factors affecting
the cell voltage. The maximum cell power is limited by the rate of the
supply of oxygen to the cathode. The oxygen supply rate is
proportional to the oxygen concentration in the seawater and the speed
of circulation. To produce the designed output of 6 W for each cell, a
minimum circulation of 20 mm/s, oxygen concentration of 3 ppm, and
minimum salinity of 20 is required. At Sites 1150 and 1151, where the
water depth is ~2500 m, an oxygen concentration of ~2.7-3.6 ppm is
expected based on previous study near these sites (M. Kawabe, pers.
comm., 1998).

Because the cells have an open structure, the isolation between them
is low, which leads to large leakage currents in serially connected
cells. The cells are consequently connected in parallel. The DC/DC
converter changes the low cell voltage (1.6 V) into the output voltage
(42.0 V). The output of the DC/DC converter is fed to the accumulator
that averages the power demand on the DC/DC converter and the seawater
cells. After deployment of the cells, the DC/DC converter is inactive
until the cell voltage becomes >1.54 V. After the cells are activated,
the DC/DC converter takes power from the cells and charges the
accumulator as long as a sufficient cell voltage (>1.28 V) is
available. If the cell voltage becomes lower than that threshold, the
DC/DC becomes inactive until the cell voltage is restored to 1.54 V.
The low threshold depends on the status of the accumulator cell
charge. The lower the cell charge is, the lower the threshold becomes.
The lowest threshold is ~1.28 V. The accumulator consists of multiple
2-V Cyclon (Hawker Energy) lead acid cells that form a 5-Ah 36-V cell
in total. The accumulator cell is float charged by the DC/DC output.
The voltage of the accumulator output is 42.0 V when the accumulator
cell is fully charged and has no charging voltage applied by the DC/DC
converter. The cell is stored in a 6500-m depth-rated pressure housing
that has four-pin GISMA series-10 underwater connectors for the load
output and the DC/DC converter. The DC/DC converter is also stored in
a similar pressure housing but has two Subconn one-way underwater
power connectors for the SWB cells and the GISMA connector for the

Battery Frame
The SWB system is mounted on the PAT, as shown in Figures F21 and F22.
The three SWB cells are stored in concentric positions. The PAT is
made of ordinary angle steel that is zinc coated; the base is coated
with tar epoxy paint to protect it from corrosion. The titanium frame
of the SWB cell and the stainless-steel pressure housings for the
DC/DC converter and the accumulator are mounted on the PAT with
polyvinyl chloride insulators. The top of the PAT is a white, flat
panel made of fiber-reinforced plastic (FRP) drainboard that has
access holes for the SWB anodes. The flat panel, which viewed from
above is circular, serves as the ROV platform and is supported by a
metal frame. The diameter of the top plate is 3200 mm. The bottom
structure of the PAT is also circular, and the diameter is 3658 mm,
which corresponds to the diameter of the reentry cone. The bottom leg
is 240 mm in height. The battery cells are elevated above the reentry
cone to improve seawater circulation through the cells. The center
bottom part of the PAT contains coaxial rings placed to guide it
smoothly over the riser assembly on its installation. The hole in the
top center part of the PAT provides space for the MEG frame. The total
height of the PAT is 2640 mm to accommodate the SWB cells. The
vertical position of MEG on the riser is set to allow ROV service.

The PAT also holds the SAM recorder frame beneath the PAT top panel.
The top part of the SAM recorder protrudes from the panel. The SAM
recorder can be lowered into the hole of the frame panel so that the
UMC at the bottom of the SAM bulkhead is mated by gravity force to a
UMC receptacle on the stab-plate placed in the SAM frame. In the
lowering operation the hole keeps the SAM canister upright; a key on
the bottom bulkhead of the SAM canister aligns with the keyway in the
hole to provide correct orientation for mating the UMC. The cable from
the UMC receptacle has a T-junction: one branch is connected to the
SWB system and the other goes to a receptacle mounted on the FRP
panel. An installed cable on the panel is used by the ROV to connect
the UMC receptacle to the MEG canister. Initially, the ROV cable is
fastened to the top panel by fastening mechanisms and a parking
connector for the ROV plug. In September 1999, the ROV removed the
fasteners and connected the ROV's UMC plug to the MEG canister. The
SAM recorder can be ejected with help from an ROV-operated lever
mechanism in the SAM frame (Fig. F23). The lever can be locked at two
positions: one at the mated position of the SAM and the other at the
released position. By using the locking positions, the ROV can easily
replace the SAM recorders.

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Page 1
De-P002Room: PosterTime: June 8 17:30-19:30Evaluation of Kongsberg
Simrad magnesium seawater battery SWB 600 aimed to verylong term ocean
bottom observation# Tomoki Watanabe [1], Masashi Mochizuki [2], Hajime
Shiobara [3], Toshihiko Kanazawa [4][1] Earthquake Res. Inst., Univ.
Tokyo, [2] ERI, Univ. of Tokyo, [3] Dep. Earth Sci., Fac. Sci., Toyama
Univ., [4] ERI, TokyoUnivFor very long term ocean bottom observation
more than several years, we made evaluation of Kongsberg Simrad
ASseawater battery SWB 600(anode: magnesium, cathode: fibre glass
carbon) around Japanese Sea in December, 1998. Inpresent experiment,
we measured voltage of seawater battery directly using a digital
recorder and cement resistors. Seawaterbattery began to produce
electric power just after touch with seawater. Maximum power output of
3W(1.83V) was observed atthe beginning of deployment, and most of this
value indicated 2W(1.5V). In this experiment, we found that output
voltagefrom seawater battery was strongly influenced by
electrochemical circumstances in seawater.


Data buoy operations safety


Following explosion in august 2001 of a moored data buoy during
maintenance onboard a ship in the Bay of Bengal which resulted in the
death of a crew member, the Indian National Institute for Ocean
Technology (NIOT) who operated the buoy consituted an expert committee
to examine the incident. The committe included distinguished
scientists in mechanical and electrical engineering, battery
development and manufacture, forensic science and pressure vessels.
This committee had concluded that the explosion was due to the
emission of hydrogen and oxygen from overcharged batteries, ignited by
an electrical spark. The recommendations of the expert committee were
then placed before the Data Buoy Cooperation Panel and the issue was
discussed further with the buoy operator represented by Dr. Premkumar
([email protected]), Panel Members, and manufacturers at its 17th
session in Perth, 22-26 OCtober 2001.

Report from manufacturer also suggested that likely causes of the
explosion were:

The release of hydrogen gas from the batteries inside the instrument
cylinder, resulting from their overcharging;
A temperature rise of the batteries resulting from the buoy being kept
on deck for 1.5 hours, leading to the generation of hydrogen beyond an
acceptable limit;
A spark generated in the electrical circuit.
After discussion, the panel recommended that manufacturers should
enhance buoy safety through improved design in the following areas

Batteries are to be placed in a vented compartment, eliminating voids
as far as possible, with a double venting arrangement;
Incorporation of an overcharge controller and temperature controlled
switch, to disconnect the batteries from the solar panels when
Incorporation of an explosive gas sensor and temperature sensor inside
the battery compartment and instrument cylinder, with the data to be
transmitted once a day, to allow corrective action, or suitable
explosive gas testing procedures, to be undertaken on buoy retrieval
or servicing;
Incorporation of continuous monitoring of battery charge current and
voltage, to be transmitted with the buoy data;
Incorporation of a suitable purging system and procedures.
The panel requested both manufacturers and buoy operators to keep it
informed of the improvements being carried out towards buoy safety, so
that it in turn can inform all other operators of these as a part of
its technical information exchange function, in the interests of the
whole community. Information on current manufacture and maintenance
recommendations will be placed in this web page.

Buoy operators and manufactuers are urged to take above information
into account.


Annex: Other accidents which already happened
UK Met. Office (information provided by Wynn Jones):

Some years ago UK Met. Office had a buoy invert because the foot had
been removed by fishermen or other unauthorised persons. When the buoy
was eventually retrieved after it had drifted ashore there was some
evidence that some of the batteries had come loose and had shorted
against the steel lid of the container pod they are housed in, causing
an explosion. However, the explosion was contained within the buoy
hull which remained water tight. There was no injury to anyone and the
buoy, and most of its electronics were reused. After that, UKMO
modified the brackets that hold the batteries in place such that they
will not move even if inverted. UKMO practise of housing them in their
own stainless steel container which is itself inside the steel hull of
the buoy probably minimises the consequences such an explosion can

NDBC (information provided by Eric Meindl, [email protected]):

A short summary of findings and activities at NDBC with respect to
dealing with explosive gases in moored buoys is given below. NDBC
efforts began in 1988 when an aluminium buoy (6-m NOMAD type),
returned from the field and just opened up within NDBC industrial
facility, exploded. As a result, NDBC now uses meters to sample the
interior of all buoys. NDBC have experienced one or two other
explosions at sea with no injuries, and many incidents when
technicians have taken air samples, found the situation dangerous, and
implemented special procedures to vent the buoy. Information below
addresses specifically the NDBC buoys, which are vented systems, not
sealed as other systems might be. Nevertheless, there may be some
information others can use to make their procedures safer. NDBC also
has specific, detailed reports of their experiences and what they
know. These can be made available upon request.

Summary of NDBC Buoy Power System Flammable Gas

Problems and Solutions

1. Hydrogen gas generation in buoys:

Hydrogen gas mixtures in air are flammable between 4% and 75% by
Accumulation rates increase with poor buoy ventilation (water
intrusion blocks the lower center compartment vent)
Electrolysis (the conductive path is from the positive terminal,
through seawater moisture on the exterior of batteries to the buoy
Reduction of battery electrolyte (potassium hydroxide and zinc),
aluminum and seawater. The primary batteries are located near the
bottom of the buoy center compartment.
Normal charging of secondary batteries and discharging of primary
Microbial induced corrosion
2. Hydrogen Gas Generation Past Incidents:

SSC/6N03 1988 Explosion resulted in one death & one injury (a)
44013/3D22 12 Sep. 97 Buoy returned to SSC with 100% LEL
46027/3D24 14 Oct. 97 Caustic residues in bottom of compartment (b)
46013/3D21 30 Oct. 97 Caustic residues; 100% LEL in 4 voids (b)
43D34/3D34 11 Nov. 97 Caustic residues; 100% LEL in void #2 (b)
46030/3DV07 21 Sep. 99 Buoy exploded prior to a service visit
46014/3D59 3 Oct. 99 Buoy Exploded during service visit (b)
42035/3D24 3 Nov. 99 100% LEL due to plugged vents (b)
42039/3D56 6 Nov. 00 100% LEL in a compartment; stuck vent valves

(a) The generation of hydrogen was caused by impurities in the primary
batteries received from the manufacturer.

(b) The generation of hydrogen was caused by seawater intrusion into
the battery compartment.

3. Hydrogen Gas Mitigation:

Obtained expert Marine Chemist Consultants
Improved tests of buoy hatch and cable penetrations
Installed a third battery compartment vent tube (if the buoy leaks,
the lower vent ) is blocked by water
Improved watertight integrity of hatch gaskets and multiplug
Increased buoy freeboard
Improved equipment compartment ventilation
Installed a seal fence to reduce excessive loading on hatch covers
Provided sufficient clearance between the hatch cover lip and the
dog-bolt tabs
Improved hatch gasket deficiencies (insufficient gasket stiffness,
gaps in the hatch gasket joint, and the position of the gasket joint
relative to the bow of the buoy)
Filled voids with inert gas
Maintain safe entry procedures and training
Installed explosive gas sensors (FAA)
Deduced the use of primary batteries.The future goal is to discontinue
the use of primary batteries.
Bilge pumps (not yet implemented)


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"We have developed an environmentally friendly power generating system
that combines the technology of a Power Cell with that of a battery.
The MagGen Power Cell system is an alternative and emergency
self-generating power source that is in a class by itself."
Shawn McGroarty, Chairman/C.E.O.

MagPower Systems Inc.
at the leading edge of New Power Technology.

News Release

News Release - January 22, 2003

MagPower completes testing of Magnesium-Air Fuel Cell on Ultra Guard's
portable water purification system.

VANCOUVER, BC, Canada – MagPower Systems Inc. announces the successful
testing of its Magnesium-Air Fuel Cell as a power source for Ultra
Guard's portable water purification system.

Having supplied to MagPower the portable water purification system,
testing was conducted at MagPower's lab facilities by Joey Jung at BC
Research Inc. with Mr. Ken Fielding, President of Ultra Guard present
for this momentous occasion.

Bruce W. Downing, President of MagPower Systems Inc. "This was the
first direct use of our fuel cell on a specific application and we are
extremely pleased with the results".

Ultra Guard has offices in Langley BC and will be making available
their system worldwide using MagPower's Magnesium-Air Fuel Cell.
MagPower's fuel cell operates with a salt-water electrolyte combined
with the companies patent pending Hydrogen Inhibitors. With its
indefinite shelf life, the Magnesium-Air Fuel Cell has distinct
advantages over heavy lead acid batteries that are currently used.

MagPower Systems Inc. is an energy systems company that is focused on
the development of innovative energy solutions based on its patent
pending hydrogen Inhibitors. Through the application of its Hydrogen
Inhibitors, MagPower has developed a Magnesium-Air Fuel Cell and the
ability to reduce production costs in the electrowinning process
(zinc, copper, nickel), coolants, hydrogen embrittlement, anodizing,
zinc alkaline batteries, electroplating, waste water recycling and
metal-air power sources (zinc, aluminum).

News Release - January 14, 2003

MagPower completes testing of Hydrogen Inhibitors for Mitsui
Corporation's zinc electrowinning process.

VANCOUVER, BC, Canada – MagPower Systems Inc. announces the successful
testing of its Hydrogen Inhibitors in Mitsui Corporation's zinc
electrowinning process. MagPower's Hydrogen Inhibitors increase the
current efficiency in the electrowinning process, thus reducing
production costs.

Having supplied to MagPower the electrolyte used in their
electrowinning process, testing of MagPower's Hydrogen Inhibitors was
conducted by Dr. David Dreisinger, University of British Columbia.
Calculated results on the first run of tests indicate annual savings
of $2.5 Million in the production of Mitsui's zinc.

Bruce W. Downing, President of MagPower Systems Inc. "We are very
pleased to be working with Mitsui and with the results of the test".

Mitsui has offices in Tokyo and Osaka with their electrowinning
facilities located in Kamioka and Hikoshima, Japan.

MagPower Systems Inc. is an energy systems company that is focused on
the development of innovative energy solutions based on its patent
pending hydrogen Inhibitors. Through the application of its Hydrogen
Inhibitors, MagPower has developed a Magnesium-Air Fuel Cell and the
ability to reduce production costs in the electrowinning process
(zinc, copper, nickel), coolants, hydrogen embrittlement, anodizing,
zinc alkaline batteries, electroplating, waste water recycling and
metal-air power sources (zinc, aluminum).

Introducing a Cleaner, Safer, Cheaper and More Versatile Fuel Cell

VANCOUVER, BC, March 29, 2002 – MagPower Systems is introducing a
proprietary Magnesium-Air Power Cell (MAPC) as a primary, alternative
and emergency power generator. MAPC's greater safety and cost savings
are significant advantages over the better-known hydrogen fuel cell

Bruce Downing, President of MagPower Systems Inc, says: "The
Magnesium-Air Power Cell supports the global push for a sustainable
environment. MAPC is more easily recycled. It is clean, green and
consumes no fossil fuels. No toxic emissions are produced, thus
reducing harmful greenhouse effects. To recharge the cell, you
basically replace the magnesium core and the salt or sea-water
electrolyte. "

The simple magnesium anode and natural electrolyte make this cell less
combustible than a hydrogen fuel cell. It does not require a
safety-sealed fuel storage like HFC. The fuel can either be magnesium
or a magnesium-alloy, while the fuel for HFC must be pure hydrogen.
This makes MAPC easily transported by plane with no special safety
permits. It is safe around children since magnesium is non-toxic. All
of these features make MAPC better for consumer products.

MAPC has an indefinite shelf life because the electrolyte can be
removed before storage. When power is needed, the electrolyte is
poured back into the cell. No other electrolyte in a non-magnesium
fuel cell, power generator nor battery can be removed, stored and
reused by the consumer. This sustainability provides a reliable source
of power for emergency situations.

In addition to the inexpensive saline solution, the cell has fewer
parts so production is less costly and faster than with HFC. This also
makes the MAPC less expensive than HFC per 12-volt system. Downing
explains the technical findings of a 12-volt unit: "There is more
electric yield per cell, 80% v. 45% to 60%. The voltage is higher per
cell, 1.6 v. 0.8. Operating temperatures are lower, 55o C instead of
70o to 100o C. And it can operate at temperatures as low as –10o C,
whereas HFC cannot operate well at low temperatures."

More Versatile
The cleaner, safer, cheaper qualities mean greater adaptability of the
technology. Four different MAPCs are being developed with strong
support from the federal and provincial governments, and industry
alliances. These include a portable unit (12 volt / 300 watt), an
industrial unit (125 volts) with BC Hydro, an automobile unit with
interest from Volvo Car Corporation, and a marine unit in
collaboration with the National Research Council of Canada. As a
member of Team Canada in the fuel cell sector, MagPower demonstrated
its expertise in Japan.

Active Ingredient
The secret to the superior qualities of MAPC over HFC is the company's
unique R&D approach to energy. Research in this magnesium-air
technology began in the sixties, but no one was able to produce a
viable product, as most of the energy loss was due to hydrogen
formation. MagPower has successfully controlled the formation of
hydrogen, which is the key to commercialization.

The company's R&D team at UBC and BC Research developed a breakthrough
hydrogen inhibitor (HIT) as the controlling agent. Independent testing
verified that instead of the usual rapidly decreasing power discharge
curve, adding a hydrogen inhibitor produces a flat line power
discharge. Downing says: "We're the only ones in the world so far who
have figured out how to control hydrogen. By adding a hydrogen
inhibitor to the electrolyte, energy outputs are now commercially

No Reverse Engineering
Most importantly, reverse engineering of the hydrogen inhibitor (HIT)
process is not possible. MagPower can develop unique and customized
HIT for various applications. This gives the company a significant
position in the marketplace. With this advantage, MagPower filed two
Intellectual Property patents in the USA for the specialized process
of controlling hydrogen for MAPC and zinc electrowinning. The company
also filed a patent with the World Patent Co-operation Treaty (PCT),
covering 84 countries.

Besides hydrogen reduction, HIT can be transferred to other
electrochemical processes such as batteries and electrowinning (the
plating out of metals from electrolytic solution in refining and
waste-water treatment). For example, independent tests for zinc
electrowinning confirmed that MagPower's inhibitor increased the
current efficiency from 89% to 97%. The primary benefits include
substantial power consumption savings with secondary savings from
increased productivity, and reduction of health and safety hazards.

MagPower licenses its MAPC technology for specific applications
(including manufacturing) and the use of HIT to mineral producers, but
retains production of the hydrogen inhibitors. The abundant market
utilizations for MAPC and HIT are significant and continuous revenues
for MagPower. The licensing structure provides long-term growth for
the company. McGroarty, a seasoned entrepreneur explains, "We're not
here today, gone tomorrow. We're here for the future of BC. In order
to develop more market niches with future applications, we're inviting
all interested investors to examine our unique business model."

The Company
MagPower Systems Inc., established 1999, is a private company whose
purpose is to license the versatile Magnesium-Air Power Cell and
patent-pending hydrogen inhibitor process. The President, Bruce W.
Downing (M.Sc., P.Geo., FGAC), has over 25 years of technical
experience and the CEO, Shawn A. McGroarty, has over 20 years of
senior management experience in the corporate sector in Canada and the

The Board of Directors is planning to list MagPower on a public
exchange in 2004.


President: Bruce Downing

CEO: Shawn McGroarty

Phone: 604.940.3232
Fax: 604.940.3233
Address: 340 - 6165 Highway 17 Delta, BC

Email: [email protected]
Web address:


This news release contains forward-looking statements relating to
future results of the company as defined in the Private Securities
Litigation Reform Act of 1995. Actual results may differ materially as
a result of certain risks and uncertainties. These risks and
uncertainties include, but are not limited to: the successful
commercialization of its alternative fuel cell technology; its ability
to acquire and develop both new and existing forms of alternative
energy technology; market acceptance and demand; pricing pressures and
other competitive factors; as well as other risks and uncertainties,
including but not limited to those detailed from time to time in the
company's Securities and Exchange Commission filings. These
forward-looking statements are made only as of the date hereof, and
the company undertakes no obligation to update or revise the
forward-looking statements, whether as a result of new information,
future events or otherwise.


Copyright 2002 MagPower Systems Inc.


Jan 1, 1970
Br Dan Izzo said:
Seawater Battery

magnesium at the anode

The power for all the NEREID system is supplied by the SWB system,

So...What's your point?