ginjawarrior
Well-Known Member
you get less power from PV farms per m2 than you do from solar thermalSolar farms have their place in the overall switch to solar as the main supplier of energy. Agree that tty is bonkers if he thinks they can provide more than 5% or total worldwide needs. Toss in 3% for geothermal, 2% for hydro and perhaps 5% nuclear.
So, what about Photovoltaic systems? Can they match 90% of wordwide demand?
Household photovoltaic systems convert sunlight to electrical energy at about 12% efficiency. Commercial systems are higher, perhaps 18% efficient. These are today's efficiencies. Maximum theoretical efficiency (wikipedia) is about 33%.
Big advantage PV has over the other power plant or energy farms is they can be located at the "last mile" and so don't incur efficiency loss and the high cost of transmission to the end user.
The sun delivers 89,000 tW to the earth. In 2001, energy demand was about 10 tW.
Fossil fuels produce about 80% of today's energy demands. We can assume the same was true in 2001.
http://www.sandia.gov/~jytsao/Solar FAQs.pdf On page ten, the work up how much surface area is needed to supply worldwide energy needs as well as that of the US. In the Sandia paper, they estimate 2% of US would be enough to replace fossil fuels. Same with worldwide. For the US, 2% surface area would be the equivalent of North or South Dakota.
The bottom line is that Solar PV systems can replace fossil fuel with alternatives making up the rest of the balance. Not saying "easy" and not saying 80% energy from PV is cast in stone. I'd like to see a panel of experts brought together with the mission to provide a working recommendation to Congress that is backed by the scientific community as the template from which our government could base their policy, spending and taxation decisions in order to free us from fossil fuels.
https://en.wikipedia.org/wiki/Desert_Sunlight_Solar_Farm
1287000mwh/16000000m2
0.08MWH/m2 a year
you'd need 10%more land
the number of pv panels needed for that aside
just think for a minute how many access roads you would need to build to criss cross somewhere the size of arizona