Personally I would have preferred a tax tariff on all incandescent bulbs to price them competitively with CFLs then let the market really decide which is best.
Where are you getting this figure? From what I've seen, solar panels in general don't even reach payback over their 25 year useful lives, though in some countries (e.g. Spain) the numbers are a bit more forgiving. Including subsidies, of course, things are different.
Am I misunderstanding "energy payback"? Is this not the same as the payback period (i.e. money)?
It measures performance in standard test conditions, which are generally speaking comparable to peak sunlight. You can find out how many hours of peak sunlight your area gets on the web pretty easily; 3-5 hours is usual, depending on your area, I think.
It's important to keep this in mind when comparing prices per watt; a solar system will be _MUCH_ more expensive than e.g. a coal system at the same investment/watt (assuming you include fuel costs in that) b/c you can run a coal system all day and night, so you get 24 peak hours.
On the other hand, solar's peak hours come at a good time- when energy usage is high and high-cost natural gas plants are on to satisfy demand- so the real measure of whether solar is good would likely be when its cost dips below that of natural gas generatation. (natural gas is used instead of coal for variable production because it is more expensive to scale coal production, and because coal plants are generally not run below ~50% capacity at any point because of the difficulties in bringing them back up to full utilization afterwards).
The variable production cost of coal is $20/KWh, natural gas more like $60/MWh, whereas solar has little if any variable production cost, but the setup costs per watt of coal and natural gas systems are far lower ($2,000/kWp, $750/kWp respectively, whereas solar is more like $8,000/kWp even if we dubiously give it credit for producing at peak performance all day and night).
$1/Wp would, obviously, be $1,000/kWp, but since this represents a peak performance number, this is still not competitive with coal or gas (equivalent to $6,000/kWp if you have 4 peak hours of sunlight, which is a fair median).
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Personally I would have preferred a tax tariff on all incandescent bulbs to price them competitively with CFLs then let the market really decide which is best.
...wow
Quite.
Am I misunderstanding "energy payback"? Is this not the same as the payback period (i.e. money)?
It measures performance in standard test conditions, which are generally speaking comparable to peak sunlight. You can find out how many hours of peak sunlight your area gets on the web pretty easily; 3-5 hours is usual, depending on your area, I think. It's important to keep this in mind when comparing prices per watt; a solar system will be _MUCH_ more expensive than e.g. a coal system at the same investment/watt (assuming you include fuel costs in that) b/c you can run a coal system all day and night, so you get 24 peak hours. On the other hand, solar's peak hours come at a good time- when energy usage is high and high-cost natural gas plants are on to satisfy demand- so the real measure of whether solar is good would likely be when its cost dips below that of natural gas generatation. (natural gas is used instead of coal for variable production because it is more expensive to scale coal production, and because coal plants are generally not run below ~50% capacity at any point because of the difficulties in bringing them back up to full utilization afterwards). The variable production cost of coal is $20/KWh, natural gas more like $60/MWh, whereas solar has little if any variable production cost, but the setup costs per watt of coal and natural gas systems are far lower ($2,000/kWp, $750/kWp respectively, whereas solar is more like $8,000/kWp even if we dubiously give it credit for producing at peak performance all day and night). $1/Wp would, obviously, be $1,000/kWp, but since this represents a peak performance number, this is still not competitive with coal or gas (equivalent to $6,000/kWp if you have 4 peak hours of sunlight, which is a fair median).
Well, for one thing, you'd have no electricity at night...