History of Solar Energy: When It Was Invented and How It Evolved
Solar electricity was discovered in 1839, when French scientist Edmond Becquerel found that light could produce an electric current, an effect we now call the photovoltaic effect. Charles Fritts described the first solar cells, made from selenium, in 1883, and Bell Labs built the first practical silicon solar cell in 1954. People have used the sun's heat for much longer: records go back to the 7th century B.C.
Here on Oʻahu, solar panels are part of the scenery, so it's easy to forget how new the technology is. This guide walks through the history of solar energy from ancient mirrors to modern rooftop systems, answers the questions people ask most about when solar power was invented, and shows how Hawaiʻi went from an oil-dependent grid to one of the country's leaders in rooftop solar. Alternate Energy Hawaii has been part of that story since 1993.
When was solar energy invented?
Nobody invented sunlight, so the honest answer depends on what you mean by "solar energy." There are three dates worth knowing:
- 1839, the discovery. Edmond Becquerel saw the electricity from an electrolytic cell increase when it was exposed to light. That was the first recorded photovoltaic effect, the same process every solar panel uses today (U.S. Department of Energy).
- 1883, the first solar cell. American inventor Charles Fritts described the first solar cells, made from selenium wafers. They proved light could become electricity, but they were far too weak to run equipment.
- 1954, the first practical solar cell. Daryl Chapin, Calvin Fuller and Gerald Pearson at Bell Labs built a silicon cell that could turn enough sunlight into power to run everyday electrical equipment. The Department of Energy calls it the moment photovoltaic technology was born in the United States.
So if you're asking when solar power was created in the modern sense, 1954 is the best single answer. If you're asking when solar energy was first discovered as a source of electricity, it's 1839.
When was solar energy first used?
Long before anyone made electricity, people used the sun for heat and fire. The Department of Energy's solar timeline starts in the 7th century B.C., when people used a magnifying glass to concentrate the sun's rays and start fires. By the 3rd century B.C., Greeks and Romans were using "burning mirrors" to light torches for religious ceremonies.
Builders used the sun too. Roman bathhouses from the first to fourth centuries A.D. had large south-facing windows to let in the sun's warmth. That's the same idea behind passive solar design today, and it's why we still talk about which way a roof faces when we size a system.
How long has solar energy been around?
- Solar heat: more than 2,600 years, back to the 7th century B.C.
- Solar electricity: more than 185 years, since Becquerel's 1839 discovery.
- Practical solar panels: more than 70 years, since Bell Labs' 1954 silicon cell.
Solar is an old idea, but the panels on your neighbor's roof are the product of a few decades of fast improvement.
Solar energy history timeline: key milestones
This timeline uses the milestones recorded by the U.S. Department of Energy's History of Solar timeline.
| Year | Milestone |
|---|---|
| 7th century B.C. | A magnifying glass is used to concentrate the sun's rays to make fire. |
| 3rd century B.C. | Greeks and Romans use burning mirrors to light torches for religious purposes. |
| 1st–4th century A.D. | Roman bathhouses use large south-facing windows to let in the sun's warmth. |
| 1767 | Swiss scientist Horace de Saussure is credited with building the world's first solar collector. |
| 1839 | Edmond Becquerel discovers the photovoltaic effect. |
| 1873 | Willoughby Smith discovers the photoconductivity of selenium. |
| 1876 | William Grylls Adams and Richard Evans Day show that selenium produces electricity when exposed to light. |
| 1883 | Charles Fritts describes the first solar cells, made from selenium wafers. |
| 1891 | Baltimore inventor Clarence Kemp patents the first commercial solar water heater. |
| 1905 | Albert Einstein publishes his paper on the photoelectric effect. |
| 1918 | Jan Czochralski develops a way to grow single-crystal silicon. |
| 1921 | Einstein wins the Nobel Prize for explaining the photoelectric effect. |
| 1954 | Bell Labs develops the silicon solar cell, the first able to run everyday electrical equipment. |
| 1958 | The Vanguard I satellite uses a small solar array to power its radios. |
| 1970s | Dr. Elliot Berman, with help from Exxon, designs a much cheaper solar cell, bringing the price down from $100 a watt to $20 a watt. |
| 1973 | The University of Delaware builds "Solar One," one of the world's first PV-powered homes. |
| 1977 | The U.S. Department of Energy launches the Solar Energy Research Institute, now the National Renewable Energy Laboratory. |
| 1980 | ARCO Solar becomes the first company to make more than 1 megawatt of solar modules in a year. |
| 1982 | The first megawatt-scale solar power station goes online in Hesperia, California. |
The evolution of solar power, era by era
Discovery: the 1800s
The 1800s were about proving the idea. Becquerel found the effect in 1839. Smith, Adams and Day showed selenium reacts to light in the 1870s. Fritts made the first selenium cells in 1883. The Department of Energy notes that selenium cells couldn't convert enough sunlight to power electrical equipment, but they showed a solid material could turn light into electricity with no heat and no moving parts.
The same century gave us solar hot water. Clarence Kemp's 1891 patent for a commercial solar water heater is a direct ancestor of the solar water heating systems on Hawaiʻi roofs today.
Science catches up: 1900 to 1950
Early solar cells worked before anyone fully understood why. Einstein's 1905 paper on the photoelectric effect explained it, and it earned him the 1921 Nobel Prize. In 1918, Jan Czochralski found a way to grow single-crystal silicon, which is still the basis of how most solar wafers are made. If you're curious about that process, see how solar panels are made.
The first practical solar cell: 1954
Bell Labs' silicon cell changed everything. According to the Department of Energy, Bell's first silicon cells converted about 4 percent of sunlight into electricity, and the lab later reached 11 percent. A year later, Western Electric began selling commercial licenses for silicon solar technology.
The space age: late 1950s and 1960s
Solar cells were too expensive for homes, but they were perfect for satellites. In 1958, Vanguard I used a small solar array, under one watt, to power its radios. Explorer III, Vanguard II and Sputnik-3 followed with solar-powered systems that same year, and solar became the accepted power source for spacecraft.
Coming down to Earth: the 1970s and 1980s
The 1970s brought solar costs down far enough for use on Earth. Dr. Elliot Berman's cheaper cell cut the price from $100 a watt to $20 a watt, and solar began powering navigation lights, offshore rigs, lighthouses and railroad crossings where running power lines didn't make sense. In 1973, the University of Delaware's Solar One became one of the first PV-powered homes. The federal government opened the Solar Energy Research Institute in 1977, and by 1982 the first megawatt-scale solar power station was running in California.
Today's rooftop solar
Modern home systems still rely on the same principle Becquerel spotted in 1839: sunlight knocks electrons loose in a semiconductor, and that movement becomes electricity. What's changed is efficiency, durability and price, plus everything that now sits around the panels: inverters, monitoring and batteries. For a plain-language walk-through, read how solar energy works in Hawaii and our guide to photovoltaic technology in Hawaiʻi.
The history of solar power in Hawaiʻi
Hawaiʻi has a strong reason to go solar. The U.S. Energy Information Administration says Hawaiʻi has the highest average electricity price of any state, reaching nearly triple the U.S. average (EIA). That cost, plus year-round sun, made the islands an early adopter.
| Year | Hawaiʻi solar milestone |
|---|---|
| 1993 | The Ekimura family founds Alternate Energy, Inc. in Pearl City, Oʻahu. |
| 2008 | The State of Hawaiʻi and the U.S. Department of Energy sign the agreement that launches the Hawaiʻi Clean Energy Initiative (Hawaiʻi State Energy Office). |
| 2010 | From January 1, a building permit for a new single-family home generally requires a solar water heater, under HRS §196-6.5 (Hawaii Revised Statutes). |
| 2015 | Hawaiʻi becomes the first state to set a 100% renewable portfolio standard, with a 2045 deadline (EIA). |
| 2015 | Net Energy Metering closes to new customers on October 13 (Hawaiian Electric). |
| 2017 | Customer Grid-Supply, one of NEM's replacements, closes on November 7. |
| 2022 | Hawaiʻi's last remaining coal plant is decommissioned (Hawaiʻi State Energy Office). |
| 2024 | Smart Export and Customer Self-Supply close on March 29. New customers now join Hawaiian Electric's Smart Renewable Energy programs. |
| 2025 | The 30% federal Residential Clean Energy Credit ends for systems placed in service after December 31, 2025 (IRS). |
| 2026 | Act 24 changes Hawaiʻi's state solar tax credit, keeping the 35% rate but adding a yearly cap, income limits and certification from 2027. |
From net metering to Smart Renewable Energy programs
Homeowners who joined Net Energy Metering before it closed in October 2015 can stay on it, and Hawaiian Electric still supports them. Everyone since has joined a newer program. Today, Hawaiian Electric offers Smart Renewable Energy Export (bill credits for power you send to the grid), Smart Renewable Energy Non-Export (no export), and Bring Your Own Device Plus, which pays an incentive for a new battery that discharges during set periods (Hawaiian Electric). If you're adding solar now, it's worth looking at battery storage alongside the panels. Our BYOD Plus guide explains how the battery program works.
Where Hawaiʻi solar stands today
The EIA's latest Hawaiʻi profile shows how far the islands have come:
- About one-third of Hawaiʻi's electricity came from renewable sources in 2025.
- Solar produced about 70% of the state's renewable electricity and 14% of all its electricity.
- Rooftop and other small-scale solar generated almost twice as much as utility-scale solar farms.
- By the end of 2025, Hawaiʻi had 1,539 megawatts of solar capacity, almost two-thirds of it on customer sites.
In other words, Hawaiʻi's solar story is mostly a rooftop story, written one home and business at a time.
What solar history means for your home or business today
A few lessons from 180-plus years of solar still apply when you're comparing quotes on Oʻahu:
- The technology is proven. Silicon solar cells have been powering satellites since the 1950s and homes since the 1970s. The question today is fit, not whether solar works.
- The rules change more than the panels. NEM, CGS and Smart Export all closed within a decade. Choose a system designed for the program you're joining now, not the one your neighbor joined in 2014.
- Incentives have deadlines. The federal homeowner credit ended in 2025, and the state credit changes from 2027. Our Hawaii solar tax credit guide explains what still applies.
- Island conditions matter. Salt air, trade winds and roof type all affect equipment choice and installation. Work with an installer that designs for them.
Whether you're looking at home solar or commercial solar, Alternate Energy Hawaii's own employee crews design and install every system. We've been doing it on Oʻahu since 1993.
History of solar energy FAQ
When was solar energy invented?
Solar electricity dates to 1839, when Edmond Becquerel discovered the photovoltaic effect. Charles Fritts described the first selenium solar cells in 1883, and Bell Labs built the first practical silicon solar cell in 1954.
When did solar energy start being used?
People have used the sun's heat since at least the 7th century B.C., when a magnifying glass was used to concentrate sunlight and start fires. Solar cells were first put to regular use in the late 1950s, powering satellites such as Vanguard I in 1958.
Who invented solar panels?
No single person did. Becquerel discovered the effect in 1839, Charles Fritts made the first selenium cells in 1883, and Daryl Chapin, Calvin Fuller and Gerald Pearson developed the first practical silicon solar cell at Bell Labs in 1954.
How long has solar energy been around?
Solar heat has been used for more than 2,600 years, solar electricity has been known for more than 185 years, and practical silicon solar panels have existed for more than 70 years.
When did solar become common in Hawaiʻi?
Solar water heaters have been required on most new single-family homes in Hawaiʻi since January 1, 2010. Rooftop solar grew quickly under Net Energy Metering until it closed in October 2015. By 2025, solar produced about 14% of all Hawaiʻi's electricity, mostly from rooftop and other small-scale systems.
Is there still a solar tax credit in Hawaiʻi?
Yes. Hawaiʻi's Renewable Energy Technologies Income Tax Credit pays 35% of a system's cost, up to $5,000 for a single-family solar PV system. The 30% federal homeowner credit ended for systems placed in service after December 31, 2025. Ask a tax professional how the credits apply to you.
Be part of Hawaiʻi's next chapter of solar
From burning mirrors to battery-backed rooftops, solar keeps getting better. If you want to see what it can do for your home or business, Alternate Energy Hawaii will look at your bills, your roof and the current Hawaiian Electric programs, and give you a straight answer. Call (808) 842-5853 or request your free estimate.
