Annual Solar Update – 2015

It has now been two full years since our first solar array came online, so it’s time for another annual report!

Haveman House - Solar Production Graph - 2014-15

As you can see from this chart, it was a pretty dynamic year. June was much sunnier than usual which resulted in a much higher production total than expected. The same might have happened back in November; but I can’t really remember back that far. I do remember that we had no snow in the winter to cover the panels and decrease production that way, which is quite a contrast to the foot of snow we had the prior year.

Overall, we ended up producing 15,873 kWh this year, which is 108% of the predicted average of 14,742 kWh. Of this, 7,719 kWh is from Phase 1 (rated at 6.0 kW) and 8,154 kWh from Phase 2 (rated at 6.125 kW). In terms of overall efficiency, this comes out to 1,309 kWh per kW of rated DC capacity, which is outstanding for our area.

Combined with the totals from the first year, this puts our total production for the first two years at 29,150 kWh. This is enough energy to drive an electric car 115,000 miles!

Speaking of electric cars: we produced enough energy each month to provide for the charging of our vehicles. The rest was used up by the house. Last summer we ended up accumulating a bank of excess energy as high as 3,880 kWh, with the peak on October 7th. This energy combined with our additional production lasted us through the end of the year and until January 2nd! That was much longer than we expected. Right now we’re at 3,776 kWh, so we’re well-positioned to end up in a similar situation this time, although it really depends on how bad the weather is this winter.

Since we had the energy bank available through January 2nd, and we were able to produce more than we used again by April, we only had to pay power bills for January, February, and March, and those were much lower than they used to be. Our total energy costs were just $173 for the year! We used to pay about $2,000, and that was before we had electric cars.

For the data-hungry readers, here’s a graph showing our household energy usage, car energy usage, energy generation, and, for fun, average temperature, for every month since we bought our house.

Monthly Electric Usage @ Haveman House - Graph

We have some other interesting news to share about our cars and the state of solar in Washington State, so keep an eye out for more posts here on our new blog!

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