A highly efficient rooftop solar panel based on space technology

EVEN THOUGH solar panels have improved over the years they are still not very efficient at doing their job. Standard panels using silicon-based solar cells typically convert 17-19% of the sun's energy into electricity. It is possible to use more exotic solar cells to make panels that are some 40% efficient, but these can cost around $300 a watt compared to just under $1 for some silicon versions. Hence the better panels are used in specialist roles, such as powering spacecraft. Now, a middle way...