[chbot] solar roads

[David Churcher]

On 26/05/2014 6:49 a.m., Geoff wrote:
> For a normal solar panel, it's energy payback time is about 7-8 years, 
> a third of it's life.

This isn't correct for regular solar panels. Energy payback for the 
panels themselves is currently between 0.4 and 1.5 years, depending on 
the technology used and sunshine levels. The technical lifetime of PV 
systems is 30+ years, hence they produce net clean electricity for more 
than 95% of their lifetime. Taking everything associated with the panels 
- inverter, mounting and cabling etc. - into account it's still well 
under 3 years, and more like one year in sunny climates. See for example 
http://cleantechnica.com/2013/12/26/solar-energy-payback-time-charts/ , 
which has charts for different technologies and insolation levels.

  If you're making them with electricity produced from solar roadways, 
of course, the payback time is immaterial. Just make more solar roads. 
;) The ashphalt and concrete that they would replace have really high 
embedded energy costs too, and no payback.