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Getting the Most Out of Your Green Buck?
batobin asks: "My dad is thinking of installing a solar photovoltaic system on the roof. After tax credits, it'll cost $12,000. In Santa Barbara, where we live, our power company grants credits when the meter runs backwards and saves the credits for 12 months, reducing our monthly power bills year round. If the contractor's math is correct, the amortization period (when our power bill savings equals the installation cost) is about 12 years. With environmental and geo-political concerns in mind, is this the best use of our money? Will reduced consumption translate into cleaner air / less dependence on fossil fuels? What other environmentally proactive investments could be made with 12 grand?"
Replace your car with a diesel VW, and run BioDiesel. Producers of BioD get a tax credit for producing it, so it's competitively priced with regular dinosaur-diesel, and the slight decrease in BTUs of the fuel is mitigated by the more complete and more efficient combustion of said fuel, due to the higher cetane rating. Figure 45 mpg, and you get a real car, with a real stereo and trunk, no banks of potentially hazardous batteries to recycle in X years, and you're not sitting in the middle of a giant magnetic field while driving.
BioDiesel solves the chicken and egg problem, and its a fuel with similar energy density to petroleum fuels, unlike ethanol, or god forbid, hydrogen.
BioDiesel also comes close to closing the carbon cycle, since the carbon in the fuel came from the air to begin with. Because it doesn't come from the ground, there's no sulphur or metals in it.
I want to delete my account but Slashdot doesn't allow it.
Not true, solar panels should have a break-even point of about 2 years. Couple this with an expected lifetime of >20 years (If you're in an area where you don't get much severe weather, this could be easily double).
http://www.solarbus.org/documents/pvpayback.pdf
In addition, semiconductor manufacturing processes do not create nearly the amount of pollutants as in years past, and most manufacturers have very aggressive recycling policies (the company I work for recycles 85-90% of all our waste)
That said, a hybrid/electric vehicle, more efficient appliances, even better insulation would probably provide a quicker ROI.
Good Luck!
You can go for a 'grid-interactive' system, which basically just has an inverter connected to both the solar panels and the grid. With grid interactive units, no batteries are needed, although there are disadvantages, chiefly that most grid-interactive systems shut off if there is no grid power.
:-)
Basically two operating modes:
Sunny day - the house gets its power from the solar panels, with any excess going 'into' the grid. You may get a cheque in the mail from your electricity provider for the power you send into the grid, you may not - it all depends. If you're at work 5 days a week and the house is basically empty, you should get some cash back, and with appropriately-sized panels, your power bill should zero out.
Rainy day and nighttime - the house gets its power from the grid, and your 20 grand's worth of panels sit useless on the roof, while your neighbours mock you
Grid-interactive's probably the way to go if your existing grid supply is reliable, and your provider has some environmental smarts about it.
You are in a twisty maze of processor lines, all alike.
There is a lot of hype here.
As far as we know, photo-voltaic systems are not "self-sustaining". That is, every kilowatt hour of energy your system produces in it's entire lifetime will not be more than the kilowatt hours that were used up to purify and crystallize the silicon, and make the PV system.
This is a myth. After two to four years, there is a net gain. (It also fails the sniff test: if the myth were true, they would have to sell them for less than it costs to make them.)
--MarkusQ