ESCO Combined Heat and Power (Cogeneration) 2

Question 1

Under FERC's PURPA rules, a natural-gas topping-cycle qualifying facility must have useful thermal output equal to at least what share of its total energy output?

Accepted Answer

5%

Answer

FERC's operating standard requires useful thermal output to be at least 5% of total energy output for topping-cycle QFs.

Question 2

A CHP generator has an electric heat rate of 10,000 Btu/kWh (HHV). What is its approximate electrical efficiency?

Accepted Answer

34%

Answer

Efficiency = 3,412 Btu/kWh ÷ 10,000 Btu/kWh ≈ 34%.

Question 3

A CHP system burns 100 MMBtu of fuel and produces 30 MMBtu of electricity plus 45 MMBtu of useful heat. What is its total system efficiency?

Accepted Answer

75%

Answer

Total efficiency = (30 + 45) ÷ 100 = 75%.

Question 4

Which CHP metric credits the system for the boiler fuel it displaces and expresses the result as an equivalent power-only efficiency?

Accepted Answer

Effective electrical efficiency

Answer

Effective electrical efficiency subtracts displaced boiler fuel from fuel input before dividing it into electric output.

Question 5

In CHP project screening, what does the term 'spark spread' mean?

Accepted Answer

The difference between the value of electricity and the cost of fuel to generate it

Answer

A wide spark spread (high power prices, cheap gas) makes CHP more economical.

ESCO - Energy Service Company Practice Test

ESCO - Energy Service Company Practice Test

ESCO Combined Heat and Power (Cogeneration) 2