Which of the following is the best example of cogeneration?
(A) A power plant uses both coal and natural gas as fuel.
A trash-to-steam power plant accepts both residential and commercial waste.
(C) Several power plants supply the same city with electrical energy.
D Emissions from power plants are captured and stripped of sulfur for commercial sale.
A coal-fired power plant captures waste heat and uses it to heat adjacent buildings.
The correct answer and explanation is:
The correct answer is:
(E) A coal-fired power plant captures waste heat and uses it to heat adjacent buildings.
Explanation:
Cogeneration, also known as combined heat and power (CHP), is a highly efficient energy process that simultaneously generates electricity and useful thermal energy from a single fuel source. The key characteristic of cogeneration is that it utilizes the waste heat that would otherwise be lost in power generation, improving overall efficiency.
In the correct answer, a coal-fired power plant generates electricity but also captures the excess heat produced during the process and uses it to heat nearby buildings. This approach maximizes energy use and significantly reduces fuel consumption, leading to cost savings and environmental benefits.
Why Other Options Are Incorrect:
- (A) A power plant uses both coal and natural gas as fuel.
This describes fuel diversification but does not involve cogeneration. It does not indicate the recovery of waste heat for productive use. - (B) A trash-to-steam power plant accepts both residential and commercial waste.
This describes a waste-to-energy facility, which is a form of energy recovery but does not specifically involve cogeneration. - (C) Several power plants supply the same city with electrical energy.
This describes energy distribution but has no connection to cogeneration, as it does not indicate the use of waste heat. - (D) Emissions from power plants are captured and stripped of sulfur for commercial sale.
This refers to pollution control rather than cogeneration. While reducing emissions is beneficial, it is not the same as using waste heat efficiently.
Benefits of Cogeneration:
- Increases overall energy efficiency (can reach 80–90%).
- Reduces greenhouse gas emissions.
- Lowers energy costs.
- Provides a more reliable energy source.
This technology is widely used in industries, hospitals, universities, and residential heating systems.
