Critics say hydrogen is inefficient. Are they right?
The laws of physics might say hydrogen is less efficient than battery technology, but a leading US expert says when you factor in the economics of running an efficient modern economy, the case for hydrogen becomes compelling.
SHARE THIS ARTICLE:
Does hydrogen have an inherent flaw as a future fuel?
According to the critics, it comes down to physics. The conventional process of electrolysing hydrogen from water results in about a 30 percent loss of energy, with a further 20 to 30 percent lost while conveying hydrogen to the fuel station for dispensing. This, they argue, makes hydrogen an inefficient system that wastes energy compared to battery electric alternatives.
Joe Powell, former Chief Scientist of Chemical Engineering at Shell says while the critics are right in theory, they’re not always right in practice.
More than one way to measure efficiency
“On paper, hydrogen is less efficient than direct use of renewables to battery and battery storage. But in terms of time, infrastructure, and broader resource utilisation it can be more efficient, and that's where the equation can change,” Powell says.
He points to the success story of hydrogen use in materials handling and warehouses across the US. Powell says many businesses adopted battery electric vehicles early on, but found the time required to charge them resulted in significant downtime, negatively impacting their operations and productivity.
“Because of the uptime and the rapid refuelling of hydrogen vehicles, they have found hydrogen to be cost-beneficial, despite the energy penalty compared to battery electric. It allows them to use their commercial equipment with very high uptime and without having to adjust their practices,” Powell says.
US retail giants Amazon, Walmart, and Home Depot are cases in point. The vast fulfilment centres owned by these companies operate 24 hours a day to keep the wheels of global e-commerce moving. Powell says there are now more than 45,000 hydrogen forklifts operating at these facilities due to their "superior efficiency”, in terms of both equipment and people productivity
“Hydrogen offers rapid refuelling, so you don’t have a queue of vehicles waiting to be charged for a significant amount of time. It's less of a logistics challenge compared to battery-electric, and you get the same benefits in terms of clean indoor air quality,” Powell says. “Put simply, you need fewer vehicles to do the same job.”
Trucking demonstrates the limitations of battery-electric
Trucking is another application where hydrogen can have an advantage over battery-electric technology. Powell says the choice comes down to the locations you are operating in and the routes you are taking, as well as your payloads and required uptime.
“For example, if you sought to electrify and then charge all of the trucks operating in the port of Los Angeles, you would have a significant infrastructure problem in terms of finding the land needed just to set up charging and getting that power density in just with the grid alone.
“Once you start to get to significant scale, then you also begin to see the advantages of hydrogen in getting all that energy into urban areas, and getting everything rapidly refuelled and up and running,” Powell says.
There will be many scenarios where battery-electric transportation will make more sense than hydrogen, particularly for light-duty vehicles or when short driving distances are involved, and where vehicles can easily be charged overnight.
“You can play the ‘electrification-only’ game if you’re willing to adjust your schedules and timing by allowing for slower refueling and rerouting to accommodate shorter allowed vehicle range. But these can be substantial inconveniences that I think will be difficult for people to accept in many situations.”
Storage potential adds to hydrogen’s efficiency
A second factor to consider is the ability to transport hydrogen over longer distances. Powell says for many urban areas, the local intensity of wind and solar is two to three times less than in the most advantaged places in the globe, and local land use costs are high. He says it is not possible to transmit electrical power over longer distances without substantial transmission losses, and shipping via batteries is not plausible due to very low energy density.
“For these cases, which are quite prevalent, the overall efficiency of using advantaged but remote solar or wind farms with transport of the energy to market via hydrogen is better than using poorer local wind and solar resource.
“The adage that electrification and batteries are always more efficient is simply not correct, if you take a broader view of ‘the system’ that can be used,” Powell says.
A further advantage of hydrogen is its ability to store energy across day-night cycles and longer periods of time.
“Hydrogen is actually quite complementary to electrification, because of its ability to provide longer duration storage for the grid. Battery electric does have inherent efficiency, but the real world is full of complexity and commercial imperatives that will make hydrogen the sensible, convenient and sometimes even the most efficient option in many situations,” Powell says.