Renewable power, benefits and challenges

Explanation

Statement 1 is incorrect. The 'duck curve' does NOT arise because net demand peaks simultaneously with solar generation. The defining feature of the duck curve is the temporal mismatch: solar generation is highest during midday (creating a belly — oversupply or very low net demand), while actual grid demand peaks in the evening after sunset when solar output collapses to near-zero. This creates the characteristic duck-shaped net-load curve — a deep midday trough followed by a steep evening ramp. If both net demand and solar peaked simultaneously, there would be no grid-balancing problem; the problem is precisely that they peak at different times. Statement 2 is correct. BESS is the canonical structural solution to the duck curve: storage absorbs surplus solar electricity during the midday surplus period and injects it back into the grid during the evening peak, effectively shifting solar generation temporally to match demand. Statement 3 is correct. In high-renewable grids, dispatchable thermal capacity and short-term power market purchases act as flexibility resources — they can be ramped up during the critical evening hours when solar falls to zero and wind output is uncertain. This is exactly the role played by thermal plants and market purchases in a grid where renewable capacity alone cannot guarantee supply-demand balance at all hours.

Explanation

All three pairs are correctly matched. First, solar and wind power output varies with weather conditions and time of day — a fundamental characteristic of renewable generation known as intermittency — making battery storage and grid upgrades essential to manage fluctuations in supply and demand. Second, lithium is a critical raw material for most rechargeable battery technologies, including those used in grid-scale electricity storage; this is why access to lithium-rich countries (such as Australia, which produces a dominant share of the world's lithium) is strategically important for India's clean energy ambitions. Third, experts and policymakers consistently emphasise that expanding renewable generation capacity alone is insufficient — grid modernisation (transmission infrastructure, smart grids, load balancing mechanisms) must scale in parallel to absorb and reliably deliver variable renewable power. The principle here is that the 500 GW target has two indispensable pillars beyond generation: energy storage and grid infrastructure.

Explanation

Statement 1 is correct. The ALMM framework requires that solar modules used in government-linked projects be sourced from manufacturers on an approved list. ALMM-II extends this logic upstream to cells, mandating that cells used in such modules also be domestically manufactured and listed — a tool to stimulate investment in cell capacity, which is the weakest link in India's solar value chain. Statement 2 is correct. India's solar manufacturing capacity follows a steep upstream deficit: module capacity is large (over 250 GW as of mid-2026), while cell capacity is a fraction of that, ingot-wafer capacity is minimal (approximately 2 GW), and polysilicon manufacturing is effectively absent. This pyramidal gap forces India to import the most technology-intensive upstream inputs, predominantly from China, making the country vulnerable to any supply disruption or export restriction from China. Statement 3 is incorrect. PLI schemes across sectors — including the solar PV PLI — disburse incentives linked to incremental sales or production output above a defined baseline, not on the basis of installed capacity. This output-linked structure is the defining feature of PLI schemes (as opposed to capital subsidies, which are disbursed on investment or capacity creation). The industry demand for a dedicated 'capital subsidy' for solar equipment manufacturing is precisely because PLI's output-linked nature may not sufficiently de-risk the upfront investment needed to build cell, wafer, and polysilicon capacity.

Explanation

Statement 1 is correct. Conventional generators have rotating machinery (turbines, alternators) that stores kinetic energy, providing inertia — a physical property that resists sudden changes in grid frequency when generation or load is disturbed. Solar PV systems, by contrast, interface with the grid through power-electronic inverters. Their capacity to support frequency and voltage is not inherent but depends on the inverter's design and programmed settings; without appropriate grid-following or grid-forming capability, large-scale simultaneous inverter disconnection during a fault can worsen the original disturbance. Statement 2 is incorrect. Net billing is specifically distinguished from net metering precisely because it does NOT pay the prosumer the full retail tariff for exported units. Under net billing, the export payment is set at a lower, administratively determined rate — as illustrated by Pakistan's shift from approximately PKR 26 per kWh (closer to retail parity under net metering) to PKR 10–13 per kWh under net billing. This reduction in the compensation rate for exports, combined with shorter contract periods, is the defining financial feature of net billing and the reason it reduces utility revenue shortfalls compared with net metering. Statement 3 is correct. When distributed solar generation on a feeder exceeds the local load being served, surplus electricity flows back upstream through the distribution network — a 'reverse power flow'. This is operationally significant because distribution networks were originally designed for unidirectional power flow (substation to consumer). Reverse flows can elevate feeder voltages beyond permissible limits, overload transformers or conductors rated for one-directional current, and confuse conventional protection relays that assume fault current flows only from the grid toward the consumer. Managing these effects requires updated protection coordination and voltage-regulation strategies.

Explanation

All three pairs are correctly matched. First, polysilicon is indeed the most upstream feedstock in the solar PV manufacturing value chain — the sequence runs polysilicon → ingot → wafer → cell → module, and polysilicon is the starting material. Second, the Approved List of Models and Manufacturers (ALMM) is MNRE's mandatory sourcing instrument: only products and manufacturers listed on it may be used in government-supported solar projects in India, giving it the character of a localisation mandate. Third, ingots occupy a uniquely China-dependent position in the value chain — unlike cells, wafers, or polysilicon where non-Chinese suppliers exist, China holds a near-monopoly over ingot production as well as the equipment (e.g., Czochralski pullers) used to make them, making this segment the most vulnerable to supply-chain disruptions.

Explanation

Statement 1 is correct. Pumped storage hydropower is the dominant form of utility-scale electricity storage globally. During low-demand or high-generation periods (e.g., when solar output is high midday), excess electricity is used to pump water from a lower to an upper reservoir. When demand peaks, water is released back through turbines to generate electricity — effectively acting as a rechargeable battery. Statement 2 is correct. The core grid-balancing argument for PSH alongside solar is precisely the solar intermittency problem: solar PV produces electricity abundantly during daylight hours but output falls to near-zero after sunset, while household and commercial electricity demand typically peaks in the evening (roughly 6–10 p.m. in India). PSH bridges this gap by storing solar-period surplus and dispatching it during the evening peak, displacing coal-fired peaking plants that would otherwise be needed. Statement 3 is incorrect. One of the distinctive engineering advantages of pumped storage projects over conventional run-of-river or storage hydropower is that they require a comparatively smaller land footprint for equivalent installed capacity, because their design is based on hydraulic head (elevation difference between two reservoirs) rather than large reservoir surface area. The Karjat project, for instance, claimed a land requirement approximately 52 times lower than a conventional hydropower project of comparable capacity — the opposite of what Statement 3 asserts. The ecological sensitivity concerns around PSH projects arise mainly from forest clearance for civil infrastructure, not from an inherently larger land requirement.

Explanation

Statement 1 is correct: agri-PV requires elevated panel structures — installed at around 3.5 to 4 metres above the ground — precisely so that farmers can continue routine agricultural operations, including the movement of farm machinery, beneath the panels. This is what distinguishes agri-PV infrastructure from standard ground-mounted solar installations, and what makes it around 25–30% more expensive. Statement 2 is incorrect: it inverts the government's own assessment. Initial studies indicate that agri-PV is suitable for fruits and leafy vegetables — crops that can tolerate partial shade — but has not been found suitable for crops such as rice and sugarcane, which require higher levels of direct sunlight. The statement has this relationship backwards. Statement 3 is correct: the fundamental rationale for integrating agri-PV under PM-KUSUM is to resolve the tension between the large land footprint of solar energy and the scarcity of non-agricultural land, especially in states with limited non-farm area. By co-locating solar generation with food production, the model aims to expand renewable capacity without fully displacing agriculture, thereby protecting food security.

Explanation

All three pairs are correctly matched. First, the ALMM (Approved List of Models and Manufacturers) is the government-maintained list that module manufacturers must appear on before their products can qualify as domestically made; the ALMM-II framework specifically extends this requirement to solar cells. Second, the Domestic Content Requirement (DCR) is a well-established condition under schemes such as JNNSM (Jawaharlal Nehru National Solar Mission) that requires solar cells and modules procured for government projects to be manufactured within India — a measure designed to prevent dumping of imported equipment. Third, India's Production-Linked Incentive (PLI) scheme for high-efficiency solar modules was designed expressly to incentivise investment not just in final module assembly but in the deeper, upstream stages of the value chain — ingots, wafers and cells — so as to reduce import dependence on China. China's proposed export curbs on photovoltaic manufacturing technologies directly threaten this backward-integration agenda and the ALMM-II timelines, since Indian manufacturers planning to enter capex cycles for these upstream stages now face potential technology and equipment access constraints.

Explanation

PM-KUSUM was launched in 2019 under the Ministry of New and Renewable Energy (MNRE) with three distinct components. Component A supports decentralised grid-connected solar power plants — these are small solar plants set up near agricultural land and connected to the grid, distinct from stand-alone (off-grid) pumps. Statement 1 is correct in drawing this distinction. Statement 2 is incorrect: it is Component A (grid-connected decentralised plants) and Component C (feeder/pump solarisation) that require DISCOM involvement for power purchase and grid coordination, not Component B. Component B stands for stand-alone solar pumps, which by definition operate independently of the grid and therefore do not require DISCOM power purchase agreements — this is precisely why Component B achieved nearly 90 per cent of its target while Components A and C lagged. Statement 3 is correct: Component C involves solarisation of existing grid-connected agricultural pumps and feeders, and its implementation inherently requires coordination among state agencies, DISCOMs, regulators, developers, lenders and landowners — accounting for its uneven progress across states.

Explanation

Statement 1 is correct: India allows 100 per cent FDI in the electricity sector under the automatic route, and renewable energy parks are a policy instrument that bundles land acquisition and transmission connectivity, lowering entry barriers for developers — both features are well-established in India's renewable energy policy architecture. Statement 2 is correct: Viability Gap Funding is a government grant mechanism designed to bridge the gap between the cost of developing a project and the revenue it can realistically generate, making it commercially viable for private sector participation — it is a standard instrument under India's infrastructure policy, applied to solar and wind projects where tariffs alone may not cover capital costs. Statement 3 is incorrect in its attribution of mechanism and direction: transmission charge exemptions are granted TO renewable energy generators/consumers (not by generators to discoms), and payment reforms have been directed at improving the financial health of electricity distribution companies (discoms) so that they honour their payment obligations to generators — the direction of obligation is inverted in the statement. The decline in discom arrears is a consequence of demand-side (discom) payment reforms, not a benefit extended by generation companies.

Explanation

Pair 1 is correctly matched: inverter ride-through settings (also called low-voltage and frequency ride-through) are configurations that allow rooftop solar inverters to stay connected to the grid during brief deviations in voltage or frequency, preventing a cascade of simultaneous disconnections that can deepen a generation deficit. Pair 2 is incorrectly matched: Under Frequency Load Shedding (UFLS) automatically disconnects selected electrical loads (i.e., demand/consumers), not generation sources, in order to reduce demand and thereby stabilise grid frequency when supply suddenly falls short. UFLS is a demand-side emergency tool, not a supply-side one. Pair 3 is correctly matched: non-dispatchable generation refers to renewable sources such as rooftop solar and wind whose output is weather-dependent and cannot be commanded to increase or decrease output in the way that conventional dispatchable plants (coal, hydro, gas) can be. The distinction between dispatchable and non-dispatchable generation is foundational to understanding grid frequency management challenges as India scales up rooftop solar.

Explanation

Statement 1 is correct: a core purpose of grid-scale BESS is temporal shifting of energy — storing surplus renewable generation (which would otherwise be curtailed or wasted) and discharging it during evening or other peak-demand windows, thereby displacing costly spot-market or short-term power purchases. Statement 2 is correct: renewable curtailment happens precisely when instantaneous supply exceeds demand and there is no mechanism (storage, flexible load, or export capacity) to absorb it — battery storage directly addresses this by acting as a sink for excess generation. Statement 3 is incorrect: solar generation peaks around midday, while electricity demand typically peaks in the morning and again in the evening. Co-located BESS can store midday solar surplus and discharge it during the evening peak — which is exactly the peak-demand management function. The claim that co-location 'does not contribute to peak-demand management' because generation and peak demand coincide is factually wrong; it is the temporal mismatch between midday solar generation and evening peak demand that makes storage valuable for peak management.

Explanation

Statement 1 is correct. A core challenge in India's renewable mix is that wind and solar generation profiles are not highly complementary on a seasonal basis. Wind output surges during the monsoon but drops sharply outside it, whereas solar output remains comparatively stable across seasons. This contrasts with certain European contexts where wind and solar can complement each other more effectively across seasons, thereby reducing overall grid variability. Statement 2 is correct. Pumped-storage hydropower is a proven grid-balancing technology: surplus renewable electricity (e.g., from midday solar peaks) is used to pump water uphill into a reservoir; when demand rises or generation falls, water is released through turbines to generate power. This makes it a critical storage and variability-management tool for grids with high renewable penetration. Statement 3 is incorrect. The IEA's characterisation is precisely the opposite: solar PV generation in India remains comparatively stable across all seasons, with relatively small monthly variations. It is onshore wind that introduces the greater seasonal variability. The combined wind-solar generation profile is therefore dominated by wind's monsoon seasonality, resulting in a more variable aggregate output — not because solar is volatile, but because wind is.

Explanation

Statement 1 is correct. Wind power repowering is precisely the strategy of replacing older, low-capacity turbines with modern, high-capacity units at already-established wind farm sites, thereby boosting output without the need for new land acquisition. This addresses one of India's primary barriers to faster wind deployment — difficulty in acquiring new land and securing right-of-way. Statement 2 is incorrect. Wind installations in India have significantly lagged behind solar additions; India's green power capacity has grown substantially since 2014, but wind energy deployment has not matched solar's pace, with land acquisition remaining a persistent hurdle. Statement 3 is incorrect. The grid challenge described is the reverse: limited battery storage combined with EXCESS daytime solar generation leads to solar curtailments (wasted power), while inadequate firm dispatchable capacity creates shortfalls at night. It is the abundance of solar power during the day — not insufficient generation — that creates the mismatch, alongside insufficient storage to shift that surplus to evening demand.