MASH Makes’ CNSL-based biofuel clears final lab test

MASH Makes’ upgraded CNSL fuel has passed a critical lab engine test that confirms its readiness for marine use without the reliability issues traditionally associated with CNSL-based fuels.
In recent years, CNSL, a fuel made from cashew nut shell liquid (CNSL), emerged as a promising, but at times unreliable alternative to existing biofuels. Its tendency to polymerise and inability to reliably blend has been a cause of frustration among shipowners. This sticky characteristic isn’t surprising, though, given that it is traditionally used as a resin to thicken paint.
But now, through a proprietary upgrading process, MASH Makes developed a CNSL-based fuel that is clean-burning, stable, and suitable for commercial shipping.
The tested blend — 20% Upgraded CNSL and80% VLSFO — was evaluated at FVTR GmbH using a marinegrade single cylinder research engine. The fuel showed clean combustion, No injector fouling or residueand Stable operation across all loads, with no tuning or pressure adjustments required.
“The upgraded CNSL fuel from MASH Makes performed reliably across all tested loads, showing clean injection behaviour and no signs of degradation,” said Robert Bank, the team lead for team lead fuels and component analyses at FVTR.
“From a technical standpoint, it behaved comparably to conventional marine fuels.”
The upgraded CNSL also showed improved emissions compared to earlier blends: NOx slightly increased but stayed within IMO Tier II limits, CO levels remained stable, indicating good combustion and smoke decreasedat partial loads and increased only slightly at full load.
This test represents a key milestone in making CNSL a viable and scalable commercial fuel for shipping.
“This result proves that with the right upgrading process, CNSL can become a serious contender in marine fuels,” said MASH Makes head of research and development Krishna Chakravarty. “It’s cost-effective, scalable, and doesn’t require fossil infrastructure changes. With our tech and learnings, we’re enabling the development of new effective biofuel solutions.”