Minerals, energy & industry

Answer: (d) All four

Distributed energy resources (DER) are small generating or storage units placed close to where power is used, usually on the consumer's side of the meter, instead of large central power stations. Rooftop solar, home or grid batteries, small biomass generators and fuel cells are all standard examples.

• ✓ 1. Battery storage, including electric-vehicle batteries that can send power back to the grid, is listed by Australia's energy market rule-maker (AEMC) as a distributed energy resource.
• ✓ 2. Small biomass generators running on waste gas or farm and industrial by-products are a DER; the US EPA also lists biomass combustion among distributed generation options.
• ✓ 3. Fuel cells, run on natural gas, hydrogen or biomass-derived gas, produce electricity on site and are counted as distributed generation.
• ✓ 4. Rooftop solar PV is the most common DER: power is produced on the building that uses it, and surplus can be fed into the distribution grid.

Remember · DER = small, local generation or storage near the point of use: rooftop solar, small wind, batteries (incl. EVs), biomass generators, fuel cells, CHP units, mini-hydro.

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (c) Long duration energy storage

Pumped-storage hydropower is a way of storing electricity, not of watering crops. When power is cheap or surplus (for example sunny afternoons with lots of solar), water is pumped from a lower reservoir to an upper one; when demand peaks, it is released back down through turbines. It can hold energy for many hours, which is why it is discussed as long-duration storage for a grid with more solar and wind.

• ✓ (c) Two reservoirs at different heights work like a giant rechargeable battery; pumped storage is the dominant form of grid-scale energy storage worldwide.
• ✗ (b) Lift irrigation also pumps water uphill, but only to deliver it to fields; nothing flows back through turbines to generate electricity.
• ✗ (d) Rainwater harvesting collects and stores rainwater for use or groundwater recharge; it has no power-generation or storage role.

Remember · Pumped-storage hydro = pump water up with surplus power, release it through turbines at peak demand. The biggest grid-scale storage technology; key for integrating solar and wind.

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (a) Both Statement-I and Statement-II are correct and Statement-II explains Statement-I

The SUMED pipeline runs across Egypt and carries crude oil from the Red Sea to the Mediterranean Sea. Together with the Suez Canal it forms a strategic route for Persian Gulf energy shipments to Europe. The Red Sea-Mediterranean link is exactly what makes it a route to Europe, so Statement-II explains Statement-I.

• ✓ Statement-I The US Energy Information Administration calls the Suez Canal and the SUMED Pipeline strategic routes for Persian Gulf crude oil, petroleum products and LNG shipments to Europe and North America.
• ✓ Statement-II The roughly 200-mile SUMED Pipeline carries crude oil northbound through Egypt from the Red Sea to the Mediterranean Sea. It is the only alternative for such crude if ships cannot pass through the Suez Canal, which is why it works as a route to Europe.

Remember · SUMED pipeline: about 200 miles across Egypt, carrying crude oil from the Red Sea to the Mediterranean; the alternative to the Suez Canal for such crude.

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) Statement-I is incorrect, but Statement-II is correct

Statement-I is wrong: Venezuela has not recovered from its economic crisis, and people have kept leaving, with UNHCR counting nearly 7.9 million Venezuelans abroad in its latest update. Statement-II is right: Venezuela holds the world's largest proven crude oil reserves, about 303 billion barrels in 2023.

• ✗ Statement-I The US Energy Information Administration says government mismanagement, sanctions and the country's economic crisis have severely hampered even its energy sector. UNHCR reports nearly 7.9 million people who have left Venezuela (December 2025 update), so emigration was not stopped.
• ✓ Statement-II Venezuela had the world's largest proven crude oil reserves in 2023, about 303 billion barrels or roughly 17% of global reserves. Its production is a small share of world output, which shows that reserves alone did not bring recovery.

Remember · Venezuela: crisis and mass emigration continue (nearly 7.9 million abroad, UNHCR Dec 2025), yet it has the world's largest proven crude oil reserves (about 303 billion barrels, 2023).

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error