Tuesday, March 24, 2009

Rain water harvesting and solar...

Solar farms could also be used to harvest water
By Jim Shuttleworth
Tucson, Arizona | Published: 03.24.2009
On average in Tucson we get about 12 inches of rain each year and have rainstorms on 41 days. Assuming there was a film of water about half a millimeter thick left on the solar cell surface after each storm, we would lose about an inch of rain each year because this surface water would evaporate. However, if the water running off the solar cells was gathered quickly using gutters and pipes, additional loss by evaporation could be small.
However, Tucson Water is already recharging Central Arizona Project water in Avra Valley with 95 percent efficiency, so why not store the rainwater collected in the same way, as groundwater?
In fact, allowing for all losses, it should be possible to gather about 85 percent of the rain falling onto a solar-energy farm and recharge it to groundwater. Because the water needed for each person in Tucson is around 173 gallons per day, the area of solar cells needed to deliver a sustainable rainwater supply to one Tucson resident is roughly twice the area needed to provide them with sustainable solar energy.

Ok, folks. I seriously thinks these 'gone green' hippies sometimes cannot think very logically. They want to spend money, adding gutters, holding tanks and a retention basin simply to collect the rain water that is running off the panels in order to recharge the water table. Is that, or is that not, what happens when the water simply runs off the panel in the first place?
Wait, here's the real reasoning behind it... it will take twice as many solar panels in the process to sustain a family compared to what is needed for the family's electrical need. You do know what is coming next? That's right, tax breaks for adding additional panels and rainwater harvesting systems for all those panels.
Here's the funny part. Most panels are added to people's ROOFS. That's right, the roofs of their houses. What happens if the water falls off the panel? It falls on the roof and on to wherever. To me, this sounds like 'green' science trying to justify the addition of extra panels, and the creation of tax breaks to pay for water harvesting cisterns. Cisterns that won't collect any more water than they normally would, because essentially the surface area of the roof does not change.
Sometimes you just have to shake your head...

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