Energy Trends: March 2026, special feature article - Review of solid biomass classifications

Good — I have the full text. Now I can write a properly grounded memo.

What this is about

DESNZ is proposing to reclassify how solid biomass is categorised in UK energy statistics, specifically in DUKES Table 6.1. The current system uses three categories — wood, waste wood, and plant biomass — but classifies partly by end-user rather than by actual feedstock. Domestic biomass gets called "wood" regardless of what it is; non-domestic gets called "waste wood." Plant biomass is a catch-all that lumps wood pellets together with sewage sludge.

This matters because the classification determines what counts as renewable generation in headline statistics. Drax Power Station burns imported wood pellets at scale under the Renewables Obligation. If pellets move to their own category — separate from "wood" — it becomes easier to scrutinise how much of the UK's claimed renewable electricity share depends on a single plant burning a single fuel. The proposed changes also create an "other solid biofuels" category for post-consumer waste wood and biomass of unknown origin, drawing a line between virgin wood and material that has already had a prior non-energy use.

Key points

Four categories replace three. DESNZ proposes moving from wood / waste wood / plant biomass to:

- Wood — virgin fuel wood, logging residues, solid wood processing residues - Non-woody biomass — energy crops, straw, bagasse, black liquor, oil plant residues, husks, shells - Pellets and briquettes — wood pellets and other biomass pellets, now tracked separately - Other solid biofuels — post-consumer waste wood and biomass of unknown origin

The driver is international alignment. The UN Statistics Division consulted in 2025 on revising its Standard International Energy Products Classification (SIEC). The draft introduces an "other solid biomass" category distinguishing post-consumer waste wood from virgin wood. DESNZ is adapting the SIEC framework rather than adopting it wholesale, aggregating by feedstock where full SIEC granularity is impracticable for UK data.

Better data now exists. Recent Defra domestic combustion surveys show that only about 75% of domestic solid biofuel is actually wood. The rest is pellets and post-consumer waste wood. The old convention of classifying all domestic consumption as "wood" overstated virgin wood use.

Indicative impact on 2024 data. Using reference year 2024, the reclassification shifts some numbers:

- Industrial consumption falls as previously "unclassified" volumes are reallocated across sectors, particularly to agriculture. - A proportion of domestic consumption moves to "other solid biofuels" because the Defra survey does not distinguish wood residues from post-consumer waste wood. - Total biomass consumption falls slightly after a deeper review removed some historical double-counting.

The pellets breakout is the significant move. Separating pellets and briquettes into their own category means Drax's fuel — imported wood pellets — will be visible as a distinct line in the national energy balance. Currently it is subsumed within "plant biomass" alongside genuinely different feedstocks. This does not change whether Drax counts as renewable (that is a policy and subsidy question, not a statistical one), but it makes the composition of the renewables share more transparent.

Post-consumer waste wood gets separated from virgin wood. This distinction matters for sustainability accounting. Virgin wood harvested for energy and waste wood diverted from landfill have different carbon and resource implications. Tracking them separately aligns with the direction of sustainability criteria under the Renewables Obligation and any successor framework.

What happens next

Feedback window is open now. DESNZ invites responses to renewablesstatistics@energysecurity.gov.uk on the scope of the fuel classifications and feedstock inclusions. No formal closing date is stated in the article, but the implementation target is tight.

Target implementation: DUKES July 2026. DESNZ is considering applying the new categories in the July 2026 edition of the Digest of UK Energy Statistics. If adopted on that timeline, the reclassified data would become the reference for all subsequent energy statistics reporting, including Energy Trends quarterly updates.

Watch for the renewables share restatement. Any reclassification that moves volumes between categories — even without changing totals — will alter the compositional breakdown of renewables in DUKES 6.1. Analysts and policymakers who cite "biomass share of renewables" will need to note the methodological break. DESNZ should publish a bridging table showing old and new classifications side by side for at least one reference year.

No policy change, but increased scrutiny. This is a statistical exercise, not a policy intervention. But making pellet-fired generation visible as a distinct category removes a layer of aggregation that has historically made it harder to interrogate the UK's reliance on imported biomass for its renewables target. The political and subsidy debate around Drax will have cleaner data to work with.