Innovations In Wind Turbine Design: Increased Efficiency & Power Output

Wind energy in the U.S. is growing by leaps and bounds. In 2022, it accounted for 22% of new electricity production in the country. This cheap, clean energy source is one of our best tools for replacing fossil fuels and halting climate change.

To maximize the benefits of wind power, we need to get as much energy as possible out of each turbine. That’s why wind turbine designs are always evolving. Each new innovation captures a bit more wind energy and gets us one step closer to a clean energy future.

Evolution of wind turbine design

Wind power has been used since ancient times for grinding grain and pumping water. But it wasn’t until 1887 that it was first used to generate electricity. Built by Scottish professor James Blyth, the original 33-foot turbine provided power for just one home: his own vacation cottage.

The year 1931 saw the deployment of the first horizontal-axis wind turbine (HAWT) similar to those in use today. Built at Yalta in Crimea, it was about 30 meters (98 feet) high and produced 100 kilowatts (kW) of energy. In 1941, the first wind turbine was connected to the power grid in Castleton, Vermont. The first modern wind turbine, the 200-kW Gedser turbine, was built in Denmark in 1956. It had three blades spanning 24 meters (79 feet) and included emergency tip brakes, a feature still used today.

Turbine designs continued to improve throughout the late 20th century. First the 1970s oil crisis and later the growing awareness of climate spurred demand for fossil fuel alternatives. Turbines grew steadily larger, and new materials made them lighter and more durable. The world’s first offshore wind farm went online in Denmark in 1991.

Core components of wind turbines

Most modern wind turbines share the same general design. Its basic parts are:

• Tower. This is the base for the turbine, typically made of tubular steel with a weather-resistant coating. A typical tower is around 50 meters (164 feet) tall, but some are as tall as 200 meters (656 feet). Wind speeds increase with height, so the taller the tower is, the more energy the turbine can capture.
• Rotor. This is the part of the turbine that spins. A typical rotor has three long blades made of fiberglass. These fit into a central hub assembly connected to the main shaft, which transits the rotation to the generator. Rotors are most efficient when the blades are long and lightweight and can be adjusted to catch shifting winds.
• Generator. The generator converts the rotor’s motion to electricity. It contains coils of copper that pass through a magnetic field as the rotor turns, producing an electric current. In most turbines, the generator doesn’t connect directly to the rotor shaft. Instead, the rotor turns a low-speed shaft and a gearbox transfers that motion to a high-speed shaft, driving the generator. However, gearboxes are costly and heavy. Some engineers are experimenting with direct-drive turbines in which the generator attaches directly to the rotor.
• Nacelle. A gear-driven turbine has a box called the nacelle attached to the back of the tower. It contains the shaft, gearbox, generator, and brake. Also inside the nacelle are devices to adjust the rotor’s pitch (angle) and yaw (position relative to the wind).
• Controller. This device starts and stops the machine. It starts the rotor spinning when the wind reaches a speed of 8 to 16 miles per hour (mph). When the wind speed reaches 55 mph, the controller shuts the turbine off to prevent damage.

Most wind turbines in use today are HAWTs like the 1931 Yalta models. Their rotors point into the wind to capture as much of its energy as possible. However, these models are noisy and, to some viewers, unsightly. Also, they can’t handle extremely strong winds (over 55 miles per hour) or the turbulent winds found in urban settings. And there’s a limit to how large they can get and still work reliably.

These factors are driving renewed interest in less common vertical-axis wind turbines (VAWTs). Their blades rotate around the vertical axis of the tower itself. VAWTS are less efficient, but also quieter and less visually obtrusive. They can harvest wind power from any direction without repositioning. And, critically, their size is virtually unlimited.

Increasing rotor size and blade efficiency

Since the rotor is the part of a turbine that catches the wind, boosting turbine efficiency often means upgrading the rotor. Improvements to turbine rotors and blades include:

• Bigger rotors. Longer blades sweep across a larger area, capturing more wind energy. They can also work at lower wind speeds, making wind energy practical in areas with less powerful winds.
• Streamlined shapes. Streamlining the shape of the blade reduces drag and increases the amount of wind power converted to electricity. It also lessens stress on the turbine’s other components, lengthening their life and lowering maintenance costs.
• Smart adjustment. Smart turbines automatically adjust the yaw and pitch of their blades as the wind shifts. This increases energy output and reduces stress on the turbine. It’s also possible to adjust the pitch and yaw of one turbine’s rotor so it interferes less with nearby turbines. This method, called wake steering, can increase a wind farm’s energy output 1% to 2%.
• Multiple rotors. The Danish wind turbine manufacturer Vestas has developed turbines with four rotors on a single tower. This design allows the turbine to harness more energy while reducing strain on each individual rotor blade. Vestas is currently testing this design to evaluate its structural stability, aerodynamics, and adjustment.

Advanced materials and manufacturing

Another way to improve turbines is to use better materials. Strong, lightweight materials such as carbon fiber composites and advanced metal alloys have several advantages. They’re easier to transport and install. They put less stress on the turbine’s supporting structures. They’re more durable because they resist corrosion. And they make the turbine blades lighter, so they can turn faster with the same amount of wind.

Along with the materials themselves, it’s possible to improve the way they’re put together. For instance, turbine blades can be built in segments, making them easier to transport. Similarly, towers can be assembled on site through spiral welding or 3D printing. This reduces costs and makes it possible to construct turbines in less accessible locations.

Another way to improve construction involves not the turbines themselves but the cranes used to assemble them. New climbing cranes are better at assembling taller turbine towers. They’re cheaper to rent and easier to move between sites than older crawlers or mobile cranes.

Offshore wind turbines

On land, wind turbines need to be situated on high ground to capture the strongest winds. But out at sea, winds are steadier and grow stronger the farther you get from shore. Offshore wind turbines, built to capture these intense breezes, are larger and more powerful than those on land. Being out at sea minimizes their visual and noise impact for cities and towns on land. And offshore wind can supply clean electricity to energy-hungry coastal areas, which currently have little wind production. The World Economic Forum predicts that global offshore wind capacity will increase tenfold from 2020 to 2030.

But building turbines at sea is challenging. It typically involves constructing a very tall tower anchored to the seabed. This makes it impractical to build in water deeper than 60 meters (about 197 feet). This limit puts the turbines too close to land to take advantage of the strongest ocean winds.

One way around this problem is floating offshore wind farms. The turbines stand on floating platforms, which are anchored to the seabed by long chains. Besides being easier to install, these floating wind farms create less noise and disruption to marine wildlife. The biggest current example is the Kincardine wind farm off the Scottish coast, with five massive 9.5-megawatt (MW) turbines. In the U.S., the Biden administration is subsidizing floating offshore wind research through its Floating Offshore Wind Shot program. Its goal is to reach 15 gigawatts (GW) of capacity by 2035 and bring costs down by 70%.

But fixed-bottom wind farms are seeing advances as well. Danish energy company Ørsted is exploring ways to turn the bases of its offshore wind turbines into artificial reef ecosystems. These can provide habitats for species such as Atlantic cod, green crabs, and corals.

Grid integration and energy storage

One big problem with wind power is that it’s intermittent. That is, wind turbines only produce electricity when there’s enough wind. This makes it harder to integrate the energy they produce into the grid. Other power sources need to be switched in and out to match the fluctuations in wind power.

One solution is advanced power smoothing techniques. These constantly regulate the power output from turbines to match the demand from the grid. This improves grid stability, reliability, and efficiency. It also reduces the need for backup power sources to take over when the wind cuts out. Since backup power plants often run on fossil fuels, power smoothing also reduces emissions.

Another option is to make the grid itself more adaptive. A smart grid integrates sensors and computers to detect changes in energy supply and demand. Built-in devices can automatically adjust electricity input and output as needed.

The final way to smooth bumps in energy supply is to add more energy storage. One option is pumped hydropower: using wind energy to pump water uphill, then releasing the water to generate electricity later. One company, Hydro Wind Energy, has developed an interesting variation on this technique. Its large offshore turbines won’t generate power directly; instead, they’ll use wind energy to lift a heavy weight. Later on, that weight can be dropped to power a generator, supplying electricity when it’s needed.

Another possibility is large batteries. Efficient but bulky flow batteries are good for this purpose, since their size isn’t a drawback for stationary storage. Electric vehicle (EV) batteries can also play a role in grid storage. Cars plugged into the grid can receive and release energy to make up for fluctuations in supply and demand. Also, EV batteries that no longer hold enough charge for road use can be repurposed for grid storage.

Predictive maintenance and condition monitoring

All wind turbines need maintenance. The traditional way to provide it is to follow a maintenance schedule, including regular inspections. However, this may result in replacing parts before it’s really necessary. On the other hand, simply waiting for things to break results in unnecessary downtime.

A better approach is to install condition monitoring systems (CMS). These contain sensors and signal processing equipment that monitor the various parts of the turbine. They analyze signals such as vibration, sound, strain, and temperature to figure out when parts need repair or replacement. Predictive maintenance minimizes downtime and extends turbine life.

Machine learning makes CMS work even better. Algorithms can analyze historical data from other turbines to get better at figuring out what various readings mean. Based on this data, the system can both optimize turbine performance and predict maintenance needs more accurately.

Economic and environmental impact

More efficient wind turbines increase both the economic and the environmental benefits of wind energy. Building a new turbine is costly, and getting more energy from that turbine provides better value for that cost. It also allows a single turbine to replace more fossil fuels.

Gains in efficiency have significantly driven down the cost of wind energy. From 2011 to 2021, advances such as larger blades reduced wind power costs by 60%. It now costs less to build a whole new wind farm than to keep running an existing coal power plant. And wind energy costs are still falling. Lawrence Berkeley National Laboratory experts predict they’ll drop another 17% to 35% by 2035 and 37% to 49% by 2050.

Lower costs, in turn, drive more adoption. In 1990, wind power accounted for less than 1% of U.S. electricity production. By 2022, it was providing over 10%. Worldwide, markets for wind energy are growing at an astonishing 25% per year. In 2022, wind provided more than 2,100 terawatt-hours—2.1 trillion kWh—of electricity worldwide. Generating the same amount of electricity with coal would have emitted over 1.1 million tons of carbon dioxide.

How individuals can contribute

The most obvious way to support wind energy is to install a wind turbine at home. Naturally, that’s not practical for everyone. However, there are other ways to lend your support to the wind energy revolution. You can:

• Invest in wind energy. There are two kinds of wind energy companies you can invest in through stocks or bonds. The first is companies that build turbines, such as Vestas and General Electric. The other is companies that operate wind farms, such as Ørsted or NextEra Energy. You can also invest in exchange-traded funds, or ETFs, devoted to the wind energy sector as a whole.
• Support clean energy policies. Read newspapers or news sites to learn about proposed federal, state, and local laws related to energy. Write and call government officials to support clean energy legislation and oppose laws that promote fossil fuels. Encourage your friends and family to do the same through social media or face-to-face conversations. If you want to make an even bigger impact, consider joining an advocacy group such as Citizens’ Climate Lobby.
• Reduce your personal energy consumption. Cutting energy use reduces the total amount of fossil fuels needed, making it easier to replace them with clean energy. You can save energy at home by adjusting your thermostat, adding insulation to your home, or upgrading appliances. For even bigger savings, consider an electric car or an energy-efficient heat pump. The federal government and many state governments offer tax credits and other incentives to help you pay for these technologies.
• Use clean energy at home. In many states, you can switch to a renewable energy supplier. Alternatively, you can sign up for a community solar program, which provides a kind of clean energy discount as a credit on your electric utility bill. Doing this doesn’t mean the individual electrons entering your home will come from solar or wind energy. However, it will increase the total amount of clean energy that goes into the grid.

The future of turbine design

Wind energy is one of the cheapest and cleanest ways to make electricity. Improving turbine efficiency boosts its financial and environmental benefits still further. Advances like bigger blades, lighter materials, smart turbines, and improved offshore wind have already reduced costs to record lows.

But there are even more innovative turbine designs on the horizon. New designs range from huge 10-MW VAWTs to small bladeless turbines that can fit almost anywhere. Companies are working on ultra-quiet helical VAWTs and even on airborne turbines that look like giant kites.

In short, we’ve only scratched the surface of what wind turbines are capable of. It’s too early to say for certain what the next generation of turbines will look like. But we can be sure they’ll play a major role in creating a world powered by renewable energy.