BPSC 70th CCE Re-exam Prelims General Studies · Question 16 of 142

Correct — D, 1 and 4 only. A renewable source is one that is replenished on a human timescale, so that using it today does not reduce what is available tomorrow. Take the four statements in turn. Statement 1, solar, qualifies without argument: the flux arriving from the Sun is not depleted by being intercepted, and India's Ministry of New and Renewable Energy has solar at the centre of its portfolio. Statement 4, wind, qualifies for the same reason — wind is driven by differential solar heating of the atmosphere and the Earth's rotation, and a turbine takes energy from a flow that is continually regenerated. Statement 3, coal, is the textbook example of the opposite. It is a fossil fuel formed from plant matter buried and compressed over tens of millions of years; the stock is finite, it is not being replaced at any rate relevant to human use, and burning it is the single largest source of carbon dioxide emissions. Any option containing 3 is therefore wrong, and that removes (a), (b) and (c) at a stroke — which is the fastest route through this question. Statement 2, 'electricity produced from thermal plants', is the one that needs Indian usage rather than physics. In Indian power statistics 'thermal' means a station that raises steam by burning a fuel — coal, lignite, natural gas or diesel — and thermal capacity is reported as the fossil half of the installed base, against hydro, nuclear and renewables. It is true that a solar-thermal or biomass station also works by heat, and that geothermal energy is thermal and renewable; but the term as the examiner uses it, and as the Ministry of Power uses it, denotes fossil generation. So statement 2 is out, and only 1 and 4 stand.

• (a)1, 2 and 3 only — Includes both of the fossil statements and, worse, drops wind — the one source besides solar that is unambiguously renewable and that carries India's second largest renewable capacity. An option that admits coal to a list of renewable sources cannot survive any definition of the term.
• (b)1 and 3 only — Pairs solar with coal, which is the sharpest possible contradiction of the definition — an inexhaustible flux beside a finite stock laid down over tens of millions of years. It also omits wind altogether. Choosing it usually means the candidate read only as far as the first statement.
• (c)1, 3 and 4 only — The most dangerous option on the page, because it gets solar and wind exactly right and then adds coal. A candidate who is confident about statements 1 and 4 and does not read statement 3 carefully will take it. On a paper with a penalty of one-third of a mark, the discipline of checking every listed item before choosing a combination is what this question is testing.

Energy sources are classified two ways, and BPSC uses both. The first split is renewable against non-renewable: renewable sources — solar, wind, hydro, biomass, geothermal, tidal and wave — are replenished continuously, while non-renewable sources — coal, lignite, petroleum, natural gas and nuclear fuel — exist as finite stocks. Note that nuclear is non-renewable but is not a fossil fuel, and is low-carbon, which is why policy documents often use the wider category 'non-fossil' rather than 'renewable'. The second split is conventional against non-conventional, which is about how long a source has been in commercial use rather than about whether it runs out; coal, oil, gas, nuclear and large hydro are conventional, while solar, wind, small hydro, biomass and waste-to-energy are grouped as non-conventional and are the charge of the Ministry of New and Renewable Energy. India's climate commitments are framed in the non-fossil vocabulary: at the Glasgow climate conference in November 2021 India announced the five-point Panchamrit, including 500 gigawatts of non-fossil electricity capacity by 2030, meeting half its energy requirements from renewable energy by 2030, and net zero emissions by 2070.

Statement-list questions are won by finding the single item that kills the most options, and here that item is coal. Coal appears in three of the four options, so establishing that statement 3 is false leaves exactly one answer without any need to adjudicate the awkward statement 2 at all. That is the efficient route, and it is worth practising deliberately: scan the options first, find the statement that appears most often, and settle that one. Statement 2 is nevertheless the interesting part of the question, because it turns on a convention rather than a fact. Physics has no objection to calling a geothermal or solar-thermal station thermal; Indian power accounting does, because 'thermal' there is shorthand for coal, lignite, gas and diesel plants. When a stem uses a term that has both a technical and an administrative meaning, take the administrative one — a State services paper is testing the vocabulary of Indian government documents, not of a textbook on heat engines.

• Renewable sources recognised by India's Ministry of New and Renewable Energy include solar, wind, small hydro, biomass and bio-power, waste-to-energy, geothermal and tidal energy.
• Coal is a fossil fuel formed over tens of millions of years from buried plant matter and is the standard example of a non-renewable, exhaustible source.
• In Indian power statistics 'thermal' capacity means stations burning coal, lignite, gas or diesel, and is reported separately from hydro, nuclear and renewable capacity.
• Under the Panchamrit announced at the Glasgow climate conference in November 2021, India committed to 500 GW of non-fossil electricity capacity by 2030, meeting 50 per cent of its energy requirements from renewables by 2030, and net zero emissions by 2070.
• Nuclear energy is non-renewable — uranium is a finite stock — but it is not a fossil fuel and is counted as non-fossil, which is why climate targets are usually written in the non-fossil rather than the renewable vocabulary.

• Treating 'thermal' as a neutral description of any heat-based plant. In Indian power statistics it means fossil-fuel generation and is reported against renewables.
• Calling nuclear energy renewable because it emits little carbon. It is non-fossil and low-carbon, but uranium is a finite stock.
• Choosing a combination because two of its items are obviously right. Option (c) here is correct about solar and wind and still wrong, because it also contains coal.

BPSC uses the numbered-statement format for definitions and expects each item to be judged separately against a government classification, usually with one clearly fossil item planted to kill several options at once. UPSC asks the same material at one remove — what a specific technology does, whether a named alliance or scheme covers what it is said to cover, whether a set of technologies counts as distributed energy resources — so the classification has to be known well enough to apply to unfamiliar terms.

• practice — not a real PYQ

  Which one of the following is NOT a renewable source of energy ?

  • (a)Tidal energy
  • (b)Geothermal energy
  • (c)Natural gas
  • (d)Biomass

  Answer(c) Natural gas — a fossil fuel and a finite stock, whatever its lower carbon content compared with coal. Tidal, geothermal and biomass are all replenished on a human timescale and all appear in the Ministry of New and Renewable Energy's portfolio.

• practice — not a real PYQ

  Under the Panchamrit announced by India at the Glasgow climate conference in 2021, India's target for non-fossil electricity generation capacity by 2030 is

  • (a)175 GW
  • (b)300 GW
  • (c)450 GW
  • (d)500 GW

  Answer(d) 500 GW — along with meeting 50 per cent of energy requirements from renewables by 2030 and reaching net zero emissions by 2070. The earlier 175 GW figure was the renewable target set for 2022.