Repowering: renewing PV plants for higher efficiency

Repowering means replacing parts of the components, most often solar panels and inverters, with newer and more efficient ones. This situation can arise in several cases where a power plant no longer meets the expected requirements. These include the aging or failure of components, their destruction or theft, or significant technological leaps. 

Accelerated degradation of the panels is also considered as damage to the panels. The threshold for what is normal degradation and what is abnormal has been set by the German Network Agency at 10% after 10 years of operation. Panel replacement is therefore possible under several conditions, the main ones being: 

• The new panels must not have a higher total installed capacity than the original panels.
• The old panels should ideally be disposed of by a certified company.

The repowering process: How old solar systems are changing and Greenbuddies' experience with repowering  

We have already carried out several repowering projects where all the panels on a solar power plant have been replaced. In practice, this means dismantling the old panels and preparing them for removal. The panels must not be destroyed to make it sensible to take them for disposal. Next, new DC cabling must be prepared, as the new, more powerful panels have different string lengths, and new panels must be laid on top of the old structures. As a rule, the structures have to be partially modified. Before starting the work, we need to find out what can be reused and what cannot — in particular, fragments of old cables that run in the ground, panel clips that tend to be rusted, etc. 

In terms of time, a major repowering project can be said to take about the same amount of time as building a new power plant. Instead of assembling the structure, it takes a similar amount of time to dismantle the old modules and adapt the structure to the new installation. Laying the new panels takes a similar amount of time using new cribbing. In addition, new DC interconnections are made. The main construction advantage of repowering is the fact that it is not necessary to do new AC, especially the HV part.

With new, more efficient panels, the same power plant needs less space, and if there is sufficient spare transmission capacity in the grid, then the spare structure can be used for a completely new PV plant expansion, which is no longer covered by repowering as it is a new construction. For example, we have implemented a repowering where the original capacity was 5.7 MW, and after replacing the panels, 1.5 MW of new capacity could be added to the free structure, i.e., 25% more capacity. See the photos for other reference repowering projects we have completed.

Repowering vs. Revamping: Making more efficient use of existing solar installations

Increasing PV production while maintaining the original installed capacity is called revamping. This is a special case of repowering, where the installed capacity of the solar plant remains unchanged, but the production of the existing PV system is maximized by replacing fixed mounting structures with dynamic trackers that constantly adjust the angle of the panels to align with the daily path of the sun. Typically, old panels are also replaced with new ones in this option. This modification significantly increases the exposure of the panels to sunlight, which improves energy capture and therefore the overall efficiency of the PV plant. Switching to tracker systems is a strategic step to maximize the performance of existing PV installations.

At Greenbuddies, we provide complete advice on optimizing the performance of an existing solar power plant. Our team will evaluate the current state of the plant components, propose a solution, prepare the necessary project documentation, and ensure all communication with the necessary authorities. We will resolve the performance problem of your PV plant as soon as possible to avoid further financial losses.