Work

Biomass ash from combined heat and power plants as a sustainable soil amendment for the United Kingdom agriculture

Year: 2026

Type: article

Abstract: Combined heat and power (CHP) plants generate around 65,000 tonnes of biomass combustion ash in the UK each year, with an estimated 52,000 tonnes of this being landfilled at a significant cost and environmental impact. This paper comprises a critical literature review and a detailed techno-economic evaluation to assess the potential of biomass ash from CHP plants as a soil amendment and partial fertiliser supplement for winter wheat ( Triticum aestivum L.) in UK agriculture. The review summarises published information on biomass ash characterisation, elemental composition, heavy metal concentrations, and the effects of thermal calcination (400–800 °C) on nutrient availability and heavy metal immobilisation. Key findings include that calcined biomass ash can be used as a liming agent or a source of secondary macronutrients (Ca, Mg, K, and P), but cannot be used as a complete NPK substitute due to high levels of near-total nitrogen volatilisation during combustion. A full-scale commercial techno-economic model (20 years, 8% WACC) confirms that, under base-case assumptions, the project is financially viable (pre-Quality Protocol) at + £7.4 M (Scenario A) and + £24.1 M (Scenario B) after regulatory reclassification. The main commercial barriers identified are the absence of a UK Quality Protocol for biomass combustion ash, compliance requirements under SI 1989/1263, PTE threshold limits, and end-of-waste legislation. All quantitative data are presented as preliminary estimates that must be confirmed through multi-location field trials, soil incubation studies, and site-specific engineering evaluations.

Source: Discover Sustainability

DOI: 10.1007/s43621-026-04450-9