At best, solar panels can be purchased at $4-5 per watt, IIRC. The commercial efficiency is about 15%. Laboratories claim efficiencies of 30% to 50% (that and $4.50 will get you a Frappuccino at Starbucks) . The real improvement over the years was in the durability of a panel; the warrantees are into 20 years, again IIRC.
The breakthroughs that the market was and is waiting for is in cost of manufacturing and efficiency. Bring the cost per watt down and get more power out per panel, and all the while keep the quality/longevity the same. We are still waiting. Of course, if you can bribe an "expert" in solar energy to endorse a new manufacturing process, you too can get a huge govmint subsidy.
The math: with an average electric bill of $200-300 a month as the method of recouping any costs ideally ($12, 000 to $18,000 over 5 years), how much is a homeowner willing to spend up front? The numbers are actually less attractive.
Because of the proliferation of Chinese panels, the arrays themselves are now down to around $1 per watt. Panels rated at 250 watts can be had for less than $300. Then add in the balance of the equipment: wiring, inverter, control center, grid-tying, installation, etc. - maybe another $1.50 to $2 per watt - less if you can DIY the install.
WITH federal and state subsidies via tax-credits (65% combined here in NC), you can re-coup costs in 5 years. Plus, you’re fixing your cost of electricity, vs. being subject to regular increases from your utility company.
WITHOUT subsidies, it’d take 15 years to pay for itself. Panels degrade over time, and the typical warranty is that they’ll produce 80% of their rating at 25 years. That means break-even at best vs. doing nothing.
If costs continue to decline, you’ll probably see more adoption - at least until the subsidies expire in 2016 (unless renewed). I’m half-considering it myself - I’m way over-taxed, and this would be a way I could get some of it back. But it will be an economic decision - not because I’m worried about the size of my carbon footprint.
“...At best, solar panels can be purchased at $4-5 per watt, IIRC.”
Not anymore. With the federal rebate, you can get grid-tie systems installed for around $2.00 per watt. Obviously systems that can take batteries cost more...and then the batteries themselves even more.
http://www.wholesalesolar.com/gridtie.html
the breakthrough will occur when the sun produces more energy density.
until then solar will only help marginally
At best, solar panels can be purchased at $4-5 per watt, IIRC
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Nope. Current price to contractors is about $0.80 per watt and expected to reach $0.50 in the near future. That $0.80 will get you about 5 watt- hrs per day in Southern Califonia. That’s about 1.8 kilowatt-hrs per year. Currently a KWH costs about $0.20 so your $0.80 investment saved you $0.36 in only one year.
Not bad.
On the other hand, professional installation isn’t cheap and there are ancillary hardware and permit costs.
The point is that the solar panel business is a terrible low margin business but, given the cheap panels, solar system are becoming more and more viable.
And the rebates are drying up as they should.