The use of alternative fuels for tractors has been studied for a long time; in fact, today we find methane-powered tractors on the market and some hydrogen prototypes have been presented in recent years
Andrea Benvenuti
Since the creation of the first internal combustion engine, many years have passed, during which we have experienced rapid technological growth that has seen efficiency increase in every aspect. Performance has been greatly improved, work capacity increased, consumption and pollution reduced and finally in the last 30 years driving support systems have been implemented that have simplified the operator’s work and increased the general efficiency of the production system. What has not changed since then is the fuel used; in fact, diesel is still the main energy source today, although it is more refined than in the past and mixed with small percentages of biodiesel to reduce dependence on oil. The use of alternative fuels has been the subject of study for many years; in fact, we find methane-powered tractors on the market, while some hydrogen-powered prototypes have recently been presented. These two new types of tractors could represent a solid future in agricultural mobility.
A well-established alternative
Methane is certainly the most concrete way to make agriculture more sustainable; New Holland Agriculture introduced a first methane-powered tractor to the agricultural market a few years ago, the T6.180. This features a 6.7-liter NEF engine specifically developed for agricultural applications by FPT Industrial, a leader in natural gas engine technologies. The differences compared to diesel lie in the combustion cycle used, the Otto cycle, which guarantees different performance. However, this engine was not designed so much for its performance advantages (now comparable to diesel) but with two very specific purposes, the reduction of CO2 emissions and the creation of corporate sustainability from an energy point of view. The collaboration with start-ups for the management of methane produced by animal husbandry and agriculture aims to train companies capable of making a profit from the sale of the gas itself and fuel for their agricultural fleet.
This concept fits in with the latest support policies adopted by the PNRR, which removed funds for the development of biogas plants and brought them to the world of biomethane. The difference between the two types of biofuels lies in the refinement of the product. Biogas is a precursor of biomethane and in fact has a variable composition; the methane content varies between 50 and 75%, that of carbon dioxide (25-50%), water vapor, nitrogen, oxygen, hydrogen sulfide and ammonia with percentages varying between 0 and 5% approximately. Biomethane, on the other hand, requires a purification process that brings the concentration of CH4 to 95-98% with the rest of the gases present in percentages lower than 1%. In addition to the chemical difference, there is a difference in their use; biogas is currently used exclusively for the production of energy through electric generators, on the other hand, with the PNRR funds the aim is to be able to connect digesters or any other methane production system linked to the agricultural world to the methane distribution network. By doing so, companies will be able to make a profit from biogas as in the past and, by modifying the agricultural fleet, to have access to a more ecological and “zero cost” fuel.
However, New Holland’s innovations did not stop at the T6.180; in fact, the new T7.270 CNG (Compressed Natural Gas) was presented at Agritechnica in 2023. This tractor enters the market by raising the technology associated with an alternative fuel and greater power. By expanding and differentiating the proposal, New Holland will allow greater involvement of companies with different needs in order to offer the advantages of an alternative fuel to a wider range of potential buyers. The T7.270 changes the engine but not the substance compared to the diesel tractor; in fact, we find inside it the technology that New Holland has so far concentrated in these machines. PLM Intelligence is present and allows you to monitor the tractor status easily and immediately, connect remotely, view machine parameters, take advantage of Intellisteer automatic guidance and have 360-degree management of the entire fleet. The operator is welcomed in the award-winning Horizon Ultra cab, particularly quiet, with an internal noise level that minimizes operator fatigue and maximizes comfort. The Horizon Ultra also offers more space for the operator and for storing objects.
But what moves this new T7? The engine presented by New Holland is the same as the one found on the previous model. However, the T7 tractor category is at a higher level in terms of power and work possibilities. To meet the requirements and enter the world of large tractors, the engine has undergone a change in mapping; remember that previously the NEF 6.7 l engine released up to 175 HP while now it delivers 270 HP and 1160 Nm of peak torque, with a substantial difference of almost 100 HP from the previous model. The transmission has also been updated: the new AutoCommand, a continuously variable transmission makes driving even smoother and reduces consumption. Furthermore, thanks also to the increase in horsepower, the new tractor is able to move easily with trailers weighing more than 18 tons. The T7.270 also surpasses the T6.180 in terms of size: a rearrangement of the spaces, with a different positioning of some of the tractor’s components, has meant that the chassis can accommodate a greater quantity of biomethane and the increase compared to the previous model is 178%, for a figure of 1265 litres (219 kg).
Also at Agritechnica 2023, the pre-production prototype of a T7 Methane Power tractor was presented again, this time however branded as LNG (i.e. Liquefied Natural Gas). The difference therefore lies in the state of the biomethane, which thanks to New Holland engineers is now introduced into the machine in a liquid state. With this LNG fuel system, autonomy is more than doubled compared to the T6.180 Methane Power; this is because the use of liquefied methane offers a fuel storage capacity four times greater than the use of compressed gas (CNG). The T7 LNG has all the features listed for the compressed natural gas model, from the power of the engine to the technology installed in it, making it a cutting-edge machine from every point of view.
Hydrogen, advantages and problems
Hydrogen was previously mentioned as an alternative to fossil fuels: the use of this element in fact involves only one waste product, water. By eliminating CO2 and particulate matter, agriculture could reduce its environmental impact and make the agricultural system cleaner from every point of view. Defining hydrogen as a fuel is not entirely correct; technology has led to the development of fuel cell engines that exploit a chemical reaction to obtain energy and transmit it to electric motors; the combustion phase has therefore been eliminated, increasing the energy efficiency of the system. The fuel cell engine is made up of a special tank to contain the hydrogen, a fuel cell, which is also the heart of the entire system and produces the energy, a power delivery control unit, a small battery and finally electric motors.
It can be said that the autonomy of a hydrogen vehicle is comparable to a diesel vehicle, that the charging times are similar while the wear of the engine is lower. Compared to an electric vehicle, however, there are no large and heavy battery packs that could affect the performance of the tractor in the field, causing for example slippage and compaction of the soil. The power delivered by a fuel cell engine remains constant even in heavy work phases, thus combining the characteristics of a diesel tractor and those of an electric one thanks to its engines. This allows for immediate torque and great modulation of power on the individual wheels in every work situation.
The main problem with this fuel is its availability; in fact, to produce “green” hydrogen, a large amount of energy is needed to split the water molecule through the electrolysis process. To make it a sustainable process, the energy used for electrolysis is produced from renewable sources such as wind or solar. In this regard, Fendt has been involved for some years now in the H2Agrar and Green H2 Hub-Haren project in the state of Lower Saxony, Germany, which is financing the development of a hydrogen infrastructure in the model region of Emsland. Here, a wind farm produces the energy needed to produce hydrogen used to refuel sustainable vehicles, including two Fendt Helios tractors. Currently, hydrogen vehicles are a reality only in projects of this type, which are necessary to study and improve this new path.
Several debates have opened on the use of green energy for the production of hydrogen; from an energy perspective, it would be better to store the energy intended for the production process in batteries and use electric vehicles. Electric vehicles are more intuitive, there are few components, safety management is simpler than with hydrogen and the overall efficiency of the system is better. It must also be considered that the infrastructure for transporting electric energy is well developed and extensive, which facilitates the expansion process of this technology. The problem with electric vehicles lies in the battery, which as we know involves lithium and rare earths in its production, which tends to lose effectiveness over time and has performance limits. Hydrogen engines bypass this problem, allowing the creation of high-powered vehicles; in fact, with the same HP, electric vehicles would require a large installation space for the battery pack, weighing down the vehicles and limiting their work capacity in the field. Hydrogen engines are able to withstand greater workloads and storing hydrogen in the car is more convenient due to its weight and reduced size. The infrastructure for managing this gas is now almost non-existent, its complexity of production, transport and the elements necessary to manage the large pressures at which it is accumulated as a compressed gas complicate its development.
In 2023, Fendt presented a prototype of a hydrogen tractor, the Fendt Helios, currently in operation in the H2Agar project mentioned above. This new machine is produced with an electric motor capable of delivering 100 kW of power (136 HP) powered by a fuel cell. The body is the same as the old Vario 700 model where the space for the hydrogen tank was created on the roof of the cabin. Here we find five 4.2 kg tanks for a total of 21 kg of hydrogen stored at a pressure of 700 bar. The tractor is still in the study phase but the first data collected, thanks to use in the farm, show an autonomy that varies from 5 to 8 hours depending on its use. Considering that the charging times are just a few minutes, the Fendt Helios is in every way comparable to classic diesel tractors.
