The History of Solar Energy: From 1839 to 2026

1839: The Photovoltaic Effect Discovered

The science behind this discovery is explained in our guide to how solar panels work.

The story of solar energy begins in 1839 with a 19-year-old French physicist named Edmond Becquerel. While experimenting in his father's laboratory, Becquerel discovered that certain materials produced small amounts of electric current when exposed to light. This phenomenon, which he called the photovoltaic effect, laid the theoretical groundwork for all future solar cell development. At the time, the currents produced were too small for practical application, and the discovery remained a scientific curiosity for decades.

In the decades following Becquerel's discovery, scientists including Willoughby Smith, William Grylls Adams, and Richard Evans Day made incremental progress, discovering that selenium exhibited photoconductivity and could generate electricity from light. In 1883, American inventor Charles Fritts built the first genuine solar cell by coating selenium with a thin layer of gold. Though less than 1% efficient, Fritts demonstrated that solar power could produce a continuous current and even envisioned solar as a future competitor to coal-fired power plants.

1954: First Practical Solar Cell

The modern solar era truly began at Bell Laboratories in 1954, when scientists Calvin Fuller, Daryl Chapin, and Gerald Pearson developed the first silicon solar cell capable of converting enough sunlight into electricity to power everyday electrical equipment. Their cell achieved approximately 6% efficiency, a dramatic improvement over previous selenium-based devices. Bell Labs called their invention "the first solar battery" and demonstrated it by powering a small toy Ferris wheel and a radio transmitter.

The timing was propitious. The space race was beginning, and solar cells offered an ideal power source for satellites where fuel-based generators were impractical. In 1958, the Vanguard I satellite became the first spacecraft to use solar power, carrying a small one-watt array that powered its radio for years. Throughout the 1960s, virtually every satellite launched by the United States and Soviet Union relied on solar cells, driving demand and funding technological improvements.

1970s: Energy Crisis Interest

Despite its space program success, solar energy remained too expensive for terrestrial applications through the 1960s. The 1973 oil crisis changed this paradigm. As oil prices quadrupled and energy insecurity became a national concern in the United States and worldwide, governments began investing seriously in alternative energy research. In 1974, the U.S. government launched the Solar Energy Research Institute (now NREL), and President Jimmy Carter installed solar thermal panels on the White House roof in 1979.

During this period, Dr. Elliot Berman designed a significantly less expensive solar cell, bringing costs down from $100 per watt to about $20 per watt. Exxon funded Berman's research, recognizing potential applications for offshore oil platforms and remote industrial facilities. The 1970s also saw the first terrestrial solar installations powering remote telecommunications equipment, navigational aids, and off-grid homes. Solar was no longer exclusively a space technology.

2000s: The Solar Boom Begins

The early 2000s marked solar energy's transition from niche technology to mainstream energy source. Germany's Renewable Energy Sources Act of 2000 established generous feed-in tariffs that guaranteed solar producers premium prices for their electricity for 20 years. This policy created the world's largest solar market virtually overnight and drove massive manufacturing scale that dramatically reduced costs.

In the United States, California's Million Solar Roofs initiative launched in 2006, and the federal solar Investment Tax Credit (ITC) was established, providing a 30% tax credit for residential and commercial solar installations. China began investing heavily in solar manufacturing capacity, eventually becoming the dominant producer of solar panels worldwide. By the end of the decade, global solar capacity had grown from 1.5 gigawatts in 2000 to over 40 gigawatts in 2010.

2010s: Cost Revolution

The 2010s witnessed the most dramatic cost reduction in energy technology history. Solar panel prices fell approximately 90% between 2010 and 2020, driven by massive Chinese manufacturing scale, technological improvements, and intense global competition. In 2010, installed residential solar cost approximately $7 per watt. By 2020, that figure had dropped to around $2.50 to $3 per watt.

During this decade, solar achieved grid parity, the point where it became cheaper than fossil fuel electricity, in an increasing number of markets. California, Hawaii, and several southwestern states saw solar become the cheapest electricity option for homeowners. Utility-scale solar costs fell even faster, reaching below 3 cents per kWh in optimal locations, undercutting coal, natural gas, and nuclear power.

The decade also brought important technological advances. PERC (Passivated Emitter and Rear Cell) technology improved cell efficiency. Bifacial panels that capture light from both sides entered the market. Module-level power electronics (microinverters and power optimizers) improved system performance and monitoring. Battery storage, led by Tesla's Powerwall, began integrating with residential solar to provide backup power and optimize time-of-use rates.

2020s: Grid Parity Achieved

Today, incentives like the federal solar tax credit make solar more affordable than ever.

By the early 2020s, solar energy had become the cheapest source of new electricity generation in history. The International Energy Agency declared solar the "new king of global electricity markets" in its 2020 World Energy Outlook. Over 3 million American homes had solar installations, and global installed capacity exceeded 1,000 gigawatts. Solar accounted for the majority of new electricity generating capacity added worldwide in 2022, 2023, and 2024.

The Inflation Reduction Act of 2022 in the United States extended and enhanced the federal solar tax credit at 30% through 2032, while adding additional incentives for domestic manufacturing, low-income solar access, and energy storage. This landmark legislation positioned solar for continued exponential growth throughout the decade. Projections suggest residential solar installations in the United States could double from 2024 levels by 2030, with commercial and utility-scale installations growing even faster.

Looking ahead, emerging technologies promise to push solar further. Perovskite-silicon tandem cells may push residential panel efficiency above 30%. Building-integrated photovoltaics (BIPV) will embed solar into windows, roofing materials, and building facades. Agrivoltaics combines solar generation with agriculture, using elevated panels that allow farming beneath. Floating solar arrays deploy on reservoirs and lakes, saving land while reducing water evaporation. The future of solar energy has never been brighter.

Key Milestones Timeline

The Future of Solar Technology

Despite rapid progress, many myths persist. We debunk them in our solar myths vs facts article.

As solar energy continues its remarkable growth trajectory, several emerging technologies promise to further transform how we generate and use clean electricity. Perovskite tandem cells, which layer perovskite semiconductor material atop traditional silicon, have achieved laboratory efficiencies exceeding 33% and may reach commercial production by the late 2020s. These cells could dramatically increase energy production from the same roof area.

Building-integrated photovoltaics (BIPV) represent another frontier, embedding solar cells directly into roofing shingles, window glass, and exterior cladding. Companies like Tesla (Solar Roof), CertainTeed, and GAF Energy offer solar roofing products that replace conventional roofing materials while generating electricity. As these products improve in efficiency and cost-effectiveness, new construction may increasingly incorporate solar generation as a standard building feature.

Energy storage integration will continue deepening, with batteries becoming standard components of residential solar systems. Vehicle-to-grid (V2G) technology may allow electric vehicles to serve as mobile batteries, absorbing excess solar during the day and discharging to power homes during peak evening hours. Smart home energy management systems will automatically optimize when to run appliances, charge EVs, and discharge batteries based on solar production, utility rates, and weather forecasts. The solar homes of 2030 will bear little resemblance to today's systems, even as the fundamental photovoltaic technology traces its lineage back to Becquerel's 1839 discovery.