Hydrogen or battery tractors: what potential for sustainable grape growing? Original language of the article: English.
Capping greenhouse gas emissions and reducing air pollution on the farm challenges the place of the diesel tractor in future sustainable vineyards. Tractors are responsible for the largest share of all CO2 emissions at vineyard plot scale, mostly resulting from pest and disease management and soil maintenance (Adoir et al., 2019). Electric vehicles will thus be required to meet climate change reduction goals. In this article, the characteristics of battery and hydrogen electric tractors are compared, and their potential in the grapevine growing sector is assessed.
Hydrogen and battery tractors
Electric vehicles are replacing internal combustion engines (ICE) as the availability of affordable petroleum reserves is decreasing and CO2 emissions need to be reduced. Electric motors are highly efficient (90 % compared to 20 % for ICE
Each of the systems - battery and hydrogen - have their own advantages and pitfalls. Batteries can retrieve 95 % of stored electricity, which, combined with a 95 % converter and 90 % motor efficiency, yields a high “tank-to-wheel” efficiency of 81 %. However, batteries suffer from a very low energy density: a classic Lithium-ion battery can store 0.13 kWh/kg, compared to 12.7 kWh/kg for diesel
Figure 1. John Deere's battery electric tractor SESAM presents an enormous battery pack

Hydrogen FCEVs are not perfect either. Their efficiency is much lower: converting hydrogen to electricity has an efficiency of 60 %, and when combined with an inverter, the motor yields a tank-to-wheel efficiency of 51 %. Hydrogen gas can be stored in a tank, which is more convenient than storing electricity in a battery. Hydrogen molecules, however, need to be compacted. Such pressurisation involves an energy cost as well. Nonetheless, hydrogen gas benefits from a high energy density of 39 kWh/kg
The factors involved in the choice of tractor (battery or fuel cell) do not stand alone. For the tractor to be sustainable, the entire well-to-wheel chain needs to be considered. In other words, the logistics between the energy source and its final use will determine its overall efficiency and sustainability, as well as the cost of the system.
Infrastructures and well-to-wheel efficiencies
Electricity and hydrogen are energy carriers, vectors used to transport and utilise energy. Both can be produced from renewable or fossil energy sources, and are not sustainable per se. As an illustration, 95 % of hydrogen is currently being produced from fossil fuels (mostly via Steam-Methane Reforming), with associated CO2 emissions
Efficiency and associated energy production
Harvesting energy from a source and transforming it into a carrier happens at a certain efficiency: the “well-to-tank” efficiency. Figure 2 compares the well-to-tank and tank-to-wheel efficiencies for a battery electric vehicle system and a hydrogen fuel cell vehicle system. The production of hydrogen from electricity and the transformation back to electricity in a fuel cell occurs at 60 % efficiency, lowering the overall well-to-wheel efficiency of the FCEV to 28 %. The BEV benefits from 77 % overall efficiency. In other words, compared to a battery electric tractor, more energy must be generated to produce the same work from a hydrogen fuel cell tractor. The following case-study highlights these differences.
Figure 2. Well to wheel efficiency diagrams for battery electric vehicles and hydrogen fuel cell vehicles. Adapted from InsideEVs.com.

Case study
An electric tractor and its support infrastructure need to be chosen for a vineyard in the South of France. The vineyard comprises 20 hectares of vines, for which one tractor is needed for approximately 800 hours per year. The maximal power required for work on the vineyard is 100 kW, such that the maximum yearly electricity demand by the tractor is 80,000 kWh. In order to be self-sufficient, the vineyard managers decided to produce this electricity on-site using photovoltaic (PV) panels. Solar energy is readily available at the location with 2000 hours of sun per year. Moreover, PV panels produce most of their electricity in summer, which coincides with the period in which the tractor is most needed. For this system, the company can choose between a battery-electric system and a hydrogen electric system. In the first case, a BEV type of tractor is used in combination with a stationary storage battery on-site. In the second case, a hydrogen fuel cell tractor is chosen, together with an electrolysis unit and a hydrogen storage tank at the farm.
An average PV panel of 1 m2 produces approximately 100 Wpeak of electricity. With 2000 hours of sun per year, a 1 m2 solar panel produces 200 kWh per year. The area of photovoltaic panels needed to supply the tractors with electricity differs per system. The overall efficiency of the battery-electric process is 77 %, which results in a PV area of 519 m2 needed to power the BEV tractor. Accounting for the losses from the hydrogen route, 1429 m2 of PV panels are needed to power the 100 kW FCEV tractor, or 2.75x the size needed for a battery system.
Stationary storage: sizing and costs
If the hydrogen system does not stand out for its efficiency, it is still competitive as a result of its size and the costs involved. For the above-mentioned vineyard, a stationary storage system is needed to cover up to 3 days of autonomy (8 hours/day) at a maximal wattage of 100 kW. Given the storage and tank-to-wheel efficiency shown in Figure 2, the hydrogen storage system would need a capacity of 5,198 kWh, the equivalent of 5.5 m3 and 131 kg of hydrogen. The yearly cost of the electrolysing system (cleaning H2, drying, compressing and maintenance) amounts to 24,500 €
Conclusion
Battery electric and hydrogen fuel cell tractors have the potential to reduce CO2 emissions of vineyards, if the electricity used to drive them is produced from sustainable sources. Battery systems are very efficient, while hydrogen systems are more compact and lighter. Choosing an option will depend on local infrastructure, available space and future development of costs.
The translation of this article into English was offered to you by Moët Hennessy.
NOTES
- US Department of Energy (US-DOE). “All-Electric Vehicles.” Fueleconomy.gov. https://www.fueleconomy.gov/feg/evtech.shtml, 2017.
- MacKay, D. "Fluctuations and Storage." In Sustainable Energy-without the hot air, p. 199. UIT Cambridge, 2008.
- Future Farming. “Gradual switch from diesel to gas and electricity”. Futurefarming.com. https://www.futurefarming.com/Machinery/Articles/2018/12/Gradual-switch-from-diesel-to-gas-and-electricity-373914E/, 2018.
- Future Farming. “Gradual switch from diesel to gas and electricity”. Futurefarming.com. https://www.futurefarming.com/Machinery/Articles/2018/12/Gradual-switch-from-diesel-to-gas-and-electricity-373914E/, 2018.
- MacKay, D. "Fluctuations and Storage." In Sustainable Energy-without the hot air, p. 199. UIT Cambridge, 2008.
- New Holland Agriculture. “New Holland presents the first NH2™ hydrogen powered tractor ready to go into service on a farm.” agriculture.newholland.com. https://agriculture.newholland.com/eu/en-uk/about-us/whats-on/news-events/2011/nh2, 2011.
- International Renewable Energy Agency (IRENA). “Hydrogen from renewable power, Technology outlook for the energy transition”, p.13, Abu Dhabi, 2018.
- Lichner C., “Electrolyzer overview: Lowering the cost of hydrogen and distributing its production.” pv-magazine-usa.com. https://pv-magazine-usa.com/2020/03/26/electrolyzer-overview-lowering-the-cost-of-hydrogen-and-distributing-its-productionhydrogen-industry-overview-lowering-the-cost-and-distributing-production/, 2020.
- Marsh, J. “Tesla Power Wall: a complete review.” Energysage.com. https://news.energysage.com/tesla-powerwall-battery-complete-review/, 2020.
- Morrison, G., Stevens, J. and Joseck, F. “Relative economic competitiveness of light-duty battery electric and fuel cell electric vehicles.” In Transportation Research Part C: Emerging Technologies, 87, p.183-196, 2018.
References
- Adoir, E., Penavayre S., Petitjean T., and de Rességuier L. "Study of the viticultural technical itineraries carbon footprint at fine scale." In BIO Web of Conferences, vol. 15, p. 01030. EDP Sciences, 2019.
- US Department of Energy (US-DOE). “All-Electric Vehicles.” Fueleconomy.gov. https://www.fueleconomy.gov/feg/evtech.shtml, 2017.
- Future Farming. “Gradual switch from diesel to gas and electricity”. Futurefarming.com. https://www.futurefarming.com/Machinery/Articles/2018/12/Gradual-switch-from-diesel-to-gas-and-electricity-373914E/, 2018.
- New Holland Agriculture. “New Holland presents the first NH2™ hydrogen powered tractor ready to go into service on a farm.” agriculture.newholland.com. https://agriculture.newholland.com/eu/en-uk/about-us/whats-on/news-events/2011/nh2, 2011.
- MacKay, D. "Fluctuations and Storage." In Sustainable Energy-without the hot air, p. 199. UIT Cambridge, 2008.
- International Renewable Energy Agency (IRENA). “Hydrogen from renewable power, Technology outlook for the energy transition”, p.13, Abu Dhabi, 2018.
- Lichner C., “Electrolyzer overview: Lowering the cost of hydrogen and distributing its production.” pv-magazine-usa.com. https://pv-magazine-usa.com/2020/03/26/electrolyzer-overview-lowering-the-cost-of-hydrogen-and-distributing-its-productionhydrogen-industry-overview-lowering-the-cost-and-distributing-production/ 2020.
- Marsh, J. “Tesla Power Wall: a complete review.” Energysage.com. https://news.energysage.com/tesla-powerwall-battery-complete-review/, 2020
- Morrison, G., Stevens, J. and Joseck, F. “Relative economic competitiveness of light-duty battery electric and fuel cell electric vehicles.” In Transportation Research Part C: Emerging Technologies, 87, p.183-196, 2018.
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