Wind Repowering: a Way Around the Opposition

Wind energy faces an uphill battle right now, but it’s still in the fight. One way to bypass much of the opposition to new development is simply not to rely on developing new wind farms. We should also repower existing wind sites to increase their capacity.

Wind repowering projects take aging wind farms with declining output, and refurbish them to boost their efficiency in generating electricity. These upgrades can take many forms. One easy option is to install an understory of shorter, vertical axis wind turbines (VAWTs) underneath the existing tall turbines. The shorter turbines can harness the wind blowing below the blades of the taller turbines, and can improve the efficiency and longevity of the tall turbines as well.

Wind Harvesters® are vertical axis wind turbines designed specifically to fill this niche in a wind farm. They are sized to fit below the spinning blades of typical horizontal axis turbines, and have features to make them rugged enough to handle the turbulent wind that blows closer to the ground. Our research shows that 18% of the wind farms in the world have excellent mid-level winds and would benefit from wind repowering with an understory of vertical axis wind turbines.

Wind Repowering with VAWTs: Examples

The quickest and easiest upgrades would be Capacity Factor Enhancement projects. Because wind doesn’t blow at high speeds continuously, and because machines need to be taken offline occasionally for maintenance and repairs, wind farms don’t usually operate at full capacity. Increasing the megawatts by just 10-25% can allow the wind farm to operate at closer to full capacity for more of the time, without needing to upgrade any of the infrastructure (substations, power lines, etc.). For example, a 100 MW farm could add about 350 Wind Harvesters to bring their rated capacity up to 125 MW. The farm would keep using the 100 MW substation and transmission line, and in addition to producing energy, the vertical axis wind turbines could boost their large neighbors’ efficiency by 5%. Even better, reduced wear and tear on those large turbines can increase their lifespan to 150% of how long they typically last.

Another option for wind repowering projects is to maximize the layout of vertical axis wind turbines and add a high-energy use facility on-site to make use of the excess electricity that is produced. In our example 100 MW wind farm, this would mean adding 3000 Wind Harvesters plus battery storage. When the wind is strong, the turbines would produce far more energy than could be sent through the transmission line to the grid. An AI datacenter or green hydrogen plant located on site could use that extra energy. On calmer days, those facilities could run off stored energy in the batteries, or draw energy from the grid using the same transmission line that usually sends electricity out.

A “Wind-Wind” Solution

As you can see, repowering wind farms by adding vertical axis wind turbines is a “wind-wind” solution to the problem of how to increase renewable energy without expanding into untouched areas. Vertical axis turbines like Wind Harvesters can make double use of land in wind farms that already exist. And they increase the efficiency and longevity of the existing turbines, too. Wind repowering projects can increase the reliability and efficiency of the grid, or even power high-energy use processes like AI and green hydrogen. These projects can be installed quickly since they don’t need new permitting or infrastructure. For all these reasons, we believe wind repowering should be a focus of the industry in coming years.