So the end of November brings with it the end of my first full year with solar panels. And my projections for production and savings were right on target.
Before I go into the numbers, I have one cool little story first. I had read that a 5-kW solar panel system would produce about 6 MWh per year. And that was the number I had based most of my ROI estimates on, both when calculating my energy savings and income from selling my SRECs. I flipped the switch connecting my panels to the grid on Black Friday, 2011. So I was down in my basement a couple weeks ago on Thanksgiving evening and for some reason I checked my meter and it read exactly 6,000 kWh. I was one day short of my anniversary and met my production goal to the watt!
I know, I know. That’s probably not that interesting or exciting but to a solar geek like me it is!
So here’s how things stand after one year:
|Period Ending||Production||As % of Usage||Savings|
|Dec 21, 2011||223 kWh||32.5%||$45.05*|
|Jan 24, 2012||288 kWh||34.5%||$59.26*|
|Feb 23, 2012||419 kWh||72.2%||$86.81*|
|Mar 23, 2012||484 kWh||87.7%||$106.48*|
|Apr 24, 2012||663 kWh||116.1%||$145.86*|
|May 21, 2012||536 kWh||117.3%||$81.62|
|Jun 22, 2012||707 kWh||121.8%||$107.72|
|Jul 23, 2012||767 kWh||75.1%||$116.86|
|Aug 22, 2012||660 kWh||67.9%||$98.93|
|Sep 21, 2012||616 kWh||77.6%||$92.34|
|Oct 23, 2012||449 kWh||69.7%||$67.32|
|Nov 23, 2012||313 kWh||50.2%||$46.93|
*NStar 100% Green Energy rate
If there seems to be some inconsistency, it is due to monthly usage fluctuations, differences in the number of days per billing period and NStar price changes.
I also just noticed that for the months when I produced more than I used, I forgot to include NStar’s $6.43 monthly flat fee in my calculations. It didn’t affect my monetary savings but did reduce my usage % a little bit. I have adjusted those numbers accordingly.
So I ended the year producing slightly more that 6,000 kWh, saving slightly more than $1,000 and producing nearly 75% of the electricity I used. These figures met or exceeded my expectations when I was investigating purchasing solar panels so I’m very glad that my estimates proved to be accurate.
My maintenance expectation was accurate also as there was hardly any. I did spray them off with the hose once in May when they were covered with pollen but that was only because I didn’t want to lose a few days’ production until it rained.
There were a couple caveats, however, that I feel must be addressed. I have mentioned before that until I had my first month of electrical surplus, I was on NStar’s 100% Green Energy program. Electricity on that program costs almost 40% more than it does on the normal residential rate. So my savings are inflated from December through April and I don’t expect to save a full $1,000 in future years.
Another disappointment was my income from SRECs. I had originally figured that they’d conservatively sell for $400 each. However, the SREC market proved to be binary: selling near the maximum when undersupplied and near the minimum when oversupplied. And unfortunately, the market became oversupplied just as my SRECs were minted. I still hope to sell them for the $285 minimum in the Last Chance Auction next July, but if I cannot I will probably keep them until the market potentially becomes undersupplied again in 2015. They will be worth much more at that time, but I still have to wait. I will get my money but they are not the automatic quarterly payment I thought they would be.
So all in all, it was a successful solar year and I still feel my solar panels are a great investment. My 4-year payback window should still be valid although due to the delay in selling my SRECs, that money will not be evenly distributed but will mostly come at the end of it.