At the DLG Test Centre for Technology and Farm Inputs, a Valtra Q 285 was tested under realistic conditions using the DLG PowerMix with two types of fuel on the DLG roller test bench: conventional diesel and the bio-based alternative fuel HVO (hydrotreated vegetable oil). In the consumption comparison, the alternative fuel performed impressively and offers a viable option for short-term use in agricultural machinery to reduce CO2 emissions.
The political guidelines for climate protection are clear: greenhouse gas emissions from the use of diesel fuel are to be reduced to zero by 2045 at the latest. Politicians are also demanding that the agricultural sector do its part and quickly switch to more sustainable alternatives. Agricultural machinery manufacturers are currently working intensively on alternative engine concepts based on liquid or gaseous fuels, including electric drive systems.
Liquid alternative fuels for high power requirements
Which alternative drive concepts can replace fossil agricultural diesel in the short, medium and long term? Experts from science, product development and agricultural practice agree that liquid fuels with high energy density will remain irreplaceable in arable farming for activities with high power requirements and long operating times, such as soil cultivation and harvesting. Even in the medium power range, gaseous fuels require tank sizes of several cubic metres, while electric drives require batteries weighing in the five-digit range.
The diesel engines of modern tractors and agricultural machinery can already be operated without any problems using a number of alternative liquid fuels, without having to change the basic architecture of the vehicles. Adjustments to the engines are usually minimal or not necessary at all, and the existing tank volume can be used without expansion. The high energy density of the fuels also makes long, heavy field work possible.
The DLG Test Centre for Agricultural Technology and Farm Inputs (www.dlg-testservice.com/en/) is one of the leading international testing and certification organisations in the fields of tractors, agricultural technology and farm inputs. The DLG's own test methods are developed by neutral commissions with a focus on practical application. In addition to testing in accordance with DLG standards, the organisation also offers comprehensive testing and certification services for quality assurance. The test and inspection reports are an important decision-making aid for investments and practical application. The seals awarded are DLG Approved, DLG Quality Seal and DLG PowerMix.
For further information:
https://www.dlg.org/en/tests/agricultural-technology-and-farm-inputs
HVO is a promising option
Hydrotreated vegetable oil (HVO), which is obtained from waste and residual materials, is particularly suitable for short-term use in agricultural machinery. HVO has almost the same energy density as fossil diesel and enables CO2 emissions to be reduced by up to 90%.
"The political framework conditions for promoting sustainable mobility are encouraging manufacturers of commercial vehicles and agricultural machinery to focus more on alternative drive systems. Our goal is to offer both manufacturers and farmers guidance on quickly implementable and practical solutions – with a particular focus on issues that are relevant to users: Will engine performance remain the same? How will fuel consumption change?" says Martin Hanstein, who is responsible for performance measurements on the roller test bench at the DLG Test Centre for Agricultural Technology and Inputs in Groß-Umstadt, Hesse.
The drop-in fuel, marketed under the name HVO 100, is a market-ready product that has been approved for use in many diesel engines without the need for engine modifications. HVO can also be mixed with fossil diesel in any ratio. Furthermore, existing storage and tank facilities can be used.
HVO also has a higher cetane number than diesel. This makes the alternative fuel more ignitable, which can have a positive effect on efficiency. The engine starts better at low temperatures.
How does HVO compare to diesel?
HVO has received a lot of advance praise. But how competitive is it actually in terms of performance and consumption compared to conventional diesel fuel? Test engineer Martin Hanstein and his colleagues provided the answer to this question in a comparative test on the DLG roller test bench.
At the DLG Test Centre, the alternative fuel HVO was tested for its impact on the fuel consumption of a tractor compared to diesel. A standardised diesel fuel that meets the current B7 standard was used for comparison. The test was carried out with a Valtra tractor (Valtra Q 285). Power and fuel consumption were recorded under full load on the PTO power test bench and measured in the DLG PowerMix test on the DLG roller test bench, which simulates realistic operating conditions for traction, hydraulic and PTO power.
No difference in power at the PTO
The maximum PTO power was determined at various engine speeds on the PTO power test bench. The measurements showed no significant difference between the two fuels. ‘When using HVO, users do not need to worry about a drop in engine power – it remains unchanged,’ says test engineer Martin Hanstein.
Small differences in fuel consumption
Fuel consumption measurements on the PTO power brake showed that HVO consumed slightly more fuel than diesel. This is due to the lower density of HVO compared to diesel, which means that the volumetric energy density (kWh/l) is slightly lower, although the gravimetric energy density (kWh/kg) is slightly higher. Since HVO is refuelled in litres and not in kilograms, consumption with HVO is therefore about 3 to 4% higher than with diesel.
In the DLG PowerMix test, various load cycles are defined based on typical workloads for a tractor in practice, under which the fuel consumption, performance and ultimately the energy efficiency of the entire vehicle are determined. The load cycles reflect typical field work and transport work.
The difference in consumption determined during the PTO measurement was also confirmed in the DLG PowerMix. By measuring transient cycles and combining full-load and partial-load ranges, a reliable conclusion can be drawn: consumption is approximately 3 to 4% higher than with diesel.
HVO is a serious alternative
In summary, the following results can be stated:
- No significant differences in power output were found between the two fuels.
- HVO was found to have a slightly higher consumption in l/h, which is due to its lower energy content (due to its lower density).
- The higher cetane number of HVO can lead to better ignition behaviour and efficiency.
- Approval must be clarified with the manufacturer.
HVO thus represents a practical, immediately implementable alternative that can contribute to reducing the carbon footprint of agriculture. This is particularly true for farms that want to improve their carbon footprint without having to invest in new vehicle technology. ‘There is hardly a better or faster way to improve the carbon footprint of existing machinery,’ concludes DLG test engineer Martin Hanstein.
Limited availability
HVO fuels are therefore a promising approach for agricultural technology. Unfortunately, they are not yet available in sufficient quantities. Their outstanding properties also make them sought-after in other sectors, such as aviation and shipping, which limits their availability. Furthermore, existing production facilities are currently unable to meet the demand for HVO. In addition, the carbon footprint of HVO is only positive if it is produced in an environmentally friendly way. However, this type of production is still very expensive at present. This is also reflected in the prices of HVO, which are currently around 10 cents higher than those of diesel.
Speaking of HVO & Co.
The DLG will continue to monitor and investigate the topic of alternative fuels in the future in order to contribute to manufacturers and agricultural practice. The DLG specialist centre continuously reviews the current development landscape around alternative drives and fuels and provides support with expert knowledge, podcasts and other information services.
The topic will also be presented and discussed at Agritechnica, organised by the DLG. The test centre is already conducting tests on electric vehicles (BEV) and hydrogen-powered vehicles (FCEV).
