This is primarily for renters of apartments who aren't allowed to alter the roofs. In the US, labor is more than half the cost of a rooftop installation which

This is primarily for renters of apartments who aren't allowed to alter the roofs. In the US, labor is more than half the cost of a rooftop installation which is hampering their adoption. The balcony solar has no labor cost at all and if the tenant needs to move, they can take it with them to their next rental so they won't lose their investment.