Life Cycle for Solar, Wind, Geothermal and Payback Investment

Photovoltaic panels: When I do a cost analysis, I use an expected life of 20 years, although my personal experience suggests 5 years would be more appropriate for an installation in a marine environment (typical failure mode in marine environment is corroded traces). Furthermore, the output of photovoltaic panels decreases with time, and I am not sure how one deals with this factor. From what I have seen, a 10 year old panel has significantly less output than the original rated output- as much as 50% less in some cases, but more commonly providing about 75% of original rated capacity (I am not sure how close these used panels actually came to their rated capacities when new, however, so this may not be a valid comparison). Charge controllers/chargers are fairly rugged pieces of equipment, and, properly housed and maintained, should outlive your panels. The real killer is the batteries. Cheap batteries will cost more in the long run, because they have to be replaced more often. The best batteries available, maintained at an appropriate ambient temperature and subjected to proper charge/discharge conditions, could possibly provide 10 years of service, although I have never seen them last longer than 4 or 5 years (mostly because people can not be bothered with treating them properly).

Wind: In the early days of offshore wind turbines in the Netherlands, mean time between failure was 18 months. The transmissions were failing. I hope they have improved on this. A couple of years ago, there were a number of operators pushing "slightly used, refurbished" wind turbines here in Central America that came from these failed European installations. I also suspect that on shore mean time between failure is much better than off shore...The main issue with wind is that you still need to have your conventional capacity on standby for when the wind isn't blowing- it does not add capacity, only reduces operating costs.

I have no experience with geothermal, but I suspect for major power installations, one is likely dealing with a very corrosive environment, which means a pretty short lifetime...

Thank you for your comments on photvoltaic's and wind, however is there anyone

who knows the life expectancy of the geothermal system as previously asked and point taken that it might be shotenened due to corrosive environments, however
I believe copper or pex tubing might last 10 to 15 years what you think?

http://www.google.co.uk/search?q=solar+cell+payback+time&sourceid=ie7&rls=com.microsoft:en-gb:IE-SearchBox&ie=&oe=&rlz=1I7GZEU_en&redir_esc=&ei=a5QaTJbwDKGT4gazx-TECg

Peter-

It seems your references only consider the payback period for the panels themselves, not the entire system. The battery system can be a pretty big part of an installation, and batteries have to be replaced normally about every 5 years (if one uses the proper batteries and installs them in the proper environment and insures the appropriate charging/discharging cycle parameters- less life for cheaper batteries or batteries not properly maintained). I see nothing in any of the references (although I admit I did not review all of them) that talks about the carbon footprint of the battery packs, or the impact on system payback from having to replace them on 5 year cycles. Some claim achieving battery lives in excess of ten years- while this is theoretically possible, I suppose, it is inconsistent with my own personal experience.

Now, if one can adjust the demand to coincide with availability, avoiding the need for battery storage, the situation changes significantly. I have some solar-powered water pumping installations that pump water into storage independent of usage when the sun is shining. With properly sized storage facilities, the user is not aware of whether the pumps are running or not. Another application that would make a lot of sense to me here in the tropics would be solar-powered air conditioning- but I have yet to see an economically feasible solution to this.

I am personally quite fond of solar water heating for domestic use, but, unfortunately, with the commercially available units selling for about 10 times the cost of a conventional natural gas water heater (coupled to the fact that, locally, natural gas is so cheap that most users won't realize much savings in energy consumption), this is a hard sell. Mostly, where these have been popular is with clients that are more interested in a visible demonstration of their environmental conscienciousness than actual cost factors...

Wind presents greater problems, because one can never know for sure when the wind will be blowing. Years ago, the Great Plains of the US were studded with wind-powered water pumps- mostly for keeping water in stock tanks, I believe. I can not see using wind for this purpose where availability of water is critical...

"Now, if one can adjust the demand to coincide with availability, avoiding the need for battery storage, the situation changes significantly" how would you do that ?? you need the power for lights at the very minimum and solar panels don't work very well at night.

other use could be changed ie cooking. washing machines etc during day.

as for the carbon footprint of batteries they shouldn't be allowed to walk about.

and the footprint issue has nothing to do with the cost in monetary terms ??

and yes my links only compare the panels and the reason is they are the single most expensive part the other parts ie the controller

Great information cwarner7_11. Could you explain based on your experience why the cost of commercial water heaters is so high? Is it a a function design constraint? Or more of a convinience issue? I have seen is some places that the cost of gas is getting higher and higher each year, and then the gas supply is also not guaranteed. So I believe there should be more R&D invested into solar solutions as eventually at least the supply of energy can be fairly consistent in countries that have abundant sun.

Most of the commercially-available water heaters I have encountered include what amounts to a conventional hot water heater and electrical heater and thermostat as a backup for when the sun doesn't shine. So, you are paying for a conventional electrical water heater AND a solar collector. My price comparison was for gas-fired water heaters, those being the most common choice locally- I'm not sure what the price comparison is with a conventional electrical water heater. Furthermore, most solar water heaters to which I have access are not sold in big box stores like conventional water heaters-i.e., there's a lot of marketing overhead that needs to be dealt with.

One can do a home-brew solar water heater for a whole lot less than the commercially-available ones...

You can work it out yourself.

Whats the present cost of your electricity usage now ?

price up a typical solar system, and divide the overhaul cost by the cost of usage now.

That should put off straight away.

http://www.altestore.com/howto/Tools-Calculators-Reference/Solar-Panel-System-Calculators-Load-Calculator/Solar-Payback-Incentive-Calculator/a65/

http://forums.moneysavingexpert.com/showthread.php?t=1838505

http://hubpages.com/hub/Residential-solar-power-systems---how-to-generate-electricity-at-home-with-solar-energy

much improved panels at last

http://www.sciencedaily.com/releases/2010/06/100617143930.htm

How long is the payback? Instantly, at the first power outage due to a major cataclysm such as an earthquake, riots, terrorist attack, drought, economic collapse, energy shortage, etc.

When you look around at your neighbors with no power, and you are running along normally, you will know that it has paid for itsself.

Just make sure you can switch off the line to the grid so YOU are getting all the power your system produces.