Biomass: reported northern fuel prices (October 2026)

No public price index exists; DEDE lists buyers, not prices. Reported
market prices: fresh chips 1,350-1,800 THB/t (LH Bank, Mar 2026),
rubberwood firewood >1 THB/kg farm gate (OIE RIU 2026, doubled since late
2025), corn residue 2 THB/kg (Sunsweet, Mae Chaem), rice husk ~1.5 THB/kg,
pellets 3,000-5,000 THB/t. Planning price 1.35-2 THB/kg delivered, so the
mature fuel bill is ~0.6M-1.2M THB/yr (was 0.35M-0.8M): still a quarter
to a tenth of electric steam. Prices follow diesel; Ratch Pathana's Pa Sak
(Lamphun) buying centre is the local price-setter. Sources filed under
docs/finance/biomass/; sustainability.md and README follow.

docs/biomass.md

@@ -18,6 +18,9 @@ recovery architecture trimming the load and realistic duty cycles:
   efficiency and ~4 kWh/kg air-dry wood)
 - Early operations (one press line, single shift): roughly a quarter of
   that, **~90 to 100 t/yr**
+- Bought as fresh wood chips (~45 % moisture, ~2.6 kWh/kg) the same heat
+  is **~540 to 620 t/yr**, which is what the fuel store and the monsoon
+  stock have to be sized for (estimate)
 
 ## The 60 rai: own-grown fuelwood
 
@@ -32,7 +35,9 @@ about **80 to 135 t/yr**:
 
 That makes the land a meaningful supplement and a strong brand story
 ("records pressed with steam from our own trees"), not a complete fuel
-supply.
+supply. At the market prices below, 80 to 135 t of air-dry wood is worth
+only ~0.1M to 0.25M THB a year (estimate): the land's value is supply
+security and the story, not the fuel bill.
 
 ### The classification check comes first
 
@@ -62,6 +67,60 @@ The region fills the remainder easily and cheaply:
 - Buying from local farmers also strengthens the local-sourcing story that
   already runs through packaging and PVC
 
+## Fuel prices (market check, October 2026)
+
+There is no public price index for biomass fuel in northern Thailand. DEDE
+publishes lists of buyers and sellers (February 2026: 42 registered buyers
+wanting 2.09M t a year), not prices, so the figures below are reported
+market prices from bank research, a government industry unit and the
+press, all checked 7 October 2026. None is a quote to this plant.
+
+| Fuel | Reported price | Source | Heat cost (estimate) |
+|---|---|---|---|
+| Wood chips, fresh (45 to 50 % moisture) | 1,350 to 1,800 THB/t delivered | [LH Bank Research, wood pellet outlook](finance/biomass/LHBank_Wood_Pellets_Industry_Outlook_2026-03.pdf), 9 March 2026: 1,700 to 1,800 THB per fresh tonne for export; a power-plant chip quota in Nakhon Ratchasima at 1,350 THB/t, at most 45 % moisture (undated trader post) | ~0.65 to 0.85 THB/kWh |
+| Firewood and rubberwood offcuts, air-dry | over 1 THB/kg at the farm gate, up from 0.55 to 0.70 before late 2025 | [OIE Rubber Intelligence Unit](https://rubber.oie.go.th/Article.aspx?id=66365), 2026; southern rubber belt, so chipping and haulage to Lamphun come on top | ~0.3 to 0.5 THB/kWh before chipping and haulage |
+| Corn cobs and stalk residue | 2 THB/kg, bought from farmers in Mae Chaem (Chiang Mai) | Sunsweet's "no burning, we buy" programme, [Prachachat](https://www.prachachat.net/economic/local-economy/news-1498508), February 2024; an incentive price set to stop field burning | ~0.6 THB/kWh |
+| Rice husk | ~1.5 THB/kg at past demand peaks | [FTI renewable energy group](https://re-fti.org/%E0%B9%84%E0%B8%9F%E0%B8%9F%E0%B9%89%E0%B8%B2%E0%B8%8A%E0%B8%B5%E0%B8%A7%E0%B8%A1%E0%B8%A7%E0%B8%A5%E0%B8%A3%E0%B8%B0%E0%B8%AA%E0%B9%88%E0%B8%B3%E0%B8%A3%E0%B8%B2%E0%B8%84%E0%B8%B2%E0%B9%81%E0%B8%81%E0%B8%A5%E0%B8%9A%E0%B8%9E%E0%B8%B8%E0%B9%88%E0%B8%87/) (undated); power plants compete for it and northern milling volumes are small | ~0.5 THB/kWh |
+| Wood pellets, domestic | 3,000 to 5,000 THB/t | LH Bank Research, March 2026; export FOB averaged 4,482 THB/t in 2025 | ~0.75 to 1.25 THB/kWh |
+
+Heat cost assumes an 80 % boiler (85 % on pellets) and ~2.6 kWh/kg for
+fresh chips, ~4 for air-dry wood, ~4.2 for corn cobs, ~3.75 for rice husk
+and ~4.7 for pellets (estimates).
+
+What it means for the plan:
+
+- **Planning price: 1.35 to 2 THB/kg delivered**, which is ~0.5 to 0.9 THB
+  per kWh of heat. The earlier assumption of 1 to 2 THB/kg of air-dry wood
+  (~0.3 to 0.6 THB/kWh) was too low at the bottom: the cheap end is
+  farm-gate wood, not chipped fuel at the plant gate. At maturity the fuel
+  bill is **~0.6M to 1.2M THB a year** (~0.15M to 0.3M early), still a
+  quarter to a tenth of electric steam (see
+  [grid tariff](sustainability.md#grid-tariff-pea-and-what-it-decides))
+- **Prices are rising and follow diesel.** With diesel near 40 THB/L in
+  2026, chip traders feeding power plants parked trucks and cut purchases
+  ([Thai Post](https://www.thaipost.net/district-news/971839/), 30 March
+  2026), and rubberwood firewood roughly doubled since late 2025. Haulage
+  is a large share of a delivered tonne, so source within ~50 km and write
+  a diesel clause into the fuel contract rather than a fixed price
+- **Supply is not the constraint.** Lamphun alone produces more than
+  900,000 t of farm residues a year (Maejo University, via
+  [ThaiPublica](https://thaipublica.org/2026/08/lamphun-reduce-pm2-5-agricultural-waste-biomass-fuel/),
+  August 2026) against the plant's ~600 t. Buying them also counts against
+  the burning season, which is part of the story
+- **The local price-setter is in Mueang Lamphun.** Ratch Pathana's
+  [biomass buying centre](https://www.ratchpathana.com/th/our-businesses/related-and-other-businesses/biomass-business)
+  at Pa Sak, Mueang Lamphun, buys wood waste, sawdust and corn cobs from
+  farmers for Saha Cogen Green's 9.6 MW, 25 t/h steam cogeneration plant
+  in the Saha Group Lamphun industrial park. It is the reference price to
+  ask for and the main competitor for the same fuel. Further out, Clover
+  Power at Wang Chin (Phrae) buys chips, corn husks and cobs, and bamboo
+  ([DEDE buyer list](finance/biomass/DEDE_biomass_buyers_2026-02.pdf),
+  February 2026)
+- **Next step:** written quotes from the Pa Sak centre and two or three
+  chip suppliers within 50 km, priced by moisture content (an oven-dry
+  tonne carries roughly twice the heat of a fresh one), before the boiler
+  decision
+
 ## Logistics on site
 
 To reflect in the facility planning: a fuel storage shed (biomass
@@ -82,8 +141,8 @@ storage are additional.
 - The electric boiler remains the alternative: cleanest permitting, no fuel
   logistics, but effectively grid-powered steam at a ~300 kW draw. On
   PEA's time-of-use tariff that costs ~4.7M to 5.5M THB a year at mature
-  load against ~0.35M to 0.8M of fuel for biomass, and ~1.4M to 1.7M
-  against ~0.1M to 0.2M at early load, because the demand charge follows
+  load against ~0.6M to 1.2M of fuel for biomass, and ~1.4M to 1.7M
+  against ~0.15M to 0.3M at early load, because the demand charge follows
   the boiler's full-power draw (estimates; see the
   [grid tariff](sustainability.md#grid-tariff-pea-and-what-it-decides)).
   The electric boiler is the more efficient machine; biomass is the far
@@ -92,6 +151,6 @@ storage are additional.
   the coppice now (first harvest in 2 to 4 years), and add the biomass
   boiler at the automated-line expansion when demand and the fuel supply
   have both matured. At the tariff above that is a permitting and logistics
-  choice, not a cost one: every year on electric steam costs roughly 1.2M
-  to 5M THB more than biomass, so the switch should come as soon as the
+  choice, not a cost one: every year on electric steam costs roughly 1.1M
+  to 4.9M THB more than biomass, so the switch should come as soon as the
   permit and a fuel contract are in place

docs/sustainability.md

@@ -37,8 +37,9 @@ at 10 bar / 180 °C) and the 250 kW cooling system.
   abundant fuel); solar-thermal pre-heating of boiler feedwater was
   considered and is not recommended. No technology choice has been made
   yet; it will be driven by honest numbers on load profiles, storage, and
-  grid backup, not by what sounds greenest. At PEA's tariff, biomass heat
-  costs about a tenth of electric steam
+  grid backup, not by what sounds greenest. At PEA's tariff and current
+  northern fuel prices, biomass heat costs a quarter to a tenth of electric
+  steam
   ([grid tariff](#grid-tariff-pea-and-what-it-decides)).
 - Whole-factory HVAC (continuous temperature, humidity, and PM control, see
   [facility systems](facility-security.md)) adds a major tropical-climate
@@ -202,16 +203,16 @@ solar, 0.5M to 0.7M of it demand charge (estimate).
 
 | | Electric boiler (~98 %) | Biomass boiler (~80 %) |
 |---|---|---|
-| Price of heat | ~3.9 THB/kWh, plus the demand charge | ~0.3 to 0.6 THB/kWh at 1 to 2 THB/kg of fuel (fuel price not yet checked with local suppliers) |
-| Running cost, mature two shifts | **~4.7M to 5.5M THB/yr**: 1,140 to 1,310 MWh plus 200 to 300 kW of extra peak demand (0.3M to 0.5M) | **~0.35M to 0.8M THB/yr** of fuel, plus fuel handling and ash |
+| Price of heat | ~3.9 THB/kWh, plus the demand charge | ~0.5 to 0.9 THB/kWh at 1.35 to 2 THB/kg delivered ([reported market prices](biomass.md#fuel-prices-market-check-october-2026), October 2026; no supplier quote yet) |
+| Running cost, mature two shifts | **~4.7M to 5.5M THB/yr**: 1,140 to 1,310 MWh plus 200 to 300 kW of extra peak demand (0.3M to 0.5M) | **~0.6M to 1.2M THB/yr** of fuel, plus fuel handling and ash |
 | Boiler package ([utilities CSV](finance/utilities-investment.csv)) | 2.5M to 4M THB | 4M to 7M THB, plus the fuel store |
 | Grid | peak demand 600 to 750 kW: bigger transformer and deposit | unchanged |
 
 The electric boiler is the more efficient machine; biomass is by far the
-cheaper heat. At maturity the fuel saving of ~4M to 5M THB a year repays
-the biomass premium in about a year (estimate). Even early, at a quarter of
-the heat, electric steam costs ~1.4M to 1.7M THB a year against ~0.1M to
-0.2M of fuel, because the demand charge is set by the boiler's full-power
+cheaper heat. At maturity the fuel saving of ~3.5M to 4.9M THB a year
+repays the biomass premium in under a year (estimate). Even early, at a
+quarter of the heat, electric steam costs ~1.4M to 1.7M THB a year against
+~0.15M to 0.3M of fuel, because the demand charge is set by the boiler's full-power
 draw, not by its average. Moving electric steam to off-peak hours barely
 helps: the presses need steam while they run, and the peak window covers
 13 of the 16 production hours. The staged electric-first path in