Biomass as an Energy Source
Environmental Engineering · FE Reference Handbook section
Handbook notes for this section
Definitions and conditions exactly as the handbook states them.
- Some, but not all, possible combinations of inputs and processes:
- CELLULOSIC PLANT MATERIAL GASEOUS
- OILY PLANT MATERIAL FUEL
- KEY: PHYSICAL PROCESSES CHEMICAL/THERMAL PROCESSES BIOCHEMICAL PROCESSES
Core formulas for this FE topic
Definitions, applicability, units, assumptions and worked examples for each relation.
This section is conceptual; there are no equations to memorise.
Worked exam-style examples
The four ways this section is written on the real exam — thoughts first, then equations, then substitution.
biomass as an energy source for a waste-to-energy power plant Given biomass mass processed (m) = 17,750 kg/day; higher heating value of biomass (HHV) = 10,180 kJ/kg; conversion efficiency (eta) = 0.5000, determine the usable energy output (E) in kJ/day.
Given
Find
usable energy output (E), in kJ/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except E is given, so isolate E symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 1 — schematic for Biomass as an Energy Source — solve for usable energy output — Biomass as an Energy Source
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for E:
Step 3 — List the givens: biomass mass processed (m) = 17,750 kg/day, higher heating value of biomass (HHV) = 10,180 kJ/kg, conversion efficiency (eta) = 0.5000.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning E = 90,347,500 kJ/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 180,695,000 — kept a factor of two that cancels in the correct rearrangement.
- 45,173,750 — dropped that same factor in the other direction.
- 99,382,250 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source conversion efficiency calculation Given higher heating value of biomass (HHV) = 13,920 kJ/kg; conversion efficiency (eta) = 0.4700; usable energy output (E) = 529,056,000 kJ/day, determine the biomass mass processed (m) in kg/day.
Given
Find
biomass mass processed (m), in kg/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except m is given, so isolate m symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 2 — schematic for Biomass as an Energy Source — solve for biomass mass processed — Biomass as an Energy Source (2)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for m:
Step 3 — List the givens: higher heating value of biomass (HHV) = 13,920 kJ/kg, conversion efficiency (eta) = 0.4700, usable energy output (E) = 529,056,000 kJ/day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning m = 80,866 kg/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 161,731 — kept a factor of two that cancels in the correct rearrangement.
- 40,433 — dropped that same factor in the other direction.
- 88,952 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source from agricultural waste feedstock Given biomass mass processed (m) = 14,860 kg/day; higher heating value of biomass (HHV) = 19,540 kJ/kg; usable energy output (E) = 778,023,000 kJ/day, determine the conversion efficiency (eta).
Given
Find
conversion efficiency (eta)
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except eta is given, so isolate eta symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 3 — schematic for Biomass as an Energy Source — solve for conversion efficiency — Biomass as an Energy Source (3)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for eta:
Step 3 — List the givens: biomass mass processed (m) = 14,860 kg/day, higher heating value of biomass (HHV) = 19,540 kJ/kg, usable energy output (E) = 778,023,000 kJ/day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning eta = 2.6795 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 5.3589 — kept a factor of two that cancels in the correct rearrangement.
- 1.3397 — dropped that same factor in the other direction.
- 2.9474 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source for a waste-to-energy power plant Given biomass mass processed (m) = 90,200 kg/day; higher heating value of biomass (HHV) = 10,120 kJ/kg; conversion efficiency (eta) = 0.5400, determine the usable energy output (E) in kJ/day.
Given
Find
usable energy output (E), in kJ/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except E is given, so isolate E symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 4 — schematic for Biomass as an Energy Source — solve for usable energy output (case 2) — Biomass as an Energy Source (4)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for E:
Step 3 — List the givens: biomass mass processed (m) = 90,200 kg/day, higher heating value of biomass (HHV) = 10,120 kJ/kg, conversion efficiency (eta) = 0.5400.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning E = 492,924,960 kJ/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 985,849,920 — kept a factor of two that cancels in the correct rearrangement.
- 246,462,480 — dropped that same factor in the other direction.
- 542,217,456 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source conversion efficiency calculation Given higher heating value of biomass (HHV) = 10,990 kJ/kg; conversion efficiency (eta) = 0.2600; usable energy output (E) = 160,678,000 kJ/day, determine the biomass mass processed (m) in kg/day.
Given
Find
biomass mass processed (m), in kg/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except m is given, so isolate m symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 5 — schematic for Biomass as an Energy Source — solve for biomass mass processed (case 2) — Biomass as an Energy Source (5)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for m:
Step 3 — List the givens: higher heating value of biomass (HHV) = 10,990 kJ/kg, conversion efficiency (eta) = 0.2600, usable energy output (E) = 160,678,000 kJ/day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning m = 56,232 kg/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 112,464 — kept a factor of two that cancels in the correct rearrangement.
- 28,116 — dropped that same factor in the other direction.
- 61,855 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source from agricultural waste feedstock Given biomass mass processed (m) = 75,350 kg/day; higher heating value of biomass (HHV) = 10,380 kJ/kg; usable energy output (E) = 927,281,000 kJ/day, determine the conversion efficiency (eta).
Given
Find
conversion efficiency (eta)
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except eta is given, so isolate eta symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 6 — schematic for Biomass as an Energy Source — solve for conversion efficiency (case 2) — Biomass as an Energy Source (6)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for eta:
Step 3 — List the givens: biomass mass processed (m) = 75,350 kg/day, higher heating value of biomass (HHV) = 10,380 kJ/kg, usable energy output (E) = 927,281,000 kJ/day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning eta = 1.1856 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 2.3712 — kept a factor of two that cancels in the correct rearrangement.
- 0.5928 — dropped that same factor in the other direction.
- 1.3041 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source for a waste-to-energy power plant Given biomass mass processed (m) = 90,310 kg/day; higher heating value of biomass (HHV) = 12,590 kJ/kg; conversion efficiency (eta) = 0.4300, determine the usable energy output (E) in kJ/day.
Given
Find
usable energy output (E), in kJ/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except E is given, so isolate E symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 7 — schematic for Biomass as an Energy Source — solve for usable energy output (case 3) — Biomass as an Energy Source (7)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for E:
Step 3 — List the givens: biomass mass processed (m) = 90,310 kg/day, higher heating value of biomass (HHV) = 12,590 kJ/kg, conversion efficiency (eta) = 0.4300.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning E = 488,911,247 kJ/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 977,822,494 — kept a factor of two that cancels in the correct rearrangement.
- 244,455,624 — dropped that same factor in the other direction.
- 537,802,372 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source conversion efficiency calculation Given higher heating value of biomass (HHV) = 12,460 kJ/kg; conversion efficiency (eta) = 0.3300; usable energy output (E) = 768,394,000 kJ/day, determine the biomass mass processed (m) in kg/day.
Given
Find
biomass mass processed (m), in kg/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except m is given, so isolate m symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 8 — schematic for Biomass as an Energy Source — solve for biomass mass processed (case 3) — Biomass as an Energy Source (8)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for m:
Step 3 — List the givens: higher heating value of biomass (HHV) = 12,460 kJ/kg, conversion efficiency (eta) = 0.3300, usable energy output (E) = 768,394,000 kJ/day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning m = 186,875 kg/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 373,751 — kept a factor of two that cancels in the correct rearrangement.
- 93,438 — dropped that same factor in the other direction.
- 205,563 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source from agricultural waste feedstock Given biomass mass processed (m) = 22,820 kg/day; higher heating value of biomass (HHV) = 11,500 kJ/kg; usable energy output (E) = 236,882,000 kJ/day, determine the conversion efficiency (eta).
Given
Find
conversion efficiency (eta)
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except eta is given, so isolate eta symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 9 — schematic for Biomass as an Energy Source — solve for conversion efficiency (case 3) — Biomass as an Energy Source (9)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for eta:
Step 3 — List the givens: biomass mass processed (m) = 22,820 kg/day, higher heating value of biomass (HHV) = 11,500 kJ/kg, usable energy output (E) = 236,882,000 kJ/day.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning eta = 0.9026 to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 1.8053 — kept a factor of two that cancels in the correct rearrangement.
- 0.4513 — dropped that same factor in the other direction.
- 0.9929 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source
biomass as an energy source for a waste-to-energy power plant Given biomass mass processed (m) = 3,000 kg/day; higher heating value of biomass (HHV) = 15,810 kJ/kg; conversion efficiency (eta) = 0.2500, determine the usable energy output (E) in kJ/day.
Given
Find
usable energy output (E), in kJ/day
Start with the thinking
- The governing relation printed in this handbook section is Biomass as an Energy Source.
- Everything except E is given, so isolate E symbolically first — never rearrange after the numbers are in.
- Tabulate each given with its unit and confirm the units are consistent with the relation before substituting.
- Biomass as an energy source converts the chemical energy of organic feedstock into usable energy at a given conversion efficiency.
Figure 10 — schematic for Biomass as an Energy Source — solve for usable energy output (case 4) — Biomass as an Energy Source (10)
Step-by-step solution
Step 1 — State the governing relation:
Step 2 — Rearrange symbolically for E:
Step 3 — List the givens: biomass mass processed (m) = 3,000 kg/day, higher heating value of biomass (HHV) = 15,810 kJ/kg, conversion efficiency (eta) = 0.2500.
Step 4 — Substitute the given values:
Step 5 — Evaluate:
Step 6 — Check: returning E = 11,857,500 kJ/day to
reproduces the given quantities, and both sides carry the same units.
Why the other options are there
- 23,715,000 — kept a factor of two that cancels in the correct rearrangement.
- 5,928,750 — dropped that same factor in the other direction.
- 13,043,250 — rounded an intermediate value before the final step.
Reference: FE Handbook — Biomass as an Energy Source