Solar panels vs reflecting surface?

[Patrick Pihl]

Assuming that a black solar panel has an efficiency of 20%. This energy could be used instead of burning oil and decreasing CO2 emission. But the black color also accumulates a significant amount of the solar energy into heat locally on planet surface.

Comparing this with a white panel (non solar) that would reflect back a lot more solar energy into space. In a global perspective, what gives best effect in reducing global heating?/ Thanks

 

[sophiecentaur]

A reflective surface is what you want - but you will need to put white reflectors (or mirrors) over a vast area of land in order to make a substantial hole in the net energy arriving here. I have often thought that loads of whit paint, all over the most desolate areas of desert, could perhaps make a difference to our situation. It would require maintenance, of course! ('Painting the Forth Bridge' pales into insignificance as an on-going project).
Houses should, of course, all have thermal and PV panels on all suitable surfaces. I see the UK's Green Deal has died a death. That could have made a real difference to us, locally if it had continued and been encouraged. Danged politicians again.

 

[Patrick Pihl]

PV panels are black or dark blue as far as I know so is it obvious that its better to put up a PV-panel compared to just paint the same surface white?
Yes one would need to brighten up a big area to make any difference :) Perhaps something that floats in the ocean water?

 

[sophiecentaur]

Perhaps something that floats in the ocean water

Problem: within a few months, marine life forms would coat the reflective stuff and it would be 'brown'. A covering with a shiny biocide (antifoul paint) would bring the environmentalists down on you like a ton of bricks.