Solar Panels Losing Power Because of Shade? It Might Be Time to Upgrade
When your solar panels were first installed, your roof may have had full sunlight—no tall trees, no nearby buildings, and no satellite dishes in the way. But things change over 25 years. Trees grow, neighbours extend their homes, or a new apartment block is built nearby. Now, your solar system might not be generating what it used to.
Why Shade Is a Bigger Problem Than You Think
Solar panels need sunlight to perform. In many older systems, panels are connected together in a "string". This means they all depend on each other; if one panel is shaded by a tree branch, a chimney, or a satellite dish, the performance of the entire group can drop.
- The Shading Culprits: Growing trees, new TV aerials, satellite dishes, or nearby construction.
- Long-Term Impact: Because solar panels last 25+ years, your surroundings will likely change significantly during the system's life.
The Energy Saving Trust explains how shading affects solar output here.
The Solution: Microinverters vs. Optimisers
To fix the "weakest link" problem, we use Module Level Power Electronics (MLPE). This allows each panel to work independently so that a shaded panel doesn't slow down the others. There are two main ways to do this:
| Microinverters: A small inverter is fitted to the back of each panel. There is no "main" central inverter; the panels convert power to AC right on the roof. |
| Optimisers: An optimiser is fitted to the back of each panel, but they are still linked to a single main inverter usually located in your loft or garage. |
A Simple Example
Imagine 6 children riding bikes tied together with a rope. If one child slows down, they all slow down. This is how a traditional string system works.
Now imagine 6 children riding separately. If one slows down to look at a tree, the other 5 keep going at full speed. This is how microinverters and optimisers work—each panel performs at its own maximum potential regardless of what its neighbour is doing.
Retrofitting to an Existing System
If your system is already installed and shading has become a problem, retrofitting may be an option. This involves upgrading your panels so they work independently. Whether you choose a microinverter retrofit or an optimiser system depends on your current inverter age, roof access, and panel layout.
When Should You Upgrade?
You should consider microinverters or optimisers if trees/buildings now block sunlight, if your roof has multiple angles, or if you are installing a new system and want to "future-proof" it against potential neighbourhood developments.
Check your system suitability here.Simple Summary
- Shading on just one panel can drag down your whole system.
- Microinverters remove the need for a central inverter.
- Optimisers improve individual panel performance but still use a main inverter.
- Retrofitting can restore lost power to older systems affected by new shade.
- Planning for the next 25 years means considering shade now.
Restore Your Solar Power
Talk to Craig about retrofitting microinverters or optimisers to your home.
