As the sun has dropped in the sky and the days have gotten shorter and shorter, so too has our solar production.
Not surprising. Thatās the nature of the sun as an energy source, or really of the earth as a planet which rotates as it orbits the sun.
Still, our solar production, and the monthly drop in that production, is interesting to examine ā at least for those of us who are āsolar-headsā.
So hereās a brief look at whatās happened to the production of our 5.59 kW home solar system as weāve moved from a peak sun month like July to a sunās-very-low-in-the-sky-plus-itās-cloudier month like December.
Itās interesting, and heartening, to note that so far, in the almost six months our 5.59 kW system has been online here in Aurora, Colo. itās exceeded the monthly projections REC Solar charted for us ā by quite a bit.
Solar system āoverā-performing
Of course, REC Solar told us that it tends to underestimate total annual production in order to account for variability in weather as well as a certain amount of uncertainty about how a given system will perform. It might also have to do with making customers feel better when they see their system āoverā-perform.
This approach has worked in our case š
In the five full months for which we have data for your system (which officially went online on June 28, 2010), itās produced 598 kWh more than REC Solar predicted it would. In September of this year, it pumped out a whopping 192 kWh than predicted.
Of course, āextraā production has dropped quite a bit as the sun has dipped in the sky in the Northern Hemisphere. In November, we produced only 74 kWh more than predicted. Decemberās āextraā margin is likely to be similar that.
Production in December lowest
As our monthly production has inevitably dropped, so too has our ability to bank what we call Sun MilesĀ® — miles driven by an electric vehicle (EV) or plug-in hybrid electric vehicle (PHEV) whose batteries have been charged using solar energy and/or using electricity from kWh credits amassed via solar offset generation — or, put differently, our monthly kWh net has dropped.
Itās interesting, and heartening, to note that so far, in the almost six months our 5.59 kW system has been online here in Aurora, Colo. itās exceeded the monthly projections REC Solar charted for us ā by quite a bit.
However, weāve still managed a plus kWh net so far in December ā the lowest sun production month of the year, albeit a small one. Weāll probably make 80 kWh more than we use this December.
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Below is a table overview of our solar production so far. Below this are screen shots of our monthly solar production as charted on Google PowerMeter (but only from Sept. ā Dec. ā we didnāt have PowerMeter in July and August). That data is pushed to PowerMeter by our TED (The Energy Detective) system.
Unfortunately, with TED and Google PowerMeter, which measure both electricity production and home use, you cannot easily publish only your solar production data to the web. Youāre forced to publish all of your data. This is a huge shortcoming, one that we hope will be addressed by TED and Google in the future so that we can easily publish our solar systemās production live to SolarChargedDriving.Com. [We donāt want to publish our home electricity use live to the web for obvious security reasons]
Month | Predicted Solar Production | Actual Solar Production | Net Electricity Production |
July | 832 kWh | 924 kWh | +684 kWh |
August | 781 kWh | 937 kWh | +707 kWh |
September | 698 kWh | 890 kWh | +650 kWh |
October | 626 kWh | 710 kWh | +440 kWh |
November | 466 kWh | 540 kWh | +210 kWh |
December | 463 kWh | 500 kWh (estimate) | +80 kWh |
How does our monthly drop in kWh production from mid-summer to mid-winter for our 5.59 kW system located in Aurora, Colo. compare to yours?
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