Turning around 100-plus years of reliance on fossil fuels won't come easily for most people until they set aside familiar assumptions about energy sourcing, distribution and consumption. Using hydrogen to power cars and trucks makes much more sense once you stop comparing it to oil-based infrastructure.

In the context of a transportation fuel, hydrogen is an energy storage medium, just like gasoline or diesel fuel or batteries. But the energy content of a kilogram of hydrogen is much greater than any other commonly used liquid, gaseous or solid fuel. The Office of Energy Efficiency and Renewable Energy says, "by mass, hydrogen has nearly three times the energy content of gasoline – 120 megajoules per kilogram for hydrogen versus 44 MJ/kg for gasoline." Diesel fuel has 45 MJ/kg, while natural gas compressed to 3000 psi has 55 MJ/kg.

By comparison, Tesla's current lithium-ion battery has an energy density of about 3 MJ/kg (several sources show varying but similar energy densities, ranging from 2.68 to 4 MJ/kg). And that is the well-understood problem in using batteries in trucking: The "fuel" in a pure battery-electric truck is simply too heavy to be practical in a long-haul application).

So, looking at the fuel simply as stored energy, hydrogen wins hands down. Getting hydrogen to the truck and then converting it into motion is the next challenge.

In pure conversion calculations, one must consider the energy consumed in getting the fuel into the tank, such as production, transportation, storage, etc. With diesel fuel, this is often referred to as "well-to-wheel:" how much energy is required to get the crude oil out of the ground, transport it to the refinery, convert it from crude to refined diesel, and then get it to market and pump it into the saddle tanks.

And there are still more conversions required, such as how efficient the "engine" is at converting the raw fuel into motion. Today's diesel engines are between 45% and 48% efficient, meaning something less than half of the energy content of the fuel actually goes to powering the vehicle. The rest is lost to heat and mechanical drag from the engine components. Then there's the efficiency of the driveline. Again, there are further mechanical losses in the meshing of gears, etc.

With hydrogen fuel cells, the hydrogen fuel is converted to electricity through an electro-chemical reaction in the fuel cell. Several sources suggest this process is between 60% and 80% efficient. Next you have the conversion of electrical energy to motion; the turning of the drive wheels. Parasitic losses are lower with direct drive electric motors than with conventional drivelines, but it's still not 1:1.

Nikola did not disclose the name of its fuel cell partner, so we could not get an estimate the efficiency of that process, but other available estimates of "drivetrain" efficiency for fuel-cell powered electric drive vehicles could be as high as 64% – and remember, hydrogen has nearly three times the energy density of diesel fuel to begin with.

Producing Hydrogen

Many of the conventional arguments for using hydrogen as a vehicle fuel fall apart because of the cost of producing pure hydrogen. Despite it being the most abundant element in the universe, there is little or no free hydrogen on Earth. There is bound hydrogen, mostly in water, but the energy required to extract it is greater than the energy it yields, or so the argument goes.

It's often pointed out that the process of producing hydrogen by electrolysis (splitting water atoms into hydrogen and oxygen) results in a 40% energy loss, and so conventional arguments would be true if you were using energy from conventional power grids. It would not be the best use of the resource. Nikola, however, plans to harness previously untapped or under-utilized energy sources.

"You have to turn the energy production equation around," says Jason Roycht, vice president of commercial vehicle business at Bosch, a technology supplier to Nikola's commercial and off-road vehicle projects. "Rather than relying on grid produced-power, Nikola plans to build its own solar arrays or will rely on purchase agreements with other wind or hydro-electric producers for their unused capacity. The process would still be only about 60% efficient, but that's 60% of energy that is currently not being harvested."

Roycht pointed to the vast hydro-electric resources of the Tennessee Valley Authority, where the water flows night and day. Electricity demand is higher during the day than at night, so at night, he says, they just open up the sluices and let it go.

"What if all that energy could be tapped and stored today and then used tomorrow to power hydrogen trucks?" he asks. "It's the same with solar energy. In places like California and Arizona, where there's tons of room for solar farms, nobody invests in solar resources because they can't use all the energy they could harvest. There's only so much you can put back into the grid. That's where hydrogen production starts looking really interesting. You're decoupled from when you generate and when you use it. That's different from using power directly from the grid."

And, you're decoupled from where the energy is generated to where the hydrogen is produced and used.

"The sun showers the Earth with enough energy in a single day to power all of humanity for an entire year," says Roycht. "There's more energy available from the sun than we could possibly use, but it's not always available at times and locations that are convenient. That's where storage and transmission make sense."

Unlike getting diesel fuel from the refinery or pipeline terminus tank farm to the truck stop, Nikola sees producing the electricity at some remote location and using the grid to transmit that energy to a hydrogen production facility that is actually a "truck stop" fueling site. In the Nikola model, hydrogen will be produced at the same location it's pumped into customers' trucks.

"At Nikola, we like to move protons, not fuel," says Nikola Motor Co. CEO Trevor Milton. "We will build solar farms out in the middle of the desert and transmit [the electricity] through the main transmission lines to our hydrogen production facilities around the country. We’re specifically putting in energy that is zero emission and pulling the same amount out at the other end, so we’re not using any dirty fuel to make our hydrogen." 

Production Facilities

Nikola has partnered with global hydrogen technology company Nel ASA of Oslo. Norway, to supply hydrogen production and vehicle fueling equipment along with the development of hydrogen station infrastructure. The two companies inked a deal in June 2018 that will eventually see 448 electrolyzers deployed around the U.S. beginning in 2020.

The electrolyzer stacks (that produce hydrogen from water) will be manufactured in Norway; the fueling equipment in Denmark. Other supporting components and sub-systems will be sourced in the U.S. to reduce costs and minimize transportation needs, Nel indicated in a press release.

A month earlier, Nikola announced that Anheuser-Busch had placed an order for up to 800 hydrogen-electric powered trucks. To support the Anheuser-Busch fleet, Nikola and Nel will need to deploy around 28 production and fueling stations.

A few days prior to the Nikola World event in Phoenix, Nel announced that subsidiary Nel Hydrogen Inc. had received a purchase order from Shell Oil Products U.S. for the delivery of two additional H2Station units for fueling of fuel-cell electric trucks in California. Those stations will be located in the Greater Los Angeles area.

Nel built its first electrolyser installation at Norsk Hydro, Notodden, Norway in 1927, and has since become a global, dedicated hydrogen company, delivering solutions to produce, store and distribute hydrogen from renewable energy. The company has installed more than 3500 electrolyzers in 80 countries. It presently has one U.S. production station operating at Nikola's Phoenix headquarters with 1 ton of storage capacity. That's used mostly for the research and development work under way at the facility and to fuel cars.

Nikola and Nel will develop hydrogen stations with an initial capacity of 8 tons per day, which they say can be scaled up to 24 tons per day where demand exists. The facility will consist of an electrolyzer stack where water is separated into hydrogen and oxygen, compressors, chillers, storage tanks and dispensing equipment. Each site will occupy about 7-10 acres, or roughly the size as a Love's diesel fueling station, according to Jesse Schneider, Nikola's executive vice president of technology, hydrogen and fuel cells. Such a site would have capacity for about 150 trucks and 200 cars.     

"The key to making this work will be the ability to produce hydrogen at scale, and build up that scale as the market for hydrogen develops," says Schneider. "Nikola will be bring the trucks and the fuel to market at the same time."

"The beauty of the Nikola business model is that it solves two things at the same time," says Jon André Løkke, CEO of Nel. "First of all, it solves the chicken and the egg problem; the stations come online at the same time as the trucks. And secondly, it solves the commercialization problem. In this case, we will not have to build the infrastructure and then wait for the customers to come."

The plan is to develop stations along the routes served by its early adopter customers, such as Anheuser-Busch. Schneider says the plan calls for deployment to begin in the West in 2021 before migrating eastward with the market. Plans call for upwards of 700 stations to be built, beginning sometime in 2022. 

Concept drawings shown during Nikola World reveal an ultra-modern looking "truck stop," complete with parking facilities, a store, restaurant, and of course the hydrogen production and dispensing facilities. These will be constructed in areas with high truck density, such as near busy distribution centers and transportation hubs.  

"If you can produce large-scale volumes on-site without transportation, it gives you the opportunity to sell hydrogen to the end user for less than $6 per kilogram," says Løkke. "That's about half the price that we see most other hydrogen customers paying in other parts of the world. The majority of the cost of electrolysis is tied to the price of electricity. If you have low-cost electricity you have low-cost hydrogen."

Nikola still has work to do to convince the market that hydrogen is a viable way of powering heavy trucks, but once you get your head around the idea that hydrogen is not so much a fuel but a highly transferrable and efficient way of converting renewable energy such as solar, wind and water into motive power for vehicles, the entire concept starts coming together.