Biomass combustion and CHP: Impact on the biosphere

The smoke behind millions of early deaths each year

What this tab covers Effects on human, animal, plant, fungal and microbial life and on whole ecosystems: in the short term (construction and early years), medium term (operating life) and long term (decommissioning and legacy).

The largest effect by far is on human health: smoke from household fires and stoves causes about 3.2 million premature deaths a year. Large-scale combustion's main ecological effect is the land needed to grow fuel.

Premature deaths from household air pollution about 3.2 million a year⁷ Deaths per TWh, biomass electricity (accidents and air pollution) 4.6¹⁷ People relying mainly on polluting fuels about 2.1 billion⁷ Land use, biomass electricity (median) 58,000 ha per TWh a year¹² Life-cycle emissions, dedicated biomass power 130-420 g CO2eq/kWh (median 230)¹⁰¹¹

Effects over time

Life affected	Short term	Medium term	Long term
Humans⁷¹⁷	Burns and scalds from open fires and unstable stoves, especially among children.	Household air pollution causes about 3.2 million premature deaths a year: 32% from ischaemic heart disease, 23% stroke, 21% lower respiratory infections, 19% COPD and 6% lung cancer, and almost half of pneumonia deaths in children under 5. For biomass power, accidents and air pollution cause about 4.6 deaths per TWh.	Switching to cleaner stoves or fuels removes the exposure; the disease burden falls over years as lungs and hearts recover.
Animals¹²	Habitat disturbance where forests are cut for fuel.	Little quantified evidence in the sources reviewed; effects depend on whether fuel comes from residues or standing forest.	Little evidence of effect where harvesting stays within regrowth.
Plants¹²	Removal of trees and shrubs around settlements and charcoal kilns.	Biomass grown for power uses a median 58,000 ha per TWh a year, the most of any electricity source studied.	Forests regrow if harvest stays within growth; otherwise woodland is degraded.
Fungi and soil life¹²	Little evidence of effect in the sources reviewed.	Little evidence of effect in the sources reviewed.	Little evidence of effect in the sources reviewed.
Ecosystems¹³⁸	Water drawn by fuel crops: biomass needs 70 to 400 times more water per unit of energy than other primary energy sources (excluding hydropower).	Carbon released on burning is reabsorbed only as replacement plants grow; for electricity, EU default values give forest-residue chips 87% savings (89% typical) but gas-heated pellets as little as 24% (37% typical).	Net climate benefit depends on regrowth and on whether residues would otherwise have rotted.

How the effects are reduced

The largest health gain is moving households from open fires to cleaner stoves or fuels (LPG, biogas, electricity); ISO/TR 19867-3 tiers rate stoves on efficiency, carbon monoxide and fine particles. Using residues rather than whole trees keeps land use near 130 rather than 58,000 ha per TWh a year. Powering pellet mills with wood-fired CHP instead of natural gas and grid power raises EU default savings for pellet electricity from 24% to 85%. Filters and electrostatic precipitators control particulates from larger boilers.

Sources

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
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
4E analysis of solar photovoltaic, wind, and hybrid power systems in southern Pakistan (Yousuf, Malik and Umair), Table 8 reproducing IPCC life-cycle emissions Science and Technology for Energy Transition (STET Review), 2024
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
Death rates per unit of electricity production (biomass figure from Markandya and Wilkinson, The Lancet 2007) Our World in Data, 2022