Wind turbines are set to soar in the coming years, as their quiet advancement over the past four decades looks set to continue. The renewable energy source, which currently provides around four percent of the world’s power, could play an even more important role as prices drop and nations move away from fossil fuels.

Researchers in Germany have analyzed the history of wind turbines and how they have developed over the years, plotting a trajectory that shows they’re likely to become larger and harvest more energy as technology improves. Modern turbines are more cost-effective, more reliable, bigger and cheaper than technologies that came before.

Because a bigger turbine can catch more wind than a smaller one, it can move the same generator with more force. While today’s rotors can reach a diameter of around 100 meters, they could soon reach double that figure. Turbines on the whole could produce triple the amount of energy they currently produce.

The findings were published Tuesday in the journal Applied Physics Reviews.

“The size of a state-of-the-art turbine is extremely impressive. The swept area of the rotor of a standard turbine is now twice the size of a football field,” Berthold Hahn, one of the authors of the paper, said in a statement. “In parallel to the development in size, the technology has also become mature, meaning cost-effective and reliable.”

The planet’s average temperature is increasing, and initiatives like the Paris Agreement are pushing states to take action. But while solar energy grabs headlines with its advancements, wind actually provides double the amount of energy to the world at present according to the International Energy Agency. Those giant turbines, long the scourge of NIMBYs that push them to less-visible locations, are quietly becoming one of the most important ways humanity can move away from collecting energy via fossil fuels.

Solar is making big advancements, but those turning windmills are also completing a revolution of their own.

Wind Energy: From Niche Curiosity to Power Player

Wind energy accounts for a total of 515 gigawatts of global energy production, reaching four percent of the global total according to the International Energy Agency. Research from the International Renewable Energy Agency showed that annual capacity additions have jumped from 31 gigawatts per year in 2010 to reach 54 gigawatts per year.

This jump hasn’t come from nowhere. Wind energy has improved dramatically over the past several decades.

The notion of using wind power dates back centuries — Jay Lehr and Jack Keeley note in the Alternative Energy and Shale Gas Encyclopedia that the Egyptians were using wind to transport goods 5,000 years ago. Windmills used by the Babylonians in 700 BCE helped with irrigation, one of the first times they were used to replace human and animal labor. At the turn of the 20th century, windmills were being used to generate electricity locally. The first megawatt-class electrical wind turbine was added to a Vermont utility grid in 1941.

Since these early beginnings, wind has suddenly soared thanks to a mix of technology improvements and price reductions. Hahn and his team found that, since the 1970s, the amount of power generated by each wind turbine has jumped so that today’s turbines generate 100 times more power than their predecessor. These efficiency savings means prices have dropped from $500 per megawatt-hour in the 1970s to just $50 per megawatt-hour today.

Other advancements include deeper offshore wind farms, like Scotland’s Beatrice project unveiled last month that ranks as the deepest offshore wind farm of its kind.

“The technical developments, like floating offshore turbines enabling the harvest of wind energy in very deep waters, integrated control strategies considering the needs of the grid, and artificial intelligence permanently assessing the performance of the turbines, have contributed to the impressive cost reductions,” Hahn said in a statement.

The size of a wind turbine over time. Fraunhofer IWES

Wind Energy: What Comes Next

Wind energy is set to move even further over the coming years. Bigger blades can mean more energy from each turbine, making it an ideal way to boost efficiency. It’s a big engineering task, as developers need to understand how to create long-lasting giant machines that don’t create too much vibration with their oversized blades.

The report claims that offshore turbines could reach an average 240 meters in diameter by 2030, and 160 meters for onshore wind. By comparison, General Electric claims the Haliade-X offshore wind turbine is the world’s largest with a 220-meter rotor diameter. Projects are about to get even larger.

This will enable each one to generate more electricity. Where current projects produce five megawatts, future ones could produce 10 or even 15 megawatts per turbine. Improvements in the grid and better maintenance data could mean each turbine lasting longer, reducing costs further.

“In many countries, wind energy has started to take over tasks of stabilizing the grid from large conventional plants, meaning that the energy systems are now eventually changing from a mainly centralized structure to a decentralized one,” Hahn said.

These giant blades may be out of sight for most of the public, but they could prove key to the future of energy.

Read the paper’s abstract below:

This review article aims to provide an overview and insight into the most relevant aspects of wind energy development and current state-of-the-art. The industry is in a very mature stage, so it seems to be the right time to take stock of the relevant areas of wind energy use for power generation. For this review, the authors considered the essential aspects of the development of wind energy technology: research, modeling, and prediction of wind speed as an energy source, the technology development of the plants divided into the mechanical and electrical systems and the plant control, and finally the optimal plant operation including the maintenance strategies. The focus is on the development in Europe, with a partial focus on Germany. The authors are employees of the Fraunhofer Institutes, Institute for Energy Economics and Energy Systems Technology and Institute for Wind Energy Systems, who have contributed to the development of this technology for decades.