Truck & Off-Highway Engineering - February 2024 - 28

Q&
A
Renewable diesel offers drop-in solution
for decarbonization
Renewable diesel (RD) fuels represent an opportunity to decarbonize
on- and off-highway diesel ICE vehicles with a minimal
investment in infrastructure and little to no disruption of
current fleet operations. However, market acceptance of these
fuels has been slow in locations where legislation has not
mandated their widespread use.
TOHE recently interviewed Matt Leuck, technical manager at
Neste, to discuss the benefits of renewable diesel for fleets and
engine suppliers in terms of reducing greenhouse gases, the
feasibility of supplying renewable fuel with the current infrastructure
and the cost-offsets that renewable
diesel fuels offer in terms of engine
performance and reduced maintenance.
Why do you see RD as the best alternative
for a sustainable fuel source?
The future will need all solutions; nobody
is going to solve the decarbonization
puzzle with one silver bullet. A lot of
these solutions will be market-dependent,
but I believe renewable diesel is the
best solution. There's no massive infrastructure
buildup, we don't need colossal
investments to move it across the country
and we're currently making it on three
continents. It's a drop-in solution.
What are the different feedstocks used
to produce these fuels?
We want our feedstock to be a waste
product that's already gone through its
first useful life. Cooking oil, animal fat,
tallows, fish oils and technical corn oil are
all things we can use for our fuel. There's
also a lot of stuff out there that we're not
even using yet. Before the hydrotreating
and isomerization production process,
there's also a pre-treatment. That's where
we could clean up some really nasty feedstocks.
meaning that we move a few molecules to different places. By
isomerizing, we can guarantee winter performance characteristics
because we can manipulate the molecules.
What is an example of a long-term benefit of running
exclusively RD?
Detroit Diesel did some testing on a DD15 where they artificially
aged the fuel and ran it through an engine on a test bed. They
were looking to see what would happen first: would the fuel
break down and go off spec as time goes on, or would the parts
physically fail because of deposits and corrosion?
The B5 bio-blend made it 13 days
in the test and then the injector just seized
up solid. B0 pure fossil made it roughly 43
days. The fuel broke down enough that it
had a lot of acids in it and the injector had
deposits. After two months of testing with
our fuel, they found that it didn't break
down or have any of those acids. They basically
got bored and pulled the injectors
apart and there were zero deposits.
Matt Leuck,
technical
manager at Neste.
" We always want to
make sure people
understand that
renewable diesel
and biodiesel are not
the same product. "
What are the main differences between biodiesel and RD in
terms of production and chemistry?
We use the same feedstocks as the biodiesel industry, but we
always want to make sure people understand that renewable
diesel and biodiesel are not the same product. Chemically speaking,
biodiesel is not a hydrocarbon because it still contains oxygen.
Once we perform our first step in the process (hydrotreating)
where we break apart that molecule, we get a straight chain
of paraffinic hydrocarbons. The only issue with that is the paraffins
we make are a solid, so we do one more step called isomerization
where we take that straight chain molecule and branch it,
28 February 2024
What are some other net benefits of RD
for engine OEMs and fleet owners?
Our fuel can help reduce NOx for 2006
and older off-road (pre-Tier 2) engines
by roughly 10%. But post-2010/Tier 4
Final engines will see reductions of up to
98%. While this fuel does not enable
OEMs to remove SCR or DPF systems, it
does offer benefits in overall maintenance
because we're putting 30-40%
less soot into those systems. That means
fewer regens, fewer ash cleanouts and
less stationary regen. For fleet owners,
it's about cost savings per mile. We have
a customer in Oregon that told us when
they switched to renewable diesel, they
started saving two cents per mile over fossil diesel.
What are the biggest challenges of market acceptance for RD?
I think the biggest challenge is education. Over the past five
years, it's become much more accepted. As of last year, more
than half of California's diesel consumption was renewable.
We're at a point now where in areas where we have renewable
diesel, we're not getting as many questions because the
fleet owners are talking to each other. But when we're looking
into new markets, it's like starting from scratch. So it really
comes down to education and getting some pilot programs
out there and showing people that it can be done.
Matt Wolfe
TRUCK & OFF-HIGHWAY ENGINEERING
Truck & Off-Highway Engineering - February 2024

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