Friday, August 10, 2012

Solar Panels 1 year in

A year ago this week we had our solar panels turned on, so its fitting to write a follow up answering the question of how well they worked.  The short answer is close to exactly as estimated, it provides the electricity we need in our house and is on track to pay for itself in under five years.

First up the raw numbers for one year of production:

The panels generated*: 5952 MWh
We used:                       5085 MWh

The most one day generation was on June 1st at 33.441 MWh
The least one day generation was on January 21st (Excluding days the power went out ) at 18Wh

Below is a screenshot of our panel generation over the course of the entire year.

As we are generating a significant amount more than we use over the past year we have picked up a few electrical appliances including an AC unit for our main floor and a small electric heater (smaller gas bill yeah!).  I expect next year our production will be more in line with our usage.

During the summer months we generate more electricity than we use and each month we get a credit from our electric company.   This credit not only pays for our winter usage (where we use more than the panels generate), but also the $6.43 monthly fee for being connected to the grid.  Due to getting the panels installed in the latter half of summer we didn't have a ton saved up for this winter, but with the light winter we only had one bill at $11 in January.

Over the year we have a number of neighbors inquire about the panels and been told several even got quotes for panel installation themselves.  The feedback has been very positive and I haven't heard anything negative.  In fact most people don't seem to notice them so going with the all black panels was a good choice.  Even a guy that runs a wind farm and is very much into panels didn't notice them when he stopped by, nor did the sales guys that go door to door trying to get me to switch electrical providers.

From the payback side so far the panels have minted three SREC's (over quarters: Q42011 Oct-Dec, Q12012 Jan-Mar) and just like initially estimated we are on schedule to mint six each year.  Electrical costs have also risen ~4% from last year and minus the $11 from January all our electric bills have been covered.  The only "excitement" is that there is oversupply in the SREC market for 2012 so assuming that continues every year from now on it will only add an extra seven months to my original estimate for our panels to pay back putting it sometime in 2017 on the conservative side.

Overall the panels performed nearly exactly as I estimated they would after taking into account sun light, orientation of the house, the lat/long of the house, angle of the roof, efficiency of the inverters, and historical and legal requirements on electrical rate change.  The first month I couldn't help but peek at the numbers all fo the time, but after a few weeks I amusingly realized that they there wasn't going to be some crazy day where we generated twice the normal amount and the day to day change was fairly boring and predictable.

*This is the post conversion and transmission loss number

Revell Big Boy Locomotive Model Kit

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