The case for replacing diesel in heavy-duty trucking

As diesel prices reach record levels, and the idiot-in-chief in the White House threatens to ban American diesel exports to the international market, it's never been clearer just how much we still rely on diesel for the transportation of goods. Almost completely, in fact - 97%.of the largest Class B tractor trailers run on diesel, although the figure for commercial trucks as a whole is about 76%.

So, what's the deal? We see lots of electric cars on the roads these days, but when was the last time you saw an electric truck? Why has the take-up of alternative-fuel trucks been so poor?

The main types of alternative fuels available for heavy-duty transportation are:

• Renewable diesel - made from fats and oils, which can be used directly in current trucks with no engine modification. It can reduce carbon intensity by as much as 68% compared to traditional diesel, but it remains relatively expensive. Incentives like California's Low Carbon Fuel Standard are starting to change that and adoption is increasing rapidly in such jurisductions.
• Natural gas (methane) - compressed natural gas offers a more stable price compared to diesel, but it is still a fossil fuel, albeit a bit cleaner than diesel. Renewable natural gas is sourced from landfills, animal waste and other organic matter, and is a net zero, or even carbon-negative, fuel, but it remains relatively expensive. They both offer diesel-like performance and good range, but require specialized engines (renewable natural gas fuel is compatible with engines designed for compressed natural gas). Natural gas is the most widely-used alternative fuel today, and there is already a reasonable network of filling stations, although it needs to be expanded if take-up is to improve.
• Electric batteries - offer zero tailpipe emissions and lower energy costs compared to diesel, but charging infrastructure is still lacking, and range, battery weight and initial purchase cost are also limitations (although all of these factors are in the process of improving). The sustainability impact also depends on the emissions profile of the electricity being used to charge them.
• Biodiesel - made from animal fats and vegetable oils, biodiesel is often blended with conventional diesel, with which it is completely compatible. It's performance in cold weather poses a challenge (it turns to gel and can harm engines), so most manufacturers do not support blends above 20%, although new technical advancements are overcoming even that drawback. Biodiesel can reduce carbon intensity by 73% compared to conventional diesel.

The main reason for diesel's continuing dominance in heavy-duty haulage is inertia, but its high energy density, strong pulling power, and the durability and reliable ignition of its engines make changes of any kind difficult. Furthermore, we are currently in a period of retrenchment, mainly thanks to Donald Trump and his ilk, and environmental concerns are not top of mind right now.

But, in this era of spiking diesel prices, the cost-benefit calculations for alternative fuels are starting to change, particularly for renewable natural gas and renewable diesel (the cost of electric trucks still makes them prohibitively expensive). By some analysis, electric trucks are expected to become economically competitive with diesel in the early 2030s. Donald Trump may have inadvertently given alternative fuels a shot in the arm.