Recently, the foreign media Equipment World launched a series of reports on Future Fuels, aiming to discuss the evolution of diesel fuel alternatives that construction equipment and manufacturers around the world are experiencing, including hybrid power, battery power, fuel cell, and hydrogen internal combustion engine and hydrogen fuel cell technologies. The following is the fourth report in a series.
Although there are many technologies available or under development to reduce CO2 emissions from heavy equipment, few fuels are closer to "net zero" emissions than hydrogen. In all respects, it will become the fuel of the future, even though it was not widely adopted until the middle of this century.
At present, two different hydrogen propulsion technologies have emerged, which have two distinct development paths:
The first is the hydrogen internal combustion engine. Its technical principle is to deliver compressed hydrogen to the cylinder of the internal combustion engine through the fuel pipeline, and ignite the gas in the cylinder through the spark plug to provide power for the traditional transmission system.
The other is a hydrogen fuel cell, which consists of two electrodes - a negative electrode and a positive electrode - clamped around the electrolyte. The hydrogen is sent to the negative terminal, and the air is sent to the positive terminal to generate chemical reaction and provide continuous current for the battery driving the motor.
No matter which technology is used, as long as there is hydrogen in the machine or vehicle, their exhaust emissions can be ignored. There is no carbon dioxide, only a small amount of water vapor.
Hydrogen has so many colors!
At present, the development of hydrogen power faces a key problem, that is, the way of hydrogen production is not necessarily "net zero". Today, the most common hydrogen production method is the steam reduction of natural gas, that is, using methane as the basic raw material, through steam methane reforming (SMR), methane is endothermically converted into H2 and CO. This is the cheapest way to produce hydrogen, accounting for 96% of the hydrogen market, most of which is supplied to the agricultural and semiconductor industries.
The industry uses colors to distinguish different hydrogen production methods and their impact on the environment. Black, grey or brown hydrogen comes from fossil fuels; Blue hydrogen also comes from fossil fuels, but it uses carbon capture technology to reduce carbon dioxide emissions. Green hydrogen is produced from electrolytic water, which is known as the holy grail that environmentalists yearn for most.
Hydrogen production by electrolysis of water is to separate hydrogen from oxygen in water. This method of hydrogen production is expected because it does not use fossil fuels, and renewable energy, such as solar energy or wind energy, can also be used to provide a continuous flow of clean electricity. In fact, nuclear power can also provide electricity for hydrogen production, but the latter will be limited by some regional policies and cannot be widely promoted and applied.
JCB hydrogen internal combustion engine excavator loader
Hydrogen internal combustion engine and hydrogen fuel cell
For a long time, JCB has been optimistic about the development prospect of hydrogen power equipment, and continues to explore hydrogen internal combustion engines and hydrogen fuel cells. "We studied many different fuels and found that hydrogen has more potential," said Tim Burnhope, chief innovation and development officer of JCB.
One of the driving factors is that hydrogen fuel cell power equipment is very practical for operation in urban areas. JCB has seven hydrogen power equipment in operation, and their construction sites are relatively close to the charging infrastructure. If some quarries far away from the power grid (hydrogen charging station) are not so lucky, the equipment contractors there will need to invest more facilities.
JCB released its first hydrogen fuel cell excavator 220X in May 2020. At that time, the excavator had been tested and evaluated in the quarry for 12 months. Therefore, JCB also brought some usage data under actual working conditions to the industry.
"Hydrogen fuel cells are a little slow in transient response." Burnhope said, "They need complex electronic equipment to manage the power supply between the fuel cell and the motor, as well as deionized water and large capacity cooling devices, and are sensitive to dust and vibration." Therefore, in JCB's view, hydrogen fuel cells are too complex and expensive for the current non road machinery working conditions.
Nevertheless, almost all OEM manufacturers are continuing to test and explore hydrogen fuel cell technology, especially large equipment and trucks with greater demand for battery motor capacity. Recently, Sany launched the concept machine of dump truck and mixer truck. Volvo Construction Equipment is testing an articulated truck. Cummins is developing a variety of hydrogen power batteries for road and non road machinery. Modern construction machinery first launched the HW155H concept excavator driven by hydrogen fuel cell on bauma 2022.
Perhaps the first commercial hydrogen fuel cell, the EODev GEH2 of Generac, which has outstanding static characteristics, can solve some problems in the application of non road equipment, such as vibration, pollution and other challenges. It is reported that this hydrogen fuel cell has been sold by joint leasing since the second quarter of 2022.
Rapid development of hydrogen internal combustion engine technology
Although most hydrogen fuel cell technologies are still being tested, hydrogen internal combustion engines provide almost the same environmental benefits as hydrogen fuel cells, and their commercial feasibility is higher and their production costs are lower. The hydrogen internal combustion engine retains the basic structure of the diesel engine - cylinder, camshaft, cylinder block and crankshaft - with spark ignition and fuel injection at the top.
In JCB, the research and development of hydrogen internal combustion engine has been carried out for decades, and engineers have built their own dedicated hydrogen internal combustion engine from scratch. At present, these hydrogen internal combustion engines have been applied to JCB backhoe loaders and telescopic boom fork trucks, and will be first introduced in May 2021.
"We have come up with a new combustion process, which can work under ultra-low pressure and temperature, and the exhaust gas is very clean, which is unbelievable." Burnhope said, "We have a great turbocharger, which provides a lot of air for the engine. Hydrogen can generate more energy, and we can maximize the use of air, while minimizing the hydrogen in the cylinder."
"Except for the piston, all the components under the cylinder head are the same as our diesel engine," Burnhope said. "Therefore, 70% of our parts and supply chain are readily available."
Low carbon fuel internal combustion engine or a bridge to the future
Jeremy Carson, Cummins' off-road director, believes that hydrogen combustion internal combustion engine is the actual transition of diesel engine. In fact, in 2022, Cummins has announced its latest Fuel Diagnostic platform, which can be compatible with hydrogen, natural gas, methane and other biofuels.
Cummins regards these latest fuel agnostic low carbon internal combustion engines as the transition technology of battery power equipment and fuel cell power. Jeremy Carson is also optimistic that the hydrogen internal combustion engine will have a good development in the past decade. Because the initial cost of this new "unlimited fuel" engine will be far lower than that of all electric or fuel cell research and development, thus reducing the threshold for entry; At the same time, it makes the hydrogen power switching of OEM manufacturers more smooth, and also wins time for the construction of hydrogen infrastructure.
Challenges and opportunities faced by hydrogen power technology
The huge challenge facing both types of hydrogen fuel technologies is the slow development of hydrogen fuel infrastructure. Hydrogen fuel is not widely available outside industrial channels.
"OEM manufacturers must also figure out where to place the hydrogen storage tank on their machines, because it is more cumbersome than liquid fuel. For example, wheeled loaders do not have much space to place the hydrogen storage tank, and excavators and some machines with large counterweights should have enough space." Burnhope said, "For generators, gantry cranes, lighthouses and other equipment that use fixed engines, the placement of the hydrogen storage tank will not be a problem."
It also has the advantages of shorter and more convenient hydrogenation time. Burnhope points out that adding hydrogen to equipment is much faster than charging. It only takes a few minutes to fill up the hydrogen, while it may take 2 to 8 hours to charge the equipment.
Burnhope said that hydrogen can be transported to the construction site like diesel oil. Even if hydrogen is temporarily required, it can be carried out at lunch time or at the end of the shift. It can be easily handled in a few minutes.
In addition, hydrogen is cleaner and greener. What excites engineers like Burnhope is that compared with fossil fuels, hydrogen fuel has a "clean and pollution-free" feature: "Not only is the exhaust pipe very clean, but also the dipstick is a powerful proof that the engine oil is still bright and clean after 100 hours of work; if you remove these engines, you will find that they are as clean as new engines." Burnhope said.
