Why I went Solar

    I have been asked a few times why I decided to go solar.  I am not someone that has ever been considered an environmentalist.  I leave that to my sister.  However, I can say this decision was all about green.  As in money.
     A few years ago, we moved from Folsom, CA to Cameron Park, CA.  A distance of about 12 miles.  In Folsom, we had natural gas for heat, the clothes dryer, the stove, and the hot water heater.  In Cameron Park, we are 100% electric.  In Folsom, electricity was provided by SMUD, in Cameron park it is PG&E.  I never knew what a difference it makes.  Our combined gas and electric bills in Folsom rarely exceeded $200 a month, and were often half that.  My first power bill in Cameron Park exceeded $600.  Talk about sticker shock.
     We did what we could to reduce the electric bill.  I replaced the 15 year old AC unit with a brand new one.  I was promised 20% savings on electricity the first year.  It was more like 5%.  Not good enough.  Electricity prices kept increasing, and my monthly bill remained way too high.  I kept hearing ads for solar on the radio promising savings, but I didn't think it was real.
      I called a few companies, and had them come give the sales pitch to us.  I did the math, and the payback periods for buying the system were long.  I am an engineer, I put the data in spreadsheets, I ran projections.  Even with the government incentives, the numbers didn't pencil out.  I dropped it for a few years.   More ads came along, promising new pricing models.  I took a look again.
      This time, the numbers came out closer.  I could achieve $60-$70 a month in savings with no upfront costs.  This was better, but would require me to commit to a long term contract.  Another company came in, and the numbers were similar.  I was on the fence.  Then, Real Goods came back with a new promotion.  I could get the same pricing they had offered before, but the first year would be free.  Now, instead of saving $60-$70 a month, I would be saving over $200 a month the first year.  I finally pulled the trigger.
      Results so far have been in line with expectations.  One thing I learned is that PG&E net billing method calls for me to pay only some of the taxes each month, resulting in a bill of about $12.  At the end of a year (I assume after my February bill), PG&E will send a bill for the net cost of what I used.  This essentially means they are providing me with a free loan.  Another side benefit.
      The key thing I have found is to take a look at all the data the salesmen throw at you, and make sure to do your own analysis.  Your savings can vary quite a bit depending on the plan you pick and how much you invest.  Sometimes, investing a little more actually lowers your savings quite a bit.  Always run the numbers, and figure out where your break even point is.

June Update

Since I was on vacation for the past week, I didn't have a chance to post about the totals from my June bill and so I will combine that with the June actual vs expected.

To start with the simple one, June generation was 786.56 KWh, while expected was 938.  While there was only 1 day of low generation in June, the higher temperatures apparently lower the efficiency of the panels, so I never had a day above 28.5 KWh generated, and had only 1 day below 23 KWh (in fact, it was only 2 days under 25 KWh, with the second lowest day coming in just over 23 KWh).  So far, the total generated is up to 2865 KWh, while the expected was 3317.  When I called Real Goods last month to ask about this, they said the expected was too high and they would work with the web guys to get that fixed, but so far, it is unchanged.  According to my contract, the estimated generation from year 1 is 7545 KWh, while the guaranteed total is 7168 KWh.  There is no breakdown by month in the contract, so I don't know if I am on track or not.  I am 4 months in, and at roughly 40% of the guaranteed number (and 38% of the estimated number).

Now for the more interesting part.  I once again used negative peak power (-18 KWh).  But, I used more part peak and offpeak power than last month (a total of 521 KWh vs 353 KWh), probably due to the increased temperature.  My total PG&E bill was $49.56 this month.  If I had used the same amount of power last year, the bill would have been $287.43.  The medical exception alone would have reduced that to  $176.20.  With solar, the medical exception doesn't even kick in, since I stayed below the baseline.  Solar this month saved me $237.87.  So, it is right in line with the $90-$100 dollar savings I expected to have if I had to pay for solar ($141 a month next year, since the first year is free!).

Real Goods makes good

I posted about all the issues I had prior to getting solar system installed.  I have talked with several customer service reps and managers at Real Goods, going over the problems, and all apologized and told me it would be corrected.  I few weeks ago, I received a call from Ben, who is an operations Manager at Real goods.  He once again apologized, and offered me a "virtual installation".  I had never heard of the that, but he explained that they would pretend my system got installed on the original date, and send me a check for the amount I would have saved on my PG&E bill for the delays.  It sounded great.  I am not sure how they calculated the amount, but when they came up with $600, I decided not to dig any deeper.  It took a few weeks, but on Saturday, the check arrived.  So, now my net cost for the system is no longer $0, it has gone down to -$600!

May totals are in

Well, the May totals are in, and it looks like there may be an issue. According to the Generated vs Expected chart, I was supposed to hit 930 KWh of solar generation in May.  However, the total generation was only 831 KWh.  I don't think the weather was a major factor, as there were only 2 days of sub-par generation.  On May 3rd, the system only generated around 11 KWh, and on May 26th, it was 16.5 KWh.  Otherwise, no day in the month yielded less than 22KWh or more than 31 KWh.  May 5th was when the system peaked at just over 30 KWh for the day.  The system is designed for 5.6 KWh max, and it looks like the most I am ever seeing is 4.5 KWh instantaneous power.  I called my contact at Real Goods, to ask about why it is generating less than expected, and it looks like they will need to send someone out to check the system out and see what is going on.  I'll see what they find.

How low can it go?

Well, my latest PG&E bill hit my inbox this morning.  Since this bill covers the period when we switched from winter rates to summer, I was waiting to see how that impacted my results.  It looks like the results were very favorable.  The weather for the last 31 days has been pretty clear, and not too hot so that helped a lot.

The first 10 days of the latest bill covered the end of April, so it was still under winter rates.  For those 10 days, I used only 15 KWh at part peak, and 153 KWh at off peak.  Solar generation was 283.44 KWh, so my total utilization was just about 45 KWh a day.  The cost for this was a whopping $17.36.  A savings of $48 due to solar.

The final 21 days of the bill were at the summer rates.  The main difference in summer rates is that the day is now broken into 3 rate periods, with the addition of peak.  Peak rates are ridiculously high.  And part peak rates are not much better.  During the winter, the difference between part peak and off peak rates is less than 2 cents a KWh.  For the summer, part peak is nearly 2x off peak rates, and peak is 3x off peak.

This actually turned out to be a good thing for me.  The panels actually generated 18 MORE peak KWh of power then I used.  So, PG&E gave me a credit of just over $5 for this.  I only used 33 KWh of part peak power, and 320 KWh of off peak.  My total cost for the 21 days of summer power was only $31.90, for a total bill of $49.

Without solar, the total would have been just over $250, so savings were just over $200.   The medical allowance was much less a factor this month, as it saved me just a few pennies.  If I didn't have solar, it would have saved me about $60.  Time of use pricing also ended up saving me about $12.  It will be interesting to see what happens when it gets hotter, as I don't think my peak usage will continue to be negative.

Calculating savings

Now that I am a couple of months in, I am finding that PG&E does not make it easy to calculate the savings from.  I started trying to calculate savings using a simple spreadsheet, and found that it wasn't simple enough.  I then decided to write a quick program in C to do it for me.  It took only about an hour to have something that was usable and accurate.  Then I tried to share it with a few friends.  Microsoft apparently doesn't make it easy to just share a program, you need to pack up various pieces to make it work.  This got me to thinking there had to be a better way.  So, I started poking around, and found that it was possible to do it as a webpage.  Unfortunately, making a webpage to do the calculations involved learning Javascript, which was a bit frustrating.  After a few days, I managed to get a slightly less featured program to work.  It doesn't allow for easily modifying the rates, but I can add that eventually if I need it.  Otherwise, it has the functionality of the program I wrote in C.  In fact, it has the same basic algorithm.  I just wish I knew of a better way to debug javascript.  Not being a compiled language, I didn't have a compiler to help spot typo's, which was very annoying.  Anyway, I have it done, and if you are interested in trying it out, click here to give it a try.  I would appreciate any feedback or questions.

April Data

Since April is now in the books, it is time to look back at how the solar system fared vs what was projected.  Total generation for April was 744 KWh.  The finance company projections show that expected generation was 794 KWh.  So, 50 KWh short of expected.  This is 100 KWh closer to expected then March, but still short.  Projections for May are 930 KWh.  We will see how it goes.