December Electric Bill

by Ben N on January 10, 2019

I just got my December electric bill! What will it be this month? December is notoriously cloudy in my area, and has the fewest hours of daylight of the year. Is this the electric bill I’ve been dreading?

Let’s open it up!

Unfortunately, I have to actually PAY an electric bill this month! I haven’t had to do that since last March!

On the other hand, the bill is lower than what most people in my area pay. Lets take a look at the numbers.

My usage was net use of 590 kWh from the power company. That’s how much power I bought from them even counting the power I SENT from my solar panels. On my actual electric bill, it doesn’t state specifically how much power I sent out. Even if it did, that still wouldn’t account for power created by the solar and then directly used at my house. (If it’s sunny out AND I’m charging my electric car, the power essentially goes right into the car, it’s not tracked at the meter!)

So, I went to the Enlighten software and ran a custom production report for the time period covered by my bill. That gave me a number of 278 kWh produced by may panels in that time. Adding the 278 kWh to the net 590 kWh gives me a total of all electricity used in my household of 868 kWh!
Wow! That’s a lot, almost exactly the current U.S. Residential average!*

I usually try to be BETTER than average, but winter means running the furnace blower more, having lights on longer, and even holiday entertaining. We’ve also been using the electric car more, and the preheat feature (while it is nice to hop into a warm car!) DOES use more power!
(Unfortunately, a project truck parked in the garage right now means I can’t keep the Mitsubishi iMiEV parked in-doors.)

So, what does that 868 kWh cost me?
Power cost at my house is actually very close to national averages, so it works out nice for comparing cost across the country.
If I simply paid the average ($0.1289) per kilowatt times 868, that would be $111.89.

Instead, my cost was reduced by a $15.87 for solar power produced in previous months and a reduction of 278 kWh for solar produced this month, bringing my final bill down to $57.30.

Solar saved me about HALF on my electric bill!

These numbers can vary quite a bit throughout the year, as available sun and electric use change depending on the season. I designed my system so that ON AVERAGE through the year, it should more or less cover how much electricity I use.

Even if I have a December electric bill, that’s covered by the fact that I didn’t have an electric bill at all for the entire spring and summer!

I also ran the lifetime production numbers at the end of last month for energy created for all time with the system. It’s still on track for paying for itself in 6.5 years. That means I hit my simple economic Return On Investment (ROI) in only 5 more years!

Take a look at my solar production anytime you want to at:

That’s it for now! We’ll see you next month for the January 2019 Electric Bill!


PS: Snow really hasn’t been an issue. We’ve had very little total snow so far this year. CLOUDY days are a problem. In my area, we often have days where the sky is just a solid gray and you can’t even see where in the sky the sun is, reducing power production to almost zero.

*2017 U.S. National Monthly Average Residential Electric Use.
Data from forms EIA-861- schedules 4A-D, EIA-861S and EIA-861U

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