Just a little more explanation regarding...

Just a little more explanation regarding retrofitting/installation of solar cells - for future reference:

Lets say we look at a single 1000 Watt,(1 kW) module.

With 10% efficient panels in full sunlight you need about 10 square meters of solar cells.
You also need the cabling and power conversion equipment to handle the 1 kW

You can't just replace the panels with a 10 square meter 50% efficient BLG unit as the built in cabling and power equipment will be rated to handle only the 1 kW. You can only put in 2 square meters of the new cells.
The only thing you will gain for your money is some free space.

However, if you want to increase the power output to say 5 kW, you have two choices.
Add another 40 square meters of 10% panels plus another 4 kW worth of cable and power equipment OR
Replace the existing panels with 50% efficient BLG panels. You will save space but you will still need to pay for another 4 kW worth of cable and power equipment.

For most solar installations space is not a big issue, but cost will be.

The real driver to capture this market will be $/watt.
And for the BLG panels that is still an unknown.

Cheers