Hydrofaction® Technology at Silva Green Fuels (SGF) Demo Plant in Tofte, Norway

Waste to Renewable Biocrude: Nature's Way in Twenty Minutes, Not Millions of Years

It Starts with Biowaste Feedstock and Ends with High-Value Renewable Biocrude

Hydrofaction® is Steeper Energy’s proprietary implementation of hydrothermal liquefaction (HTL) which applies supercritical water as a reaction medium for the conversion of biomass directly into a high-energy density renewable biocrude, referred to as Hydrofaction® Oil.

Steeper’s unique process mimics and accelerates nature by subjecting wet biomass to heat and high pressure. Hydrofaction® process conditions are carefully chosen to promote reaction pathways that favor high yields of high-quality renewable oil.

Hydrofaction® achieves an industry-leading 45% biomass-to-oil conversion on a mass basis, and up to 85% of the biomass input energy recovered in the biocrude.


Hydrofaction® uses water above its critical point (high temperature and pressure conditions known as “supercritical”) as the reaction medium. This drives the thermochemical conversion of biomass feedstocks into a biocrude that resembles fossil crude oil. Under supercritical conditions, water exhibits unique thermophysical properties that are very different from those at ambient conditions. This favors certain reaction pathways that facilitate the production of high quality biocrude. During the Hydrofaction® conversion process the properties of the biocrude are tunable by varying parameters such as temperature, pressure and by introducing catalysts which are customized for Hydrofaction®.

Hydrofaction® Oil is of higher quality than other biomass-derived oils. It has a particularly low oxygen content of less than 10% by weight. Hydrofaction® Oil can often be used in its raw form as a heavy fuel oil (HFO) replacement in large reciprocating internal combustion engines, such as those used for marine propulsion, or used in heating, or power generation applications.  Alternatively  it can be further upgraded and fractionated into more stringent fuel types (finished fuels) such as diesel, jet fuel, and gasoline.

The inherent low oxygen content of Hydrofaction® Oil supports less secondary upgrading to convert the biocrude into finished fuels.  This feature of Hydrofaction® Oil is key to facilitate its processing in existing  oil refineries with little or no modification.

The unique composition of Hydrofaction® Oil means that it is particularly energy-dense with a heating value of about 38 MJ/kg. This is close to conventional crude oils which have heating values of 42-46 MJ/kg.

Simplified Hydrofaction Process
Simplified Hydrofaction® Process
Hydrofaction® – Mass Balance – (thickness of lines reflect relative mass flows)
Hydrofaction® – Energy Balance – (thickness of lines reflect relative mass flows)

Summary of Overall Process Performance:

  • Mass yield of biomass to biocrude (dry-ash-free basis): 45%
  • Calorific value of biocrude (HHV basis): >38MJ/kg
  • Biomass input energy recovered in the biocrude: 85%
  • Transfer efficiency of carbon in biomass to biocrude: 74%
  • Carbon efficiency number: [confirm with technical team]