Thermochemical biomass conversion: Resources and labour

Why each tonne of fuel needs several tonnes of residue

What this tab covers The natural resources (land, water, materials, fuel or feedstock) and the labour needed to capture this energy, per unit, with the reason each is needed.

Thermochemical plants need dry (or, for HTL, wet) biomass, hydrogen for upgrading oils, and high-temperature, pressure-rated equipment.

Natural resources

Resource	How much	Why it is needed
Biomass feedstock	About 5.6-7.1 t of residue per t of Fischer-Tropsch distillate (calculated from 14-18% yield); about 1.3-1.5 t of dry wood per t of bio-oil (calculated from 65-75% yield)⁵¹²	Every tonne of product needs several tonnes of feedstock because part of the carbon leaves as gas, char or CO2.
Land	Median 58,000 ha per TWh a year for biomass grown for energy; about 130 ha per TWh a year from residues¹⁰	Using residues avoids dedicating land to fuel; purpose-grown biomass needs large areas because plants capture sunlight thinly.
Hydrogen	Not quantified in the sources reviewed⁹⁸	Pyrolysis oils and HTL biocrude contain much oxygen, which must be removed with hydrogen to make stable transport fuel.
Capital equipment (gasifiers, gas cleaning, reactors)	USD 2,500-5,500/kW for IGCC; USD 4,560-5,560/kW for gasification-FT⁴⁹	Equipment must withstand high temperatures, pressures and corrosive tars and acids.

Labour

Phase	How much	Skills	Why it is needed
Construction	Not quantified per MW in the sources reviewed; Fischer-Tropsch plants take about 5 years to build⁵	Process plant construction, pressure vessels, gas cleaning systems	These are chemical plants rather than simple boilers.
Operation	Not quantified in the sources reviewed⁴	Chemical engineers, process operators, catalyst and gas-safety specialists	Syngas contains toxic carbon monoxide and tars that must be controlled continuously.

Sources

Torrefaction and pyrolysis (European Industrial Bioenergy Initiative factsheet EIBI-4) ETIP Bioenergy
IEA Bioenergy Update 29: Task 34 technology report on fast pyrolysis IEA Bioenergy
Energy Technology Essentials ETE03: Biomass for Power Generation and CHP (2007 cost estimates) International Energy Agency (copy hosted by nachhaltigwirtschaften.at), 2007
Progress in commercialisation of biojet / SAF (van Dyk, IEA Bioenergy workshop presentation) IEA Bioenergy Task 39 (hosted by DBFZ), 2023
Biojet fuels: technologies and status of commercialisation (van Dyk and Saddler) IEA Bioenergy Task 39, 2020
Reaching Zero with Renewables: Biojet fuels IRENA, 2021
Land-use intensity of electricity production and tomorrow's energy landscape (Lovering, Swain, Blomqvist and Hernandez) PLOS ONE, 2022