Moving to a future technology is a constant process. Technology is constantly evolving and changing the world we live in. We do not live in an idle universe. A few years ago, electric engines were in low numbers, although the technology is as old as the internal combustion engine. Today, there are large numbers of electric cars and a growing number of EV trucks on the highways. In the future, there will be millions of electric cars and perhaps hundreds of thousands of trucks. The changes are not only driven by technology, but also by government policy in a quest to have a carbon-free future. Although the future will see a lot of electric cars and light trucks, the conversion of the commercial truck fleets into an all-electric future is more mixed. Battery-powered commercial trucks are a viable alternative to an internal combustion engine, but this must be framed in the doable universe. Although battery-operated trucks will gain market share in coming years, they are not the perfect solution to all of trucking’s needs. Battery-powered trucks still face an uphill climb to the long-haul market. The future of long-haul trucking may well depend on the emergence of a fuel cell vehicle or even a hydrogen-powered vehicle in the quest for a carbon-free future.
The technological future for heavy-duty trucking is not clear
Electric vehicles are one possibility, but battery weight is a problem. Hydrogen internal combustion engines and the use of fuel cells are two other possibilities being developed. The record of both is somewhat mixed, with both having some good points and some limitations.
A hydrogen internal combustion engine vehicle (HICEV) is a modified version of the traditional gasoline-powered internal combustion engine.
Hydrogen fuel cell vehicles use an electrochemical breakdown of hydrogen rather than combustion.
Hydrogen internal combustion engine vehicle
Francois Isaac de Rivaz designed in 1806 the De Rivaz engine, the first internal combustion engine, which ran on a hydrogen/oxygen mixture. Eitienne Lenoir produced the Hippomobile in 1863. Paul Dieges patented in 1970 a modification to internal combustion engines that allowed a gasoline-powered engine to run on hydrogen. Mazda has developed Wankel engines that burn hydrogen. The advantage of using ICE (internal combustion engines) such as Wankel and piston engines is that the cost of retooling for production is much lower. Existing ICE technology can be used to solve some problems where fuel cells are not a viable solution, for example in cold-weather applications. That stumbling block is being worked on. Since hydrogen internal combustion engines are heat engines, their maximum efficiency is limited by the Carnot efficiency. In comparison, the efficiency of a fuel cell is limited by the Gibbs free energy, which is typically higher than that of Carnot. Hydrogen combustion engines are particularly sensitive to transients in load and in terms of efficiency and therefore more suited to constant load operations.
The combustion of hydrogen with oxygen produces only water vapor as its only product. However, within an air hydrogen combustion, nitrogen oxides (NOX) are produced. In this way, the process is much like other high-temperature combustion fuels, such as diesel, kerosene, gasoline, and natural gas engines. As such, hydrogen is not a zero-emission engine. Hydrogen has a wide flammability range in comparison with other fuels. As a result, it can be combusted over a wide range of fuel-air mixtures. Although NOX is produced, hydrogen combustion engines generate little or no CO, CO2, SO2, HC, or PM emissions.
Hydrogen fuel cell vehicle
A fuel cell is an electrochemical cell that converts the chemical energy of a fuel, often hydrogen, and an oxidizing agent, often oxygen into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requiring a continuous source of fuel and oxygen to sustain the chemical reaction. In batteries, the chemical energy comes from metals and their ions already present in the battery. Fuel cells can produce electricity continuously, as long as the fuel and oxygen are supplied. The first fuel cells were invented by Sir William Grove in 1838. The first commercial use of fuel cells came more than a century later following the invention of the hydrogen-oxygen fuel cell by Francis Thomas Bacon in 1932. The alkaline fuel cell, also known as the Bacon fuel cell after its maker has been used in the NASA space programs since the mid-1960s to generate power for satellites and space capsules. They are useful for generating backup power in remote areas and can power forklifts, automobiles, buses, boats, motorcycles, and submarines.
Fuel cells come in many varieties, but they work in the same general manner. They are made of three adjacent segments, the anode, the electrolyte, and the cathode. Two chemical reactions occur at the interfaces of the three different segments. The result is that fuel is consumed and electricity, heat, and water are created. A typical fuel cell produces a voltage from 0.6 to 0.7 at a full rated load. Voltage decreases as current increases. To deliver the desired amount of energy, the fuel cells can be combined in series to yield higher voltage and in parallel to allow a higher current to be supplied. Such a design is called a fuel cell stack. The cell surface can be increased to allow a higher current from each cell.
Pros and cons of fuel cell trucks
The big pluses are that hydrogen has an energy density of around 120 MJ/kg, almost three times more than diesel or gasoline. Half the energy generated by an internal combustion engine is wasted as heat, whereas electric drivetrains used by FCEVs only lose 10%. Nikola Motors, a U.S. maker of hydrogen trucks, claims its vehicles can get 12 to 15 mpg, well above the average of 6.4 mpg for a diesel truck. In order to compete with diesel trucks, hydrogen production needs to scale up rapidly and reduce costs. Diesel trucks beat fuel cell vehicles on range, although 500 miles is enough for most trucking operations. The essential technology is coming down on price. One OEM said its new module, introduced last June, is a third cheaper than its predecessor. The Nikola Motors Class 8 rig is expected to retail for $375,000 when it goes into production in 2022, compared with $180,000 for the all-electric Tesla Semi with a 500-mile range. A comparable diesel truck sells for about $120,000. These figures are approximate and undoubtedly changed in the last few months.
The big question now is how hydrogen-powered trucks perform relative to diesels. Essentially, as long as hydrogen is stored in the tank, the truck will go. The electric motors installed are the same as in electric vehicles. The difference is that the energy does not come from a battery but from a fuel cell-powered by hydrogen. Hydrogen fuel cells are lighter than batteries, but because the motor is still electric, the trucks have more horsepower and accelerate faster than diesel trucks, roughly twice as fast. Maintenance is cheaper, as they are for electric trucks because there are fewer moving parts. Even brake wear is down because stopping power is boosted by the energy storage system.
One of the benefits of FCEVs is that hydrogen uses a fueling infrastructure that is similar to a conventional truck. That means FCEV’s could be fueled at existing truck stops and the fueling experience would be similar. A truck can be filled with hydrogen in less than 15 minutes and similar to fueling a diesel truck, using a gas pump and a nozzle that is similar to a traditional diesel pump. Still, the transformation to fuel cell trucks will take time, likely to take place in traffic corridors, and will take a heavy government presence to make an industry-wide transformation.
China’s goal is to get 1 million fuel cell vehicles on the road by 2030 and the EU will not be far behind. In seeking a carbon-free future, hydrogen is widely accepted as one of the cleanest forms of propulsion. The only tailpipe emission is water vapor, albeit heated. Currently, nearly all hydrogen is produced by fossil fuels. Although that is changing, it will be some time before all hydrogen comes from renewables, mainly because there is not enough renewable energy to go around. Using truck stops as giant solar farms is one partial solution, although a lot of refueling for some time will take place at the grid.
Shipping hydrogen
Hydrogen is touted as an inevitable green fuel of the future. Tell that to the people who’ll have to ship it across the globe at a hyper-cold temperature close to that in outer space. That is exactly what designers are trying to do. In the biggest technology challenge in decades, companies are beginning to develop a new generation of seagoing vessels that can deliver hydrogen to heavy industry. They are betting plants worldwide will convert to the fuel and propel the transition to a lower-carbon future. The major challenge is to keep the hydrogen at a minus 253 degrees Celsius, only 20 degrees above absolute zero, the coldest possible temperature, so it stays in liquid form, avoiding the risk parts of a vessel could crack. That’s almost 100 degrees Celsius colder than temperatures needed to transport liquefied natural gas (LNG), which required its own shipping revolution about 60 years ago.
Japan’s Kawasaki Heavy Industries has already built the world’s first ship to transport hydrogen, the Suiso Frontier. The company said that the ship is undergoing sea trials, with a demonstration maiden voyage of some 9,000 km from Australia to Japan expected in coming months. The next phase of the project is to build a commercial-scale hydrogen carrier by the mid-2020s, with an aim to go commercial in 2030. The 1,250 cubic-meter tank to hold the hydrogen is double-shelled and vacuum-insulated to maintain the temperature.
Other companies are getting involved in transporting hydrogen. The Korea Shipbuilding & Offshore Engineering Company is the first company in that country to try and build a commercial liquefied hydrogen carrier. To tackle the hyper-cold, the company is working with a steelmaker to develop high-strength steel and new welding technology, along with enhanced insulation, to contain the hydrogen and mitigate the risks of pipes, or tanks cracking. In Norway, efforts are also underway to build a hydrogen supply chain on the west coast of the country, with one group looking to pilot a test ship that would transport hydrogen to planned filling stations, which would service ships as well as trucks and busses.
Such endeavors are not risk-free. They are expensive, for a start. Analysts say that such ships would cost more than a vessel carrying LNG, which can run to $50-$240 million depending on size. The cost of vessels carrying hydrogen will be mainly driven by the cost of storage. Storing hydrogen could be very expensive because of its complexity. These pilot projects must overcome the technical challenges, and also rely on hydrogen catching on as a widely used fuel in coming years. None of this is certain although the state support being thrown behind this cleaner-burning fuel suggests it does have a future in the global energy mix. More than 30 countries, including several in the EU bloc such as France and Germany and the likes of South Korea and Australia, have released hydrogen rollout plans. The role of shipping will be important to unlocking the potential of converting industries such as cement and steel to hydrogen. Those two heavy industries alone account for 10% of global CO2 emissions and overcoming their need for fossil fuels is one of the keys to a transition to a lower-carbon economy.
Gas form of hydrogen
Other companies are looking to transport hydrogen in a gas form. The advantage is that it does not require any extreme temperatures. The downside is that less hydrogen can be transported as a gas than liquid hydrogen. A 40-foot container would carry about 8,00-1,000 kg of pressurized gas, but up to 3,000 km of liquid hydrogen. Analysts say the shipping industry is in better shape to handle the change to hydrogen than it was in developing ships for transporting LNG. Specialists the development of LNG took decades before it was rolled out, partly due to infrastructure and ships required and the few companies willing to invest initially. With state support, the switch to hydrogen looks more solid and companies want to be in on the future of hydrogen.
Hydrogen has seen false dawns before, but this time the low carbon alternative is being pushed by some of the largest companies on the planet across multiple sectors. Major OEMs are investing in smaller companies in order to stay at the forefront of the changing nature of the technologies. The future looks brighter. A research team from Lancaster University has identified a method of making smaller, cheaper, and more energy-dense fuel cell storage systems. Leading researcher Professor David Antonelli says: “We could see hydrogen fuel cell systems that cost five times less than lithium-ion batteries.” Even more impressive, he foresees “much longer range-potential journeys up to four or five times longer.” The future of hydrogen may be dawning and may be inevitable. With state support, it would be more efficient and the transition less costly. The future may belong to dreamers, but the dreamers are already sketching out the future.