Here Comes the Sun: Going Solar

For as long as I can remember I’ve had a strong fascination with renewable energy sources. Not just out of a sense of eco-responsibility (though I did watch a ton of Captain Planet as a child) but also because of the dichotomy between the advanced technology involved and simple elegance of wind, hydro, and solar power. So, my plan has always been to gain grid independence and carbon neutrality and, on March 29th of this year, I’ve finally taken the first step by having solar panels installed on my house.

The above was shot throughout the single day required for NC Solar Now, a local Raleigh company, to install my new 7.15kW solar system. But I’m getting ahead of myself. I’ve had so many questions about the system, finances, hurdles, etc. that I really should back up a little…

Doing the Research

As with most things I do, I went through a slow and, in this case, years long period of research and information gathering before a breaking point that rockets the project from contemplation to complete in a matter of weeks. As I mentioned, I’ve been thinking about this sort of thing since childhood. And I compiled a list of major questions I needed answered:

• Does my house even work for solar?
• Lifetime of System
• What happens when I need a new roof?
• How does it interact with the power grid?
• Can it be used when the grid power is down?
• Federal or state incentives
• Amount and value of energy produced
• System initial cost
• System maintenance cost

There are other things you may need to figure out for your situation, but I see the above as the major things that need to be answered. So, without further ado…

Does my house work for solar?

Fortunately, if you are in the United States this is made pretty easy with a quick visit to Google’s Project Sunroof. Pop in your home address and, with any luck, yours will be one of the significant portion of the united states already analyzed by google.

As you can see above, Google’s tools shows a “light map” of my roof, estimated hours of peak sun annually, usable roof size, and recommended installation size. There’s also a ton more information provided about local installers and a more exact breakdown of the estimated cost and savings of the system. It ended up being quite close to my final install and costs. Numbers on savings remain to be seen, of course.

Lifetime of system

This one is actually pretty easy since, though residential solar had only recently started to gain mass popularity, it’s actually a proven technology that has been in use for decades. Of every company that I spoke with, the expected lifetime was insanely consistent: as much as 40 to 50 years. And all came with warranties in the range of 10 years against defects and 25 years on the power output of the panels. Most are expected to be at 80% or more of the originally specified rating after 25 years, but many sources have seen that that is often too conservative and in reality they will perform much better over time. Remember, solar panels were originally designed to operate in harsh, remote environments, including outer space. This is one of the beauties of solar panels, they are tried and tested as well as have zero moving parts. There’s really not much to go wrong.

What happens when I need a new roof?

This was one of the major things that kept me from looking further into the project as the roof on my house is not brand new but is no where near needing to be replaced any time soon. It seemed logical that, since a typical roof lifetime is 25-40 years, a solar panel system should be installed around the same time as a new roof. But after speaking with all the panel installers the general answer given was that, at worst, it would cost $1000-$1500 to have them remove the panels before the new roof is installed and then put them back when complete. But two of the installers (including NC Solar Now) stated that the cost would be waived if we used them for the roof replacement. Technically, they aren’t roofers but as you can imagine solar panel installation requires that they have either a roofing licensing or a good relationship with a roofing sub-contractor. Yes, this could be a risk as any company could no longer exist in 20 years when I need a new roof. But even if the cost of panel removal and reinstall is not free, it’s good to know it likely won’t add to the overall cost, relative to the generally high expense of a new roof, that is.

How does it interact with the power grid?

When most people think about solar panels they often assume it means that you are getting “off the grid”. Which, yes, in some cases that is an option but typically not with only solar panels alone. In the case of my system, the panels act as my own microgrid which generates its own power to be used locally and all power that is not used immediately is exported back to the central power grid (Duke Energy in my case). Without some way to store the power locally (to be discussed later), you have to do something with the power as there’s that pesky conservation of energy law.

While we here are Maniacal Labs are all about openness that doesn’t mean I’m just going to put the unused power back onto the central power grid out of the goodness of my heart. So, there’s two main ways that most power companies will allow you to get credit:

• Net Metering: This is the most common as it’s the closest to how residential power is charged (in the United States at least) in that there is a fixed value per kilowatt-hour, both in and out. With net metering, that rate is actually exactly the same as it is for unidirectional power use. As of the writing that rate for Duke Energy is 9.871 cents July through October and 8.903 cents November through June. So, yes, they are sort of implementing peak/off-peak billing but on an annual basis, not daily. So, with net-metering, for every kilowatt-hour of power your system puts back onto the central grid you are credited for that at those same rates. For example, if during July you consumed a total of 100 kWh, but 75 kWh of that was from solar, your bill from the power company would simply reflect a net 25 kWh usage. Yes, there are times you are placing power back onto the grid, but the net difference is what shows up.
• Time of Use Metering: This billing method is available to even regular, non-solar having, residential users (at least with Duke Energy) and bills based on when you used your power. At the time of writing this, Duke Energy charges: 22.955 cents on-peak, 11.236 cents “shoulder-peak”, and 6.211 cents off-peak. As you can see, this is fantastic if you can manage to use most power during the off-peak times but could be horribly more expensive if you use during on-peak. Using this method is not, however, recommended for use with solar unless you also have a way to store excess power generated. If that is the case, you can just use that stored energy during the on-peak times and in some cases even charge the storage system from the grid during off-peak times (typically at night). Modern energy storage systems are typically intelligent enough to, with the knowledge of the billing rates and times, automatically handle where the energy comes from and goes to throughout the day, acting to minimize your central grid power bill as much as possible. Without the storage, you are back to having to monitor when you use power to avoid those peak rates!

Note that in either case, you will actually need a new power meter installed by your power company! NC Solar Now actually turned on my panels after installation for testing and at the time they were generating about 2000W more power than my house was using. Even without the new meter that excess power happily flowed out to the central grid but with one big difference… the meter I had doesn’t differentiate between power in and power out. I was actually getting charged for the power being sent out of my system! Granted, it was only for a short time and probably only cost me a few cents.

At this time I opted to not install a energy storage system, for reasons to be discussed in another post, so I went with the net-metering option. And with that new meter installed the power company now knows the difference between power in and power out.

Can it be used when the grid power is down?

This one surprised me as I naively assumed that since solar panels can generate power whenever there is sunshine, that I could use that power whenever it was available. Solar panels are supposed to get you off the grid, right? Well… it’s not that simple. You can blame that pesky law of conservation of energy again for totally mucking up your off-grid plans. The problem is this; I have a ~7kW system and if it is operating at peak output but at a particular moment my house is only using 5kW, then I have a 2kW excess in power. But that power has to go somewhere and the only options are to use it, store it, or waste it. Wasting the power would just mean converting it to some other form in some useless way, with the easiest being creating heat. But 2kW or, worse yet, the full 7kW is an exceptional amount of power to have to dump into a heating coil without setting your house on fire.

Storing the energy is a fantastic option and the typical household option is a rechargeable battery pack, but that specific topic I will touch on more in another post. So, when your panels generate power and your house doesn’t use it, that excess power would normally go back onto the grid as mentioned about. This is actually why you can’t use your panels (in lieu of having a battery) when the grid power goes down. When the grid power goes down, the workers trying to fix any issues are used to assuming that power only comes from one location; the local power plant(s). But now there’s your house, trying to put power back into that system and this makes for points in the system that they cannot control to provide a safe way of working on power lines. The power from your solar inverter will literally leave the house, go to the nearest transformer and actually be stepped up, energizing local lines with potentially lethal high voltage.

So, because of this risk, all home solar and wind inverters are required to automatically shut off in a manner of seconds when they stop sensing any grid power. The particular inverter installed on my home actually checks for this 30 time per second and will immediately initiate system shutdown if it senses a loss of power.

This is why many people opt for installing local battery storage to provide power during a grid outage along with it’s other advantages, which I’ll discuss more below.

Federal or state incentives

I won’t sugar coat it… solar panels are expensive. They could very likely be one of the most expensive home improvements short of a full remodel or extension to your house. However, there’s not really a single other improvement you can do that will actively save you money on your home. Yes, there are passive energy usage things you can do like improving insulation and buying LED bulbs, but solar panels are actively generating value. But, at least for now, federal and state governments are in many cases providing decent financial incentives to help lessen the blow.

First, I highly recommend heading over to Solar Power Rocks which is a fantastic site that breaks down a ton of information about solar by state and even help you find qualified installers in your area. You can see from their site that in North Carolina, where I live, they rate very low in terms of state incentives. This is unfortunately because North Carolina killed off their tax incentive in 2016… just missed it!

If you are a resident of the United States, however, you can still bet on a pretty great tax credit though! Currently available through the end of 2019 (though who knows if that will stick around), the US federal government provides a 30% tax credit to residential solar installations. Now, I am not a tax professional and I implore you to seek one’s advice before moving forward with a solar system (I did!) but it’s relatively simple. If your system cost $10,000 installed, you can file for the a $3,000 credit (form 5695) when filing your taxes for the year the system was installed. But note that you must have that much tax liability, as in you were going to pay that much at least in taxes, to get the full 30% back. If you don’t have that much liability for a single year you can, in some cases, roll that credit over the course of 5 years. And since in most cases you will have already paid that tax as part of your paycheck, yes, you will get that credit as part of your refund… but again; consult your friendly tax pro! (no advice given here is legally culpable).

System initial cost

Okay, okay! You want numbers! So here they are:

My final installed system includes:

• 26 - CanadianSolar CS6K-275M 275W Solar Panels
• 26 - SolarEdge P350 Power Optimizers
• 1x - SolarEdge SE7600A-US Single Phase Inverter
• 1x - Neurio whole home energy monitor
• A whole bunch of roofing brackets, conduit, junction boxes, and wire

And the grand total: $27,870

Now, this is the pre-tax-credit cost to me and includes all labor, permitting costs, setup, etc. NC Solar Now provided a completely turnkey service and there were absolutely no surprises on the cost. $27,870 is what they quoted me at our first meeting and house assessment, and $27,870 is what we paid.

But, I said there were tax credits! Right, right… That’s easy: $27,870 - %30 = $19,509 final cost once we receive the credit.

You already, of course, know that unlike most home improvements these panels will be actively creating value in the form of power but solar panels can also be a huge boost to your home’s value. Note that I’m talking about _equity_, the value for which you could reasonably sell the home. For comparison, check out the chart below of project cost vs. value added to your home:

Notice something there? There is only one project list that is worth more than it costs and it’s even only one of three that will then actually save you money on energy costs! Everything else has a lower perceived value to someone buying the home than what it actually costs you. But what about solar?

Fortunately, this research has been done already by the US Department of Energy and Berkeley National Laboratory with some fascinating results. Definitely read through the whole paper but even though Raleigh, NC was rated as one of the lowest in terms of added home value, it was still rated at $2.68/W, which yes, is lower than my per-watt cost ($27,820 / 7150W = $3.90/W) before the tax credit but when you account for the after tax credit cost, it’s a lot closer: $19,509 / 7150W = $2.73/W. Therefore, we have immediately recouped 98.16% of the system installation cost in value added to the home. And as I said, Raleigh rated very low! As you can see in the linked paper, most cities rated at about $3.00/W which would’ve put us considerably over the installation cost in terms of added home value.

System maintenance cost

One of the beautiful things about solar panels is that unlike other renewable energy sources such as wind or hydro there are absolutely no moving parts. As mentioned above regarding the lifetime of the panels they do degrade in output over time but aside from keeping the panels clean there should be little to no maintenance. And since everything comes with significantly long warranties any issues actually caused by a component failing should generally be covered for many years to come.

Now, one thing to note is that, as you can see in the video and satellite pictures above, my house has no trees that are close or tall enough to cause any real issues with the panels. One of the options for the installation given to me by nearly all solar companies I spoke with was some sort of “critter guard” which was basically just a wire mesh installed around the border of the panels to cover the gap (a ~5” gap is left to provide airflow and cooling between the panels and the roof, preventing debris and animals from getting under them and possibly messing with the wires. So, in some cases you may have to inspect the panels more regularly to make sure they stay clean and clear but in the case of my insulation I should not have to have them inspected nearly as often.

Wow, that was long

I think that’s all for now. There’s a ton more information about the actual installation, usage, and monitoring of the panels, but this post is already long enough. So be sure to check back for the next installation!

-Adam