A power plant which is most efficient but has high initial cost is:

Explanation:

Hydroelectric Power Plant

Definition: A hydroelectric power plant is a type of power generation system that converts the potential energy of water stored in reservoirs at a height into electrical energy. This energy conversion process is achieved by allowing water to flow through turbines, which drive generators to produce electricity. Hydroelectric power plants are known for their high efficiency, low operational costs, and eco-friendly nature.

Working Principle: The basic principle of a hydroelectric power plant lies in the utilization of gravitational force exerted by water. Water stored in a reservoir at a higher elevation is released through penstocks (large pipes) to the turbines located at a lower elevation. The kinetic energy of the flowing water rotates the turbine blades, which in turn drive the connected generator to produce electricity. The process can be summarized as:

• Potential energy of stored water → Kinetic energy of flowing water → Mechanical energy of turbine → Electrical energy from generator.

Advantages of Hydroelectric Power Plants:

• High Efficiency: Hydroelectric power plants have one of the highest energy conversion efficiencies among power generation systems, often exceeding 90%.
• Renewable Energy Source: Since water is a renewable resource, hydroelectric power plants provide a sustainable and eco-friendly way of generating electricity.
• Low Operating Costs: Once constructed, hydroelectric plants have minimal fuel costs, as they rely on the natural water cycle.
• Long Operational Life: Hydroelectric power plants have a long operational lifespan, often exceeding several decades with proper maintenance.
• Environmental Benefits: Unlike fossil fuel-based power plants, hydroelectric power plants do not emit greenhouse gases or air pollutants.
• Support for Grid Stability: Hydroelectric plants can quickly adjust their power output to meet varying electricity demands, contributing to grid stability.

Disadvantages of Hydroelectric Power Plants:

• High Initial Cost: The construction of dams, reservoirs, and associated infrastructure requires a significant capital investment.
• Environmental Impact: Large-scale hydroelectric projects may lead to the submergence of land, displacement of communities, and disruption of local ecosystems.
• Dependence on Water Availability: The efficiency and output of hydroelectric power plants depend on the availability of water, which can be affected by seasonal variations and droughts.

Applications: Hydroelectric power plants are widely used for generating electricity on a large scale. They are also employed for purposes such as flood control, irrigation, and water supply management.

Correct Option Analysis:

The correct answer is:

Option 4: A hydroelectric power plant is the most efficient type of power plant but has a high initial cost.

This is accurate because hydroelectric power plants are renowned for their high efficiency and low operational costs. However, their construction requires a significant initial investment due to the infrastructure needed, such as dams and reservoirs. Despite this, the long-term benefits and sustainability of hydroelectric power make it a preferred choice for many regions worldwide.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: Nuclear Power Plant

Nuclear power plants are known for their ability to generate large amounts of electricity with a small amount of fuel. They are efficient but are not as efficient as hydroelectric power plants. Additionally, nuclear plants involve high initial costs and raise concerns regarding radioactive waste disposal, safety measures, and decommissioning expenses.

Option 2: Diesel Power Plant

Diesel power plants are relatively cheap to construct and can be used for small-scale power generation. However, they are not as efficient as hydroelectric power plants and have high operating costs due to the price of diesel fuel. Additionally, they contribute to environmental pollution through greenhouse gas emissions.

Option 3: Steam Power Plant

Steam power plants, which are often coal-based, are less efficient than hydroelectric plants. They require significant amounts of fuel, leading to higher operational costs and environmental concerns. Furthermore, these plants have a substantial carbon footprint, contributing to global warming and air pollution.

Option 5: No Option Provided

This option does not provide any information or alternative that aligns with the question, and hence, it is not relevant for analysis.

Conclusion:

Among the options provided, a hydroelectric power plant stands out as the most efficient type of power generation system. Despite its high initial cost, the long-term benefits, including low operating costs, environmental sustainability, and high efficiency, make it an excellent choice for electricity production. In contrast, other power plants like nuclear, diesel, and steam power plants have their own advantages and disadvantages but cannot match the efficiency and eco-friendly nature of hydroelectric power plants.