How It Works
Components
In order to produce, store, and use hydrogen for generating electricity, the patented technology utilizes reliable, off-the-shelf technologies and equipment - some of which are already widely used in the marine industry. A number of mechanisms must be onboard to realize the HB Marine benefits. The following is a list of components needed to power a boat with hydrogen:
In order to generate hydrogen onboard the boat, the system consists of:
A water purification system – these “watermaker” systems are already in use in the marine industry and meet the appropriate standards for making hydrogen.
Sources of electricity – renewables (solar panels and wind turbines) are already deeply penetrated into the market. Most of the industrialized world has boat harbors equipped with grid electricity at every slip, useful for refueling on shore. In addition, when sailboats are under sail, the propeller is turned by the passing water and the motor becomes a hydroelectric generator of electricity.
A way to produce hydrogen – an electrolyzer is a device that is fed purified water and electricity in order to generate hydrogen and oxygen. This equipment is new to the civilian boating marketplace and a central innovation to the adoption of onboard hydrogen production. Submarines have used these same devices for decades, powered by nuclear reactors, to produce oxygen for extended underwater missions.
A way to transport (or compress) hydrogen on the boat – some electrolyzers can compress the hydrogen sufficiently to transfer it into storage, but some electrolyzers in conjunction with some storage systems need additional compression devices. These hydrogen compression systems are available. Other storage systems using metal hydride technology do not require compression, and use hot and cold water to transport the hydrogen to and from storage.
Once the hydrogen is on the boat, it may be put to use with the following:
Hydrogen storage – hydrogen is stored either in high-pressure tanks or in metal hydride solids until it is needed for generating power on the boat.
A means to convert the hydrogen into useable electricity – either fuel cells or hydrogen burning internal combustion engines can be used to transform hydrogen into electricity. Internal combustion engines are readily available and cost-effective. Fuel cells on the other hand have superior performance benefits, but presently come at a price premium. Both systems will be tested and made available to meet customer preferences.
An electric drive motor – for propulsive, non-auxiliary loads, an electric motor is used to turn the propeller. Electric motors have been shown to be much more effective than combustion engines at driving propellers. They can be 30-40% of the size of their counterparts and operate seamlessly in forward and reverse without the expense and upkeep of a mechanical transmission. On sailboats, the electric motor is also used as a generator when the boat is under sail.
Power electronics – these electronics are required to integrate the above components into a complete energy solution. The communications systems are also connected to the energy systems for convenient control and monitoring.
Note: Rather than purchase new equipment, one can also modify existing engine blocks to run on hydrogen, as has been done by BMW and Ford. In this case hydrogen is combusted in the diesel engine to mechanically propel the vessel through its standard transmission instead of the scenario above where electricity is generated to run an electric drive. Modifying engine blocks is a less efficient, but cost effective intermediate power management scheme.
Frequently Asked Questions
- What is a Hydrogen Fuel Cell?
- Why not just use batteries?
- Is water a fuel?
- Does the fuel cell power the Electrolysis unit?
- I need to motor a long way in my sailboat before I get to my favorite anchorage. Is HB Marine’s technology, the right solution for me?
- How far, fast, much?
- When will I be able to buy a HB Marine-powered sailboat?
- How much will a HB Marine system cost?
Q. What is a Hydrogen Fuel Cell?
Fuel cells have been in use for many years, particularly in the aerospace industry. Fuel cells, like batteries, contain positive and negative electrodes (the anode and the cathode). These electrodes are separated by a polymer membrane electrolyte.
Unlike batteries, which store their energy in the power-producing electrodes, fuel cells have the distinct advantage of using energy from external sources like hydrogen (H2). When the chemical energy in a battery’s electrodes is depleted, it is either discarded or recharged. This does not occur with fuel cells, which function and produce clean energy as long as they have an external fuel supply.
H2 enters the fuel cell and, as the hydrogen molecules come into contact with the negative electrode, they split into two atoms and then react electrochemically, forming protons and electrons. The electrons are conducted out of the cell to be used as electrical energy.
Meanwhile, the protons pass through the polymer membrane to the positive electrode where they combine with atomic oxygen (split from oxygen molecules brought into the fuel cell from the air) and with the electrons from the external circuit to form pure water and heat. The heat may be reclaimed to increase the already high efficiency of the fuel cell even further.
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Q. Why not just use batteries?
The amount of energy existing batteries store as a measure of their volume is much lower than metal hydride hydrogen storage tanks. In addition, high voltage battery banks are prone to serious performance problems if a single cell in the bank malfunctions - both on charge and discharge. If batteries are over charged, they can be damaged. If batteries are over discharged, they can be damaged. While batteries accept a higher percentage of the energy introduced during charging, they self discharge over time. Metal hydride and compressed gas hydrogen tanks in HB Marine’s systems do not.
With batteries, energy release under high load is uneven at best - think about an electric golf cart or toy running out of "juice." A hydrogen tank releases hydrogen (energy) consistently like the gas tank in your car. Also, flooded acid batteries are a safety hazard if their cases rupture - if the acid mixes with sea water (like in the bilge), chlorine gas results (ask any submariner who has served on diesel electric subs).
Batteries also suffer performance problems under regular use - some technologies are prone to developing "memories" and others fail in frustratingly short periods of time. The life cycle of metal hydride hydrogen storage should exceed battery technology by an attractive margin.
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Q. Is water a fuel?
No. Highly purified water (desalinated/deionized H2O) is one of two feedstocks (ingredients) required for hydrogen production by electrolysis. The other feedstock is electricity. Hydrogen in this process technically becomes a secondary energy carrier or a "storage medium."
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Q. Does the fuel cell power the Electrolysis unit?
The fuel cell is a chemical "powerplant" which provides power for propulsion (sailing vessels) and, or, non-propulsion "hotel" loads such as lights, radar, navigation instruments, etc. Think of the fuel cell as a replacement for the typical diesel engine in a cruising sailboat. It can propel the boat and charge the house batteries. So, no, the fuel cell does not power the electrolysis unit.
I’m unclear on the process. Where does the power come from to make the hydrogen?
Think of hydrogen in the tanks of a HB Marine-equipped boat like electricity in a bank of house batteries. Only better! In the same way that solar panels and wind generators and engine alternators and shore power can be used with charge controllers to charge house batteries, HB Marine systems use solar panels, wind generators, regenerative electric motors and shore power to "charge" or fill hydrogen tanks by splitting (electrolyzing) water (H2O) into hydrogen and oxygen. The oxygen is vented harmlessly to the atmosphere; and the hydrogen is plumbed into hydrogen tanks. The very pure water required is produced onboard as well with customized reverse osmosis water makers and de-ionization systems. Each step in the process takes power and imposes an energy "loss" on the original source of energy. Of the original energy "in", a percentage remains unrecoverable in the tanks. There are further losses on use of the hydrogen, but at a much lower level (greater efficiency) than fossil fuel (diesel or gas) at the fuel cell and electric drive steps.
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Q. I need to motor a long way in my sailboat before I get to my favorite anchorage. Is HB Marine’s technology, the right solution for me?
HB Marine’s technology is right for you if, the voyage combines either a 6-1 (average) sailing to power ratio on a passage, or better, or if the voyage involves a dash under power for 100 miles, followed by time at anchor, before the need to return under sail or power home. If you need more auxiliary propulsion than that, HB Marine’s technology is likely not right for you.
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Q. How far, fast, much?
HB Marine is not currently releasing detailed performance or price specifications for either the Demonstrator vessel or series production boats. Full specifications will be released after the extensive sea trials. However, HB Marine has stated publicly that for a series production boat, a 300 statute mile un-refueled (or regenerated) range is the minimum acceptable for a cruising vessel. Of course, a key benefit of HB Marine technology is that it can regenerate or self re-fuel so its practical range should be far greater. A typical sailboat keel weighs several tons in order to provide sufficient ballast. In the "ultimate" embodiment of HB Marine's patent, the hydrogen could be stored in a metal hydride structure within the keel. Assuming 50kg to 100kg of Hydrogen could easily be stored within a metal hydride integrated into the keel structure, 750 kwh to 1500 kwh of energy would be available in a sailboat configuration using PEM (Proton Exchange Membrane) fuel cells.
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Q. When will I be able to buy a HB Marine-powered sailboat?
Subject to many variables, at least one sailboat builder could offer HB Marine systems in new mono hull sailboats as early as the 2010 model year, in limited quantities. In any event, retail delivery for such systems should be available in 2011. Custom installations in sailboats and as gensets in powerboats are available for quotation now.
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Q. How much will a HB Marine system cost?
Custom installations will cost more than a comparable diesel powered system but will offer new features including:
(a) lower direct operating costs;
(b) reduction/elimination of noise, smell, vibration and pollution which, will be worth the price premium to many luxury boat owners.
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