Why is it not feasible? I run 32 panels on my roof, in the pacific northwest which is known for its rain, it covers 100% of my residential and electric car usage when considered on an annual basis. If roofs required solar panels we would have a large part of power generation done at a much lower intallation cost and could focus on large scale energy storage projects instead. My payoff period is 11-12 years, system is warranted to 20. No breakthrough required.