As of today it’s been one year since I turned on my SolarCity solar electric system. And it’s been an interesting year.

The verdict: Better than I expected.

So – let’s start with the numbers. In one year the panels have generated 5200 KWH of energy. And that’s just about what was predicted. Basically when you compared the deal I was offered and what I got it was exactly the same. I was told that they would install the system and that it wasn’t going to cost me anything out of pocket and that it would generate about 5000 KWH of power, and that they would charge me 15 cents a KWH, and that exactly what happened.

5200 KWH x 15 cents is $780 for the year. That’s $65/month, or $10/month less than the $75/month average during the previous year.

Most people would have some more exact stats than I’m going to give you now but in addition to the SolarCity system I also built a second system of my own.

I built this after the SolarCity install and eventually I turned it into a tracking solar collector. It just has 4 panels but now they always face the sun. As of right now it’s produced 1700 KWH of energy so that makes a grand total of 6900 KWH.

On the day I turned on the SolarCity system I wrote down the meter reading. 21309. The meter now read 18378. So I made 2931 KWH of excess power that was pushed back into the grid to power other homes. If you subtract the 1700 KWH from my system that’s 1231 KWH of excess power that the SolarCity system generated than I used.

For what it’s worth SolarCity oversized the array. But what they didn’t know is that the previous year I wasn’t living alone and my power usage dropped due to that and other factors. I’m cooling my home with a home made air conditioning system that uses far less power than normal air conditioners. This year I added computer controls to the system making it even more energy efficient. And last year August was very hot and it pushed my into a higher PG&E rate making a $200 electric bill for that month. All these led up to getting a bigger system than I needed.

But I’m OK with this because if not for those factors my usage would have been too small for SolarCity to justify the install. And my goals are not all about money. I wanted an oversized system because I wanted to generate more power than I was using. Saving money wasn’t my primary objective. I wanted to make some clean power to offset the generation of dirty power and it was worth me paying extra because that’s what I wanted. All things being equal had my usage not dropped I would have saved $10/month Because my usage did drop I was paying 15 cents a KWH for the excess power.

My second collector will never pay for itself but I don’t care. I built it because it was a kool project, it’s yard art, and I had fun. But it made power too and after a year I did get about $120 in credits from PG&E for the excess power. Of that $120, $70 was earned by my system and $50 was earned by the SolarCity system making the real bill for SolarCity $61/month. And it would have been less than that if not for me getting them to oversize the system.

The verdict: I’m happy with the system. I recommend SolarCity.



  1. NewFormatSux says:

    Wait, when you generate excess power, you are charged money?

    • Marc Perkel says:

      Yes – that’s why they usually size it right at usage levels.

      • NewFormatSux says:

        Mark, there is a secondary market.
        Solar City is charging you 11 c and probably collecting another 15c from the utilities.

        You would be better off detecting excess and using it for a battery backup.

        I never noticed when you wrote it before. I see no reason to accept SolarCity if I’m getting charged for unused power.

        Now what happens when you are using more power than you are generating? Do you get a separate bill from another utility?

    • Marc Perkel says:

      That’s actually the problem. What we need to do is create a secondary markey for excess clean solar power so that it’s profitable to fill the roof.

  2. Tom says:

    They are charging you more than I pay for power from the LADWP… No ROI there for me!

    • NewFormatSux says:

      Call SolarCity and see if they offer you a lower price quote. Report it here. My suspicion is they charge just a little less than the local price and not the actual production price + small profit.

  3. Solar panels are a great future of our civilization. We need to take what nature gives us, because if we do not soon run out of energy from other sources.

  4. davefretty says:

    Seems a bit crazy you are penalized for excess power. Maybe when the Powerwalls come out a secondary market for electricity will become a reality. A more intelligent power grid needs to be possible , a bit like the internet but for power.

    • NewFormatSux says:

      The Powerwalls are pretty useless, intended only for in case of power outages and not as regular storage. The max output is 2kilowatts so you would need multiple units.

  5. david says:

    Seems a bit crazy you are penalized for creating extra electricity. Maybe when (relatively) cheap storage of electricity becomes a reality in the shape of Powerwalls things may change.

  6. Mike Cannon says:

    1) I would be interested in receiving the thermal mass calculations that you used to engineer your air conditioner.
    2) Where did you buy the controllable duct damper and the fan?
    3) Do you have any concerns about mold growing in the blocks due to the drip system. Years ago, I used drip water to humidify a custom HVAC system and had problems with mold growth and calcification of minerals in the water…

    • bobbo, we think with words, and flower with ideas says:

      Moldy drip water can be a real problem especially if you are sensitive to chlorine smell as I think I am and you don’t want a more expensive uv light system or other alternatives. I thought about using a constant stream of fresh water with the out go into a drip water or other gray water system that all houses should eventually get to?

      Its more playing with the hobby than a real need for we in the First World?

  7. This is so cool! I’ve been waiting for the outcome of Solarcity. A new technology I want to see come to Canada! It should be mandatory we try and diversify our energy usage, otherwise I don’t think it’s sustainable the way we’re going!
    Great post!

    Jullian

  8. Ah_Yea says:

    This is why I like Perkel’s blog entries. It’s interesting!

    For example, learning that SolarCity CHARGES Perkel for the excess power and then CHARGES PG&E for that same power Perkel already paid for!
    This is by design, and it’s not gonna change. Perkel’s secondary market is a pipe dream. SolarCity will fight tooth and nail to keep the secondary market from happening because they want the extra revenue.

    Perkel should read this article. It has the evidence which details why his secondary market will never happen.
    http://sltrib.com/sltrib/news/58243410-78/power-customers-net-utility.html.csp

    The only way I see Solar working is to use Perkel’s tracking arrays with battery backup for night use and disconnect from the grid entirely, and this is still much more expensive than using utility power.

    For the rest of us, Coal fired and Nuclear are the only options.

    • NewFormatSux says:

      The secondary market is there, you just have to install the panels yourself, rather than get them for ‘free’ like Perkel.
      Imagine he uses no power at all, and has to pay a big bill each month.

      • Ah_Yea says:

        No, there isn’t. Read the link I posted. The utility goes into detail why there is no secondary market, but in a nutshell the utility says the grid is more efficient than people have been led to believe. That power can be shuffled and moved as demanded. That means that when Tuscon needs peak power the utility can tap into Georgia’s now off peak production, and visa versa. That cheapens the need for solar because solar only produces excess during peak power and the utilities can share power during these times at lower rates.

        Again, it’s all in the article, if it’s read carefully.

        • NewFormatSux says:

          The link doesn’t say anything about that. Instead it says there are huge losses with transport.

          Even if you are right, it is irrelevant to my point. The market exists for everyone but Mark Perkel, who doesn’t seem to understand the solar situation despite all his posts. Anyone can sell energy back to the grid.

          Whether it is worthwhile to the utilities is another matter.

  9. presidentpicker says:

    “My second collector will never pay for itself but I don’t care”

    The fact that a DIY system is not profitable should give you a hint that thee solar city project is taking you for a ride. Your bill dropped because you are using less electricity (efficient AC, living alone and whatnot) and not because of this ridiculous reverse financing scheme.

    Thanks for posting this and not letting us fall into the same trap.


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