Fossil-fuel dependant transport accounts for nearly one quarter of worldwide CO2 emissions linked to energy, and the trend is set to increase as access to different forms of transport becomes more widespread in developing countries. This raises questions over the future of mobility: how will people move around cities, around countries, and across oceans in the future, in a sustainable manner?

Looking to the future, a potentially revolutionary form of transport is set to be available for visitors to Expo 2020 Dubai, the next World Expo. According to developers’ plans, an integrated Hyperloop system will be ready by the opening of the Expo to transport people and goods at supersonic speeds between Dubai and Abu Dhabi.

The intertwined relationship between food and energy is a fundamental question when considering future energy and future food supplies. The cultivation, processing, storage, packaging and transport of food accounts for a major share of energy consumption worldwide, of which an estimated 79% comes from fossil fuels.

Expo 2015 Milan – organised around the theme “Feeding the Planet: Energy for Life” – was an opportunity to address this challenge, which by its very nature impacts all countries and all people. The Expo was a platform for participating countries to exhibit the latest technologies regarding the production and consumption of food, and dealing with food waste. Participants thus demonstrated how feeding a growing population can be achieved in a sustainable manner, for example by economizing on land use and minimizing the energy-intensive practices of large-scale agriculture.

Strategically-placed vegetation can cut energy consumption by up to 50% and play a crucial role in filtering atmospheric pollutants in a city. Urban greening – planting living, green walls or roofs, wherever possible in urban spaces and cities - has become the trend for overcrowded cities, seeking to conserve energy and reduce air pollution and greenhouse gas emissions.

The concept, which has been around for over 2,000 years, combines nature and architecture, and has tremendous potential for improving energy efficiency in a city.

Imagine a house that generates all of its own energy, collects its own water and efficiently manages its waste system - an autonomous house. The technology for such self-sufficient homes, able to meet the pressing energy demands of the future, is available today, by using a combination of alternative energy sources such as geothermal energy, solar panels, wind turbines and hydropower.

A fully functional, working model of a self-sufficient home was showcased in the Oikos pavilion (meaning “house” in Greek) at Expo 2008 Zaragoza. Putting innovative solutions to the use of reduced energy and water consumption encapsulated the theme of the Expo – “Water and Sustainable Development.”

Fuel cells, a promising and virtually limitless energy source that can be used for various applications including transportation, portable appliances and stationary installations, were first discovered in 1839 by Sir William Grove. However, it is only in the past two decades that the technology has become a viable and practical solution. With water as its only by-product, fuel cell technology is in line to become one of the key next-generation solutions for Future Energy.

This forward-looking and eco-friendly technology, which involves an electrochemical process where hydrogen and oxygen are converted into water to produce electricity, was showcased at Expo 2005 Aichi in Japan via a fleet of specially designed buses.

Energy consumption in buildings accounts for over one third of final energy consumption globally. The OECD estimates that buildings account for more than 40% of energy consumption in developed countries, largely through electricity use.

Fortunately, buildings have the capacity to make a significant contribution to a more sustainable future, if energy-saving methods are integrated into their design. An early example of sustainable construction was showcased at Expo 1992 Seville, which celebrates its 25th anniversary this year. The United Kingdom’s pavilion at Expo 1992 embodied the concept of energy self-sufficiency by combining avant-garde architecture with the capacity to generate renewable energy such as solar power.

Extreme weather conditions and rising global temperatures are leading researchers to reconsider unconventional solutions such as Space-Based Solar Power (SBSP), as envisioned by scientists since the 1960s. This would be the perfect solution to climate change because solar power captured in outer space would not be vulnerable to poor weather, have zero greenhouse gas emissions and be unaffected by day and night cycles, unlike 23% of current incoming solar energy.

This untapped potential for Space-Based Solar Power was revealed when Telstar 1 (the world’s first active communication satellite) was used to beam scenes from Expo 1962 Seattle and transmit the first intercontinental television broadcast. The sphere satellite was powered by 3,600 solar cells and weighed over 77 kilos. It was a joint project by NASA (National Aeronautics and Space Administration) and the British and French governments, which broadcasted a panoramic view of the striking Space Needle and other interesting sights and sounds from the Expo.

Nuclear energy is one of the largest contributors to electricity production across the world, and its importance is not set to diminish in the near future, despite the controversy that has always surrounded it.

The glorious nuclear future envisioned in the mid-20th century, with bountiful, cheap and safe energy supplies, is not exactly the reality of today. However, humanity’s continuous need for safe and affordable energy means that the search to unlock the power of the atom remains relevant to this day.

The water-energy “nexus” – the intricate connection and special relationship between water and energy – has long been at the heart of humanity’s efforts to harness and manage energy for its own uses.

The importance of this nexus was already evident in 1939, when the Belgian city of Liège hosted a Specialised Expo under the theme “Water Management”, celebrating the completion of the Albert Canal.

Organised under the theme “World of Tomorrow”, Expo 1939 in New York celebrated the “Dawn of a New Day”, which was partly made possible by the electrification of the country. Increased access to safe and reliable energy in the first part of the 20th century lead to a wave of optimism and hope for a future shaped by technological prowess and societal changes.

In 1900, only around 2% of homes in the United States were electrified, but by 1939, this proportion had increased dramatically to approximately 70%.

Sustainable architecture and the passive house concept are undoubtedly subjects of priority among urban planners and architects in the 21st century. But long before concerns about reducing emissions and minimising energy use, one of the first concept homes integrating sustainable design was showcased at Expo 1933 in Chicago.

Built in the backdrop of the Great Depression, the House of Tomorrow, designed by American modernist architect, George Fred Keck, was presented at the “Century of Progress Exhibition”. It was a vision of what the future could offer and is considered as a pioneer in modern housing solar design.

The development of renewable energy alongside urbanisation and population growth has made the transmission of electricity a pressing issue for policymakers. Urban centres are often located hundreds or thousands of kilometres from the source of energy, and unlike fossil fuels, renewables cannot be transported. In response to this challenge, “supergrids” are being developed using specially built cables using direct current as very high voltages (HVDC), allowing large volumes of electricity to be efficiently transported over long distances.

The development of supergrids in the 21st century is the continuation of efforts since the dawn of the electric age to increase capacity and scale up access to electricity. As early as Expo 1904 in St. Louis, Chester H. Thordarson showcased a half-million volt transformer, winning a gold medal for the invention which he built in only 28 days. But it was not until Expo 1915 in San Francisco that Thordarson set the bar for electrical transmission when the public were introduced to the million-volt transformer, part of the High Tension Research Pavilion within the Machinery Palace.

The transfer of electricity has long been a conundrum for inventors and electrical engineers, and the question of power supply to different devices continues to be a focal point of research and development. Wireless systems and radio frequency signals increasingly look to be the future of powering devices, with many of the latest innovations to be showcased at Expo 2017 Astana.

Before the 1904 Louisiana Purchase Exposition in St. Louis, there was no standard method of the various electrical appliances and devices that had been invented. Thomas Edison had already wired a number of homes in New York City, but one vital element was missing that changed the way we consume power forever: the plug and socket.

Expo 1900 Paris featured awe-inspiring pavilions that showcased the ingenuity of participating countries, but one exhibit that stood out was the stunning Palais de l’Electricité (the Palace of Electricity), which was as remarkable for its beauty as its essential function on the Expo site.

Designed by Eugène Hénard, this architectural marvel was a 130-metre-long and 70-metre-high façade, covered with thin stained glass and an intricately designed ceramic decoration; crowned at the top by a chariot drawn by hippogriffs spewing showers of multi-coloured flames.

Expo 1893 in Chicago, the World’s Columbian Exhibition, surpassed all previous World Expos in size and unapologetically embraced progress and the modern era. The widespread use of electricity on the site of the Expo was a symbol of the positive side of modernity.

For the organisers, this major endeavour was essential, and it led to one of the most significant corporate and technical rivalries of the time so much so that it shaped the future of electricity in the United States.

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.

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.

On 10 June, Expo 2017 will open in Astana, Kazakhstan, under the theme “Future Energy.” The Specialised Expo will be an opportunity for host country and international participants alike to showcase the latest technologies and innovations in energy production, storage, access and use.

While the organisers, participants and visitors to Expo 2017 Astana will rightly focus on the latest innovations and trends that will shape the future of energy, the past can also provide inspiration. Previous Expos, at which innovation has been showcased and celebrated, may serve as an example and teach us lessons about the future.