Renewable and non-renewable energy sources: Practice Questions

Which of the following represents a significant environmental advantage of large-scale hydroelectric power generation over thermal power generation (e.g., coal-fired plants)?

In a nuclear fission reactor, the moderator plays a crucial role in sustaining the chain reaction. What is the primary function of the moderator material (e.g., heavy water or graphite) within the reactor core?

Which of the following statements about hydroelectric power generation is incorrect?

The binding energy per nucleon curve is fundamental to understanding energy release in nuclear reactions. Which of the following statements accurately describes the relationship between the binding energy per nucleon curve and nuclear fission and fusion processes?

When comparing different energy sources for their potential to store a large amount of energy in a compact form, energy density (energy per unit mass or volume) is a key factor. Which of the following energy sources typically has the highest energy density by mass?

What is a key advantage of renewable energy sources over non-renewable sources in terms of their long-term availability?

Explain why nuclear fission is classified as a non-renewable energy source, even though its operational greenhouse gas emissions are minimal, and discuss one major environmental challenge unique to its fuel cycle.

Why is biomass considered a renewable energy source, despite its combustion releasing carbon dioxide, which contributes to the greenhouse effect?

Ocean Thermal Energy Conversion (OTEC) is a renewable energy technology that harnesses the temperature difference between warm surface ocean water and cold deep ocean water to generate electricity.

(a) Briefly explain the fundamental principle by which an OTEC power plant generates electricity.

(b) Describe the geographical requirements for the viable operation of an OTEC plant and explain why these are crucial.

(c) State two significant advantages of OTEC as a renewable energy source compared to intermittent sources like solar or wind power.

(d) Discuss one potential environmental disadvantage of large-scale OTEC power plants on marine ecosystems.

A municipality is investing in a large-scale Battery Energy Storage System (BESS) with a usable capacity of $$100\text{ MWh}$$ to enhance grid stability and integrate more intermittent renewable energy sources like wind and solar. The BESS has a round-trip efficiency of $$85\%$$ (meaning $$85\%$$ of the energy put into the battery is recoverable). The electricity used to charge the BESS comes from a grid with an average CO$_2$ emission factor of $$0.7\text{ kg CO}_2\text{ per kWh}$$. The BESS is typically charged from 1 AM to 6 AM (when electricity demand is low) and discharged from 4 PM to 9 PM (during peak demand).

(a) Calculate the total electrical energy (in MWh) that must be drawn from the grid to fully charge the BESS from empty to its usable capacity.

(b) If the BESS is fully charged once per day, what is the maximum useful electrical energy (in MWh) that can be delivered back to the grid daily?

(c) During a full daily charge, what is the total energy (in MWh) lost due to the inefficiency of the BESS?

(d) Discuss one significant environmental benefit of using grid-scale BESS for integrating renewable energy.

(e) Discuss one major environmental concern associated with the manufacturing and disposal of large-scale lithium-ion batteries used in BESS.