Browse Topic: Biodiesel
State and federal legislation has helped double the consumption of renewable and biodiesel in North America over the past half decade. But is policy alone enough to make them ready for prime time? As crude oil prices continue to fluctuate globally, creating budgeting and logistical headaches for fleets of all sizes, renewable diesel (RD) fuels have quietly gained ground in North America. According to Chevron, total biomass consumption of renewable fuels in the U.S. has grown exponentially over the past five years, from 2.7 million gallons in 2020 to 5.1 million gallons in 2024. While that represents a fragment of annual diesel consumption in the U.S., the environmental benefits and viability of renewable fuels are growing greater everyday thanks to legislative support and technological investment from various fuel producers.
How to ensure off-highway combustion systems operate with sufficient control to meet tightening emissions standards and evolving fuel landscapes without sacrificing reliability. Off-highway equipment is being asked to do more with less. Less margin for emissions, less tolerance for downtime and less room for inefficiency, while operating under some of the most demanding duty cycles in the transport sector. Tier 4 and Tier 5 emissions standards have reshaped engine calibration strategies. Renewable diesel and biodiesel blends are entering worksites and farms at scale. At the same time, construction, mining and agricultural machines are expected to run for 20-25 years, often at sustained high load and far from service infrastructure. In this environment, combustion systems are far from being phased out.
We hear it often at industry events, in keynote speeches and during expert panel discussions: There is no silver bullet. Peter Voorhoeve, president of Volvo Trucks North America, says as much in this issue's Q&A (page 44). “Electric is one solution, but biodiesel is another solution, and hydrogen is, too. So we have these different fuel solutions to get to better sustainability.”
The goal of this research is to better understand the methodologies for manufacturing biodiesel worldwide and the main raw materials used in its production. We aim to compare the solutions established by relevant countries with those used in Brazil, identifying their advantages and disadvantages. Our primary areas of interest include the United States, Indonesia, and Europe, where we will analyze the solutions and, whenever possible, understand the commercial and political interests involved. We will highlight aspects related to sustainability in the production, transportation, and use of biodiesel. The methodology is based on research from recent publications and news, organized into graphs to facilitate analysis and comparison. Next, we will also examine the consequences of the solutions adopted in Brazil, envisioning future scenarios and recommended paths. In the short term, biodiesel is expected to be replaced by renewable diesel (also known as green diesel in some regions, including Brazil), which can also be produced from biomass. Ethanol is likely to be a global solution in the short to medium term, with hydrogen expected to take the lead in providing renewable energy. In the long term, around 2050, the use of fossil fuels for power generation should be significantly reduced, and technologies for energy storage, along with clean, renewable, and sustainable energy sources, should prevail.
Heavy duty engines for long-haul trucks are quite difficult to electrify, due to the large amount of energy that should be stored on-board to achieve a range comparable to that of conventional fuels. In particular, this paper considers a stock engine with a displacement of 12.9 L, developed by the manufacturer in two different versions. As a standard diesel, the engine is able to deliver about 420 kW at 1800 rpm, whereas in the compressed natural gas configuration the maximum power output is 330 kW, at the same speed. Three possible alternatives to these fossil fuels are considered in this study: biodiesel (HVOlution by Eni), bio-methane and green hydrogen. While the replacement of diesel and compressed natura gas with biofuels does not need significant hardware modifications, the implementation of a hydrogen spark ignition combustion system requires a deep revision of the engine concept. For a more straightforward comparison among the alternative fuels, the same engine platform has been considered. The hydrogen engine has been optimized with the support of CFD-1D simulation (GT-Power), using models calibrated with experimental data, obtained on the diesel and compressed natural gas versions. The numerical tool includes a predictive combustion model (SI-Turb), also calibrated with experimental data on a hydrogen prototype. The study shows that the implementation of a combustion system running on lean mixtures of hydrogen, permits to cancel the emissions of CO2, while maintaining the same power output of the compressed natural gas / bio-methane engine (but about 20% lower than the biodiesel). Moreover, the concentration of NOx is very low (<20 ppm) at all the operating conditions, enabling a strong simplification of the after-treatment system, at least in comparison to the original diesel/biodiesel version. Finally, the hydrogen solution exhibits an average increase of approximately 9% in efficiency respect to the compressed natural gas configuration, but it remains less efficient if compared to its biodiesel counterpart (-11%).
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