I'm making a lot of assumptions here, but you could argue that the solar panels do not need a long lifespan. What they need is a mounting framework that has a long lifespan, including robust hardware that interconnects with the electrical system. If the conversion efficiency of the panels will improve every few years, the cheapest panel possible would be a better benefit, as long as they are easily replaceable and recyclable. This would provide a more cost effective system in the long run.
I think your arguments ignore many of the actual economic costs of a solar panel installation. The mounting framework is the cheapest part of the structure. The solar panels themselves are expensive, but the major issue with your idea to re-install them every few years would be the labor costs. It takes a few hours and a few men to install the panels, so throwing in $1000 every 2-3 years would make this type of quick-replace plan non-cost effective.
I'm not an expert in solar panels by any stretch, but my understanding that the two major breakthroughs we need are a) how to make the solar panels themselves more efficient over a long life-span. Typically they lose 2-4% of their efficiency every year, meaning 20 years down the road, they've lost 50% of their energy power. b) a more efficient converter from the DC generated by the solar cells to the AC we put back into the grid.
Let me re-iterate: as long as they are easily replaceable
In others words, design it with replacement by do-it-yourself homeowners in mind. I looked up the spec for one and it was 1250x800 mm (~4x3 ft) and weighted 12 kg (~25 lbs). That's a little awkward for one person to cart up a ladder, but what if they were half the size and had a strap handle on the side? What if they used quick disconnects for mounting? If you set out with these as design goals, then I'm sure a feasible solution could be found.
How common is it for homeowners to have a friend replace roofing tiles for them? Such a job is as easy or easier (and cheaper in terms of materials) than replacing solar panels.
In practice such things are not common at all, people don't have friends who will just go up on roofs and do serious work. The best you can hope for is something as easy as installing Christmas lights (which doesn't even require getting on the roof itself, just up to the eaves).
That's the idea, it shouldn't be in the same class as replacing roofing, it should be in the same class as repainting your shutters, or cleaning your gutters.
Typical degradation rates for crystalline silicon solar panels is 0.5% per year. When you read about efficiency being an area of innovation it's conversion of solar radiation into electricity that's usually the issue. Inverters are 95% efficient (the other 5% goes off as heat) but there is R&D going on to improve this. The other innovation is micro-inverters - meaning each panel has it's own inverter. This means that a panel that is shaded only loses production from that panel. In a central inverter system, partial shading can kill production for the entire string - meaning all panels connected to that inverter. The tradeoff for micro inverters is higher expense and some would say more maintenance and points of failure, although there are counter arguments I won't bore you with.
We're not saying $50/month would pay for all the electricity, it would only pay for its replacement costs every 2-3 years. You still need to pay the $20,000 for the solar panels themselves. And it's a misconception that solar panels replace all your electricity needs. Doing the math last year here in Texas, it only covered 20% of my needs in the summer, 75% of the needs in the winter.
You probably don't have enough space then. In most locations and for most homes or businesses, you can easily replace over 80% of your grid power. You could even replace 100% but the risk there is that most utilities have "no negative net metering" regulations approved by the local PUC that mean if you produce more than 100% of what you use, the utility keeps it for free. This makes installing a system at close to the limit uneconomic (and is also one of the reasons that Germany has more installed solar per capita despite far less favorable solar radiation than the US).
The cost of installing new panels can be quite high, depending on where they are installed. Also I'd be worried of a format war - I bet that each manufacturer comes up with his own standard, which would lead to higher prices for the replacement and the possibility that your format disappears from the market in a couple of years.
Look I like the sound of this but please : get it into production! I was reading these stories 4 years ago. They need to launch the product in a specific niche (camping? boating?) and iterate and learn. It's like a startup that never gets to launch.
Not really. Most big users of power pay incredibly low per kwhr rates (in the US anyway). Without a realistic feed in tariff (meaning the utility buys the power generated, not the data center) the deal won't be economic (unless the data center agrees to pay more than grid for solar, which they won't).
Take into account the existence of night, cloudy days, and the fact you're probably not at the equator: divide that by four.
Efficiency of these solar cells: they have a "goal" of 10%, so let's optimistically assume they make it.
So we're collecting, on average, 0.11001000/4 =2.5 kW.
Actually, y'know, when I started this calculation I was anticipating something ridiculously small, but that's a not-insignificant fraction of your usage. Am I missing a factor somewhere?
> Take into account the existence of night, cloudy days, and the fact you're probably not at the equator: divide that by four.
That's still somewhat optimistic; about 10--20% of peak is more realistic, based on what we've seen with existing solar installations. It's closer to 20% in sunny places, and closer to 10% in places with less sun.
However, that still leaves us with a respectable amount of electricity. Good for them.
Of course, the panels themselves are not the whole cost. There's other electrical equipment needed to make that energy usable, for example, and someone has to install and maintain the solar panels. I think the next big source of money in this market, after they get the cost of manufacturing the panels down far enough, is streamlining installation and maintenance. Perhaps someone could make durable "solar shingles" that are relatively easy to put on a house, or some such thing.
Longer-term, solar photovoltaics look like they could provide a pretty hefty amount of energy cheaply, if we solve a lot of engineering issues. Where they fall down is producing power reliably, close to where it's needed. One way of dealing with this is to have the solar panels in space, but obviously that's pretty tricky. Another way of dealing with it is to use something else to provide the base load of your electrical grid -- nuclear could handle this with cheap green aplomb -- and use the solar power for things which can easily soak up cheap intermittent power, such as charging the batteries of electric or plug-in hybrid cars. Theoretically, it could also be used to power interesting energy-hungry chemical processes, like ammonia synthesis or aluminum refining. Making this financially viable is another big engineering challenge, but definitely a worthwhile one if it works out.
Your math isn't horribly wrong. In fact, Wikipedia mentions ~1kWh/day as achievable. That's why cheap, efficient mass-produced solar cells are so damn attractive.
They just have the minor hitch of not, in fact, existing.
Pet peeve: I don't like the unit "kWh", since it's a unit of energy, divided by a unit of time, multiplied by a different unit of time, to give a unit of energy. Why don't they just give it in Joules?
kWh/day is even worse -- it's a unit of power made by dividing a unit of energy by a unit of time, multiplying it by a second unit of time, and dividing it by a third unit of time!
And now if you'll excuse me, I'm going to go for a jog at 0.11 meter days per hour per second.
They don't give it in Joules because I have no way of understanding how many Joules it takes to run my 17W bulb for two hours per day - but I do understand rather easily how many kWh/day that comes to. So while kWh/day may be confusing from the standpoint of relating it to the amount of coal burned, in point of fact it is the natural unit to use when discussing consumption.
It's especially "not insignificant" if you have batteries and can store the excess power generated during the times of day when you aren't using much power. Most houses are empty a large fraction of most week days.
Just because of day and night divide by three. (2 for day night, plus some extra due to twilight).
Then for upper latitudes divide by 2 again, and then finally divide by 3 because only part of the roof will face the sun. So your factor should be 18 not 4, i.e. your numbers are 4.5 times larger than they should be.
BTW your multiplication symbols turned the number inside it italic.
In US units one square foot of roof can support 10 watts. So a kilowatt takes 100 sf of roof space. In much of the US you would generate 1,400 to 1,600 "AC sun hours" per year, so a 1 Kw system generates 1,400 to 1,600 kwhrs per year. If your grid electricity costs $0.20 per kwhr, 1 kwh then produces $280 to $320 worth of electricity per year.
the numbers work out pretty well when you disregard the reality . Only in fantasy land the sun is always at peak, technology that claims to be 10% efficient is actually 10%, DC-AC conversion and storage is 100% efficient, and if you disregard the government subsidies and the energy needed to manufacture.
Well, I set out to debunk the economics of it, but my back of the envelope calculations gave better numbers than I was expecting. You're right, though, lots of factors I have failed to take into account.
Another big one not mentioned yet: ever noticed how dirty your car looks after being left outside for a couple of weeks? Well have fun washing your roof as often as you wash your car.
Actually oil, gas and coal get more than 10X (in dollar amounts) the subsidy that renewable energy and technologies get. Granted, it is because the quantities are much higher, but it's not a "subsidized vs not subsidized" argument.
I know you're joking, but a big problem in discussing energy sources is that a lot of people assume that anybody who tries to explain the difficult engineering issues must be a paid shill for a big energy company. It's kind of irritating, even if it is both false and an ad hominem fallacy.
Flexible plastic solar cells will go everywhere the sun shines, produced in long rolls, covering roofs and even windows (the cells can be made transparent).
How would transparent solar cells work? Would the light coming in be part of the <90% of the light not being converted to electricity?
I don't know, but presumably the solar cells would primarily absorb light from the invisible part of the spectrum, ie. infrared. Your cats are going to hate you for it, though (no more hot spots in the sun..).
Thankfully I don't have cats :~)... however, that does bring up a good point about some of the sunlight being converted to electricity instead of heating your house passively.
Sounds great, except for the fact that every inch of this stuff will be in a landfill after 10 years of use, where it will essentially never break down, and likely leach whatever exotic compounds it uses into the soil/water, trading one form of pollution for another.
It seems like a "disposable society" solution to solar power, and I'm not convinced unless it comes with a clear recycling program.
In light of zeteo's comment, could you take a moment to actually research your naysaying before you go all NIMBY on the technology? How many environmentally-sensible technologies must we sacrifice at the hands of people who think they are environmentalists but are actually just unthinking naysayers? (Perhaps you won't mind if we replace them with thorium reactors?)
I brought up the recycling program because it's an important part of the life-cycle of the technology and it wasn't really discussed in the article. As I implied in my comment, I'm fully in favor if something can be done about the loads of plastic that this process will produce. As was mentioned, even 100% recyclable doesn't mean anywhere close to 100% will be recycled unless it is prioritized by the producers and consumers of the product.
I recently finished "The World Without Us" by Alan Weisman, and his discussion about the long-term impacts of our reliance on plastics struck me as a very under-appreciated burden on the environment - a huge amount ends up in the ocean, where it breaks apart but doesn't actually go away - it just becomes bite-size for smaller and smaller organisms, with predictable effects along the food chain.
I am wary of a "race to the bottom" in terms of cost/watt because it undervalues other aspects of energy production, where the "good enough" mentality hasn't turned out very well in the past (nuclear and coal in particular). This particular technology seems aimed more at being financially-sensible, and I am concerned that the long-term environmental impacts are not being weighed heavily. It's important to factor in the cost, convenience, and logistics of the whole life-cycle of a technology, not just the cost/watt for a limited time frame.
How many 100% recyclable products that we use end up being 100% recycled? I'm all for cheap solar but you can't just wave your arms and say "it can be recycled" without considering the costs of an effective recycling program.
The important question isn't the percentage recyclability. It's the amount (if any) of chemicals which cannot simply be put in a landfill, and the amount (if any) of scarce minerals used which cannot be recycled economically.
It has 40% of a crystal solar cell's service life, but I'll also wager it has far less than a crystal solar cell's mass, being a printing press technology. That should be a net gain for landfilling.
Not to worry though. If these are used in any kind of large installations then the scrap value of the expired cells will be part of their profit. At the very least they might be fuel for cement kilns. If they can burn tires (when not in anyone's backyard) then thin sheets of plastic should be easy.
They say its organic plastic solar cells being used. Does anyone know how quickly they break down? Maybe that's part of the reason why these panels only last 10 years?
what if we could recycle these into next gen solar panels? i.e. break them down to however possible, and remelt the plastic into new more modern cells 10 years from now? (I have NO idea if this is chemically/physically doable, just speculating)
Solar is a scam. Every solar technology advancement turns out to be a lie. I'm willing to bet money that this technology will never actually work or if it does will cost 100x and be 1/100 as efficent as they say it will be. (reference: nano solar, or any solar company since the 70s)
Commence the down voting.
For most of us, paying $5 for a solar cell to replace a $0.50 battery in a calculator. However, that doesn't imply we can afford the same sort of tradeoff when real money is involved.
