Q19DQ - University Physics with Modern Physics

Question

An advertisement for a portable electrical generating unit claims that the unit’s diesel engine produces 28,000 hp to drive an electrical generator that produces 30 MW of electrical power. Is this possible?. Explain.

Step-by-Step Solution

Answer

No, it is not possible for a diesel engine to drive an electrical generator that produces 30 MW of electrical power.

Step 1 Calculation of Horsepower to MW.

The horsepower is calculated to MW as below:

  $$\begin{gathered} 28,000 \mathrm{HP}=\left(28,000 \mathrm{HP}\right)\left(\frac{746 \mathrm{W}}{1 \mathrm{hp}}\right) \\ =20.9 \mathrm{MW} \end{gathered}$$

Step 2: Explanation of the reason

The output power (30 MW) is greater than the input power which is 20.9 MW.

And this violates the law of conservation of energy. 

Thus, it is not possible for a diesel engine to drive an electrical generator that produces 30 MW of electrical power as conservation of energy does not allow it.