# Biomass combustion and CHP: Techniques

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

Source page: https://www.materialinsights.org/energy/e_bio_combustion/techniques/

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 firewood**^[3](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf)^[1](https://cleancooking.org/news/10-16-2018-voluntary-performance-targets/)^[7](https://www.who.int/teams/environment-climate-change-and-health/air-quality-and-health/sectoral-interventions/household-air-pollution/health-risks) | 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 stoves**^[8](https://eur-lex.europa.eu/eli/dir/2018/2001/oj) | 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 coal**^[3](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf)^[9](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2026/Jul/IRENA_TEC_RPGC_in_2025_2026.pdf)^[10](https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf)^[8](https://eur-lex.europa.eu/eli/dir/2018/2001/oj) | 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 CHP**^[3](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf)^[4](https://old.etipbioenergy.eu/images/ETIP_Bioenergy_Factsheet_Biomass_CHP_facilities.pdf)^[2](https://task32.ieabioenergy.com/?p=4686) | 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 making**^[5](https://www.fao.org/4/x6796e/X6796E05.htm)^[6](https://task34.ieabioenergy.com/?p=4482) | 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.^[3](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf)^[1](https://cleancooking.org/news/10-16-2018-voluntary-performance-targets/)^[7](https://www.who.int/teams/environment-climate-change-and-health/air-quality-and-health/sectoral-interventions/household-air-pollution/health-risks)
**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](https://eur-lex.europa.eu/eli/dir/2018/2001/oj)
**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.^[3](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf)^[9](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2026/Jul/IRENA_TEC_RPGC_in_2025_2026.pdf)^[10](https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf)^[8](https://eur-lex.europa.eu/eli/dir/2018/2001/oj)
**Biomass CHP**

A turbine or engine makes electricity and its exhaust heat supplies a factory or heating network instead of a cooling tower.^[3](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf)^[4](https://old.etipbioenergy.eu/images/ETIP_Bioenergy_Factsheet_Biomass_CHP_facilities.pdf)^[2](https://task32.ieabioenergy.com/?p=4686)
**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.^[5](https://www.fao.org/4/x6796e/X6796E05.htm)^[6](https://task34.ieabioenergy.com/?p=4482)

#### Sources

1. [Voluntary Performance Targets for cookstoves (ISO/TR 19867-3:2018 tiers for thermal efficiency, CO and fine particulate emissions)](https://cleancooking.org/news/10-16-2018-voluntary-performance-targets/) Clean Cooking Alliance, 2018
2. [Power generation and cogeneration](https://task32.ieabioenergy.com/?p=4686) IEA Bioenergy Task 32 (Biomass Combustion)
3. [Biomass for Heat and Power, Technology Brief E05](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA-ETSAP_Tech_Brief_E05_Biomass-for-Heat-and-Power.pdf) IEA-ETSAP and IRENA, 2015
4. [Biomass CHP facilities (factsheet)](https://old.etipbioenergy.eu/images/ETIP_Bioenergy_Factsheet_Biomass_CHP_facilities.pdf) ETIP Bioenergy (European Technology and Innovation Platform)
5. [Review of the existing studies related to fuelwood and/or charcoal in Mozambique, section 3.2 Charcoal production](https://www.fao.org/4/x6796e/X6796E05.htm) FAO
6. [Fast pyrolysis: key points (table of product yields by pyrolysis mode)](https://task34.ieabioenergy.com/?p=4482) IEA Bioenergy Task 34 (Direct Thermochemical Liquefaction)
7. [Household air pollution: health risks](https://www.who.int/teams/environment-climate-change-and-health/air-quality-and-health/sectoral-interventions/household-air-pollution/health-risks) World Health Organization, 2024
8. [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](https://eur-lex.europa.eu/eli/dir/2018/2001/oj) European Union (EUR-Lex), 2018
9. [Renewable Power Generation Costs in 2025 (Executive summary, Figure S1)](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2026/Jul/IRENA_TEC_RPGC_in_2025_2026.pdf) IRENA, 2026
10. [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)](https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_annex-iii.pdf) IPCC, 2014

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_bio_combustion/index.md)
- [Overview](https://www.materialinsights.org/energy/e_bio_combustion/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_bio_combustion/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/e_bio_combustion/efficiency/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/e_bio_combustion/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_bio_combustion/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_bio_combustion/links/index.md)