Just as a refresher we spend about $13K on our solar system which came out to around $10K after the 26% federal tax credit. We did have to pay an electrician $3k to upgrade our service panel from a 100 to a 200 amp panel because our panel was a fire hazard before we added solar and didn’t want to burn down our house. We got a 5.1 kW solar system so we ended up paying $1.97 per watt.

 

I know most readers are just going to want the base cost and saving so I created a chart of that information that I will add to the top of the blog and update it as the months go on. The first two columns are what we paid with the solar panels, followed by what our bill would have been if we did not have solar. The last three columns are what we saved and how long it will take for those savings to add up to our $10K ‘investment’.  

 

  Solar Bill Non-Solar Bill      
  Net Usage Cost Usage Cost Savings Return Payback
December 141 kWh $56.73 561 kWh $120.62 $63.89 7.97% 12.5 years
January 115 kWh $50.90 529 kWh $113.74 $62.84 7.84% 12.7 years
February -5 kWh $30.28 566 kWh $120.62 $90.34 11.27% 8.8 years
March -158 kWh $2.75 547 kWh $117.61 $106.22 13.25% 7.5 years
April -689 kWh -$126.66 321 kWh $69.02 $195.68 24.41% 4.1 years
May -412 kWh -$51.41 608 kWh $130.72 $182.32 22.72% 4.4 years
June              
July              
August              
September              
October              
November              
Year -1430 kWh $33.60 6055 kWh $1,300 $1,266 13.16% 7.6 years

Nerd Alert

 

For those of you that want to nerd out on the number here is a month by month breakdown of our electric bill along with some of my thoughts.

 

December: Our total energy usage for the month was 561 kWh and we produced 420 kWh. We ended up using 120 kWh before it hit the grid, pushing 300 kWh to the grid, and pulling 441 kWh from the grid. This left us with 141 kWh to pay for and it cost us 40 cents per kW which is about twice what we were paying per watt before. Hopefully we can start to shift our energy usage to the day and use more solar before it hits the grid to reduce our cents per kW. It was hard to do this month because of Christmas lights and space heaters at night. I am a little sad about the 12.5 year payback time frame for the project, but then again December is the month we produce the least amount of solar, so that number will go down.

 

January: Realistically the numbers are nearly identical to December with us just using less energy all around. We used 529 kWh and produced 414 kWh. Only 106 kWh were pre-grid while pushing 308 kWh and pulling 423 kWh. The cost per net kW use was 44 cents. In general our panels were producing more power per day and each panel was maxing out more (we have 320 watt panels, but at peak last month they did 230 watts and 240 watts this month), but we had more cloudier weather this month.

 

February: It is funny to think that we paid the electric company $30 to send them 5 kWh of electricity, but in reality it is more like we spent $30 to use the electric grid as our battry backup for our solar.  I have not done the math, but at this point it is probably a good return to use the electric grid as our backup instead spending another $10K on a tesla power wall.  Plus the battery backup would not have worked during the last two months.

 

March: Our total energy usage for the month was 547 kWh and we produced 705 kWh. We ended up using 220 kWh before it hit the grid, pushing 485 kWh to the grid, and pulling 327 kWh from the grid. This left us with a net energy usage of -158 kWh.  I don’t know if all electric bills are this way, but ours is impossible to read and figure out.  Our online bill estimator said our bill was going to be -$9 for the month and our bill shows a $9 credit, but somehow we were charged $11 for the month.  From what I can tell there are certain charges that cannot be offset, but we have some off settable credits to use later. IDK I guess we will see how the year ends.

 

April: Our total energy usage for the month was 321 kWh and we produced 1,010 kWh. We ended up using 175 kWh before it hit the grid, pushing 835 kWh to the grid, and pulling 146 kWh from the grid. This left us with -689 kWh on our monthly bill.  We were in Idaho for 21 of the 31 days of the billing cycle so our house basically doing nothing uses 300 kWh which for the most part is our kitchen fridge and office with our security system and internet connections.  Also our bill had a climate credit which I think everyone gets twice a year, but I didn't factor that into any of the cost projections ($11.48 bill with $138.14 bill credit and a $29 climate credit).

 

May: Our total energy usage for the month was 608 kWh and we produced 1,020 kWh. We ended up using 371 kWh before it hit the grid, pushing 649 kWh to the grid, and pulling 237 kWh from the grid. This left us with -412 kWh on our monthly bill. For the past month our system has been producing abour 34 kWh a day with only a slight viariation for cloudy days.  To the point where I thought something was going on and went up to wash off the panel which were dirty, but didn't help production.  Then all of the sudden the last two days it is  producing 38 kWh with no real change in cloud cover.  We did have a huge wind storm come through so it might have cleared some haze, polution, or smoke from the air.