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Present and future fuels in the shipping industry: diesel

Join us as we take a look at diesel, in the first in a new series that delves into the pros and cons of present and future fuels.

With industries, governments and society all striving for a cleaner and more sustainable planet, the fuels we embrace in future will play a critical role. Over the coming months, we’ll be looking at the fuels which can help the shipping industry to meet stringent emissions targets. It makes sense to start at the beginning, so let’s look at the benefits, pitfalls and potential improvements for the current most widespread fuel of choice: diesel.

For more than 100 years, since the advent of the 4-stroke internal combustion engine that set the template for the majority of today’s engines, and Rudolf Diesel’s desire to create a highly efficient ‘‘Carnot engine’, diesel as a fuel has played an incredibly influential part in the evolution of the internal combustion engine.

Over the decades, we’ve seen diesel engines become ever more efficient, with power density, efficiency and emissions improved hugely through the development of forced induction, with turbochargers from Accelleron leading the way. Even now, as we look towards a cleaner and more efficient future, diesel still has a lot to offer.

The benefits of diesel

While alternative fuels such as ammonia, methane and hydrogen deliver benefits that will inevitably prove key to their adoption in future, specifically when it comes to emissions, diesel will remain a mainstay in the marine industry for some time, providing a completely different set of benefits to ship and fleet owners and operators.

The biggest benefit of diesel, at least in the short term, remains value for money. Diesel is cost-effective for several reasons. Engines in the vast majority of vessels were designed to run on diesel, and the marine industry typically sees companies keeping the same machinery for decades (sometimes even half a century or more!). This means that running engines on diesel can help owners and operators to avoid expensive overhauls or even replacing engines completely.

Diesel is also the most cost-effective option when it comes to infrastructure spending. We already have the infrastructure in place to produce, store and distribute diesel at an international scale, keeping its cost lower.

Another benefit is the fact that engine designers and engineers are already accustomed to working with and refining diesel engines, making them ever-more efficient. That means ship owners and operators can turn to Accelleron for advice on cutting costs and emissions, and we can provide the upgrades to make their engines more efficient. 

The downsides of diesel

Cost efficiency has helped to make diesel the most popular fuel when it comes to shipping, but it does have two major downsides: Emissions and a finite amount of oil.

Emissions play a huge part in the shipping industry working towards alternative fuels, with sustainability and decarbonization a hot topic in 2022. With companies aiming to meet stringent IMO 2030 and IMO 2050 legislation, we’re already on the journey towards a zero-carbon maritime industry, but we can’t achieve that using fossil fuels like diesel.

That’s not to say shipping using diesel is inherently bad; according to DNV GL, the freight shipping industry delivers more than 90 percent of the world’s trade, yet accounts for just two-three percent of anthropogenic (human-based) CO2 emissions (air cargo used for one percent of overall freight movement accounts for a similar two percent output of anthropogenic CO2), but cleaner and more efficient fuels are required in order to meet targets.

Oil-based fossil fuels such as diesel are also a finite resource, with an estimated 1.65 trillion barrels of proven oil reserves available. With various industries consuming over 97 million barrels of oil per day, it’s estimated that we’ll run out of oil within the next 50 years.

How we can make it cleaner

It’s clear that the shipping industry will move onto alternative fuels, but it’s also critical that we look to make existing options cleaner in the meantime in order to meet emissions targets. Turbocharging is a great example of what we can do to help.

For starters, turbochargers can dramatically shrink engine sizes. For example, while a naturally aspirated Diesel engine putting out 2,000 kW is likely to weigh around 110 tons on average, the turbocharged equivalent is a lot smaller, weighing an average 20-30 tons.

There’s a huge difference when it comes to fuel efficiency with turbocharging; using an example of an average 2,000 kW engine with a 25-year lifecycle at 50% load, the turbocharged version is likely to be around 14% more efficient, requiring 41,600 tons of fuel compared to 48,200 tons for the naturally aspirated version.

CO2 emissions see a similar 14% drop, with the ship owner/operator saving 23,000 tons of CO2 over 25 years simply by opting for a turbocharged engine, and NOx emissions are reduced by 9%, at 2,900 tons compared to 3,200 tons.

What’s likely to replace Diesel?

We’re already starting to see a shift when it comes to fuel, with ship owners and operators looking towards LNG in the short term, and ammonia, methanol and hydrogen as viable alternatives as technology and infrastructure progresses. As with diesel, there are naturally benefits and downsides to each, with challenges for the shipping industry and society at large to overcome, and we’ll be looking at each fuel individually here on charge! in the future.

Image credit: Avigator Fortuner/Shutterstock

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