Solar cells environmentally worth it?

I’ve been thinking about what I as a single person can do to help the environment even a litte, and solar power is an obvious thing that comes to mind. I could cover the roof of my house with solar panels and switch to electric heating, maybe even get an electric car. If I’m lucky maybe I’d even have some surplus to sell back to the electric company, and either way it’s some small reduction in the amount of pollution caused by burning fossil fuels to generate the electricity. But from an environmental standpoint is it really a net gain?

I’ve heard that financially solar panels rarely if ever pay for themselves - the initial cost of acquisition and installation is so high that you’ll never recover it from a reduced power bill. If that’s changed, great, but either way this isn’t really a concern for me. I’m willing to pay extra to do some good in the world.

So environmentally are solar panels a break-even or better proposition? Is the pollution saved on the electricity-generating end more than the pollution caused by manufacturing the panels in the first place?

As for production payback I couldn’t say.

However to cover a portion of my roof it was going to take about 15-20 years for it to pay for itself.

Good luck.

Solar panels are indeed very expensive, and even if you cover your roof, you probably won’t be able to power your whole house with them. You will save a little on your electric bill, though. But probably not enough to justify the cost of buying the panels. (Unless you’re doing it for pure environmental altruism.)

Another concern is that many noxious chemicals are used in the manufacture of solar panels.

Excellent question, and we’ve talked about this in other posts.

There have been “payback” studies done on PV arrays, though I question the results from one study I read. IIRC, the researchers “added up” the amount of energy it took to manufacturer a PV array, and concluded the payback period was around 7 years, but I’m very skeptical of that number.

I have little to base this on, but it is my opinion that (based on current technology) PV arrays never really “pay for themselves.” In other words, it is very likely more energy is expended to manufacture a PV array that what the array would produce over a typical lifetime. (The manufacturing energy would include the energy to mine the silicon, purify it, assemble the arrays, etc. etc. etc.) Assuming this is true, a PV array does not produce any net energy, and is actually an energy vessel (much like a battery). Hopefully future technology will turn this situation around.

Maybe solar air/water heating would be worth it? These systems are much simpler/cheaper than PV systems and thus can pay for themselves more readily.

brian

There are economies in scale. I do not believe photovoltaic pays for the small owner. Heck I do not even believe water heating solar panels are worth it and they are much cheaper and more productive as far as energy is concerned. Solar energy has been discussed in several past threads and you can find them if you search. My opinion is that it is not worth the trouble for the individual homeowner but it may make more sense for a larger institution. There’s pleanty of maintenance and other issues which will make it a PITA for a homeowner.

A number of “solar plants” have been built, and (from what I’ve read) many are being dismantled because the scrap value exceeds the total profit over the plant’s operating life. Suffice to say, I don’t think PV arrays ever “pay for themselves,” regardless of scale. Of course, a breakthrough in the technology could change this scenario.

Current solar cells aren’t efficient enough to compete with large-scale commerical power production. At this piont, it’s a materials tweaking game to try to eek out another 1-2% efficiency. One of the main problems is something known as the Stabler-Wronski effect. This rather unfortunate effect is that solar cells lose efficiency with prolonged light exposure. The good news is that the effect plateaus (the materials don’t degrade to 0% efficiency) which leaves hope for the materials people to come up with something.

I don’t believe solar panels use more energy to create than make. (See the calculations done by Q.E.D. in this thread, 1/2 way down). I know one professor a the UofA outfitted his house with lots of energy efficient stuff, as well as various solar equipment. I met him at a retirement party, and he said he gets calls from new hires in the EPCOR billing dept. wondering why his balance is negative. He has to explain that that particular month, they’re paying him.

He did get most of it paid for from a grant or some experiment fund, I’m not sure. Proper solar panels are quite expensive, and not all places and power companies can handle running the meter backwards into the grid. I have noticed that even Canadian Tire has large 120v panels for RVs now, so they’re certainly cheaper than they were even a few years ago. There’s probably a small club of rabid fanatics near you that you could ask. :wink:

Electric heat is terribly wastful (unless you are using a heat pump as opposed to resistance heating). Use that electricity to power other things or sell back to the grid.

You could do better by using energy efficent light bulbs, getting a tune up for your car(s), and aviod jack rabbit starts.

I once heard that solar panels get less profitable at a larger scale. A rooftop unit utilizes an otherwise unused space and needs very little in terms of mounting structure. If you try to scale up you will need a big structure to support the solar panels and you end up with a lot of space underneath that’s difficult to utilize. And the cost of the solar panel doesn’t benefit from larger size - it’s pretty much a fixed cost per unit area.

:dubious:
In our case, solar power has been an economic positive. The local electric company would have charged around $3000 to bring power to our home, which is sited 500 feet from the lines. We paid about that for an eight-panel (.6 kwh) 24-volt DC system with a Trace DR 3600-watt 120 volt AC inverter. Plus we do not have to pay the $250-$300 per year service bill. We have had the system for four years now, it works great; we run lights, washing machine, power tools, computer, stereo, TV, vacuum, and 120-volt submersible well pump. We use a propane refrigerator and stove ($200 per year), and heat the house with wood (free).

Environmentally, the panels represent a small amount of silica, plus some metal wiring which can be recycled. The batteries can also be recycled. Coal, oil, natural gas are use-it-once. Hydro dams carry their own baggage (large-scale river habitat degradation or destruction). I can personally attest to the large-scale destruction of habitat and agricultural land from coal mining here in the Midwest. Plus there is acid rain. With oil and natural gas we can also consider the environmental consequences of militarism and war to defend our “interests” in the Middle East.

My home (which I sold not too long ago) had solar panels for hot water on the roof and I did all the maintenance myself but, believe me, if you had to pay for the maintenance you’d go broke.

The panels were mounted on the roof. Any needed maintenance to the roof underneath meant removing the (huge and heavy) panels. The supports for the panels created leaks. The antifreeze mixture (expensive) needed replacing and then you had to bleed the air, adjust the pressure, etc. The electronic controller malfunctioned once and it took me quite a bit of effort to repair. Then you have to deal with the fact that the system gives you hot water when it wants, not when you want. In the winter it just preheated the water a bit so you still need a gas water heater. In the summer it will give you more water than you can use and you have to use it. I found myself flushing the toilet with buckets of close to boiling water in the summer. It clearly is not worth it for private homes.

Now, a large institution has a maintenance guy on site at all times and this is part of the cost of the installation. There are economies in scale.

PV will never be economic if free enterprise stays the norm in the US. They only work, economically, in remote locations, like space (what they were developed for) and remote cabins and houses. PV’s will work politically if legislatures require it in Renewable Portfolios. Some areas are requiring 20 % renewable by 2020. This will drive the cost of electricity up and damage those economies. Let the free market determine where our energy comes from, not environmentalists or big corporate executives.

[nitpick]

Do NOT lump oil and natural gas together. 84% of the natural gas used in the US is mined in the US. Of the other 16%, 95% comes from Canada. So, not only is its use more environmentally friendly than all other petroleum products, it does not have any baggage from international relations.

Link to 2001 DOE Report on Natural Gas

[/nitpick]

One statistic to consider is that sunlight produces 1.5 horsepower per square yard (at the Earth’s surface).
1.5 horsepower is 1,120 watts. And no matter how efficent you make the solar panels you will never generate any amount higher than this. Then there’s the problem of nighttime.

The late Dr. Peter Glazer had a plan top mount solar arrays on satellites, in geostationary orbits. These would convert the solar electricity to microwaves, which would be beamedto receiver arrays on earth…seems like a good idea tome.
Did anybody ever research this?

Yeah. Too expensive.

Besides which, you would very likely expend more energy creating the satellites, and especially in the fuel needed to launch them, than you’d ever recover from the satellites themselves.

The “microwave beam” is also woefully inefficient- yes, you can project power this way, but at a fraction of the efficiency of hardwire systems.

In other words, you’d have a better net use of energy by leaving the PV arrays here on earth and burning the rocket fuel chemicals in something like a normal powerplant.

In retrospect I think I want to ask a different question.

Given that I’m willing and able to pay somewhat of a premium for energy (within reason of course), what can I do as an individual that will be a net positive for the environment? A secondary goal is reducing the US’s dependance on foreign oil.

And related to the OP I recently saw an article on a company with a different approach to using solar for power generation. Instead of using PV cells, they used reflectors to concentrate sunlight and run a Stirling engine hooked to a generator.
<url>http://www.discover.com/aug_03/featfire.html<\url>