Has the potential for an upside previously unavailable at low cost. By stacking layers of different solar cells you can surpass the theoretical limit of a singl

Has the potential for an upside previously unavailable at low cost. By stacking layers of different solar cells you can surpass the theoretical limit of a single layer which is 32% (or around 28% in practical terms including spaces that aren't solar cell). Single layer silicon is in the 22-25% range now with the 22% modules being the optimal cost in most areas. The modules also only make up a small fraction of the cost of a PV install (around 25-30%), so increasing efficiency from 22% to 32% reduces BOS costs by almost as much as the entire module currently costs Perovskites are also dirt cheap, so are a good candidate for increasing efficiencies. The difficulty is in making them last. Accelerated aging tests are promising but they haven't hit market yet.