Japanese majors to form a research association.
On four wheels, electric drive has acquired a degree of “green cachet” among those for whom the higher price is of little importance. No similar trend exists among riders of motorcycles outside the basic commuter category. Indeed, motorcycle manufacturers continue to design and release new models with internal combustion power.
Despite a chorus of voices asserting that “batteries continue to improve by leaps and bounds,” the actual fact is that batteries remain too heavy to deliver the motorcycle’s traditional appeal of agility and rider unity with the machine. They take inconveniently long to recharge and suitable charging points can be hard to find.
Now the four Japanese motorcycle manufacturers—Honda, Yamaha, Kawasaki, and Suzuki—have received a go-ahead from that nation’s influential Ministry of Economy, Trade and Industry to form a Hydrogen Small mobility and Engine technology research association to consider the possibility of powering motorcycles and other light power applications with hydrogen as an internal combustion piston engine fuel.
This would allow such applications to eliminate the emission of the “greenhouse gas” carbon dioxide as a component of exhaust gas, making them as carbon-neutral as the operation of electric cars is. The exhaust from a hydrogen-burning internal combustion engine is water. This would allow continued use of existing engine production tooling (save for the fuel system, which would be specialized). And perhaps most importantly, it might allow motorcycles to retain their traditional character and appeal.
The major problem with hydrogen is essentially that facilities for its large-scale production from non-petroleum sources or for its wide and convenient distribution do not now exist. The liberation of hydrogen from water by electrolysis requires that the same energy be invested as may theoretically later be realized when the hydrogen is used to produce power. It is for this reason that hydrogen is considered an energy carrier and is not an energy source.
The source of energy presently planned for the future liberation of hydrogen in this way is the hoped-for “large excess of zero-carbon electricity from wind and solar power.” This “excess” does not at present exist either.
Aside from the light-weight power applications described in the fourth paragraph above, there are also high duty-cycle applications such as long-distance trucking and harvest-time agricultural use for which hydrogen is seen as advantageous. The reason is that in near-continuous operations such as these, the recharging time of battery-electric power is a serious drawback.
Bear in mind that when futurists speculate that new battery technologies may make possible “battery charging in seconds” it is necessary to compute from the necessary power flow the current that would be required.
As an example, imagine a technology capable of supplying 80 percent of a Tesla auto battery’s 88kWh energy storage capacity in 10 seconds. This would require supplying 70kW for one hour, which is a wattage equivalent to about 94 hp (1 hp = 746 W), or wattage 360 times greater if we plan to charge the battery in 10 seconds (there are 3,600 seconds in an hour, so 360 is that number divided by our 10-second charging time). Our 10-second charging current would then equate to a rate of energy flow equal to 94 hp x 360 = 33,840 hp. A 200-amp home breaker panel at 240 volts provides a possible 48,000 watts of power, equivalent to 48,000/746 = 64 hp. Our notional 10-second charging time will therefore require 33,840/64 = 528 home electrical services, all operating at 100 percent of their capacity.
The numbers become impressively large for the greater battery capacities required to power heavy trucks or agricultural machines. This makes it attractive to power such applications with fuels that can be put on board in minutes. At present, that is diesel fuel. In other possible futures, it could be hydrogen.
Aside from the fact that large supplies of “green” hydrogen don’t exist, the other major drawback of hydrogen power is that the storage of hydrogen requires large volume. Liquid hydrogen, requiring extreme insulation to prevent it from boiling away before we can use it, contains only one-fourth as much energy per volume as does gasoline. If our original motorcycle has a 4-gallon gasoline tank, it will require a 4 x 4 = 16 gallon tank to carry equal energy in the form of liquid hydrogen. Add to that the necessary volume of insulation required. This is why artists depict notional future hydrogen-powered bikes as carrying large ADV-style top and side containers; they are there to carry the fuel.
Also add the fact that cooling and compressing hydrogen to liquid form at -423 degrees Fahrenheit consumes energy equal to 30 percent of what’s contained in the hydrogen. This makes other storage systems look attractive. Perhaps we’d prefer to carry gaseous hydrogen in heavy pressure tanks at 5,000 or 10,000 psi?
What else is there?
There are solid materials into which hydrogen can be absorbed, and there also exist reversible chemical means of storing it. This is why the motorcycle manufacturers are forming a research association—to see if there is a practicable way to power future bikes with hydrogen.