Conventional solar technology has thus far dictated that solar panels be mounted on south-facing roofs, or in locations where the sun source is unrestricted and strong.
That said, it is striking that in the boom years before the crash of 2007-8, none of the big banks replaced their so-called legacy systems with new modern ones - which some would see as another example of how they did too little sensible long-term investment when the sun was shining, and are now struggling to mend their roofs in less clement weather.