As part of the hoopla surrounding the official introduction of Toyota’s Mirai fuel cell car this week, the company announced that customers would receive free hydrogen for up to three years. Previously, Hyundai also said it would provide free hydrogen for buyers of its Tucson fuel cell vehicles. Are the manufacturers just being generous or is there something else going on here?

Actually, according to AutoBlog, the real reason is it’s not possible right now to accurately measure how much hydrogen is being dispensed at today’s refueling stations. Says Toyota’s national manager of environmental, safety and quality communications, John Hanson, “There are no set standards, so there is no way to charge people for anything.”

Alberto Ayala, the deputy executive officer for the California Air Resources Board, told the group attending the Mirai introduction, ” If you think about it, it’s a real simple yet real practical challenge. If you’re going to pay for X amount of hydrogen, you’re actually getting that amount of hydrogen.” Ayala said it’s not a difficult technical problem to measure the hydrogen as it goes into the car, but “we just have not done it. We are at a point where we are solving multiple remaining questions [with hydrogen infrastructure], and that just happens to be one of them.”

Last summer, the National Institute of Standards said it wants to set the standard tolerance for delivery accuracy at 1%. That’s half of the current 2% standard and would allow motorists to be sure of getting the amount of hydrogen they pay for every time they fill up. Last summer, NIST announced it had developed a hydrogen pump with an accuracy of 99.55%, but that equipment is not in widespread use yet.

Also earlier this year, the Society of Automotive Engineers (SAE) promulgated new standards for hydrogen refueling, including the shape of the nozzle and the pressures at which the gas will be delivered.  The new SAE J2601 establishes two standard pressures – 35 and 70 megapascals (MPa) – it says will permit refueling times of 3 to 5 minutes.

Hydrogen is the most active element on the periodic table. Containing it and making it bend to man’s will takes some doing. A few years from now, hydrogen refueling standards will be finalized and fuel cell cars will go mainstream. Or not. Until then, we all get free hydrogen.