Maritime Energy Trading, LNG Cryogenics & Shipping Economics
LNG Carrier Boil-Off Gas (BOG), Heel & Delivered MMBtu Formula
Calculate LNG Carrier Voyage Boil-Off Gas Loss (m³ LNG), Arrival Tank Volume (m³), Net Discharged Cargo After Cryogenic Heel (m³), and Delivered Regasification Energy (MMBtu).
Compound daily Boil-Off Rate (1 - BOR)^Days—and deduct the -162°C ballast cooling heel!
Liquefied Natural Gas (LNG) is transported at atmospheric pressure near -162°C inside insulated membrane or spherical tanks. Ambient heat ingress continuously vaporizes a daily percentage of cargo—the Boil-Off Rate (BOR, ~0.08%–0.12%/day on modern 2-stroke ME-GI/X-DF vessels vs ~0.15%–0.18%/day on legacy steam carriers)—so Arrival Cargo Volume follows geometric decay V_arrival = V_loaded * (1 - BOR) ^ Voyage_Days! Furthermore, LNG charters cannot pump tanks dry at the regasification terminal: ~1.5% Cryogenic Heel (e.g., 2,500 m³) must remain aboard to spray-cool the tanks during the return ballast voyage!
Verify on a US Gulf-to-Europe Spot Cargo—Loaded_LNG_Volume = 170,000 m³ (B2), Charter_Daily_BOR = 0.0012 (0.12%/day, B3), Loaded_Voyage_Days = 15.0 days (B4), Retained_Cryogenic_Heel = 2,500 m³ (B5), and Cargo_Energy_Density = 22.50 MMBtu/m³ (B6): Voyage Boil-Off Gas equals 170,000 * (1 - (1 - 0.0012)^15) = 3,034.43 m³ LNG (E2), Arrival Volume is 166,965.57 m³ (E3), Net Unloaded Volume after Heel is 164,465.57 m³ (E4), and Delivered DES Energy hits 3,700,475.34 MMBtu (E5)!
| LNG Voyage Cargo KPI (170,000 m³ Loaded, 0.12%/d BOR, 15 Days, 2,500 m³ Heel) | Formula | Verified Output |
|---|---|---|
| Voyage Boil-Off Gas Loss (m³) | Loaded_m3 * (1 - (1 - BOR) ^ Days) | 3,034.43 m³ (4,532.61 @ 0.18%) |
| Arrival LNG Tank Volume (m³) | Loaded_m3 * ((1 - BOR) ^ Days) | 166,965.57 m³ |
| Net Discharged Volume (m³) | Arrival_Volume_m3 - Retained_Heel_m3 | 164,465.57 m³ |
| Delivered DES Cargo (MMBtu) | Net_Discharged_m3 * MMBtu_Per_m3 | 3,700,475.34 MMBtu |
Compounding Boil-Off Gas & Net Delivered MMBtu Formula
Validate Loaded_Volume > 10,000, Daily_BOR in (0, 0.01], Voyage_Days > 0, 0 <= Heel < Arrival_Volume, and Energy_Density in [18, 26]!
=LET(vl_0, B2, br_d, B3, dy_v, B4, hl_m, B5, ed_m, B6, IF(OR(vl_0 <= 10000, br_d <= 0, br_d > 0.01, dy_v <= 0, hl_m < 0, ed_m < 18, ed_m > 26), "Invalid LNG Cargo Input", LET(vl_a, vl_0 * ((1 - br_d) ^ dy_v), IF(hl_m >= vl_a, "Invalid LNG Cargo Input", ROUND((vl_a - hl_m) * ed_m, 2)))))Legacy Steam-Turbine Tanker Boil-Off Penalty Check (Set Daily BOR = 0.0018)
Increase Charter_Daily_BOR B3 from 0.0012 (0.12%/day) to 0.0018 (0.18%/day older steam vessel without reliquefaction): Voyage Boil-Off Loss E2 jumps from 3,034.43 m³ to 4,532.61 m³—burning an extra 1,498.18 m³ (~33,709 MMBtu) of LNG cargo in transit!
=IF(ISTEXT(E5), E5, ROUND(B2 * (1 - ((1 - B3) ^ B4)), 2))Try the example
Use the original values or change them to test your understanding.