Biomass combustion and CHP: Resources and labour

The land and water hidden inside every tonne of fuel

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.

Biomass combustion needs land and water to grow the fuel but few special materials; the plant is a conventional boiler and steam turbine.

Natural resources

Resource	How much	Why it is needed
Land	Median 58,000 ha per TWh a year for biomass electricity; about 130 ha per TWh a year if only residues are used¹²	Plants store sunlight slowly and thinly, so large areas are needed to grow enough fuel. Residues are by-products of land already farmed or logged, which is why their footprint is tiny.
Water	Average water footprint of biomass 24 m3/GJ (Netherlands) to 143 m3/GJ (Zimbabwe), against 1.06 m3/GJ for crude oil¹³	Growing plants transpire water through their leaves while photosynthesising; the drier and hotter the climate, the more water each unit of energy needs.
Wood fuel	Dry wood holds 18-20 MJ/kg; earth mound kilns need about 6-8 t of wood per t of charcoal (calculated from 12-16% yield); large pits about 4.5 t¹⁴⁵¹⁵	Charcoal making burns part of the wood to supply the heat that drives water and volatile gases out of the rest.
Fossil energy for the supply chain	As little as 2-5% of the final energy produced, for forestry and agricultural fuels (2007 estimate)¹⁸	Harvesting machines, chipping, drying and trucking run mostly on diesel and grid power.
Capital equipment (steel boilers, turbines)	USD 3,606 per kW installed (2025 average); quantities of steel and concrete per MW not found in the sources reviewed⁹	Biomass is bulky and low in energy per tonne, so boilers, fuel yards and handling systems are larger per MW than for coal.

Labour

Phase	How much	Skills	Why it is needed
Fuel supply (harvesting, collecting, processing)	Solid biomass employed about 729,000 people worldwide in 2024, about 215,000 of them in China¹⁶	Forestry and farm work, machine operation, haulage	Biomass must be cut, collected, dried and moved continuously, unlike wind or sunlight.
Operation	Not quantified per MW in the sources reviewed⁹	Boiler and turbine operators, fuel-yard staff, maintenance fitters	Combustion plants run continuously (78% capacity factor) and need fuel handling and ash removal.
Household fuel gathering	Not quantified in the sources reviewed⁷	Unpaid household labour	Where wood is gathered rather than bought, the time cost falls on the household, and carrying heavy loads risks musculoskeletal injury.

Sources

Review of the existing studies related to fuelwood and/or charcoal in Mozambique, section 3.2 Charcoal production FAO
Household air pollution: health risks World Health Organization, 2024
Renewable Power Generation Costs in 2025 (Executive summary, Figure S1) IRENA, 2026
Land-use intensity of electricity production and tomorrow's energy landscape (Lovering, Swain, Blomqvist and Hernandez) PLOS ONE, 2022
The water footprint of bioenergy and other primary energy carriers (Gerbens-Leenes, Hoekstra and van der Meer, Value of Water Research Report 29) UNESCO-IHE / University of Twente, 2008
FAO publication P2396E, Part Two: thermal properties of wood fuels (heating values) FAO
Simple technologies for charcoal making, Chapter 5: Earth pits for charcoal making (FAO Forestry Paper 41) FAO, 1987
Renewable Energy and Jobs: Annual Review 2025 (Table 1, 2024 employment) IRENA and International Labour Organization, 2025
Energy Technology Essentials ETE03: Biomass for Power Generation and CHP International Energy Agency (copy hosted by nachhaltigwirtschaften.at), 2007