Expo 1889 Paris is remembered for introducing the world to the Eiffel Tower. However, it was also the site of another important debut: French visionary engineer Aristide Bergès’ demonstration of hydroelectricity, a concept known as “Houille Blanche” or “White Coal”, that swept through Europe and the world.

In the mid 19th century, the industrial revolution made coal the major source of energy and thus, a precious commodity. So when at the Expo, Bergès’ exhibit informed visitors about an alternate energy source, he called it “Houille Blanche”, to draw attention from visitors and to highlight the energy potential of water from the mountains, which had been ignored in favour of coal.

Augustin Mouchot’s solar device made its debut at Expo 1878 Paris. At a time when France was seeking to rebuild itself following the Franco-Prussian war, the inventor of the first parabolic solar collector was seen as a genius.

A brilliant French mathematician who possessed a futuristic mentality that led him to foresee a time when the world would no longer be able to depend on non-renewable resources, Mouchot first built a solar-powered steam engine using a concave mirror to reflect the sun’s rays onto a glass-covered boiler. To his amazement, it worked perfectly and motivated him to experiment further in Northern Africa.

Expos are more than just events to showcase accomplishments; they are also laboratories where breakthroughs are made. At Expo 1873 in Vienna, a major discovery was made when Belgian inventor Zénobe Gramme’s dynamo was inadvertently transformed into the first ever industrial electric motor.

As with previous Expos, the majority of machines showcased in the capital of the Austro-Hungarian Empire were powered by steam. Electricity was largely seen as an oddity, even if scientists and engineers had greatly improved their understanding of electrical currents. Werner von Siemens showcased one of the first dynamo-electric machines at Expo 1867 in Paris, but the industrial use of electricity as a source of power was constrained by the small and inconsistent amount of energy it could supply.

Expo 1889 in Paris is most famous today for the Eiffel Tower, but it was equally a major gathering of inventors, producers and artists from across the globe. While earlier Expos had mostly focused on manufactured products and machinery, by 1889 there was increased interest in other sectors, notably food and beverages, including beer.

At Paris’ first Expo in 1855, samples of beer were presented, but exhibitors did not take part in competitions. The widened scope of Expo 1867 allowed brewers to increase their presence, with 40 exhibitors showcasing their selection of beers. By the time of Expo 1878, this participation doubled, featuring mostly French and Belgian beer producers as well as a growing contingent from the United States.

At Expo 1867, the second World Expo to be organised in Paris, a newcomer in energy production made a breakthrough – the gas engine. The emergence of this alternative form of energy production was the subject of significant rivalry at the Expo and it would go on to make ripples as a new method of powering machines and transportation.

In the mid 19th century, demand for accessible and reliable energy was increasing at a rapid pace, driven by the inventions and discoveries of the industrial revolution. The coal-powered steam engine enjoyed a near-monopoly in the production of energy for machinery and locomotives, but improvements in its functioning were beginning to plateau. This gave rise to a quest to find more efficient, more powerful and more practical ways to source, produce and use energy.