Guide
Bifacial solar
Panels that collect sunlight on both faces, including light bouncing off the ground.
How it works
A conventional panel has an opaque backsheet. A bifacial panel uses cells that respond to light on both sides, usually sealed between two sheets of glass, so light reflected from the ground or surroundings also generates electricity.
Where it works best
The extra output depends on how reflective the ground is, how high the panels are mounted and how far apart the rows are. Pale sand, gravel or snow reflect much more light than dark soil or grass. Bifacial panels are now common in large solar farms, often on trackers.
Advantages and limitations
Advantages
- More energy from the same footprint
- Glass-glass designs are durable
- Pairs well with trackers
Limitations
- Gain varies widely by site
- Less useful on rooftops close to the surface
- Slightly higher cost
Current development
As bifacial becomes standard, designers are optimising ground surfaces, mounting heights and row spacing to maximise the rear-side gain.
Further reading
- Bifacial solar cells (Wikipedia)How bifacial cells and modules work