Biomass steam in both plans, PV on the factory roof only

User, 17 Oct 2026: "only put solar on the factory, prepare the other
buildings for solar, option a and b should operate on biomass".

- Steam: two 500 kg/h biomass modules (Getabec class, 6M to 10M THB) plus
  a fuel store and handling block (1M to 2M, estimate) in both plans; the
  electric bank becomes the alternative. ~0.67M THB of fuel a year against
  ~4.9M for electric steam; grid demand ~264 kW instead of ~980 kW.
- Solar: ~520 kWp on the factory roof (the biomass-case optimum is ~500 to
  550 kWp, hourly sketch in sustainability.md "PV size with biomass
  steam"); office roof and parking canopies built PV-ready (~120 kWp
  later). ~87 % used on site, ~61 % of the plant's electricity.
- Calculator: biomass default, bFuel row, pvKWp 520, pvSelf 87, iso fills
  the factory roof first and shows the other roofs as PV-ready.
- Numbers: launch plant ~168M / 232M / 296M with contingency; Plan A
  ~182M (~2M above 180M: the Chinese-route lever priced only electric
  boilers; a Chinese biomass quote is the way back), Plan B ~217M (label
  ~215M), ~35M more. Calculator EBITDA A 2.17M, B 2.23M USD.
- CSV, total-investment, revenue-model, sustainability, scale, biomass,
  site-candidates, boi, steam-cooling, construction RFQ (canopies
  PV-ready), README, roadmap; business plan draft 0.3 rebuilt (A and B
  63 pages) with new renders.

docs/scale.md

@@ -298,19 +298,20 @@ small against the connection, but its own feeder and meter.
   roof plane, per the [construction RFQ](finance/phase1-construction-rfq.md)).
   This supersedes the older rule of thumb of 150 to 200 kWp on a
   ~1,500 m² building, which the massing model has overtaken
-- **Decided 17 October 2026: every roof and canopy carries PV.** On this
-  hall that is the 247 kWp roof plus the canopies' ~40 to 54 kWp, ~300
-  kWp; on the Payap scenario plot ~640 kWp, the size the investment and
-  the business plan carry
+- **Decided 17 October 2026: PV on the factory roof only, the other
+  buildings PV-ready, biomass steam.** On this hall that is the 247 kWp
+  roof (canopies PV-ready); on the Payap scenario plot ~520 kWp, the size
+  the investment and the business plan carry, about the ~500 to 550 kWp
+  optimum for a biomass-steam load
   ([sustainability](sustainability.md#roof-design-for-pv-candidate-mueang-chi-site))
 - Northern Thailand yield ~1,400 to 1,500 kWh/kWp/yr, so 300 kWp produces
-  roughly **420 to 450 MWh/yr** and ~640 kWp ~900 to 960 MWh/yr
+  roughly **420 to 450 MWh/yr** and ~520 kWp ~730 to 780 MWh/yr
 - Plant consumption at mature two-shift operation: roughly **1,000 to
   1,500 MWh/yr** without electric steam, up to **~2,500 MWh/yr** with it
   (estimate), so 300 kWp covers roughly **28 to 45%** of consumption
-  without electric steam, falling to **~17%** with it; ~640 kWp, at
-  ~85 % used on site under zero export, covers ~38 % of the launch
-  plant's ~2,000 MWh with electric steam (calculator, estimate)
+  without electric steam, falling to **~17%** with it; ~520 kWp, at
+  ~87 % used on site under zero export, covers ~61 % of the launch
+  plant's ~1,036 MWh with biomass steam (calculator, estimate)
 - Battery: **271 kWh** Gobel stack (ride-through, roughly
   an hour of the chiller bank's peak electrical draw; peak shaving earns
   little under PEA's time-of-use tariff, see