“It was very dramatic holding such a thing in your hand, with the blades passing in front of your nose at a speed of hundreds of kilometres per hour.”
Henrik Stiesdal was a 16-year-old student living on his parents’ farm in a small town in eastern Denmark when the oil crisis hit in 1973. More than 90% of Denmark’s energy supply came from imported fuel. Oil prices tripled and, with it, electricity prices. Stiesdal’s family, along with many other Danes, struggled to pay high energy bills.
Even before that energy crisis, thousands of small windmills had been installed on farms across Denmark.
Some even produced electricity. Stiesdal wanted to buy a wind turbine that could power the farm and reduce his parents’ bills, but nobody was selling them. “If we can’t buy one,” he thought, “let’s build one ourselves.”
First, he experimented with a small two-blade turbine. “It was very dramatic holding such a thing in your hand, with the blades passing in front of your nose at a speed of hundreds of kilometres per hour,” Stiesdal remembers. He soon built a bigger wind turbine, adding another rotor blade. This turbine’s rotor diameter stretched 10 metres, and it could provide almost enough energy for the whole farm.
In 1979, Stiesdal and a local blacksmith, who helped him build the turbine, sold their design for a three-blade wind turbine to Vestas, a Danish manufacturer of kitchen appliances, milk coolers, and, later on, hydraulic cranes. The design would come to be known as the “Danish concept,” and it has since spread throughout the world.
Thanks in part to Stiesdal’s designs, Denmark became a leader in renewable energy production and use, while Vestas grew into the world's largest wind turbine manufacturer. Today, wind power supplies more than half of the electricity generated in Denmark, enabling it to become one of the most energy secure countries in the world.
Europe is working to copy this success across the continent. It wants wind power to supply 35% of all electricity by 2030, and 50% by 2050. It’s part of a broader push for renewable energies, which the European Union is counting on to reduce its dependence on fossil fuels and radically cut carbon emissions. But if Europe had the technology to produce renewable energy even before the 1970s, why did we allow ourselves to become so dependent on fossil fuels? Here’s the story.
- Read about Europe’s energy transition
Humans harness the elements
The Industrial Revolution ushered in an age of fossil fuels, which were cheap and readily available. But the truth is that prior to the Industrial Revolution in the 19th century, most energy was renewable.
Early humans discovered renewable energy a million years ago, when – to put it in more poetic terms – we discovered fire. The energy unlocked by setting dried plants and wood ablaze is known as bioenergy today. The discovery of bioenergy was critical to human evolution. Fire provided a source of warmth and lighting, protection from predators and a way of cooking food.
The first depictions of wind power date back to 3 200 BC. Ancient Egyptians harnessed wind to sail up the Nile. By 200 BC, simple windmills were used to pump water in China and the Middle East.
Romans used solar and geothermal energy to heat their homes and baths, and ancient Greeks developed the first waterwheels, harnessing hydropower to grind wheat into flour.
Hydropower became one of the most important energy sources available to the medieval world. By the 19th century, when the principles of electricity were first discovered, scientists began developing ways to generate electricity using renewable energy.
Those efforts largely died during the Industrial Revolution, which brought the combustion engine and a reliance on fossil fuels, primarily coal. Fossil fuels – including oil –went on to dominate the world’s energy supply, maintaining their leading position until today.
Advances in the 20th century, however, would revive wind and solar, eventually turning them into the protagonists of the green transition.
- Read about other forms of renewable energy
Hydropower: The rise of white coal
The one renewable energy that thrived during the Industrial Revolution was hydropower. The waterwheel became the hydraulic turbine, and hydropower became known as “white coal.”
It's still important today. Hydropower supplies one-sixth of the world's electricity, more than all other renewable sources combined. But unlike other renewables, hydropower dams are a mature technology, with limited room to increase the amount of energy they produce.
More than half Europe’s hydropower infrastructure is over 40 years old and needs to be updated. Meanwhile, some countries have already developed hydropower fully. And damming up or altering the flow of rivers can severely affect wildlife and entire ecosystems.
Those limitations are largely why solar and wind power gained prominence in green energy.
Wind picks up
Stiesdal’s idea to power his parents’ farm using wind was inspired by a 19th century Danish inventor and wind pioneer, Poul la Cour. La Cour believed that wind energy was crucial to the country’s electrification, underway at the time.
In 1891, he constructed one of the first wind turbines that produced electricity. His vision was to share this knowledge with the country’s rural population. Wind power would help modernise agriculture, enabling farmers to pump water for irrigation and generate electricity for their homes. Similar initiatives were being rolled out at the same time in North America.
Already in 1918, 120 wind turbines were connected to the grid and supplied 3% of Denmark’s electricity, while more than 25 000 farms generated energy with small, private wind turbines. However, those turbines would soon be replaced by the diesel motor.
During World War II, wind turbines were welcomed again as a power source, when resources were scarce. The largest wind turbine of the time operated in the United States, on a hilltop in Vermont. It provided enough energy to power the local utility network for several months during the war. But the interest in wind power dissipated when fossil fuel imports were restored after the war.
Denmark takes the lead
It wasn’t until the 1970s energy crisis that wind finally picked up. The Danish government introduced subsidies for wind turbines and supported wind power research. “The wind turbines were still too small to generate a lot of electricity,” explains Peter Karnøe, a professor at Aalborg University who researches the history of renewable energy. “The original intent behind the subsidies was to create jobs and support rural communities, but it soon showed effectiveness at reducing our energy imports.”
In the late 1970s, a small Danish fishing village built a wind farm to cover all its electricity and heating needs. The world’s largest wind turbine at the time also went up in Denmark in 1978.
At a height of 53 metres and a span of 54 metres, Tvindkraft wouldn’t be surpassed until the 1990s (Tvindkraft is currently the world’s oldest wind turbine still in operation).
In 1979, Vestas started to mass produce wind turbines. “The subsidies proved to be successful in the follwing years, as Danish wind turbines sprang up in California,” Karnøe says.
Denmark was becoming a world leader in wind power. Wind power was ready for the next step. Turbines were heading out to sea.
The tide turns for wind energy
“In 1989, the Danish government decided we should do offshore wind,” Stiesdal remembers. “They realised that sooner or later we would run out of space on land, so they decided to make it happen offshore.”
Stiesdal worked on the construction of the Vindeby Offshore Wind Farm, the world's first wind farm at sea. “My responsibility was to ensure the turbines were designed for purpose and that we had the right technical solutions to go offshore.” The wind farm, which was installed in 1991, sported 11 turbines, each capable of producing 450 kilowatts of energy. That meant Vindeby could power 2 000 to 3 000 households a year.
Offshore wind farms in Denmark had proved a success, but they were built close to the coast. Mounting the still relatively small turbines onto foundations in the seabed and installing the blades over water wasn’t so different to building on land. The Netherlands and United Kingdom followed Denmark’s lead, setting up offshore wind farms of their own. The shallow coastal waters of the North Sea made it particularly well suited to offshore wind.
But building wind farms close to land posed problems. Shipping lanes and protected nature reserves made it almost impossible to develop wind farms near the German coast. Locals and tourists also thought wind turbines marred the view. What if wind farms could be hidden farther out at sea, where winds were stronger and more consistent?
The German government first contemplated developing offshore wind farms in the 1990s. The emerging wind power industry enthusiastically embraced the idea.
And then, for about 10 years… nothing happened.
- Read about how Europe needs to develop more wind power
Alpha Ventus: Going out to sea
In 2006 the German research community was invited to gather in Kassel, a town in the centre of the country, to hash out the challenges facing the Alpha Ventus offshore test site. The Vindeby offshore wind farm had been built in Denmark 15 years earlier, but Germany still had no offshore wind projects, largely because conditions made it harder to build close to the shore. Germany wanted to set up a research effort to identify and overcome the obstacles facing offshore projects farther out at sea.
The Alpha Ventus initiative was created. Scientists involved in the initiative put together various research projects to address questions raised by the pilot. Could the turbine towers be safely anchored to the seabed in deep water? Would the turbines disturb sea life and marine ecosystems, particularly when hammering support structures into the seabed caused significant noise and vibrations? Would submarines or other vessels crash into the turbines?
“Not many people really knew about offshore wind,” says the Fraunhofer Institute’s Bernhard Lange. “The aim was to build a community that could actually provide knowledge that would help with the development.”
Scientists tested the resilience of the wind turbines in rough, North Sea conditions. A wave machine simulated the force of water crashing onto the turbines. Scientists measured wind speeds, waves and currents in the area dedicated to the pilot project, and created models simulating whether turbines could withstand the force. Researchers also delved into how to design and monitor wind turbine foundations in deep waters.
A particularly thorny issue was the distance of the pilot wind farm from the shore. What kinds of ships and harbour infrastructure did they need to transport 800-tonne wind turbines and their blades, along with other materials needed for construction, like cranes. How much would it cost to get these structures to the middle of the sea and erect them on deep-water foundations?
By the time Alpha Ventus began operating in 2010, many of the technical challenges of building turbines at sea had been solved. Bubble curtains proved effective at mitigating the noise of hammering piles into the seabed, further reducing the ecological impact. And marine mammals, which had fled the area during construction, came back.
The pilot project showed that offshore wind farms using bigger turbines in deep waters were possible. “It gave confidence to everybody that it’s feasible. It could be done,” Lange says, “and technologically, it worked.”
Today, more than 1 500 offshore wind turbines are turning in German waters, a far cry from the original 12 turbines of the Alpha Ventus project.
Solar power: More than a magic trick
Humans have tried to capture the sun’s power since antiquity. Roman bathhouses often included south-facing rooms with large windows that directed the sun’s warmth into one area, the solarium. Greeks used “burning mirrors” at ceremonies to concentrate the sun’s rays on torches, creating enough heat to light them.
Real advances in solar technology, however, didn’t happen until the 1800s. Edmond Becquerel, a French physicist interested in the sun’s power, figured out in 1839 that shining the sun on two electrodes, one coated with silver chloride and the other with silver bromide, generated an electric current. Becquerel is often credited with discovering the photovoltaic effect that powers modern-day solar panels.
Another Frenchman, a maths teacher named Augustin Mouchot, invented a solar water-heater for baths and a solar oven for cooking. Mouchot’s inventions were largely born of his fear that coal, the primary energy source of the time, would one day run out. He even won a gold medal the 1878 Universal Exposition in Paris for his solar inventions, stunning crowds by producing blocks of ice from refrigeration device powered by solar power concentrated in a large, reflective metal cone.
The rise of the internal combustion engine, however, quashed interest in Mouchot’s innovations.
Solar’s big breakthrough came in 1954, when Daryl Chapin, Calvin Fuller and Gerald Pearson created the silicon photovoltaic cell at Bell Labs in the United States. The invention marked the first time sunlight was used to power an electric device for several hours at a time.
Solar research labs popped up in Europe and the United States, spurred in part by the 1970s oil crisis. But what really set solar power ablaze was deliberate, thoughtful renewable energy policies forged in cloudy Germany. One such policy was the “Thousand Roofs Programme.”
Solar panels on every roof
In 1990, Germany rolled out the “Thousand Roofs Programme” to encourage the installation of solar panels on the roofs of one- or two-family homes. Federal and state grants and affordable loans helped homeowners pay for the panels. The programme proved so successful that in 1999 Germany expanded it to cover 100 000 roofs.
Environmental concerns, such as pollution and climate change, were already bubbling in Germany. The “100 000 roofs” policy set a goal of developing 300 megawatts of solar capacity, largely by offering advantageous financing for solar panel installations. By the time the programme was phased out in 2003, it had supported 55 000 solar panel installations that added 261 megawatts of capacity.
Germany further pushed the rollout of clean energy with the Renewable Energy Sources Act, which entered into force in 2000. The act created feed-in tariffs that paid solar energy producers more than the market rate for electricity they sent to the power grid. Those tariffs made solar projects viable, since producing electricity from solar panels was still more expensive than using fossil fuels like natural gas.
Spain copied Germany’s method, introducing its own feed-in tariffs for solar projects. “The establishment of feed-in tariffs was very, very important,” says Ignacio Antón, a researcher at the Institute for Solar Energy at the Polytechnical University of Madrid. “It made photovoltaic installation financially attractive at that moment.”
A few years after introducing the schemes, Spain was the largest installer of photovoltaic (PV) panels in the world. That support created a thriving solar power industry, not just in panel production, but also in the engineering know-how, skilled labour and materials needed to install solar panels. “Spain was very important for the deployment of PV not only in Europe, but in the world,” Antón says.
The problem for Spain, like Germany, was that the government incentives were costly, and probably were not selective enough in choosing projects that were supported. At one point, Spain was spending €2.6 billion a year supporting the solar industry. It was untenable, and the expenses were growing just as the financial crisis began to unfold.
“The interest was much higher than expected,” Antón remembers. “The government needed to stop because the amount subsidies were taking in the budget was much, much higher than what was anticipated.”
Spain scaled back the tariffs, effectively pulling the plug on an emerging industry. The tariffs were already proving unpopular with consumers, who saw them as an expensive subsidy. “There were a lot of projects, and no real ceiling generally. As long as you had a solar project, you would get the support,” says Boschi of the European Investment Bank. “And then, of course, there was the financial crisis. The impact of those hidden tariffs on the final prices paid by consumers became quite a political issue.”
- Read about how solar panels will soon be everywhere
A renewable resurgence
Today, solar energy is one of the cheapest sources of electricity globally. “Since 2008, we have seen something like a tenfold decrease in the cost of electricity from solar power,” says David González García, a lead engineer in the European Investment Bank’s energy transition division.
González García says that solar plants reduced costs by scaling up and reconfiguring installations to get the most energy generation. The Cestas Photovoltaic plant near Bordeaux, which opened in 2015, packed 1 million solar panels in an area the size of about 600 football fields.
Instead of being placed at a slight incline, the panels were pitched against each other at a 45-degree angle. That allowed Neoen, the plant developer, to build the project more quickly and to produce more electricity in a smaller space.
“You are losing a bit of the solar production because the panel isn’t facing south, but you can accelerate the construction process and cram in more capacity,” González García says.
When it was first inaugurated, Cestas was the biggest solar park in Europe, and it produced enough power annually to cover the electricity needs of about one-third of residents in metropolitan Bordeaux, or about 300 000 people. The European Investment Bank supported the project with a €56 million loan.
Solar is again booming across Europe.
Capacity is estimated to have grown to almost 260 gigawatts in 2023, a 60% increase in two years. The European Union wants to more than double that amount to 600 gigawatts by 2030. Europe is also trying to revive solar panel production, with a big gigafactory planned in Catania, Sicily. The European Investment Bank and a pool of Italian banks are lending €560 million to the project.
Once unimaginable
Together, wind and solar power generated nearly one-fifth electricity in 2022, surpassing the share of natural gas for the first time. Europe is counting on renewable energy to meet its ambitious climate goals and reduce its dependence on fossil fuels, whose prices skyrocketed when Russia invaded Ukraine. The European Union recently increased its 2030 goal for the share of final energy consumption from renewable energy to 42.5%, with the hopes of reaching 45%.
That renewable energy would power so much of Europe was once unimaginable. The Fraunhofer Institute’s Bernhard Lange got involved in wind power 30 years ago when he was working on his master’s thesis at the University of Oldenburg in Germany.
Wolfgang Schmidt, one his professors at the time worked on wind power. In his office, the professor had a map of northern Germany with dots marking all the wind turbines installed at that time. “There were so few of them that he knew them all,” Lange recalls. He says he understood even then that Germany, and Europe, needed to move away from fossil fuels – scientists were already sounding the climate alarm – and the only real alternative were renewable energies such as solar and wind power.
“Even then, I was already convinced that it had a big future,” he says. “But I never believed that it would become as big as it is today.”
