Warning, you may find the following blog somewhat turgid and technical...and hopefully inspiring.
Gina and I leased a Chevy Volt last Friday, completing the circuit from our photovoltaic array through our house to our car battery. Here is a picture of the dynamic duo...the car and it's array. In reality, we have a grid connected system, so the power produced by the PVs goes onto the grid and the car battery charging takes place in my garage, plugged in to grid power.
Many people don't think about the smokestacks in their lives but we all have a few of them...the dirty power plants we don't see consuming massive amounts of fossil fuel (the biggest CO2 emitters world-wide), our vehicle tailpipes (add them all up and you'll start to wheeze) and the chimneys sticking through our roofs. Wouldn't it be great to eliminate or at least eviscerate these polluters before it's too late?
Your monthly power bill probably hovers well below your phone/internet/TV bill (unless you are unfortunate and you heat your house with electricity). At our house, our monthly electric bill is less than $50 per month. Electricity is a bargain!
So, you may be thinking, if electricity is such a bargain, why spend the money on a photovoltaic system? Isn't that expensive? The short answer is no.
The 6.4 kW double axis tracking system we installed cost $24,600 after the 30% federal tax incentive and the $2,000 state rebate. I figure our annual savings on household electricity are a paltry $500. We don't use a lot of electricity here. But our PV system produces more than twice as much electricity as we use in the house. We can drive the Volt 14,000 miles per year on the excess electricity!! Driving around central Maine in an endless loop of work, play, schmoozing, partying, errands and food shopping. Assuming 30 mpg on our old car and $3.50/gallon for gas, the annual gasoline savings will be $1,600. Of course we'll have to drive the Volt at least 38 miles (the Volt battery's range) every day of the year to save that much. Alternatively, with two electric cars, Gina and I can each drive on the solar power. This will require each of us to drive our car at least 3.5 times a week....not unreasonable at all. It will be interesting to see what other plug-in cars become available...I looked into the Tesla but the nearest dealer is in Massachusetts. Prices are coming down.
As you can see, the $1,600 per year gasoline saving is more than 3 times the $500 annual savings on household electricity. This points out how expensive it is to drive gasoline cars and how efficient it is to drive on solar electricity. Electricity is well suited for driving...so much better than the internal combustion engine. (Important note: charging your car on coal fired electricity is way more polluting than running your car on gasoline!)
The combined gasoline and household electricity savings from our $24,600 system are $2,100 per year. So the payback (that holy grail for people who don't include unquantified externalities as well as misinformed naysayers) is about 12 years on a system expected to last 25 years. That's equivalent to a 7% return on investment at present gas and electricity prices. Not bad at all.
A smaller roof mounted solar system designed to meet household requirements costs about $9,200 as opposed to the $24,600 spent on the larger tracking system we had installed...and the savings would be about $700 per year...
So how does this relate to those lovely smokestacks in your life? Eliminating exhaust from 14,000 miles of driving every year is huge. Plus, you have eliminated power plant emissions by substituting solar for household electricity use. The new, less expensive PV systems combined with the new plug-in electric vehicles are the best energy technology developments of the early 2000's. If someone developed a large solar farm and started leasing solar powered plug-in electric vehicles would you lease one?
We, the public, have paid a massive amount, literally trillions of dollars, for electrical infrastructure...the grid. What we need now is the political will to overcome vested interests and invest a little more to replace the coal fired power plants that hang on the grid producing massive quantities of CO2 and the nuclear plants that resemble radioactive time bombs. A utility grid powered primarily by renewable sources supplemented with natural gas combined cycle plants will be a beautiful thing!
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