Small-scale wood gasification CHP: LCOE with heat and biochar credits

Zero, used in guards and credit signs.

Market range Exact.

Unity, used in the CRF and share complements.

Market range Exact.

Protects divisions by a quantity that can reach zero.

Market range Not applicable (numerical parameter).

Converts a percent to a fraction.

Market range Exact.

Converts a fraction to a percent.

Market range Exact.

Upper limit of the full-load hours.

Market range 8760 (8784 in a leap year).

kWh to MWh.

Market range Exact.

USD/kWh to USD/MWh, for the IRENA reference range.

Market range Exact.

Identifier of the reference case 'SynCraft Typ 500 (CW1800-500) datasheet'.

Market range Not applicable.

Identifier of the reference case 'Hargassner KWK 60/20 prospectus'.

Market range Not applicable.

Identifier of the reference case 'C.A.R.M.E.N. measured annual efficiencies, 20-50 kWel plants'.

Market range Not applicable.

Default size of the calculator: the fuel heat input of the SynCraft Typ 500, a catalogue product.

Market range Catalogue range: 85 kW (Hargassner KWK 60/20) to 3527 kW (SynCraft Typ 1000).

Gross electrical efficiency of the SynCraft Typ 500 reference case (printed electric output over printed fuel heat input).

Market range 23.5 % (Hargassner KWK 60/20 prospectus) to 30 % (SynCraft company page); 25 % measured annual average for 20-50 kWel plants (C.A.R.M.E.N. 2022).

Electrical efficiency of the Hargassner KWK 60/20 reference case, the smallest unit in the catalogue.

Market range Lowest printed electrical efficiency among the reference units.

Upper end of the electrical efficiency claimed by a vendor, shown as a reference next to the case value.

Market range Vendor claim, not a measured annual value.

Measured annual electrical efficiency of small wood-gas CHP plants, the 'measured' reference case.

Market range Annual average of a fleet of 20-50 kWel plants; datasheet values are higher.

Thermal efficiency of the SynCraft Typ 500 case, including the optional ~50 C low-temperature package.

Market range 53 % measured annual (C.A.R.M.E.N. 2022) to 71.8 % printed (Hargassner).

Thermal efficiency of the Hargassner KWK 60/20 reference case.

Market range Highest printed thermal efficiency among the reference units.

Measured annual thermal efficiency of the 'measured' reference case.

Market range Annual fleet average of 20-50 kWel plants.

Printed overall efficiency (electric + thermal) of the Hargassner KWK 60/20: the highest printed total, a ceiling for electric plus thermal.

Market range Datasheet value; measured annual totals are lower (78 %, C.A.R.M.E.N.).

Printed overall efficiency of the Froling CHP, a benchmark for the overall efficiency output.

Market range Datasheet value.

Overall efficiency reported for the Ternitz plant; it includes the energy in the biochar, which this calculator does not count, so it sits above the model's electric plus heat figure.

Market range Includes biochar energy: not the same boundary as overall_efficiency_pct.

Austrian subsidy threshold on the annual overall efficiency, a benchmark for the overall efficiency output.

Market range Eligibility threshold, not a performance figure.

Share of the gross electricity used by the plant itself (gasifier, gas cleaning, conveyors, fans). Derived from a single plant and applied to all three reference cases; the vendor sheets do not say whether their printed efficiency is gross or net, so it is treated as gross.

Market range Single-plant figure (< 40 kWel on ~500 kWel); no independent range cited.

Lower heating value of the dry wood that the fuel heat input is counted on. 1 kWh/kg equals 1 MWh/t, so the yearly fuel energy in MWh divided by this value gives dry tonnes.

Market range Two vendor datasheets agree at 5.0; no independent range cited.

Printed specific dry fuel need of the SynCraft Typ 1000. Shown next to the model's figure as a consistency check only: the model's value comes from the same datasheets (efficiency and dry LHV), so agreement is expected and is not an independent validation.

Highest moisture a downdraft gasifier accepts; wood bought wetter must be dried to this level with the plant's own heat.

Market range Fixed-bed gasifiers commonly need W10-W15.

Moisture at which the reference wood-chip price is quoted, the default of the moisture input.

Market range TFZ also quotes W20.

Thermodynamic floor of the heat needed to evaporate the water removed in drying; a real dryer needs more (sensible heat, air losses).

Market range Real belt dryers use roughly 1.1-1.5 times this floor; no independent range cited.

Biochar mass yield per dry feed, applied to the SynCraft case only (floating fixed-bed staged gasifier built to co-produce char). It is a generic gasification figure, not specific to SynCraft; Huber 2022 economics imply about 7 % (derived).

Market range About 7 % implied by Huber 2022 economics (derived); 10 % generic.

All-in specific investment per kW of gross electric power: fuel logistics, dryer, screening, gasifier and engine, buffer, transformer and building. Also matches the 6000 EUR/kWel total plant cost for a 200 kWel gas-engine plant (Swedish Energy Agency 2011, Table 7.22).

Market range 5000 (CMD ECO20 2017; Shingu 2019) to 8750 EUR/kWe (Ternitz 2022, all-in).

Floor of the model's specific CAPEX clamp: the lowest sourced specific cost, found at both ends of the size range.

Market range Lowest of the sourced points.

Ceiling of the model's specific CAPEX clamp: the highest sourced specific cost (Ternitz, all-in with infrastructure).

Market range Highest of the sourced points.

Gross electric power of the plant behind the 6000 EUR/kWe anchor: the reference size of the cost law.

Market range Not applicable (reference size).

Exponent 1: no economy of scale is applied. The sourced plants show no economy of scale between 20 kWe and 1.6 MWe (5000 EUR/kWe at both 20 kWe and 1.6 MWe, 6000-8750 in between); the scatter is a matter of scope (infrastructure, dryer, building) rather than size. Larger SynCraft plants are built by numbering-up identical CW1800 gasifier-engine modules (Shingu: 4 x CW1800-400), so cost scales linearly with module count. Below 20 kWe (fuel input under ~80 kW) and above 1.6 MWe (fuel input over ~5.5 MW) no source exists.

Market range Specific cost 5000-8750 EUR/kWe with no trend in size.

Investment of the 20 kWe CMD ECO20 micro-CHP: small-end cost point.

Market range Single point.

Electric power of the CMD ECO20.

Market range Not applicable.

All-in investment of the 400 kWe Ternitz plant.

Market range Single point.

Electric power of the Ternitz plant.

Market range Not applicable.

Investment of the ~500 kWe South Tyrol plant.

Market range Single point.

Gross electric power of the Greiler plant.

Market range Not applicable.

Contract value of the 1.6 MWe Shingu plant: large-end cost point.

Market range Single point, press figure.

Electric power of the Shingu plant.

Market range Not applicable.

Total plant cost per kWel of a 200 kWel gas-engine gasification plant.

Market range Single point.

Low end of the IRENA installed cost range for gasifier CHP, USD 2010; shown for context, not converted.

High end of the IRENA installed cost range for gasifier CHP, USD 2010; shown for context, not converted.

Yearly upkeep of the non-engine parts as a share of the total investment.

Market range No independent range cited.

Full-service maintenance contract of the gas engine, per operating hour, for the 350 kWel enpro example.

Market range 7 (minimum) to 9 EUR/h (full-service contract), same source.

Vendor O&M figure per kWh of electricity, shown next to the model's O&M per MWh.

Market range Vendor benchmark.

Default full-load hours a year.

Market range 7537 h measured on 20-50 kWel plants (C.A.R.M.E.N.); 8333 h at Ternitz in 2021; 4000 h subsidy minimum (UFI).

Measured full-load hours of 20-50 kWel plants in 2017.

Market range Fleet average.

Operating hours of the Ternitz plant in 2021, the upper reference of the usage lever.

Market range Single plant, single year.

Subsidy minimum on full-load hours, the lower end of the usage lever.

Market range Eligibility threshold.

Default share of the produced heat that is sold. The unsold 20 % covers, among others, the drying of wet wood chips to the gasifier's moisture limit.

Market range Eligibility threshold, used as default; real shares depend on the heat customer.

Default price of the heat sold.

Market range 40 (SynCraft 2022) to 45 EUR/MWh (enpro guide value).

Second heat price guide value.

Default wood-chip price at 35 % moisture, as delivered.

Market range 108 EUR/t at W35, 159 EUR/t at W20 (same source).

Same W35 price per kWh of as-received fuel (LHV of the wet chips), shown for context; the model counts the fuel bill in tonnes.

Price of drier chips (W20), the reference to use when the moisture input is lowered.

Market range Same source as W35.

W20 price per kWh of as-received fuel, context only.

Market range Same source.

Default biochar price.

Market range 200 (soil use) to 1000 EUR/t (BBQ / premium), same author.

Top of the biochar price range, the slider maximum.

Market range Premium market.

Default discount rate of the CRF (real, constant-money basis as in IRENA).

Default economic lifetime; also the service life exported to project mode.

Vendor power cost after heat and biochar credits, same method as this calculator but at 90 EUR/t fuel, cheaper financing and 3 ct/kWh O&M: a low reference, not a target.

Market range Vendor benchmark; IRENA 2012 gives 110-280 USD2010/MWh.

Low end of the IRENA gasifier CHP LCOE range (USD 2010, heat credited).

High end of the IRENA gasifier CHP LCOE range (USD 2010, heat credited).

LCOE with credits, IRENA 2012 method: yearly cost (annualised CAPEX + fixed O&M + engine maintenance + fuel) minus the heat sold times the heat price minus the biochar times its price, divided by the net electricity. Same decomposition as Huber/SynCraft 2022 (investment + financing + O&M + fuel - heat yield - biochar yield = power cost).

Market range Not applicable.

The size slider runs from 80 to 5000 kW of fuel. Cost sources cover 20 kWe (about 80 kW of fuel) to 1.6 MWe (about 5.8 MW of fuel at 27.7 %): below 80 kW no cost source exists, and the specific cost is held constant across the range, not extrapolated from a trend.

Market range Not applicable.

Operating labour is NOT included. C.A.R.M.E.N. 2022 reports 0.9 h of work per MWh of electricity on 20-50 kWel plants, but no labour rate is sourced here, so no cost is put on it; add it in project mode if staff are paid.

Market range Not applicable.

Costs come from sources dated 2011 to 2026 and are used as published, without escalation, in constant euros; the discount rate is therefore read as a real rate. IRENA figures in USD 2010 are shown for context only and are not converted or compared numerically.

Market range Not applicable.

The plausibility band of the LCOE, 80 to 400 EUR/MWh, covers the reference case and every single-lever sweep from it. Pushing all sliders to their favourable ends together (8500 h, 3 % rate, cheap dry wood, all heat sold at 50 EUR/MWh, biochar at 600 EUR/t) gives about 19 EUR/MWh; pushing them all to their unfavourable ends (4000 h, 12 %, 160 EUR/t, half the heat sold at no value) gives about 545 EUR/MWh. Both are arithmetic corners of the slider box, not observed plants.

Market range Not applicable.

The heat credit allocation strongly moves the LCOE (IRENA 2012), so both the heat price and the share of heat sold are inputs. The unsold heat covers the drying of wet chips; the calculator shows the thermodynamic floor of that drying need and any shortfall.

Market range Not applicable.

Biochar is credited only in the SynCraft case, whose staged floating fixed-bed gasifier is designed to discharge char. The Hargassner prospectus and the C.A.R.M.E.N. evaluation print no char output, so none is credited there. The energy left in the char is not counted in the overall efficiency.

Market range Not applicable.