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Solar Energy Explained

The economics of solar power, how costs have plummeted, and the technology behind the fastest-growing energy source.

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Educational content only — not personalized financial, legal, or tax advice.

The Global Expansion of Solar Energy

Solar photovoltaic (PV) power generation is the fastest-growing source of electrical power capacity in history. Global installed solar capacity expanded from 40 GW in 2010 to over 1,600 GW (1.6 Terawatts) by year-end 2023, according to IEA and SolarPower Europe data. In 2023 alone, the world added 447 GW of new solar PV capacity—an 87% increase in annual installations compared to 2022.

Solar generated over 1,630 Terawatt-hours (TWh) of electricity in 2023, accounting for 5.5% of global electricity production, up from 0.2% in 2010.

Economics of Solar: Wright's Law and LCOE Decline

The unsubsidized Levelized Cost of Energy (LCOE) for utility-scale solar PV dropped 89% between 2009 and 2023, falling from $359 per Megawatt-hour (MWh) to between $24 and $96 per MWh (Lazard LCOE Analysis v16.0). Solar is now the cheapest source of new bulk electricity generation across 82% of the global economy.

Cost declines follow Wright's Law (the experience curve): every doubling of cumulative solar manufacturing volume reduces module costs by approximately 20%.

Primary cost components:

  • Solar Modules: Silicon module prices plummeted from $4.00 per Watt in 2010 to $0.11-$0.15 per Watt in 2024. Polysilicon raw material prices fell from $400/kg in 2008 to under $8/kg in 2024 due to scale.
  • Solar Inverters: Central and string inverters convert direct current (DC) power from solar panels into grid-synchronized alternating current (AC) power. Inverter costs fell from $0.50/Watt in 2010 to under $0.08/Watt in 2024.
  • Balance of System (BOS): Structural racking, cabling, land acquisition, grid interconnection, and installation labor now constitute 55% to 65% of total utility-scale system capital expenditure.

Silicon Technology and Manufacturing Concentration

Photovoltaic Cell Efficiency Breakthroughs:

  • PERC (Passivated Emitter and Rear Cell): Dominant technology through 2022, achieving commercial efficiencies of 22% to 23%.
  • TOPCon (Tunnel Oxide Passivated Contact): Next-generation n-type cell technology pushing commercial efficiency to 24.5%-25.5%.
  • Perovskite-Silicon Tandem Cells: Layering perovskite thin films over silicon base cells allows absorption of broader solar spectrum wavelengths. In 2023, LONGi Green Energy set a laboratory world record tandem cell efficiency of 33.9%.

Chinese Supply Chain Dominance: China controls over 79% of global polysilicon production, 97% of silicon wafer production, 85% of solar cell manufacturing, and 75% of finished solar module production. The top global module manufacturers—Tongwei, LONGi Green Energy, JinkoSolar, Trina Solar, and JA Solar—each shipped over 40 GW of modules in 2023.

In response, the United States enacted Section 301 tariffs and antidumping/countervailing duties (AD/CVD) on Chinese-sourced solar components, alongside Inflation Reduction Act (IRA) tax incentives to incentivize domestic manufacturing facilities in states like Georgia, Ohio, and Texas.

Grid Integration, Duck Curves, and Battery Storage

The Duck Curve Paradox: In regions with heavy utility-scale solar penetration—such as the California Independent System Operator (CAISO) grid—midday solar generation creates excess power supply, driving wholesale electricity prices to zero or negative levels between 11:00 AM and 3:00 PM. As solar generation drops at sunset, grid operators face steep net-load ramps exceeding 15,000 MW over a 3-hour period.

Grid-Scale Storage Mitigation: Utility-scale Lithium Iron Phosphate (LFP) battery energy storage systems (BESS)—such as the 3,000 MWh Moss Landing Energy Storage Facility in California—absorb excess midday solar generation and discharge power during evening peak demand periods, smoothing grid stability.