Comments on: NREL Report Firms Up Land-Use Requirements Of Solar Power Plants

By: globi

globi — Sat, 03 Aug 2013 15:08:00 +0000

This factory produces 448% as much energy as the entire building consumes (including energy for heating and hot water) with photovoltaics on the surface area of the building alone:
http://www.solaragentur.ch/images/content/PDF/G-11-09-12%20Solarpreispublikation%20def_Heizplan%20Gams.pdf

And this building is in foggy Switzerland and not in sunny US.

By: JamesWimberley

JamesWimberley — Sat, 03 Aug 2013 12:20:00 +0000

I'd like to see more encouragement of multiple-use solar farms. In hot, dry climates shade is valuable to plants and animals. There's no reason why a solar farm should be sterile. A good example from India here. And of course solar-covered car parks are a no-brainer. Here's one of IKEA's in Spain.

By: PhilipKGlass

PhilipKGlass — Sat, 03 Aug 2013 02:14:00 +0000

I would have liked to seen a scatter plot of module efficiency against total project land use. It seems like First Solar’s thin film modules would need more acres than SunPower’s high efficiency silicon, or even Trina’s average-efficiency silicon.

By: Omega Centauri

Omega Centauri — Sat, 03 Aug 2013 01:46:00 +0000

Have tilt, want to avoid shading other panels. Thats the biggest source of the area inefficiency. Of course we also have access paths, off sets from fences, etc. etc.
Give up on the per panel benefits from tilting and tracking, with horizontal panels, and you might be able to do 90% coverage. But then you need more panels. And they are hard to clean. Tilting allows water to run off.

By: Wayne Williamson

Wayne Williamson — Fri, 02 Aug 2013 21:18:00 +0000

32 acres to produce power for 1000 homes is a steal. Usually 4 houses per acre which is the equivalent of displacing (4×32=128) home sites or for every potential 1000 homes, you could only build 872 of them…that’s if they don’t have solar on the roof. This comes out to 250(1000/4) acres for 872 homes that are solar powered.

Looking back, I probably messed up on the math;-)

Maybe better is 282(250+32) acres for 1000 homes.

By: RobS

RobS — Fri, 02 Aug 2013 21:15:00 +0000

Or simply put them on rooftops where the effective land use efficiency is infinite because no extra land is used per Kwh generated. There are enough mega warehouses to still have some utility scale plants and surely the lease costs of a warehouse roof is cheaper then a greenfield site. The only good bare land site for solar farms are old industrial sites like old decommissioned chemical or power plants with significant contamination rendering it useless for other purposes. I can see little point occupying greenfield sites until we approach saturation of rooftop systems.

By: Marion Meads

Marion Meads — Fri, 02 Aug 2013 20:17:00 +0000

In California, 21.93 GWh of solar radiation energy falls on 2.7 acres of land, 30.87 GWh of solar radiation falls on 3.8 acres of land. In other words, on a total enclosed land area basis, the overall efficiency of solar to electric is between 6.5% to 9.1%. If the solar PV nowadays are very efficient, between 15% to 30%, it means that land use is not optimize, IOW, the spacing are poorly designed wasting a lot of land that are not capturing sunlight. We need to be more creative in how to pack the solar PV’s as efficiently as possible, such as those arranged naturally in sunflower’s seed array within the flower.

But overall, the 6.5% to 9.1% overall efficiency is not that bad, compared to plants, whose energy capture is between 0.5% to 2% before fuel conversion. It means that we could make a lot of improvement by simply using proper geometric layout in the installation of solar PV. Simple math CAD, with simulation and graphics and a little bit of time in the drawing board is all it takes.