Biomass Energy Output Calculator

Input Assumptions

Technology profile Solid biomass boiler with power and heat recovery.

Wet biomass feed rate (kg/h) Total incoming wet biomass mass flow.

Moisture content (%) Water fraction in the wet feedstock.

Ash content, dry basis (%) Non-combustible solids on dry mass basis.

Lower heating value, dry basis (MJ/kg) Usable fuel energy from dry combustible matter.

Electrical efficiency (%) Gross electric conversion before parasitic load.

Thermal recovery efficiency (%) Useful heat recovered from total thermal input.

Parasitic load (%) Internal consumption for fans, pumps, handling, and controls.

Plant availability (%) Expected uptime after planned and forced outages.

Operating hours per day Scheduled running hours each day.

Operating days per year Planned operation across the year.

Feedstock cost per wet ton Used for annual fuel cost estimation.

Electricity price per kWh Used for annual electricity revenue.

Useful heat price per kWh Used for heat revenue in CHP cases.

Grid emission factor (kg CO₂/kWh) Applied to net electric output for avoided emissions.

Example Data Table

Use this sample to test the calculator quickly.

Technology	Wet feed rate	Moisture	Ash	Dry LHV	Electric eff.	Thermal eff.	Parasitic	Availability
Combustion CHP	2500 kg/h	20%	3%	18 MJ/kg	24%	46%	8%	90%
Gasification CHP	1800 kg/h	15%	2%	17.5 MJ/kg	31%	38%	7%	92%
Anaerobic Digestion CHP	3200 kg/h	10%	1%	15 MJ/kg	36%	42%	6%	95%

Formula Used

1. Dry mass flow
Dry mass flow = Wet feed rate × (1 − Moisture fraction)

2. Combustible dry mass flow
Combustible dry mass flow = Dry mass flow × (1 − Ash fraction)

3. Thermal input
Thermal input (MJ/h) = Combustible dry mass flow × Dry basis LHV
Thermal input (kW) = Thermal input (MJ/h) ÷ 3.6

4. Gross electric output
Gross electric output = Thermal input (kW) × Electrical efficiency

5. Net electric output
Net electric output = Gross electric output × (1 − Parasitic load fraction)

6. Useful heat output
Useful heat output = Thermal input (kW) × Thermal recovery efficiency

7. Annual energy
Actual annual hours = Hours per day × Days per year × Availability
Annual electricity = Net electric output × Actual annual hours
Annual useful heat = Useful heat output × Actual annual hours

8. Avoided emissions
Avoided CO₂ (tons/year) = Annual electricity (kWh) × Grid emission factor ÷ 1000

How to Use This Calculator

Select a technology profile to preload reasonable efficiency values.
Enter the wet biomass feed rate in kilograms per hour.
Input moisture, ash, and dry basis heating value carefully.
Adjust electrical efficiency, heat recovery, and parasitic load.
Set uptime assumptions using hours, days, and availability.
Add cost, price, and grid emissions inputs for planning outputs.
Press Calculate Output to display results above the form.
Use the CSV and PDF buttons to export your results.

Frequently Asked Questions

1. What does this calculator estimate?

It estimates biomass thermal input, net electric power, useful heat, yearly energy production, fuel use, revenue potential, and avoided grid emissions.

2. Why does moisture reduce output?

Higher moisture lowers the dry combustible fraction. More incoming mass carries water instead of useful fuel, so available thermal energy drops.

3. Why is ash included separately?

Ash is non-combustible. It occupies part of the dry mass but adds almost no fuel value, so it reduces usable thermal input.

4. What is parasitic load?

Parasitic load is the power consumed internally by conveyors, pumps, fans, controls, and emissions systems before electricity reaches export.

5. Can this be used for CHP systems?

Yes. The calculator supports electricity-only and combined heat and power cases by separating electrical efficiency from thermal recovery efficiency.

6. Are the built-in technology values fixed?

No. The profile sets practical starting values, but you can overwrite the efficiency fields to match your actual design or vendor data.

7. What does avoided CO₂ mean here?

It represents grid emissions displaced by the calculated net electricity output, using the emission factor you provide.

8. Is this suitable for final plant design?

It is best for screening, comparison, and early feasibility work. Final design still needs detailed fuel testing, process modeling, and vendor validation.