Thursday, December 20, 2012

Sunny Money

Julie and I have generated 60 megawatt hours of electricity. We own our own micro power plant.

60 Megawatt hours is the amount of energy our Solar PV system has created since its installation in 2007.  Around July of 2012, the 30K we spent on the system was completely recovered by the savings in utility and gasoline cost.

A little background,
The site shows  50.5 megawatt hourss in total generation.  In late 2007 we installed our first 4.5kw (21 panels) system when we built the house,  that system had no data logger, it generated 7500kwh per year.   In 2009 we installed our “Sungas Station” when we became BMW Mini-E drivers, an additional 3kw solar PV system for a total system size of 7.5kw. (35 panels) It is at that time we installed the data logger and began the website count.   The total energy created pre data logger and post data logger is very close to 60 megawatts.

The basics of the system are that it generates approximately 11,700 kwh per year on average.   Our home uses 8000 kwh and our ActiveE uses 4000 kwh for 15,000 miles of driving.  With the benefits of TOU pricing where the energy is cheaper at night when we charge the car, we have accumulated a small credit from our utility over the last couple of years.  This year with the addition of the Honda Fit EV which uses 3000kwh, we will now have a bill from SDG&E for around $500.

What this system and two EV’s replace is $4000 a year in home electricity cost, $3000 in gas savings for Julie and $2200 in gas savings for me for a total of $9200 a year.   You can see the $8700 in annual savings can quickly pay for a 30K solar PV system.    We expect this system to produce for another 30 years with one inverter change out. That’s a future savings of $250K at the cost of gasoline and electricity today.  If, and its a small if, in the future the cost of gasoline goes up, then the savings would be far greater.

Do you think gas will go up in price in the future?

What does the 60 megawatt hours of electricity that I have generated to date do?

It will power the BMW Active E in normal everyday life about  210,000 miles. (3.5MPK)  This is the equivalent of 10,000 gallons of gasoline at approximately $40k in cost for a similar gasoline car. 

What will the 345 megawatt hours of  electricity that I will generate in the future do?

It will power the BMW i3 in normal everyday life over a million miles, 1,552,500 miles. (4.5 MPK) This is the equivalent of 74,000 gallons of gasoline at approximately $296,000 at today’s cost of fuel  for a similar gasoline car.

Together past and future,  that’s $336,000 in avoided fuel cost for a 35k investment, allowing for an inverter or two in the future.

Only electric cars can drive on solar energy.  In California it is 1/10 the cost of gasoline and it is saving us  hundreds of thousands of dollars. 

That’s what we refer to as “Sunny Money”
...and yeah, it feels good.

65,000 Solar powered miles. 

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