One Year – Let’s Run the Numbers
This is the first anniversary of the first successful meter reading by PSE&G after activating the panels. That means that we can run the numbers.
All values are kWh. This year’s date is 7/21/2005 – last year was 7/21/2004.
Inverter 1 This Year: 4279 Last Year: 677 Total Inverter 1: 3602
Inverter 2 This Year: 3544 Last Year: 565 Total Inverter 2: 2979
Total Solar Generation: 6581
Meter Out This Year: 8724 Last Year: 1365 Total Bought: 7359
Meter In This Year: 4823 Last Year: 564 Total Sold: 4259
Net Metering Purchase: 3100
Total Electricity Use = Total Solar Generation – Total Sold + Total Bought = 9681
Solar Generation Percentage = Total Solar Generation / Total Electricity Use = 68.0%
Our installer predicted that we’d generate 2/3 of our usage. He was pretty much dead on – the real numbers are just a smidge better than that. Additionally, we reduced our utility demand by that much – reducing utility pollution.
When it comes to dollars, we actually did better than these numbers show. PSE&G rates increase above 600 kWh per month in the summer. Our usage allows us to avoid going over 600 kWh net purchase per month, avoiding the higher rates.
Our savings works out this way:
Green Mountain Energy Supply Charge: $0.07508 / kWh
PSE&G Delivery Charge: $0.0.30305 / kWh (the lowest rate – it’s higher above 600 kWh in the summer and higher in the winter as well at $0.0384/kWh)
Total Rate: $0.10539 / kWh
Our Savings: $693.57 for one year
That would produce a 23 year payback but with the added $1251 from the sale of the SREC, it’s a 8.5 year payback.
And the air is cleaner.
One Year Later
On June 14, 2004 in the late afternoon we turned on our system for good. We haven’t thrown the breakers since.
Tomorrow I’ll give you statistics on energy produced by the system. I believe that the total is about 6,300 kWh. I don’t have numbers on our home’s usage for the year – the first good meter reading after installation was July 2004 (PSE&G botched the June reading), so I’ll come back with more details later.
The system has been completely maintenance free. We do write down the production numbers every night for our interest, but there’s no reason to do so. The system just hums along in the basement when the sun is shining.
The only minor annoyance is that the system disrupts AM radio. We hear what sounds like R2D2 perking away behind the radio station when the system is active. That is not usually a problem – we only listen to AM radio in the morning – but when production is high it does overpower the station sometimes.
We’ve only had one indirect complaint from a neighbor – a co-worker who knows a neighbor reported that they sometimes get sun reflected onto the front of their house in the morning. They haven’t approached us. I suspect that this will get better over time as the glass on the panels gets less smooth (though we’ll lose some power at that point as well).
Would I do it again? YES. No question about it – this helps the environment and saves us electricity costs in the long run. One unexpected savings is in air conditioning – the panels block the morning sun from reaching our attic and therefore our cooling requirements are lessened. For that reason alone, I’d love to put an array on the back of the roof as well.
A Spring Update
It was recently pointed out to me that this site hasn’t been updated recently. Time to fix that with a few little notes.
Power production is up as expected now that spring is here. We’re getting about 30kWh on sunny days. Of course, if you get 2.5 inches of rain and the Delaware has a 50-year flood, you produce nothing. (The flood didn’t affect the house – just my commute.)
We still have not sold our SRECs (Solar Renewable Energy Credits). My wife and I are leaning towards NOT selling them, based on the premise that this will force utilities to pollute less. We’d retire them instead. A reader points out that we could sell them to renewable companies and help the environment. Right now, the highest offer that we’ve received (unsolicited for the most part) was $150 each. Reportedly $175 is the going price now – I expect it to continue to climb until near the end of the SREC fiscal year in a few months.
I’m also in the hunt to buy a hybrid car – probably a Toyota Highlander Hybrid SUV. So far no local dealers are willing to take my deposit – though one dealer thinks he’ll be able to accommodate me in a month or so. I plan to write more about that quest and the final results here, and therefore I’ve started a new category.
That’s all of the news for now. Once I get a full year under my belt, I plan to write up the full statistics on my solar usage and production.
Shortest Day of the Year
Well, yesterday was the shortest day of the year here in the Northern Hemisphere.
I haven’t seen the numbers from yesterday’s production, but we’ve been getting 9-12 kWh out of the solar panels on a sunny day in December. Compare that to the record of 42 kWh on a sunny day in June, and you can see what a difference the lower angle of sunshine and shorter days has on the system.
Of course, we aren’t using the air conditioning at the moment either, so our usage is down. We are using lights for longer hours in the evening and even morning now.
So now we turn back to longer days. Our “net producer” months are predicted to be April, May and a bit of June.
Zero Day
We had our first zero production day last Friday. It rained heavily all day long, and the inverters never “woke up” from the night before.
At this point about midway through Fall, we’re getting about 15 KWh between the two inverters on a solid sunny day (which have been many lately).
One MegaWattHour
Today, our solar electric system finished generating it’s first MegaWattHour (MWh). That happened in about a month, given that we turned the panels on for real on June 14 and they had run in test for one week.
Of course, that’s ideal performance. We haven’t had many rainy or cloudy days in the last month and these are the longest days of the year. I’m sure this will be balanced by days where the panels are snow-covered in the winter. However, it’s looking good!
Some Early Numbers
We officially turned our solar electric system on last Monday evening. As of last night, we have some early production numbers.
For the past week, our system produced 210 KWh of electricity. It was a particularly sunny week, including the longest days of the year. Last month while we were in test mode, we produced 183 KWh during a cloudy week.
For June of 2003 (reading on about the 20th of the month), we used 790 KWh. For June of 2002, we used about 900 KWh.
If you multiply the 200 KWh by 4 (for four weeks in the month), we’re due to produced about 750-800 KWh. That is well over the 2/3 of usage estimate, but it’s only one month.
July will be tougher – with the air conditioning requirement last year we used 1460 KWh, against which we’ll probably produce about 750-800 KWh.
Looking good so far!
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