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One year with solar energy at home: Mostly sunny!

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Enphase Envoy solar panel monitoring serverJust over a year ago, we took the plunge at my house and covered the back roof with solar panels: 41 of them, to be exact. After 12 months, we’ve created 13.8 megawatt hours of electricity while using only 7.59 megawatt hours. The energy surplus becomes a credit on our electric bill and once per year, our electric company issues us a check for any unused credit. So what was the installation and usage experience like? Overall, it’s been excellent and I’ll share the pros, cons, and actual costs of our project in an effort to shed more light on any solar panel projects you might be considering.

First things first: Decisions and costs

Our family has always tried to be green when possible. We’re avid recyclers, we tried a small composting project, we use CFL or LED bulbs throughout the house, and I can’t tell you how many solar-powered chargers I’ve tried for my mobile devices. (The most recent one is outstanding.) But we never had the money to “go solar” even though we wanted to. That changed due to a unique financial situation. In the spirit of transparency, I’m going to share the details.

My wife inherited a family member’s IRA account several years ago and the law required that the funds be liquidated over a five-year period. We got to the final year in 2011 and realized we were going to be hit with a large tax bill on the remaining IRA funds and decided to invest the funds into something with a tax incentive. After much research on solar energy — this is a great site to estimate system sizing, pricing and benefits — return on investment and such, we decided to go with solar panels, moved in part because our rear roof faces south.

It turns out that a local contractor nearby put solar panels on his office and became a certified solar panel installer. I requested a number of quotes from companies in the area, but he gave the best price at the time: $5.50 per watt. I then looked at our electricity usage for the prior year — we’re a family of four, with two full-time work-at-home people — and over-specified the system by 25 percent capacity for two reasons. We have a four bedroom house, so I planned for the next homeowner to have five occupants. And I wanted to maximize the tax benefit, which was a 30 percent federal tax credit on the entire project.

The specified 9.43 kW (DC) system turned out to be 41 panels — 230 Watts each — which produced 12.05 megawatt hours of electricity from Nov. 1, 2011 to Oct. 31, 2012. That cost us $51,865 up front, including installation, permits, inspections, parts, labor and warranty. Yup, it’s a big chunk of change but that federal tax credit totaled $15,560, which helped offset taxes on the IRA liquidation. And many states offer rebates on solar projects; ours provided us a check for around $7,100 once the system was up and running. Our net cost then was $29,205.

It’s also worth considering companies in some states offer no-money down solar panel systems: essentially you let them install a system on your property and then lease the system. The company itself reaps the incentive benefits, but you may save money on your electricity bill.

Installation of the puzzle pieces

Enphase microinverter

I had thought the system would be complicated by many parts, but it’s actually quite simple. Obviously, we have the panels, which generate electricity from sunlight. All of that power is DC, or direct current, so the system needs an inverter for AC power. We considered one single inverter but instead opted for individual microinverters attached to every panel. There are several benefits to this approach.

For starters, if one panel or inverter fails, it’s easier to locate and fix the issue. Second, the microinverters feed real-time data from every panel via Ethernet over powerline  to a small web server included for monitoring purposes. I can get tons of useful information from the system. You can view most of my system details here online, for example.

Solar panel framingThe microinverters, as well as the small web server that tracks them, are made by Enphase. Each one converts the DC power from its connected panel to AC power. Each microinverter is linked to the next one in the solar panel array so essentially, these are plug-and-play devices. Each connects to the next, and the last microinverter feeds a power line, which we fed through our attic and down along the outside of our house near our electrical meter. The panels themselves are attached to the roof with aluminum framing so the install process is fairly simple: Install the frame, connect the microinverters to their respective panels, attach the panels to the frame and link the microinverters.

Because of the solar panels, two additional electrical meters were needed. We still have the original meter that measures our electricity use from the grid but a new meter is needed to measure power output and a third measures the difference between electricity created and used. More on that in bit.

Smart meters for solar panels

So how well is the system working?

In a word: great! In this graph below — from Enlighten’s web service that creates reports from our solar panel system — you can see exactly how much energy we produced on a daily basis.

In fact, this graph gives you rough history of the weather where we live in southeastern Pennsylvania. The drops on the graph represent days with little or sun, although even on a cloudy day we make a little energy. You can also see when the days get longer and provide more direct sunlight to our roof; we’re in the downward trend now as the shortest day of the year is approaching. Here’s a look at the numbers for production and usage by month:

[googleapps domain=”docs” dir=”spreadsheet/pub” query=”key=0Am0TBeNu7HSedFA0QnZJSnRLNnNnYTR0TFl4Q3hhMVE&single=true&gid=0&range=A2%3AC15&output=html&widget=true” width=”500″ height=”320″ /]

There’s no maintenance to the system; it’s just always working to create power when there’s enough light. I haven’t yet had to do a thing to the panels, which have a 25 year warranty, same as the microinverters. So with the solar panels then, you’d think we’d be fine during a power outage, like the one we experienced for 4 days last week. Not quite….

Different systems for different needs

One of the upfront decisions you’ll need to make when planning a solar panel system is will you still be tied to the electric grid? Or will you go off-grid? There are pros and cons to each; the former costs less up front while the latter provides stored power during the evening hours or during an outage. Since we had no power during Hurricane Sandy, you can guess which system we have: One that keeps us tied to the grid.

That means all of the power our panels create is actually fed back into the grid; we still get all of our power from our electric company in this configuration. And in the case of an outage, grid-tie systems such as ours are automatically disabled. Why? Because if we were feeding power into the grid during an outage, it would be unsafe for the workers trying to fix the outage.

To go completely off-grid and have batteries store excess power would have added approximately 20 percent to our up-front project costs. My wife felt we’d never regain that cost because we rarely have outages. During Hurricane Sandy, of course, I gave her one — and only one — light-hearted “I told you so.” And at this point, I’m reconsidering what to do for backup power, but that’s another post for another time.

Is solar right for you?

Solar panel materialsI can’t answer that question, but hopefully, I’ve provided some insights to help you decide. Having a house some south-facing roof is a must unless you plan to have panels on your grounds. Local or state incentives vary by location as well so you’ll need to check them in your area.

The biggest issue for most is likely the large up-front cost involved although you could start small and build up the system over time. I can’t argue that the costs are still high, although they should be lower now than a year ago. And the payback period — which will vary based on your system, location and energy costs without solar — can be high. Our break-even point is around 7.3 years, but that includes the home appreciation expected due to the system.

We may not be here long enough to break even but we’ve already gained an appreciation benefit from the panels. Taking advantage of the low rates, we refinanced our home last month and the added value of the solar panels was around $30,000. And why not when the next owner of this home is unlikely to have an electric bill ever? We were paying around $2,500 per year for electricity before the system was built; now build up a credit in most months. But for us, it’s not all about the money or the investment, even though we have a hedge against a rise in electricity costs: Any price increase means we’ll get more for our excess energy production.

We feel we smartly took advantage of certain tax incentives, added value to our home and are one step closer to being energy independent, save for a backup system. If I could go back in time, I’d probably add some type of battery backup. At this point, we’re making enough excess power that we’re considering a plug-in car to replace our current vehicle. Why not let the sun power our home and our wheels while cutting down on our annual gasoline costs at the same time?

93 Responses to “One year with solar energy at home: Mostly sunny!”

  1. There’s an ugly side not mentioned here. The Fire Department inspections have a gray area on the 3-foot offset. This has caused a lot of grief for installers and homeowners. You can google this issue. My PV system is installed, after the city inspectors passed it, but it’s not officially turned on since the Fire Dept inspection nitpicked on the 3ft from eaves interpretation. This is costing me the benefit I would otherwise have gained already, as well as making PG&E smile. There should be a law. By the way, my neighbor has it up to the edges and it passed. This is such a murky interpretation. It’s a terrible thing caused by bureaucrats.

  2. It’s unfortunate if there are only two options. I always thought that grid-connected systems used their own power first and would work fine in a grid outage. I’m afraid if you got an off-grid system, you’re just as likely to have storm damage to your own house that would leave you will no power for weeks while your neighbors enjoyed full power from the grid.

  3. Gary Silverstein

    We moved from Los Altos Hills in 2000 to Santa Barbara (Montecito). The home has single pane divided light windows that we would have loved to replace but budget stopped us. With two heater/airconditioners we found that our energy costs were averaging over $300 per month. Upon balance, we decided to not chase every dollar back but wanted to just stay within the tier one bracket. Our return on the investment will be about 5-7 years max. Almost there!

  4. Good article. Based on your location, I presume you are a PECO customer. In that case, I believe that at the May 31 “true up”, you will be credited for any extra prodution at the wholesale rate of electricity, not the retail rate. No? Essentially, once you produce more than you consume in the measured timeframe, then PECO treats you as any other supplier of electricity they buy from (thus you will not be credited for the T&D charges you are accustomed to offsetting). So, your ROI calculation should take into account the lower price for the additional kWh you produce above/beyond those that you consume from PECO.

    • Thanks, Hogie. And you’re right, I’m a PECO customer. They pay the PTC or Price To Compare rate:

      “PECO pays customer-generators at the Price To Compare (PTC). The Price To Compare is the price used to evaluate offers from competitive electric generation suppliers (EGS). It is a figure based upon average generation prices over the last 12 months for your rate class.”

  5. Nice Article Kevin & thanks for sharing the details.

    We went solar ourselves last year here at Maryland (with solarcity) but are leasing instead of buying.

    We have 5.59 Kwh system and are leasing it for 20 years. We paid the entire lease cost for 20 years ($6321) upfront and it looks like have zeroed out our electric bills altogether.

    & not to mention the “feel good” factor :)

  6. From what I’ve seen, it’s relatively easy to add a charge controller and batteries to your setup so you have both grid-tie rebate income *and* backup power in the even of a grid outage. You’ll have to be careful about what loads you use during the outage, but it’s not too bad.
    Thanks for a great article. I’ve often wondered about the actual numbers in this kind of install, but haven’t found many articles that discuss it. great to see into your decision-making process.

  7. Adrian Atkins

    Brilliant article. Thanks for sharing.

    To go off-grid, just cut the connection to the outside, and add a pure-sine inverter in it’s place (never have the two connected at the same time!)
    This fools my grid-ties into working normally, and gives me an off-grid option in my situation.

    Works for me, but i’d test it on one of your panels/inverters first tho …..

    • Sounds simple. What is powering your sine wave inverter for the 5 to 10 minutes the Enphase inverter needs to see the grid? What make and model is this sine wave inverter?

  8. I’m putting in a solar thermal system based on vacuum tube heat pipes and I can get 4KW worth of heat energy for only a few thousand dollars which has the nice advantage of being easy to store. I’d like to encourage people who have south facing access to consider doing half half solar thermal and PV and saving serious bucks.

    You should be able to do 4KW of thermal and 1KW of soloar PV for less than eight grand easily and come close to covering much of the energy needs of a typical household excluding adding transportation of course. But one step at a time right?

  9. Kevin, I been reading your articles for many years and this is one of your best ones. Hopefully in the future you will post more articles about your personal/family experiences with technology.

  10. Sweet system. I work for a solar install company in texas and lately the majority of installs have been enphase systems. Easy to install and troubleshoot, reasonably priced, and the envoy is great for monitoring system output. Good luck with battery backup installation, decent storage batteries are VERY expensive.

  11. Kevin, something doesn’t sit well with your narrative. You shouldn’t at all have to endure black-out inconveniences of Sandy if you have, in reality, a power generating plant on your own roof. As I understand the arrangement you described, you effectively haven’t liberated yourself from the power-grid save when the power generation from your own roof is inadequate (which I assume must have been your intention). Rather, you’re still umbilically tied to the grid and your life depends on it even when your own power plant (the one on your own roof) could have saved your life (at least whilst the sun shines).

    Something is a bit off with what was recommended to you, or how it was implemented. Further, and even given the arrangement you described, it’s technically a no-brainer to break the supply of power to the grid from your own roof-generator. If done, your system would effectively be as if it initially weren’t connected to the grid — in splendid isolation.

    • Thanks for the great comment, Gareth. Actually, the system is working as designed and powers off during a grid outage so we don’t fry the utility workers. ;) We simply didn’t include the needed parts / batteries to work off-grid due to cost. There are hybrid inverters that allow the system to be used locally when the grid is down, i.e.: not feed the grid, but again we didn’t opt for that as we didn’t want a central inverter.

      • I think you’re missing the point of the first poster. There’s no need for batteries, nor special inverters at least during the day when you’re getting sunshine. A simple disconnect switch that breaks the connection between the grid and your house will allow you to use whatever is coming from the panels without any downstream danger to the utility company. People use this same method for more traditional permanently-wired generators all the time. It’s not expensive, especially if you put in a manual switch. It can get more pricey if you use an automatic transfer switch.

  12. Daniel Phelan

    Nice inverters. No single point of failure and allows for panels that vary in productivity. One thing about Enphase though, I think they need to let the user record the data on-site and not have to report to their servers. They charge for the reporting service too, which negates some of the cost savings.

    I installed a two panel system on my friends garage using Enphase inverters and they produce about 60 Kw/hr per month using Sharp 175’s. Perfect for asymmetric arrays or slowly expanding the system over time to spread out the investment.

    I’d say that this system is overkill as far as size. I would have recommended building a system about 2/3rds this size to reduce upfront cost, but then again, if you have the money then why not cover that huge flat roof! Looks great! Now put up a tower and get some wind going!

  13. Great article! Many, many thanks for being so forthcoming and open about the costs. Thanks to you, we are one step closer to making the switch (and pulling the plug). THANKS!

  14. Jonne Comlatelee

    Its a great feeling to go solar. Saving electricity. Money. Taxes. The list goes on.
    Thanks for documenting a common type of residential solar installation experience that is occurring thousands of times daily in the USA today.
    Made possible by microinverters, the lower cost of Chinese modules, and tax incentives.
    I have been looking at doing the exact same thing, many times, over the past 4 years.
    I am now part of the solar industry and I am finally going to move ahead on my own home, but after being a Enphase fan the past 3 years, I am no longer going to install Enphase or the 250w variety of solar panels. I have found a better way.
    Thanks for your article. I will share it with friends.

  15. Kevin,

    This is interesting. We also installed 41 panels for a 9.3 kwh system at ~ the same cost earlier this year. We moved to Honolulu from the Bay Area last December. Hawaii electricity is diesel-generated, at 33-35 cents, 3x that of Los altos! Our payback period is <4 years. We consume only 60% of our production. HECO will not send us a check, instead, they sell the energy to our neighbors. We just reserved an EV for mid-2013. This would cut carbon close to zero. Solar economics is very compelling here.

    We also wish there is a battery for storage. The next evolution would be networking the neighborhood and sell and buy from each other!

  16. adrian cockcroft

    It’s interesting that some states/power utilities cut a check for the full dollar credit each year, but others pay a reduced rate for the aggregate power difference. The effect is that it’s worth over-sizing the array in Pennsylvania, but not in California.

  17. So your electricity bill use to be $2500 and you decided to pay $56k for a solar panel system. That would take you 22.4 years just to break even unless I’m missing some stuff.

    How much is you yearly refund?
    How much does is the kw/h cost where you live and what state do you live in?

    Also solar prices are going UP not down because the US has placed tariffs on Chinese made panels. I would have liked to see more math in this article

    • Hi Jason, I appreciate the feedback. I didn’t put any more math in this article because everyone’s system needs / electricity consumption is different. That’s why I shared my specific costs/benefits and provided a link to the solar panel calculator for others to use.

      I live in southeastern Pennsylvania and it costs about $0.09 per kWh for energy production from my provider. Based on the 12 month surplus shown in the graph, that’s $558. The utility company keeps my account credited for any surplus until May each year, when it then cuts me a check. So that additional money should be part of the break-even. I also didn’t pay $56k if that’s what you used for the break-even math.

      As stated in the article, the up-front cost was just under $52 but you can’t use that in your analysis, which I know you did (because 56,000 / 2,500) is where you go the 22.5 years. Reduce the cost by the tax incentives and rebates. Even without any home appreciation benefit, the net cost was $29,205. If you want to use that and my old electric bill of $2,500, that’s an 11.6 year payback. Factor in the home appreciation and the refund for excess energy and the payback is even shorter.

      • I guess, even tho I have no say in it, I will say you are welcome.

        You took my tax dollars to pay for your solar system.

        IT’S NOT YOUR MONEY!!!!!

        How do you think this would work out if every home in the USA did the same?

        I guess it is no problem – just raise taxes, huh?

        What about the cost of maint on the system – did you estimate that?

        • So I’m not going to get into political debates or the tax system here, because that simply detracts from the point of the post which is to inform people on the solar power experience. But I will say 2 things in response and leave it at that. 1: The incentive is there for all; I didn’t get any special permission for it. We can disagree if it should be there, but the fact is: it exists and you, I or any other tax paying American can take advantage of it. Second: I doubt you paid *anything* towards my system – this was essentially a swap of money, meaning: the tax benefit of the solar panels essentially offset the tax costs I would have paid on the inherited IRA. Thanks!

      • Jean Simenon

        @lyle Don’t worry Lyle, the govt has been printing money with no end in sight (they call it QE), so Kevin here didn’t take your money, but actually freshly printed money. For your money? Well it’s going to the department of defense, fossil fuel companies subsidies, and monsanto/ADM/Dupont subsidies… and for the rest mostly medicare/medicaid. So don’t pretend he’s using your money.

        Actually he’s reduced your overall in the long term: less green house gases (less weather catastrophes, less money wasted thru FEMA), less power plants (less wasted on subsidies to power generation companies), more value to his home (more taxes for you)…

        So you see, it’s always good to think twice before you write ;)
        Have a good day!

      • Holy crap! You write an informative article about switching to solar and you get hated on.

        lyle – nothing stopping you from doing the same thing. the author is just trying to explain the cost/benefit of switching to solar. If you put your fists down and took the time to do some simple arithmetic, you might figure this could work for you too.

        btw: great article

      • I have 46 panels.
        I have questions on that math.
        $2,500 / .09 cents per KWH = 27,777 KWH / 12 months= 2314 KWH per month.
        You said your system only made 13,803 kwh per year.
        27,777 kwh used – 13,803 kwh made = 13,974 kwh more used than you made.
        You are are short 13,974 kwh?

        What am I missing here?

    • Jason, Lyle you suck!

      This guy was in no way shape or form pushing his political opinions in my face. Kevin was sharing a personal experience and left it up to the readers to see if this would work for them.

      A guy and his family (thank you Mrs. Tofel, it was your money) takes the initiative to go green at their cost and they get criticized. I guess BP, Exxon, and other oil companies exist to solely make the world a better place. Making billions of dollars doing it is simply a coincidence. Folks like the Tofel are bad Americans who take advantages of tax incentives and rebates. SMH…

      Word of advice: READ do not skim an article. If you do not fully understand something, RESEARCH. THEN, post your opinion.

      Sometimes internet anonymity is a curse.

  18. Geek with Gun

    Electricity from the grid *will* increase in price.

    Solar panels will steadily improve in price, performance, and durability.

    Eventually, that will come to a point where I can afford it. At that point, I will probably also buy an electric car. I just hope that time comes fairly soon.