The solar pioneer was so far ahead of his time that he was forgotten

Built to collect the sun’s radiant energy, the facility consisted of long rows of glass and steel gutter-like solar collectors. The light reflected from the solar collectors was so intense that it made the invited guests squint.

When Frank Shuman turned on the device, a loud hissing sound came from the man-tall steam engine. People watched in amazement as the machine suddenly came to life as if by magic and began pumping water from the Nile River at a rate of over 22,000 liters per minute – powered by solar energy alone. For Frank Shuman, it was the culmination of seven years of work. He wanted to convince the world that solar energy was cheaper and better than energy from fossil coal and oil.

“Mankind must start using direct solar energy or fall back into barbarism,” he warned.

Shuman calculated: if one percent of the solar energy falling on the Sahara desert was converted into electricity, it would cover the electricity needs of all the nations of the world. His mission to promote solar energy was very close to success, and in that case the world’s development would have taken a completely different course.

Used the greenhouse effect

The solar collector was by no means the first invention of Frank Shuman. An American whose grandfather had emigrated from Schleswig-Holstein to the United States received a patent in 1892 for shatterproof safety glass with a fine steel wire mesh inside. Shatterproof safety glass was used, for example, in large skylights and skylights that provide light. The invention was a success, and Shuman, with the help of investors, built a factory that supplied safety glass all over the United States.

By 1906, the 44-year-old Shuman had earned enough to devote himself fully to invention, and he soon began experimenting with solar energy. At that time, coal was the most used energy source in the world. Steam engines consumed about 200 million tons of coal per year. However, burning coal led to pollution, and many feared the day when the coal deposits would run out. Among them was Frank Shuman, who saw the possibilities of the future in solar energy.

Among other things, his interest in solar energy was aroused by the knowledge that glass surfaces have the ability to retain heat, i.e. create a greenhouse effect. The sun’s short-wave rays pass through the glass of the greenhouse unhindered. Their energy is absorbed by soil and plants and radiates back as long-wave infrared radiation that cannot penetrate through glass. Therefore, the temperature in the greenhouse is higher than outside.

Shuman believed that the effect could be used to so-called capture solar energy. He experimented with transferring energy from the sun to a machine in the backyard of his house in Tacony, a suburb of Philadelphia. The American’s first solar machine consisted of wooden boxes filled with ether, made leakproof and covered with plate glass.

Ether has a much lower boiling point than water. Shuman led his son to the toy steam machine, which started working as soon as the pistons popped. With this, he had proved that he could convert solar energy into mechanical energy with simple means. Now we had to think about how to make the invention more powerful and practical.

The solar collector must be cheap

Shuman’s next facility consisted of the same ether boxes as the first, but now they covered a hundred square meters. A system of pipes ran through the hot boxes, as he called them, which served as a boiler. During the trial run, the Shuman facility operated a steam engine rated at 4 horse power. This was enough to run the water pump.

To draw attention to the project, Shuman invited everyone to see his facility, proudly demonstrating his solar-powered pump himself, wearing a suit, cap and bow tie.

Shuman constantly improved the facility. Ether vapor was too volatile for a large steam engine, so his next goal was to use solar heat to produce water vapor. This required water, which expands approximately 1,600 times during the evaporation phase and can thus operate more powerful machines. However, the water also required a higher temperature.

Therefore, he built an even bigger facility with better boilers, an additional layer of glass and mirrors that raised the temperature of the water under the glass up to 120 °C. His solar system was able to generate enough water vapor to power a modified 25 horsepower steam engine.

The inventor knew that businessmen would not open their wallets after a mere clever idea. The development of a commercially usable solar plant required investments.

The race to tame solar energy

Before Frank Shuman, many had tried to use solar energy, but the practical benefits of the experiments had been meager.

“To be practical, a solar system must have high efficiency, be cheap to install and maintain, have a long service life, and must not require specially trained mechanics,” he wrote in Scientific American.

Above all, a solar plant had to be cheaper in the long run than a coal-fired plant. The best way to achieve this was to build a solar station in a sunny location. In 1911, Shuman traveled to England, whose colonies included the sunniest regions of the world.

The timing was good. In the same year, British Field Marshal Lord Kitchener was appointed British Consul General to Egypt, which had been under British control since 1882. The energetic Kitchener wanted to improve the country’s economy, which required the establishment of better irrigation systems.

“Prosperity and water go hand in hand in Egypt,” he confirmed.

Kitchener’s desire was to increase Egyptian cotton production. Egyptian cotton was considered the best in the world and in 1900 the country produced nearly 300,000 tons of it. In order for the cotton bushes to grow in the desert landscape, a huge amount of water was needed – 25 tons per hectare per day.

The British had tried to use steam-powered pumps, but the coal for the machines had to be sourced from Wales, 5,600 kilometers away. This raised the price of coal to $40 per ton. Shuman thought that a solar plant could pump water much more cheaply, and asked for a meeting with Kitchener, who immediately recognized the possibilities of solar energy.

Imperial support attracted British investors, and in 1912 Shuman began construction of a solar plant in the city of Maadi on the banks of the Nile, south of the capital Cairo. The American’s plan was to build a device similar to the one he had built in the US, only much larger. The facility was to run a 1,000-horsepower steam engine, which was 40 times more powerful than Shuman’s most powerful device to date.

In London, nervous investors asked one of the most famous physicists of the time, Sir Charles Boys, for an assessment of the project, who was not satisfied with the venture. Boys thought that instead of boxes, solar energy should be captured with parabolic mirrors. Shuman paled. Such a solution would make the station much more expensive. To make the price cheaper, he would have had to build a smaller facility – this would have meant that the capacity of the facility would have been reduced from 1,000 horsepower to 85 horsepower.

However, his protests were of no avail. In the following months, rows of mirrors in the shape of long gutters appeared in the desert, and in June 1913, a facility measuring just over 1,200 m2 was completed.

The war shattered all dreams

Among those invited to the opening was Lord Kitchener. After seeing how the facility pumped over 400,000 liters of water to the fields per hour, he excitedly offered Shuman to finance the construction of the next solar systems.

Calculations showed that the energy obtained from the solar plant was 16 times cheaper than the price of coal imported into Egypt. The British therefore also saw good opportunities in the dry Sudan under their control, which was also perfect for cotton production. The German ambassador was also present at the opening of the Maadi facility. Soon after, Shuman was proposed to build solar plants in Germany’s African colonies.

“Solar energy is now a fact, no longer just a ‘beautiful possibility,'” Shuman wrote happily in 1914.

Intoxicated by success, Shuman calculated that if a 51,800 km2 solar plant were to be built in the Sahara, the energy obtained from it would cover the entire world’s energy consumption needs. However, his dreams never came true. In August 1914, the First World War broke out. Shuman was sent home and the Maadi facility was abandoned.

In the same year, Britain bought a majority stake in the Anglo-Persian Oil Company in order to gain access to oil deposits discovered in Persia a few years earlier. A single-minded investment in oil put an end to Shuman’s dreams. As a matter of fact, the largest oil deposits were located in the sunniest regions of the world. However, Frank Shuman did not have to see the victory of oil with his own eyes, because he died in April 1918 at the age of only 56.

It wasn’t until 60 years later that the world took up his vision again. Nowadays, solar energy is back in vogue.