PERFORMANCE HISTORY
I have 39 solar panels installed ranging
from 175 W to 375 W per panel. In 2021 I installed heat
pumps in both buildings and only use propane as backup, the
trade-off of having these energy intensive devices is I have a
significant electric bill in January February and March that
runs to many hundreds of dollars due to the low solar production
here in Maine. However, from May through October I only
pay the utility for connection fee of about $24. In the late summer and
fall I accumulate kilowatt hour credits that are applied to my
bill in the winter.
The statistics shown come from my Enphase energy monitoring
system data that I put into a spreadsheet to create the charts
below and also from my electric bill. |
|
PERFORMANCE STATISTICS |
The chart below
shows the estimated power that my solar panels should
generate based on calculations from the
PVwatts calculator provided by the National Renewable
Energy Labs. The calculations factor in weather data from
the nearest reporting weather station to account for
seasonal overcast. The actual energy produced is obtained
from my monthly reports provided by the Enphase Enlighten
web interface (the real-time performance data from my
micro-inverters). I update the graphs in the middle of each
month after I get my utility bill.
In the chart below actual usage lags behind the estimated
due to the discrepancy between monthly estimated data and
the billing cycle that ends mid-month. The increases
in production are due to adding solar panels.
Enphase have released a
study showing that their microinverters
out perform PVWatts calculations by up to 8%. They
looked at regular string inverters and found that they
underperformed PVWatts numbers by up to 8%. So this
validates my decision to invest in
Enphase inverters.
My electrical power usage varies due to variations in
my use of energy intensive power tools, miles driven in my
EV. Energy consumption also peaks in the winter when
I use the heat pumps - it stays below freezing
for months here in Maine. When I purchased my first
Chevy Volt in May
2012 my monthly usage went up by around 3-400kWh/month - and
a bit more in 2024 when I got a 2021 Chevy Bolt.
|
date |
array |
panels
installed |
Watts/
panel |
|
Total
panels |
Total
Watts |
|
September 2009 |
W |
21 |
175 |
|
21 |
3675 |
|
August 2010 |
W |
+2 |
175 |
|
23 |
4025 |
|
June 2011 |
W |
+2 |
175 |
|
25 |
4375 |
|
July 2011 |
W |
+1 |
180 |
|
26 |
4555 |
| May
2012 |
- |
Purchased
Chevy 2012 Volt
(uses
around 3-400kWh/month for charging) |
|
June 2012 |
W |
+3 |
230 |
|
39 |
5245 |
|
March 2013 |
S |
+2 |
245 |
|
31 |
5735 |
|
October 2016 |
S |
+1 |
245 |
|
32 |
5980 |
|
November 2017 |
- |
Purchased 2017 Chevy Volt |
|
April 2021 |
- |
Installed
Heat pump in house |
|
November 2021 |
- |
Installed
Heat pump in workshop |
| November 2021 |
S |
+5 |
375 |
|
37 |
7855 |
|
March 2022 |
S |
+1 |
375 |
|
38 |
8230 |
|
January 2024 |
- |
Purchased 2021 Chevy Bolt |
|
|
|
|
|
|
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