A few months ago. Hyundai has announced a global plan for the development and production of a new generation of electric propulsion vehicles powered by fuel cells. The plan is broad, it aims to achieve the competitiveness of electric vehicles with fuel cells by reducing their production costs at least to the level of those with batteries. The plan, which involves other major global brands, also includes the development of rational hydrogen production systems at competitive costs. The project is expected to reach the operational stage by 2040.
Opel has decided to proceed more quickly and is already offering the Vivaro medium commercial vehicle in the e-Hydrogen version, the result of an admirable technological effort and which has its roots in the late 1900s, when Opel, part of the American giant General Motors, was involved in the Sequel project, later called HydroGen. The original Sequel, a beefy SUV similar in size to the Chevrolet Tahoe, was the world’s first vehicle with fuel cell-powered electric propulsion. During the tests it proved to be functional and capable of very brilliant performances, even in the scorching heat of Palm Spings, in California, with the air conditioning on full blast.
As part of the Sequel project, various fuel cell Opel Zafiras were then built, a hi-tech solution in which Bob Lutz, the then president of General Motors, strongly believed. The program collided with the very high costs of fuel cells and was progressively shelved, both in the USA and in Europe. But research has never stopped and the Opel Vivaro e-Hydrogen is the brilliant practical demonstration.
That the cold oxidation process of hydrogen produces electricity has been known since the mid-1800s, but only a century later the first fuel cells were built and NASA began to use them in the early 1960s to provide energy to satellites and space capsules, especially of the military type, but it took another forty years before the fuel cell made its timid and brief appearance in the automotive sector.
The obstacles are significant and range from the still high costs to the weight/energy generated and size/energy generated ratio. But scientific research is itself a magnificent source of energy, creative in this case, and the progress, especially in the last ten years, has been extraordinary and the cost barrier has also been significantly reduced.
Stellantis Group technicians managed to create Vivaro e-Hydrogen based on Vivaro-e, the electric propulsion version powered by lithium-ion batteries. By removing the heavy group of batteries, they obtained, still under the loading platform, the housing for the three tanks capable of containing 4.4 kg of compressed hydrogen at 700 bar. These tanks are made of reinforced aluminum with carbon fiber wrap-bonding and are therefore totally safe and enormously lighter than the battery pack. The loading surface has remained unchanged, a very significant result for the user of a commercial vehicle. The fuel cell, the energy management system and the electric motor have very compact dimensions and have been able to be placed in what is normally the compartment of the thermal engine, and this too is a result that confirms how advanced Stellantis technology is in the field.
Vivaro e-Hydrogen is available in two sizes, one of 4.95 and one of 5.30 metres, with a loading surface length of 2.51 and 2.86 meters respectively and a payload of up to 1000kg. The propulsion system is electric of the hybrid type since, in addition to the fuel cell group, there is also a lithium ion battery of relatively limited power, which is located under the seat and can also be used alone, when driving city, also helping to extend the range by about 40 km, up to a total of 400 km. Used in parallel with the fuel cell, the battery improves starting and climbing qualities.
The fuel cell delivers a power of 45 kW, the battery has a capacity of 10.5 kWh, the electric motor has a power of 100kW, adequate for a maximum speed of 110kmh. The fuel cell doesn’t need to be paired with a lithium-ion battery to offer perfect functionality, but Opel engineers started with the Vivaro-e and found it logical to keep some aspects of it. The battery maintains its functionality thanks to the flow of energy it receives from the fuel cell, as well as the classic energy recovery during braking. Furthermore, the hybrid combination has a significant value as it allows the versatility of the two propulsion solutions to be evaluated in parallel. Starting from the refueling times: three minutes to refuel the high pressure hydrogen tanks and 90 minutes to recharge a battery of only 10.5 kWh with the rapid charger. Additionally, the fuel cell boasts a higher delivery density that translates into more responsive engine power response.
The Opel project started with dutiful prudence, production is scheduled strictly on the basis of orders and is very consequential to the current accessibility of filling stations and production capacity. And this is a sore point because hydrogen is currently obtained through the decarbonisation of methane, a complex process which also requires the recovery of carbon dioxide because otherwise we return to box number one in our anti CO2 goose-turn.
Let’s not forget that methane is the optimal fuel for Otto cycle internal combustion engines which still have many good reasons to survive. Current technology, or an upcoming venture, allows us to create Otto cycle engines powered by direct injection of liquid methane which would ensure a significant reduction in emissions, including CO2 and zero primary pollutants. Furthermore, the high octane number of methane (130 RON) would allow the compression ratios to be raised to levels close to those of diesel-cycle engines, with significant benefits in terms of thermodynamic efficiency and consequent reduction in consumption and, therefore, in emissions. And they would also be engines capable of very high specific performance, which never fails.
The natural cycle of access to hydrogen is that of the decomposition of the water molecule. The process of electrolysis of water has been known to us for well over a century, but it is a process that involves a deadweight loss of 5 percent and we cannot afford it. But to come to the rescue is nuclear energy. In nuclear power stations, the steam that drives the turbines of the generators reaches temperatures of up to 800°C and at this temperature even the very stable water molecule begins to feel bad. The major nuclear research centers in the world (including ours in Ispra) have since the seventies identified and patented processes for the decomposition of that red-hot water vapor into hydrogen and oxygen simply by channeling it into a chamber into which a chemical catalyst is inserted which is then recovered at the end of the operation.
It is the true gateway to hydrogen, in quantities and at costs competitive with those of oil (at extraction, not at the pump), given that the red-hot steam has already done its job; it has produced electricity so it has already absorbed the primary costs of the reactor. Why this potential source of energy has been frozen for fifty years, we have to ask the politicians and the oil companies. Meanwhile, Opel has made a real, real fuel cell electric vehicle available today. It is a fundamental first step.