OT_079: Residual Biomass Fuel Projections for NZ 2024 (Scion / IEA Bioenergy Task 43)

OT_079: Residual Biomass Fuel Projections for NZ 2024 (Scion / IEA Bioenergy Task 43)

Source

https://task43.ieabioenergy.com/publications/residual-biomass-fuel-projections-for-new-zealand-2024-indicative-availability-by-region-and-source-tr2024-03/ — original source (opens in a new tab; the file is not redistributed)

Summary

Scion / IEA Bioenergy Task 43 national assessment (Peter Hall, Scion; Oct 2024; PAD 92781397; publicly available; © NZ Forest Research Institute) of woody biomass residue resources in New Zealand by volume, type, energy content, region and over time (2024–2053, five-year steps). An update/expansion of Hall (2017, 2021). It quantifies ~13 residue streams, gives indicative delivered costs and a national cost-supply curve, fuel characteristics (moisture / ash / calorific value) and recoverability factors. Excludes new-forest and energy-crop (short-rotation coppice) potential — existing resources only. This is the primary Scion source behind the “7–8 Mt/yr residues available” figure carried into the wiki via OT_074, and the NZ delivered cost-supply curve behind the biomass fuel-cost figures in CR_028.

Key claims

• Long-run recoverable supply ≈ 7.3 Mt green tonnes/yr (recoverability level 1) at the mid-2030s low point; the report also frames this as “up to 7.6 Mt/yr mid-range” — the level-1 national total (Table 8) bottoms at 7,209,478 g.t./yr in 2034–2038 and rises to ~9.9 Mt by 2049–53. Excluding materials with an existing market (pulp logs, domestically-used and K-grade export logs, sawmill chip), genuinely-surplus fuel is ~3.5–4.1 Mt/yr. ⚠ the in-forest post-harvest stream is tabulated in m³/yr while other streams are green tonnes; the report sums them (green radiata ≈ 1 t/m³, so roughly interchangeable). OT_079
• In-forest post-harvest residues are the single largest stream (~2.35–3.84 Mt or m³/yr, level 1 over the period) and the most variable (driven by the 1990s planting boom age-class; harvest/residue low point ~2035–2039). Other streams (level-1, ~g.t./yr): sawmill-chip surplus ~569k, MWW ~236–343k, straw & stover ~295–325k, orchard ~122–134k, port bark ~228k, shelter belt ~82k, thinnings (production/waste) and prunings smaller. OT_079
• Delivered cost-supply curve (90 km delivery, 2024 cost inputs incl. 10% margin; indicative, not market price): cheapest streams are port bark 21/g.t. (3.04/GJ), shelter belt 36 (3.27/GJ), horticultural 26 (3.77/GJ), MWW 30 (4.35/GJ), wood-processing residue 48 (7.02/GJ); in-forest landings 85 (12.32/GJ) and cutover 94 (13.62/GJ); sawmill chip 108 (15.71/GJ); dearest are A-grade logs 117 (16.96/GJ), prunings 120 (17.39/GJ) and stumps 145 (21.07/GJ). ⚠ methods cite 2024 cost inputs but the results text states a January-2022 operating-cost basis (internal inconsistency). OT_079
• Fuel characteristics (Table 3): green in-forest residues ~51–57% moisture (wet basis), net calorific value ~6.8–7.7 GJ/green tonne; air-drying by stockpiling 3–4 months to ~35% moisture lifts NCV to ~11 GJ/t; municipal wood waste ~11.0 GJ/t (31.5% MC); straw 14.4 / stover 13.8 GJ/t (oven-dry basis); softwood typical ~18.7–18.9 MJ/kg oven-dry (radiata resin can reach 22–23). Corroborates CR_028’s GJ/t ≈ 19.2 − 0.2164 × MC relationship. OT_079
• Current use is tiny relative to the resource: ~260,000 green tonnes/yr known wood-fuel use by non-wood-processing heat plants >1 MWth (Table 7, “at least”; exec summary cites ~290,000 t/yr of residual woody resources used); the wood-processing industry separately consumes ~2.6 Mt green tonnes/yr across ~100 sites / 106 boilers / ~400 MWth. So nationally the residue resource is far from fully utilised. OT_079
• Regional concentration: in-forest residues are dominated by Bay of Plenty (~1.2–1.4 Mt/yr, far the largest), then Northland/Waikato/Gisborne/Hawke’s Bay etc.; orchard/viticulture residues concentrate in Hawke’s Bay, Gisborne, Marlborough, Tasman; straw & stover in Canterbury; Douglas-fir thinnings and SRF eucalyptus (~340k g.t./yr) in Otago & Southland. OT_079
• Use & recoverability constraints: recoverability level 1/level 2 factors discount gross volumes (e.g. in-forest landings 80%/65%, cutover 70%/55%, wood-processing 95%/90%, MWW 80%/60%, straw 70%/60%); 50% of straw is retained on-field for soil nutrition; cutover residues are partly retained for soil fertility/erosion; straws need purpose-built straw boilers (high ash, low ash-fusion temperature → fouling risk) or low-% co-firing; stumps carry soil-disturbance /erosion limits (steep land excluded, 1-in-4 removed). OT_079

Neobiome Intelligence relevance

• Confirms feedstock supply is not the binding national constraint for community biomass heat — primary Scion substantiation of the “7–8 Mt/yr” figure in OT_074. A community district-heating plant (biomass_district_heating, 1–5 MW) draws a tiny fraction of a ~7.3 Mt/yr recoverable resource against ~0.26 Mt/yr current non-processing use. The binding constraints are local airshed (NES-AQ), logistics (~50–100 km radius), and regional concentration — not national availability.
• Primary NZ delivered /GJ benchmark for the biomass fuel cell.** In-forest residue chip at **12–16/GJ (~4.4–5.8 c/kWh-fuel) corroborates CR_028’s 12.50–18/GJ, but cheaper residue streams (**bark / MWW / wood-processing residue at 3–7/GJ ≈ 1.1–2.5 c/kWh-fuel**) exist where locally available — refines the fuel-price assumption behind RT_247 with a primary source.
• Drying is a model lever: stockpiling residue 3–4 months (~57%→~35% MC) nearly doubles delivered energy density (~7→~11 GJ/t) — relevant to a community’s fuel-handling design.
• Regional biomass layer: availability is regionally concentrated, so for the coordinate-first engine biomass resource should be a regional input, not a national flat value (Appendices A–T hold per-region / per-TA tonnage and cost). See RT_268.

Research targets

Documents to retrieve

• (none — this report’s appendices A–T already hold the underlying regional/cost data in hand)

Research gaps

• RT_268 — regionalise OT_079’s Appendices A–T (per-region / per-TA residue tonnage, energy and delivered cost by stream) into a per-region biomass availability + delivered-cost layer for the NI engine, replacing the national flat figure. (D01, NI, nz_specific)

Connections

Links to

Sources (2): CR_028 · OT_074

Technologies (1): Biomass District Heating (Wood Chip)

Referenced by

Technologies (1): Biomass District Heating (Wood Chip)

EDT domains (1): D01: Renewable Energy & Storage Systems