Method for $1/Watt Solar Panels Will Soon See Commercial Use

An anonymous reader writes "A method developed at Colorado State University for crafting solar panels has been developed to the point where they are nearly ready for mass production. Professor W.S. Sampath's technique has resulted in a low-cost, high-efficiency process for creating the panels, which will soon be fabricated by a commercial interest. 'Produced at less than $1 per watt, the panels will dramatically reduce the cost of generating solar electricity and could power homes and businesses around the globe with clean energy for roughly the same cost as traditionally generated electricity. Sampath has developed a continuous, automated manufacturing process for solar panels using glass coating with a cadmium telluride thin film instead of the standard high-cost crystalline silicon. Because the process produces high efficiency devices (ranging from 11% to 13%) at a very high rate and yield, it can be done much more cheaply than with existing technologies.'"

cost benefit analysis

[acdc_rules]

ya, but for how long do they last

13% is considered "high efficiency" now?

[Anonymous Coward]

You know, $1/watt panels are good and all, but shouldn't someone be more concerned with making them useful? It doesn't matter if the panels are $0.01/watt if I still need the entire neighborhood covered in them to run the coffee maker. You need to get to the point where covering the roof of the house is sufficient to make a major impact on the power needed from the rest of the grid (if not replace it totally, a pipe dream).

Impresive

[Jarik C-Bol]

if it turns out to not be vaporware, it may very well actualy make a dent in our use of coal and other fuels for generating electricity.

Re:cost benefit analysis

[arivanov]

I agree. A few obvious questions: what is the actual performance deterioration curve, what is the efficiency after 5-10 years and what are the disposal requirements (it has the dirty "C" word in so do not expect them to be accepted at the tip).

So, how many watts per sq. meter ?

[fymidos]

The article doesn't mention how many watts per square meter this panel will produce. The cost of the panel is important, but so is the cost of the land required and the return of your investment.

Simple conversion

[Khyber]

One square meter of land on a bright sunny day will get appx 1.6kW of light in an hour. Assuming 11-13% efficiency as mentioned in the article, you'd get just a little over 160 watts per square meter per hour.

Re:13% is considered "high efficiency" now?

[xs650]

There are several houses on my area in Northern California that have photovoltaic installations that produce more electricity than the homes consume. The excess goes to the power company for a credit against future use. These are homes with air conditioning and people that don't live austere lives. Their installations cover less than the entire south facing slope of a conventional roof. The problem is that they wouldn't come close to paying off without big fat gumnt subsidies. At $2.00/Watt they would be economically feasible without subsidies.

Assume the panels are 1/2 the cost of the system so the total system costs $4/Watt, or $8,000 for a 2 kW system. Assuming 6 hours a day generation, that's 4380 kW-hrs a year, or at $0.10 kW/hr that's $438 worth of electricity. 438/8000 = 5.4% tax free return on investment. If you live in the US with a decent income, you would have to earn over $700 to have $438 for your power bill after taxes.

If you don't like my numbers feel free to substitute your own.

Found some.

[BlueParrot]

From TFA:
The cost to the consumer _could_ be as low as _$2_ per watt.

Anybody spot the weasel word? Then there is the $2 cost to the consumer, rather than the $1 which is the cited production cost. Also, the article makes no mention of what levels of incoming radiation these numbers were calculated for. $1/W means something quite different in Egypt than it would mean in Sweden. Is the $2/W derived from the peak efficiency under ideal weather conditions, or is it the average over a year?

Essentially, if you want a real estimate of the price of a power technology you don't want price per power, you want Energy per Life-cycle costs. So if these cells last for 10 years you want to know how much total energy they could be estimated to produce during that time, compared to the cost of the panel. Other aspects like intermittent production and so on factor in, but in any way, price per [peak ?] power output is not a very useful number from an economical point of view. For solar cells you want at least the estimated cost over a life cycle with the assumed weather conditions specified. Less than that and you can easily massage the data by making strange assumptions.

Re:Simple conversion

[BlueParrot]

One square meter of land on a bright sunny day will get appx 1.6kW of light in an hour

Eh? Power = Energy / Time
1.6kW is a measure of power, not energy. You probably meant that 1 square metre receives 1.6kW hours of energy in an hour, which would give 160W hours per hour per square meter, or in power terms, 160W/m^2. That is, about the same power as would be necessary to power 3 strong light bulbs.

Somehow I think a 1m^2 window would be simpler, and if you use a triple glazed argon filled one ( as the Germans do for the passive-house standard) then you can neglect heat loss (in fact, you can get a net heat-gain ), making them considerably more efficient than chaining a 11% solar panel to an energy saving light bulb with 7%-8% efficiency (giving an overall efficiency of about 0.8% ).

No, really, in the vast majority of cases your money is better spent on insulating your house.

Re:13% is considered "high efficiency" now?

[btempleton]

Note that it's very hard to be green with an off-grid system. Off-grid systems tend to use batteries, and for proper operation you don't want to discharge the batteries too deep, and so quite often you overprovision your cells and you end up throwing away the energy from the cells into mostly full batteries a lot of the time. You can try to live greener (more efficient appliances etc.) and that's almost a must off-grid, but the off grid electricity itself is very expensive.

On grid, every watt generated by the panels goes somewhere and does something, because you feed it back to the grid, where it reduces the demand for fuel-burning electricity.

So living off the grid can be rewarding for those who want to be very non-urban, but it should not be confused with being green, energy wise.

Irrevelant

[Anonymous Coward]

It doesn't matter how cheap and efficient solar panels become. The electric companies will do everything in their power to keep this kind of thing off the market to ensure the status quo.

Re:The trouble is cost.

[rrhal]

"The Grid" is highly subsidized. If people had to pay the full capitol costs of bringing the Grid to their property up front they would find many situations where solar arrays on the house was the cheaper option. It's also pretty easy to save most of the electricity we use:

- efficient lighting
- 12v brushless dc motors in appliances
- use gas to heat stove, dryer, water heater

You can buy a nice solar array for the actual cost (not the subsidized cost) of bringing residential electric onto your property to the meter base and on into the breaker panel.

Another baby step along the way

[Whuffo]

Assuming this actually turns into something that you can really buy - and it actually is 15% efficient for $1 per watt then this should be the "push" that starts the large-scale conversion of homes and businesses to solar electric power.

More is needed, though - even with cheap and plentiful solar cells you're still up against some physical limits. You've only got so many square feet of southern exposure you can put panels on - and it's not anywhere near enough to support your current level of electric power consumption. Keep in mind that solar panels are rated at "full sun" and in the middle of winter you'll be lucky to get 10% of that on a bright sunny day.

So a good place to start is to find ways to reduce your power consumption. Not "feel good" little reductions, but serious cutbacks. Think about things like skylights in kitchens / bathrooms (free lighting), better insulation and weather stripping, and even some automatic controls on things like lighting, heating, etc. - these will remember to shut off the lights, turn down the heat, etc. even when you forget.

Pick up a small watt meter; something like the "Kill a Watt" can help you discover where the power is going. You'll find that a lot of it is pure waste and easily eliminated. Use task lighting instead of lighting up the whole room / house, look for more ways to reduce consumption.

You'll have to make some concessions and adjustments to live a low power consumption lifestyle - it's up to you to determine how far you can comfortably go. But if you can cut your consumption by 50% or more (very possible) then you're getting to the point where those solar panels can supply enough power to keep you going.

And you're going to need some kind of backup generation for those dark and dreary winter days. House sized generators are usually NOT cost effective, battery banks are expensive and troublesome. Grid-tied systems are clean and easy - but get the facts from your local utility before going this way. Some are very reasonable, some want to pay you their "generated cost" (less than wholesale) for the power you put into the grid - but charge you peak rate for the power you pull from the grid. This can wipe out your solar savings; be careful. Choose which ever of these best fits your needs and hope you never need to use it.

Re:Back of the envelope

[goombah99]

I don't dispute that there's a big pile of assumptions there. The thing is there is geometric rate of increased consumption in power and we are not building new capacity at a parallel rate. As consumption curve starts to hit the production cruve the cost of power which has varied little for decades is going to go through the roof. 25 cents per KW-hour will seem like a pipedream in 2040.

Since this may seem implausible consider this. The world is on track to double its energy consumption by 2040. To reach that point in a linear fashion--not geometric one--would mean bringing on line three gigawatt class power plants every day from now until then. Right now the figure is about 10 GW plants per year because we are in early long tails of that geometric growth curve.

About now your jaw should be dropping as you ponder the implications.

Thus what has to happen, other than permanent blackouts in most of the world and carbon poisoning of the planet, is that the growth rate must be stifled. And that is going to happen when the price of electricity hits ~$10/KW-hour and all then people will economize and buy energy saving appliances.

I did not make up those numbers. read the 2030 report from the department of energy.

So I was being generous assuming 25 cents per KW-hour grid rates.

Of and by the way, note that the plant for solars cells will produce 200MW /year. That's a drop in the GW/day bucket.

Re:The trouble is cost.

[rrhal]

Great, so instead of electricity, we're burning more fossil fuels. This is progress?

It is more efficient than burning coal/oil/natural gas to produce heat, converting that heat to electricity, transmitting that electricity for several miles, and converting it back to heat. However you are correct - there is no dryer that is anywhere near as efficient as a clothes line.

Re:One more question

[An Onerous Coward]

Yes.

And after they place the condemnation notice on your front door, they'll kick your dog.

Seriously, what makes you think that the engineers building this thing are so incompetent that they haven't considered the possibility of hail falling on your roof? They actually do run tests like that. Second to last paragraph here [colostate.edu].

I also find it very interesting that you didn't mention the dangers of actually living in a poison-dusted home, but only the danger that the EPA might deny you your God-given right to live in said death trap.

Tell you what, when serious people who actually know about the toxicity and regulatory requirements of cadmium telluride start telling me that this solar technology may present problems, then maybe I'll start worrying.

Re:Batteries

[Doppler00]

What is so bad about lead acid batteries? They are 100% recyclable. The lead can be re-used for new batteries.

Re:13% is considered "high efficiency" now?

[Hadlock]

I would mod you up for that if I could. I try to not think about places that require AC at night :-)

FWIW, this area has around 30 days over 100 per year. Nights are usually comfortable and the daytime humidity is low.
 
Shit, durring the summer in TX we're lucky if it gets below 90 at any point durring the night. Last night around 3am it got down to 87, and the AC was off for more than 15 min. AC units pretty much run 24/7 may-october here and a $350 july or august electric bill isn't at all uncommon ($.11-.13 per kw/hr here in Dallas). Temps typically only fluctuate 8-10 degrees between highs and lows here. I think solar would be a great argument here durring the summer...

Colorado and reverse metering

[careysb]

I live in Colorado and I find this story interesting in relationship to another story about a year or so ago about a man in Colorado who installed a roof's worth of solar electric panels which gave him juice to spare. The spare electricity was fed back to the grid, causing his electric meter to spin in reverse. When the local power company found out about it, they installed a "special" meter that would only spin in one direction (in their favor, of course). I think we need some legislation to require power companies to buy back any excess generated power. CB

Re:Back of the envelope

[feepness]

Since this may seem implausible consider this. The world is on track to double its energy consumption by 2040. To reach that point in a linear fashion--not geometric one--would mean bringing on line three gigawatt class power plants every day from now until then. Right now the figure is about 10 GW plants per year because we are in early long tails of that geometric growth curve.

You know who else was concerned about exponential growth? [wikipedia.org]

economics and population growth

[falconwolf]

You do realise that he was right? The green revolution along with declining birth rates in the western world has ensured that we have enough food - but starvation is a reality elsewhere.

That's the thing about many, I won't say all because I consider myself one, environmentalists don't and won't consider, as people improve their economics they have fewer children. Up until recently the countries with the highest population growth were China and India. However now that their economies are booming their population are leveling off. A concern in China is that in a generation or two there won't be enough working adults paying for an aged population. Whereas now there's something like up to 10 people working for every retired person then there will be only 3 workers. Where population growth is now a concern is in Africa which due to conflicts and politics is doing poor economically.

Falcon

Still skeptical

[tjstork]

Here's the thing. It always seems like solar cell wattages are not average, but rated assuming a sahara desert level of sunlight. So, you'll rarely see 1watt out of a 1 watt panel - and if you did, it would be for perhaps an hour or so on a july day, and not much more. On average, you would get a curve going from zero to something like a fraction of the watt, and from there, you can extrapolate that you'd need a lot more solar cells to actually power your house.

Re:The trouble is cost.

[balloonhead]

there is no dryer that is anywhere near as efficient as a clothes line.

Balls. The sun produces about a bazillion gazillion megagiga superwatts, and about a squazillionth of that actually goes into drying your clothes. That must be the least efficient clothes dryer you could possibly imagine, unless you try and dry your clothes from a more distant star or mabe by bouncing sunlight off the moon.

Re:The trouble is cost.

[Oktober Sunset]

as opposed to all that, but instead of applying the sunlight directly to the clothes, absorbing the light millions of years ago with trees, so that the light falls on the leaves, the trees photosynthesise, and store the solar energy as cellulose, then burying and preserving those trees and then compressing hem for millions of years to process them into coal or oil, then digging into the ground, sending people down to mine the coal out with huge drills and cutters, or pumping the oil out, often at sea on huge floating platforms and carrying the coal in trucks, and pumping the oil through pipelines, so a place where it is burned to heat water, which tuns turbines, which turn big magnets which move electrons down wires,which turn other magnets and heat bits of metal, so that fans attached to the magnets can punch air over the hot bits of metal, and other magnets can turn a big drum.
nah, I think the sunlight directly onto the clothes is more efficient.

Re:Back of the envelope

[mr_mischief]

This is exactly why rooftop panels are so popular. It's area that already needs covering with something. Getting more panels then roof size, though, comes to a trade-off of what else the area could be doing, like growing crops or forests.

I for one am a big supporter of earth-berm homes for their efficiency and ground-source heat pumps as well. Put a greenhouse on your southern exposure above ground, and use the heat from that in the winter. Eating more fresh fruits and vegetables grown locally cuts down on cooking energy and transport energy. In short, making smart choices for how to live with the land instead of separating ourselves from it so much can make a big difference.

Of course, in a 40-story high-rise, it's a little difficult to do many of these things. It's also not like we're going to get everyone to switch to a rural lifestyle. Mass transit, green rooftops, and light-colored exterior surfaces are some steps in the right direction in cities. It's an architectural challenge to make the interior rooms on the middle floors of a skyscraper passively heated, cooled, and lit. Yet it's not like we want all that vertical space to sprawl out horizontally either. This is tough stuff to figure out, and I hope some very smart people are working very hard on it.

Re:13% is considered "high efficiency" now?

[Dun Malg]

Anyway, point is on the many days when you use less than capacity and the batteries are fully charged, you are just throwing away the power when the batteries are full.

How is that "not green"?

Do you need it spelled out for you? His point is that if someone is so concerned about the environment that they'd invest in all that solar, going completely off-grid is actually a step backwards because excess power can be fed back into the grid. Every excess solar generated watt that doesn't get used by some smug monied neo-enviro who's disconnected himself from the grid on principle could essentially buy off a "dirty" watt and reduce the generation of CO2, nuclear waste, or other detrimental emission by a grid power plant. Plus, the power company has to pay you for that power, and that money could go to more solar equipment, or soybean curd, or donations to dang Greenpeace, or whatever. There's nothing particularly "righteous" about disconnecting from the grid. It's just a form of lefty dick-waving: "oh yeah? I'm off the grid!" It's something done by little men with inferiority complexes, who need to feel big by physically cutting the lines, rather than just being satisfied with an electric meter that only runs backwards.

Re:Back of the envelope

[Rutulian]

Hmmm...well, let's try a different tack. According to my electric bill, I used 929 kWh this month. If I spread that energy usage out evenly (assume 10 hours a day you are consuming energy like you did above), that's 929/720 = 3.1 kW of continuous consumption. To put up a solar panel that will meet these requirements, it would cost me $3, whereas my bill for this month was $165.

I think something was lost in your unit conversions because the cost you calculate seems too high. But mine also seems too low....

Re:13% is considered "high efficiency" now?

[misleb]

Not to quibble, but electricity isn't most inefficient in terms of energy usage. It is just a more expensive form of energy (MUCH more expensive, Joule for Joule). For heating it can often be most efficient. With an electric heat pump you can get more energy into your house than you use in electricity. When burning a fuel, you can never get more heat into your house than you burn in fuel. Unless, perhaps, you were to devise some sort of steam powered heat pump. In which case you'd get the heat from burning the fuel PLUS the heat extracted from the outside air or ground.

Re:economics and population growth

[falconwolf]

The population has leveled off in China because the dictatorship there has decreed that couples may only have one child each. It has little to do with the economy there 'booming.' The booming economy may, however, be a result of the 'one child' dictate. That's one of the benefits of the 'one child' policy that the government explicitly cites.

While China's one child per family has had an affect, the booming economy also has a part in reducing the reproductive rate. India has no such law mandating only one child per family yet their population has leveled off as well. In both cases the economy has had a big impact. And in the west, the developed nations of North America and Europe, if it weren't for immigrants their populations would be falling:

"Developed countries [wikipedia.org] usually have a much lower fertility rate due to greater wealth and their individualistic culture. Mortality rates are low, birth control is easily accessible, and human beings are often deemed (by other human beings) as nothing but an economic drain, specially when they cannot produce income: because of education costs, clothing and feeding. Longer periods of time spent getting higher education often mean young people have children later in life. The result is the demographic-economic paradox."

In case you don't accept the wiki article, which was the first result from Google of "population 'replacement rate' economy" [google.com], here's more:

"In Mexico and India [industryweek.com], for instance, rates have fallen, respectively, from 6.7 and 6 children per woman in 1950 to 2.2 and 3.1 today. Of course, fertility in the most advanced nations (in terms of wealth) such as in Europe and Japan is now below the replacement rate of 2.1 children per woman. The spread of wealth, education and urban living contributes to lower fertility almost everywhere."

Falcon

Re:1 child per family

[warsql]

So after the first child, you keep killing until you have the other gender?

Re:cost benefit analysis

[russellh]

I think the most important question is what would mass adoption of solar power due to our power grid. Non-solar generated electricity would go through the roof, for starters - causing the adoption rate to increase - again causing rates on non-solar energy to increase - until at some point the power companies wouldn't be able to afford to operate their grids anymore.

It's an interesting thought, although I have to admit it reminds me of that guy in college who didn't want to work out because he didn't want to look like a huge, gross bodybuilder... as if he was in any danger of that. I think such a level of solar adoption would take so long and require so much work that the entire landscape of our construction infrastructure, politics, zoning, state-to-state regulations, etc., will be so entirely changed that we can't predict what the actual problems will be. So: not to worry.

Re:Back of the envelope

[bcrowell]

Also there is perceived value in the "status" derived from such a purchase, and the value of "feel good" has supported many causes.
It's true that the feel-good effect was a factor in my family's decision to get photovoltaics. As far as status, you actually can't see our panels very easily from the street, so I don't think most of the neighbors even know :-) To the extent that you can classify motives as rational and nonrational, I've also noticed some nonrational reasoning by people who could get a PV system, but don't. They do the math, and figure out that they can get a guaranteed 5% ROI over 25 years, and possibly much higher if electric rates continue their historical upward trend. (Of course the ROI depends on a lot of factors -- which way your roof faces, how much shade you get, etc.). They then compare with what they're hoping to make on the stock market, or what the stock market has returned in a good year, and conclude that PV is a bad investment. I think people respond well to any investment that offers them the possibility of daydreaming about getting rich quickly with no effort. A risk-free 5% return, with the possibility of being significantly higher, is actually a much better investment then government bonds, but people don't think about it that way.