How Mária Telkes Powered the Green Revolution

She was called the „Sun Queen”—and it’s hard to imagine a more fitting title. For decades, Mária Telkes was ahead of her time, creating technologies that are now seen as obvious hallmarks of the green energy revolution. Her inventions saved lives during wartime, heated homes without coal or oil, and even helped astronauts survive the extreme conditions of space.

From Budapest to American Laboratories

Mária Telkes was born on December 12, 1900 in Budapest, then part of Austria-Hungary. Even as a young woman she displayed exceptional scientific talent—in 1920, she graduated from the University of Budapest with a degree in physical chemistry, and just four years later she earned her doctorate. An academic career in her homeland seemed a natural choice, but a visit to a relative serving as the Hungarian consul in Cleveland changed the course of her life.

In 1925, Telkes decided to emigrate to the United States. 1920s America offered opportunities to scientists that Europe could only dream of. The young biophysicist joined the Cleveland Clinic Foundation, collaborating with surgeon George Washington Crile on a pioneering project—a photoelectric device for recording brain waves. She was already fascinated by converting one form of energy into another.

Twelve years after her arrival in America, Telkes became a U.S. citizen in 1937. That same year, she began working as a research engineer at Westinghouse Electric, developing instruments to convert heat into electricity. But fate had even bigger challenges in store for her.

The Invention That Saved Castaways

1939 proved to be pivotal. Telkes joined the Solar Energy Conversion Project at the Massachusetts Institute of Technology—one of the world’s most prestigious research centers. When the United States entered World War II two years later, her talents were directed to urgent military needs.

As part of the U.S. Office of Scientific Research and Development, Telkes created a device that would soon save hundreds, maybe thousands, of lives. It was a solar still—a compact system capable of evaporating salty seawater and condensing it back as drinkable water. For sailors and airmen adrift in lifeboats after their ships sank or planes were shot down, it meant the difference between life and death.

The invention didn’t remain just an emergency tool. After the war, the technology was scaled up and used to supply drinking water to the Virgin Islands, where fresh water was scarce. The simple principle—using free solar energy to purify water—proved useful far beyond the battlefield.

The Sun-Heated House

After the war, Telkes remained at MIT, earning a promotion in 1945 to professor in metallurgy. But her true passion—solar energy—drew her toward a project that would make architectural and engineering history.

In 1948, with architect Eleanor Raymond, Telkes designed and built the world’s first modern residential home heated by solar energy. The Dover Sun House, erected in Dover, Massachusetts, was decades ahead of its time. Its system used ingenious box-shaped solar collectors to capture sunlight and heat air in the space between two layers of glass and a black metal plate.

Heated air was then piped into the house’s walls, where it transferred heat to Glauber’s salt—crystallized sodium sulfate. This phase-change material stored thermal energy and released it gradually as temperatures fell. It was a revolutionary way to store solar energy for use at night or on cloudy days—a problem engineers still grapple with today.

A Solar Cooker for the World

The success of the Dover Sun House opened new opportunities for Telkes. In 1953, she received a $45,000 grant from the Ford Foundation—a huge sum at the time—to create a universal solar oven. Her vision was ambitious: the device would be adaptable for people living at all latitudes, from the equator to the far north.

Telkes continually refined heat-exchanger technology, inventing solar cookers and heaters that could function without access to conventional energy sources. At a time when oil seemed inexhaustible and coal dominated energy production, her work was seen by many as a curiosity—not a sign of things to come.

But Telkes did not slow down. Her research expanded to materials that could withstand the extreme temperatures of space—both the searing heat of the sunlit side and the icy cold of the shadow. In 1980, at the age of 80, she participated in a U.S. Department of Energy project that led to the world’s first solar-electric powered residential building, built in Carlisle, Massachusetts.

A Recognized Pioneer

Mária Telkes’s achievements did not go unnoticed. In 1952, she became the first recipient of the Society of Women Engineers Achievement Award—an honor created especially to acknowledge women’s achievements in traditionally male-dominated fields. A quarter-century later, in 1977, the National Academy of Sciences Building Research Advisory Board honored her with a lifetime achievement award in solar heating technology for buildings.

That same year, the American Solar Energy Society awarded her the Charles Greeley Abbot Award, one of the solar energy industry’s most prestigious honors. Telkes remained active almost to the end of her life, constantly developing solar energy applications and receiving more patents for her inventions.

She died on December 2, 1995 in Budapest, just ten days before her 95th birthday. Fittingly, she spent her final days in the city where she was born and—nearly a century earlier—began her scientific adventure.