When building at a large height, big amounts of energy are needed for hoisting operations. Tower cranes installed on tall structures have longer hoisting movements, which means higher and longer power peaks. These peaks can put significant strain on a site’s grid connection and drive up connection costs. So you might wonder: Can a 4 kWh flywheel system reliably peak shave a tower crane at height without running empty?

Together with VolkerWessels, we tested our flywheel system on a real construction site. We measured the power use of the tower crane and the entire construction site. The data quickly revealed that not only the crane, but also the two construction hoists were major power users with significant peaks that often overlapped with the crane’s activity. The findings showed:

• The tower crane’s continuous power stayed below 65 kW.
  
  
• Each crane peak ranged from 0.5 to 2.1 kWh.
  
  
• Longer hoists increased the chance of overlapping peaks, especially when combined with the hoists.
  
  
• Without the crane, the site’s maximum power demand was ~170 kW; with the crane, it rose to ~230 kW , with a single spike up to 250 kW.

The Flywheel in Action

Our analysis confirmed that a flywheel system with 300 kW of power and 4 kWh of storage easily handles these peaks. The flywheel has enough storage to reliably peak shave the tower crane, even when lifts are long or multiple peaks overlap,making it fit for purpose in construction sites with cranes at greater heights.

• The flywheel is able to reduced the site’s peak load from 250 kW down to 80 kW, cutting the required grid connection from ~400 A to ~125 A.
  
  
• The system reliably peak shaved the tower crane, even when other heavy peak consumers like construction hoists were running simultaneously.
  

This use case clearly shows the value of having a high-power flywheel on site. It helps manage multiple peak consumers at once, keeps energy usage stable, and reduces the cost and complexity of the grid connection. For projects with tower cranes at height, or any operation with unpredictable peak loads, flexible flywheel energy storage is a practical, proven solution.