Biomass combustion and CHP: Techniques

Cookstoves, pellet boilers, co-firing and charcoal kilns compared

What this tab covers The methods used to capture this energy: how each works, and how they compare on efficiency, cost, life-cycle emissions, maturity and scale.

Five ways of burning biomass are covered, from household fires used by about 2.1 billion people to power stations costing about USD 3,600 per kW.

Comparison

Method	Efficiency	Cost	Life-cycle emissions	Maturity	Scale
Cookstoves and firewood³¹⁷	10-20% traditional; 20-50% or more for ISO Tier 2-5 stoves	Fuel often gathered, not bought; stove prices not quantified	Not quantified	mature	About 2.1 billion people rely mainly on polluting fuels
Boilers and pellet stoves⁸	Not quantified	Not quantified	EU default savings against fossil heat (80 g CO2eq/MJ), under 500 km transport: forest-residue chips 91% (about 7 g CO2eq/MJ, calculated); pellets 49-90% depending on how the mill is powered	mature	Not quantified
Biomass power plants and co-firing with coal³⁹¹⁰⁸	16-40% (dedicated); 36-44% (co-firing)	USD 86/MWh average LCOE and USD 3,606/kW installed (2025), LCOE slightly down on 2024; co-firing retrofit USD 140-850/kW (2015 estimate)	130-420 g CO2eq/kWh, median 230 (IPCC 2014); about 72 g CO2eq/kWh for EU forest-residue chips (calculated: 11% of 183 g CO2eq/MJ)	mature	Capacity factor 78% in 2025; plants typically 2-350 MWe
Biomass CHP³⁴²	70-90% total; about 10% to over 30% as electricity	LCOE USD 70-290/MWh (2015 estimate)	As for power plants, but shared across more useful output	mature	About 1,000 biomass-fired CHP plants in the EU28 in 2016
Charcoal making⁵⁶	12-16% of wood mass in earth kilns; about 35% under controlled carbonisation	Not quantified	Not quantified	mature	Not quantified

Household fuel is cheap in cash but costly in health and time. Utility biomass power, at about USD 86/MWh, costs more than new wind or solar because fuel must be bought, dried and moved. Co-firing is the cheapest route because it borrows a coal plant; CHP extracts the most energy per tonne. Emissions depend more on fuel than device: residues score well, while pellets made with natural gas heat and grid power save as little as a quarter of fossil electricity emissions.

How each method works

Cookstoves and firewood

Wood, crop residues or dung burn on an open fire or in a stove under a pot. Improved stoves add an insulated chamber and a skirt or chimney that forces hot gas along the pot.³¹⁷

Boilers and pellet stoves

Wood chips or pellets are fed automatically into a burner that heats water for a building or district heating network.⁸

Biomass power plants and co-firing with coal

Fuel burned in a boiler raises steam that drives a turbine. Co-firing replaces part of the coal in an existing coal boiler with biomass.³⁹¹⁰⁸

Biomass CHP

A turbine or engine makes electricity and its exhaust heat supplies a factory or heating network instead of a cooling tower.³⁴²

Charcoal making

Wood is partly burned with little air in an earth mound, pit or kiln, driving off water and volatiles and leaving mostly carbon, which is lighter to carry.⁵⁶

Sources

Voluntary Performance Targets for cookstoves (ISO/TR 19867-3:2018 tiers for thermal efficiency, CO and fine particulate emissions) Clean Cooking Alliance, 2018
Power generation and cogeneration IEA Bioenergy Task 32 (Biomass Combustion)
Biomass for Heat and Power, Technology Brief E05 IEA-ETSAP and IRENA, 2015
Biomass CHP facilities (factsheet) ETIP Bioenergy (European Technology and Innovation Platform)
Review of the existing studies related to fuelwood and/or charcoal in Mozambique, section 3.2 Charcoal production FAO
Fast pyrolysis: key points (table of product yields by pyrolysis mode) IEA Bioenergy Task 34 (Direct Thermochemical Liquefaction)
Household air pollution: health risks World Health Organization, 2024
Directive (EU) 2018/2001 (Renewable Energy Directive II), Annex VI: typical and default greenhouse gas savings for biomass fuels and biogas; fossil comparators 183 g CO2eq/MJ (electricity), 80 (heat), 94 (biomethane). Default values not changed by amending Directive (EU) 2023/2413 (RED III); a Commission revision of Annexes V and VI was in draft in 2026 European Union (EUR-Lex), 2018
Renewable Power Generation Costs in 2025 (Executive summary, Figure S1) IRENA, 2026
Annex III: Technology-specific cost and performance parameters, Table A.III.2 (Schlomer et al.), in Climate Change 2014: Mitigation of Climate Change (AR5 WGIII) IPCC, 2014