Solar photovoltaic power

Also called: Solar PV, Solar power · Topic: Environment and Sustainable Development · NCERT: Class 11, Ch 7 "Environment and Sustainable Development"

Meaning

Solar photovoltaic (PV) power is electricity made directly from sunlight by photovoltaic cells. These cells are thin layers of a semiconductor, usually silicon.

It matters because it causes no pollution while running and works well in remote places the grid cannot reach. Solar is also the largest part of India's renewable energy growth. Capacity rose from 2.8 GW (2014) to 150.26 GW (31 March 2026) [2][3].

Explanation

How it works

• Sunlight → PV cell → electricity.
• Sunlight falls on the semiconductor layer in the cell.
• This produces an electric current directly.

• Nothing burns and no steam is used.

• No moving parts. There is no turbine or engine, so maintenance is low.

• Where panels can go:
• Rooftops of homes, offices and farm sheds. No new land is needed.
• Solar parks, which are large ground-mounted plants. They need land.
• Standalone (off-grid) systems in hill villages, islands, deserts and border posts. In these places, building grid lines is impossible or too costly.

Why it is a "non-conventional" source

• Non-conventional sources of energy are renewable, spread out and produce little pollution. Wind, the sun and small streams are examples.
• Conventional sources are coal, oil, gas and large hydro.
• Solar avoids the harms of the conventional sources:
• Thermal plants release CO2 (a greenhouse gas) and leave fly ash (fine powder left after coal burns), which pollutes water and land.

• Large dams flood forests, displace people and change the natural flow of the river.

• NCERT error: the Class 11 chapter calls solar "conventional". In the exam, treat it as non-conventional.

Advantages and limits

• Advantages:
• Pollution-free while running.
• Low maintenance.
• Ideal for remote areas.
• Rooftop use saves land.

• Decentralised, meaning power is made where it is used. This cuts transmission loss (electricity lost as heat when power travels long distances through wires).

• Limits:

• Intermittent (not always available). There is no power at night and less power on cloudy days.
• So it needs batteries or back-up power.
• Solar parks need large areas of land.

Worked examples

• Growth multiple:

• 150.26 GW (2026) ÷ 2.8 GW (2014) ≈ 54 times in about 12 years [2][3].

• Rooftop subsidy under PM Surya Ghar:

• A household installs a 3 kW system.
• CFA (Central Financial Assistance, the Centre's share of the cost) = (2 × ₹30,000) + (1 × ₹18,000) = ₹78,000. This is the maximum [5].
• A 3 kW system makes about 300-360 units a month in Indian sunshine. That is roughly the scheme's "300 free units".

In India

• Ministry: MNRE (Ministry of New and Renewable Energy) manages solar policy and schemes.
• Latest capacity:
• Solar was 150.26 GW on 31 March 2026, out of 274.68 GW of total renewable energy (RE) capacity [2].
• Solar makes up about 48% of India's RE capacity (2026) [3].

• India ranks third in the world in installed RE capacity (2026) [2].

• Climate targets:

• 50% of installed electricity capacity came from non-fossil sources in June 2025. This was five years ahead of the 2030 NDC (Paris Agreement pledge) target [3].

• The next target is 500 GW of non-fossil capacity by 2030 [3].

• PM Surya Ghar: Muft Bijli Yojana (February 2024):

• Aim: rooftop solar on 1 crore households, with up to 300 free units a month.
• Outlay: ₹75,021 crore [5].
• CFA: ₹30,000 per kW for the first 2 kW and ₹18,000 for the third kW, up to a maximum of ₹78,000 [5].
• Progress: 10.09 lakh installations by 10 March 2025 [6]. 26,19,879 systems by 19 March 2026, with ₹17,967.53 crore of CFA disbursed [4].

• The target of 1 crore by March 2027 remains [6].

• PM-KUSUM (2019): solar for farmers

• Aim: de-dieselise farming, which means replacing diesel pumps with solar pumps [7].
• Component A: small solar plants up to 2 MW on farmers' land.
• Component B: standalone solar pumps, which are not connected to the grid.
• Component C: solarising existing grid-connected pumps. Farmers can sell extra power to the DISCOM (the electricity distribution company) [7].
• Target: 34.8 GW, with central support of ₹34,422 crore. The scheme was extended to 31 March 2026 [7].

• Progress by October 2025: more than 9 lakh standalone pumps installed [7][8].

• International Solar Alliance (ISA):

• Launched by India and France at COP21, Paris, on 30 November 2015.
• Its Framework Agreement came into force in December 2017, making it a treaty-based intergovernmental organisation.
• Headquarters: Gurugram. It is the first international intergovernmental body with its headquarters in India.

• Vision: One Sun One World One Grid (OSOWOG).

• In cities: Delhi and other cities use solar street lighting to cut demand on the grid.

Don't confuse with

• Solar thermal power: it uses sunlight's heat, for example to make steam that drives a turbine. Solar PV turns light directly into electricity, with no moving parts.
• Wind power: it also has high capital cost, low running cost and intermittent supply. But wind turbines have moving blades, which bring noise and bird deaths, and they need strong, steady wind sites. PV works anywhere with sunlight, including rooftops.
• ISA vs OSOWOG: the ISA is the treaty-based organisation with its HQ in Gurugram. OSOWOG is its vision of linking solar grids across countries and time zones.
• PM Surya Ghar vs PM-KUSUM: Surya Ghar (2024) is rooftop solar for households, with free units. KUSUM (2019) is solar for farmers, covering pumps and small plants.

Prelims Hooks

• Solar is a non-conventional source. NCERT's label of "conventional" is a known error.
• India's solar capacity was 150.26 GW (31 March 2026), up from 2.8 GW (2014). That is about 48% of RE capacity [2][3].
• ISA: India and France, COP21 Paris, 30 November 2015. Framework Agreement in force December 2017. HQ Gurugram.
• PM Surya Ghar (February 2024): 1 crore households, 300 free units a month, maximum CFA ₹78,000, 26.2 lakh installations (March 2026) [5][4].
• PM-KUSUM: A = plants up to 2 MW. B = standalone pumps. C = grid-connected pumps solarised [7].
• Trap: "Solar PV needs no storage." This is wrong. There is no output at night, so it needs batteries or back-up.

Mains Points

• Decentralised solar for inclusive growth:
• Rooftop panels and solar pumps make power where it is used. This cuts transmission losses and reaches remote villages.
• Households and farmers become "prosumers" (people who both produce and consume power) by selling surplus power to DISCOMs. This raises rural incomes.

• Links: PM Surya Ghar [5], PM-KUSUM [7], SDG 7 (affordable, reliable, sustainable and modern energy for all).

• The intermittency and land trade-off:

• Solar gives no power at night, so the grid needs storage and balancing.
• Solar parks compete with farms and forests for land.

• A balanced mix is needed to reach 500 GW non-fossil by 2030 [3]. This means solar plus storage, plus wind and small hydro, with gas as a bridge fuel [9].

• Climate diplomacy and equity:

• Through the ISA, India leads the Global South in solar energy.
• Meeting 50% non-fossil capacity in June 2025, five years early [3], makes India's NDC commitments more credible.
• It also supports intergenerational equity: meeting today's needs without harming future generations' ability to meet theirs.

Related concepts

• Non-conventional sources of energy
• Wind power
• Mini-hydel plants
• LPG as clean fuel
• Biogas
• Compressed Natural Gas
• Road space rationing
• Energy poverty

Read more

• Strategies I: clean energy for villages, cities and remote areas